Original subtitles

so um let's start the recording as well

okay let's get started hello everyone

and welcome to the second escarsa

webinar on earthquakes and traditional

construction

my name is tim michiels and i am a

structural engineer at old structures

engineering in new york

and an adjunct professor at columbia

university

today's webinar is brought to you by

there we go by iskarsa

or the international scientific

committee on the analysis and

restoration of structures of

architectural heritage

while more people join i want to briefly

introduce our scientific committee

we are an international group of

engineers scientists and educators

dedicated to the restoration and care of

build heritage

we focus on the structural and technical

aspects of conservation of architectural

heritage

we have an elected board our president

is gorun arun

and our secretary general is tom

morrison he is

leading the discussion in the chat today

the goals of escarsa are amongst others

to disseminate knowledge

promote international cooperation and

organize international training programs

another goal is to collaborate with

other scientific committees

and we are happy to welcome members from

a wide variety of icomos committees

attending today in the past years

iskarsa has published

principles for the analysis of

conservation and structural restoration

of architectural heritage

we publish newsletters and currently are

developing

guidelines for the analysis and

restoration of heritage structures

pre-pandemic we were organizing yearly

workshop

the latest one was in um

the latest ones were in korea turkey

and the very latest one in iran

you can reach us on iskarsa gmail.com

follow us on facebook or find our

website

okay that brings us to our

webinar on traditional construction and

earthquakes

in this webinar series we are

highlighting traditional structures

because these buildings are often seen

as the most vulnerable

to earthquakes often though these

buildings have seismic mitigation

strategies built in

as part of their original construction

or plastic there unfortunately

the built-in knowledge has sometimes

been lost or is misunderstood

and thus as safekeepers of all buildings

in earthquake areas we all grapple with

the same

question how do we ensure the life

safety of the users of a building

while also making sure that the building

is preserved

with all its valuable features for

future generations

sometimes engineers take a conservative

approach that tries to maximize

structural strength

yet they go well beyond beyond what is

actually needed to ensure life safety

often this damages valuable elements of

the building

and those well-meaning interventions

might paradoxic paradoxically in the end

provide um or contribute to a building's

destruction additionally the regulatory

framework provided by building codes to

properly deal with traditional buildings

is often lacking thus we need to study

learn and discuss traditional

architecture and that's why

why we are here today building

technology in seismic regions has

evolved over centuries leading to local

seismic cultures

today we have another five distinguished

speakers who will discuss the local

seismic cultures they work on

we also hope to hear from you we look

forward

to taking your questions after all the

presentations please feel free to post

them

in the q a section at any time you can

also

upvote questions that you would like to

see answered from other people

we would also already like to let you

know that a third and final seminar on

this

topic is scheduled for thursday april

14th

and in that webinar we will have

speakers talking about kashmir

greece iran nepal and pakistan so mark

your calendars

for thursday april 14th

then before handing over the floor to

our speakers i would like to thank evan

speer

and tom morrison who are my co-hosts

today

i would also like to thank the other

members of the organizing webinar

committee

steve kelly kai weisser goron arun

krieger anjali you

chula aquintudine

finally i would like to thank all of you

distinguished speakers for agreeing to

share with your work with us

today okay

so then without any further ado

i would like to introduce you to our

first speaker stephen j

kelly

[Music]

steve is an architect

and engineer who has devoted these

skills to the preservation of our build

cultural heritage

with 40 years of experience his projects

range from small to immense

simple to sophisticated and cover a wide

range of building materials and systems

his projects are located throughout the

us europe the middle east

asia and north africa steve is a fellow

of the american institute of architects

the association of preservation

technology and u.s icomos

he is a unesco tangible heritage expert

and is the former president

of iskarsa serving from 2008 to 2014.

steve welcome thank you very much i hope

everybody can

hear me okay and you can see my screen

yes i've worked on large projects but

i'm going to talk on i'm going to talk

about some of my smaller and

and very interesting projects that i've

done i've

called this presentation this morning

full of two regions that's a that's a

take off on

a tale of two cities of a

well-known novel but today i'm going to

talk about haiti

and bhutan um

also i wanted to shout out to the world

monument

can you put your presentation full

screen please

oh you can't see it yes i can see it but

go to

window or view and then full screen

review

full screen mode

thank you very much thank you very much

i wanted to give a shout out to the

world monuments fund

because many of the projects two of the

projects i'm talking about i did through

the world monument is fun but the first

area that we're going to speak

about is the island nation of haiti

haiti shares uh the island of hispaniola

with dominican republic you can see this

is

this is my country the united states

cuba

mexico over here and the south american

continent

and talking about projects in

port-au-prince the capital of haiti

haiti has a very interesting history

the the european the europeans landed on

the island

in the uh in the 17th century they

enslaved

the uh taino population it turned out

that the

the indigenous people there

were not very hardy as slaves

and they were decimated and that was

when

the uh the slave trade started from the

west coast of africa

down here um uh enslaved people were

brought from the west coast of africa

and at a time it was like 10 enslaved

people to one

colonist the interesting thing

that happened in um in haiti however

is they had a successful slave rebellion

that happened in 1799

and um and this is this is a very

important

part of the character of the people in

that island is that they

they they've had their freedom for a few

hundred years

it's a very interesting place but we're

going to be talking about the earthquake

and aftermath of the earthquake which

occurred

in uh in january of 2010 it was a 7.0

magnitude earthquake that killed between

two and three hundred thousand people

and left three million homeless

um it was a humanitarian disaster um

we first went there as a world monuments

fund

group um in april of

2010 and uh i've i've been back to the

island

more than ten times the last time

actually um

just about a year ago right before the

pandemic hit

so what i'm going to talk about is the

gingerbread houses

of port-au-prince and when we went in

2010 there were about 300

gingerbread houses they were all built

from the 1880s to the 1920s

there we looked at about 200 of them and

there

are about 150 remaining

the construction types that are well

known for haitian gingerbread houses are

number one uh timber frame or pandubois

waddle and dab or columbage and

unreinforced masonry bearing walls

the mortar that's used is a mixture of

clay and lime

and um and the wood was um the wood was

locally

uh harvested and so the first part the

timber frame i think that many of you

are familiar with this type of

construction this is a this is a wood

construction that has a brace frame in

it

and there's an example of a gingerbread

house with uh

with uh made mostly from timber frame

and then there's the columbage or waddle

this is a this is a timber frame

building where the infill

is filled with with either a rubble

with stone or with brick

and then the third time kind is the

unreinforced masonry

and as you can imagine the unreinforced

masonry

did not do as well during the earthquake

as the pandubois or the colombage

and this is an example of some of the

larger buildings and many of them

strictly out of um masonry are still

standing as

wrecks and they have not been they have

not been restored

an interesting aspect of this is that

you don't see

these three distinct types they're all

mixed together this is a good example

with this

particular building that has an

unreinforced masonry

first level the second level is columbus

in the third level

is brace frame and of course i have to

mention that

after 1925 when wood construction was

banned in port-au-prince there were a

lot of uh

either concrete block or reinforced

masonry structures that were built

um next to as an addition to many of

these buildings

these uh these building forms did not

work well together

and that was some of the things that we

saw when we were doing our first

assessment

but that's going to be a talk for

another time

because this morning i'm going to talk

about two buildings

um in uh in port-au-prince one

is the meson du four which we first

visited in 2010

this is a photograph of it maybe a year

after the earthquake

but the interesting thing that we saw

with this particular building

is the first floor which was

unreinforced masonry

was entirely destroyed

and you can see the the condition we

were able to go up those stairs very

carefully

and we found that the second floor was

in

was in fair condition

and i'm going to have to give a shout

out to our colleague randolph langenbach

who we were with

and randolph was the person who noted

that we had these

horizontal metal ties

in just about all of these unreinforced

masonry

gingerbread houses that we saw and they

had

these wonderful floor delete patterns

where they came outside the outside of

the building

and at the uh this here

is from the meson du four and this is

one of the reasons why the maison de

ford didn't entirely collapse

is because these masonry ties were

holding up these corner piers

if these corner piers had collapsed the

building would have just fallen onto the

ground

and so randolph came up with this idea

that

since some labor was fairly inexpensive

in haiti then what we should do is we

should hold up the second floor

with with uh with emergency shoring

and then reconstruct the first floor

unreinforced masonry

and we came up with this idea of putting

in new horizontal ties

although we were going to put in many

more horizontal ties we made them out of

stainless steel

and here is a stainless steel plate that

we had fabricated in miami

we cut it using lasers and you can see

that this is a

this was about the same size as that

you'll be able to see some of those

where we put them in

so we came up with this scheme to hold

the second floor in place

and we worked with our partners the ins

institute to petra manuel

which is out of um out of belgium the

southern part of belgium

and uh that they were they were mason

jars

and sharpened chairs and they came in

and they were working with the drawings

that we were providing

with our local architectural partner

and this the idea that we came up with

now you can see that

this is a this is a drawing of the

reconstructed first floor walls

and here we're adding in these

horizontal ties

and instead of just putting one in at

the top we put in one

two three four layers of them

and the second layer actually goes

through the

through the spring point of the arches

of the first floor

of course it takes a village to do this

type of project so you can see in this

photograph

[Music]

haitian workers and architects um

uh partners from belgium and france

and from the united states and we were

all working together on this particular

project

and here is the building with

the first floor removed and the second

floor held in place it was not moved it

was

left employed we had to do some

we had to do some work on the

foundations which i will show you

there was there was plenty of brick to

be salvaged you can see

piles of foreground that the um

that our our local counterpart was

purchasing and having it delivered

onto the site here is the foundation

system this is the only place where

we introduced reinforced concrete into

the project

we uh the the original foundations are

rubble stone laid in uh

laden clay and we poured

a grade beam on top of the foundation

system but below

grade and that this is what we use as a

basis to

to erect the new um the new masonry

walls

um the photograph of this gentleman here

this is patrick lacroix from the

institute to petra manuel he was our

he was our mason and he was actually

doing a capacity building exercise

teaching local masons how to use how to

work with lime

mortars so we put the whole thing up

with lime water here you can see

the walls almost being erected

and if you look here you can see the

florida leaf pattern

and here is the here here are the walls

ready to receive the second floor um i

wanted to run

these horizontal uh stainless steel uh

ties through all of these uh through all

of these harsh spring points but uh

madame pierre louis would not have it

she uh she agreed that i could do it in

one area i always like to show

what the intervention is and she was she

allowed us to do it in this

one particular area

and so this is what the building looks

like

fully restored this is during one of my

visits

on another project in 2017

and this has become an art gallery and a

venue for um music and

art performances and you can see that we

were able to develop this very

open atmosphere um by the way this uh

this building was built

by haitian architects who were trained

in paris because haiti though it had its

independence

people who were going to the university

many of them went and they studied in

paris so this was

this was designed by a haitian architect

the

the forums are very um french and

european

however the forms have been adapted for

the caribbean

in that the entire first floor there are

no windows or doorways on

all around on the first floor and the

second floor has these large

windows that have got uh they've got

shutters on them so they can

promote uh they can promote ventilation

through the entire

building and these uh these buildings

are extremely comfortable to be in

uh on a on a caribbean hot

caribbean day with a cool breeze

these are some uh i pulled images off of

facebook so i can see what they're doing

at the

meson before and this is they usually

have um musical performance on the

outside

okay the second project i wanted to

share with you

is the mesonet this is a this is a later

gingerbread house also designed by a

by a haitian architect however

in this particular example

there has been a large two-story

uh promenade that made out of reinforced

concrete

that has been built around the outside

of it and um

in most cases something like this would

have destroyed this particular building

but since

the building is almost completely

surrounded by uh concrete editions

um it actually held the building in

place by the way this photograph was

taken

10 years after the earthquake so this is

a recent project

and when i was working on this building

there were squatters on the inside of it

i had to i had to get to know the people

who were

living there and some of the children

were helping me with my

analysis this is a photograph of the

inside of the building

so this is this building has been

standing for 10 years

except being just being uh it's been

rehabilitated

you can see the openness of the

atmosphere and the damage to the

exterior walls this is an image from

their prom

[Music]

front and to give you an idea

of the way this building was constructed

the walls in red

are from the original structure

those that are in uh that are post shade

in pink

are the reinforced concrete editions

which

um which i believe have helped

to hold this building together and for

this particular project we took a little

bit more of a

of a well-known seismic rehabilitation

technique

we were picking areas where the masonry

walls were damaged and we were

picking areas where we could put in a uh

put in shear walls and so these were

areas where we located

shear walls the shear walls that are

being put in

are not made out of reinforced concrete

they're made from

confined masonry that is they put in

a they put in a a a small

column on either side of reinforced

concrete and the interior

is filled with um with masonry

and so it's a it's a it's a it is a

shear wall but it's not quite as rigid

as a

as a as a reinforced concrete shear wall

and to give you an idea of what that

type of thing looks like

this is these are the types of

interventions that they were doing

my last visit there was almost a year

ago it was

my last international visit before the

uh

before the pandemic came and we were

i was all i was worried about about

being able to leave the country

and i've been able to follow what

they're doing

over social media second area i want to

talk about is bhutan

bhutan is located between

india and tibet which is now part of

china so it's

it's in this arc of the himalayas on the

southern slope of the himalaya

my project was located

which is where their international uh uh

airport is

and i'm also going to talk briefly about

the wang du

fa drang zong which is here so i was

working these two areas here

by the way for those of you who are able

to join us during the first

uh during the first webinar uh professor

aaron

and he talked about his work at the

wengdoo federang song

so the thing to know about bhutan is it

is a agrarian society and they have no

industry and if you want if you need

wood

then you have to arrange to have the

the wood filled and they they

mill the wood right on site and that's

what this gentleman is doing he's

milling the wood on site they

use hand tools almost extensively almost

exclusively

and another aspect is this particular

of bhutan they use rammed earth

construction

and they still use it a lot um

this is a photograph of the dedication

of

building that's going up and obviously i

think this woman is one of the one of

the queens

of bhutan but this is something that you

will see

uh pretty much uh everywhere as you're

driving around

and here they put up the formwork on

either side

they normally lay a horizontal wood

member within the uh within the rammed

earth wall

that's something that's important to

remember in this talk

and then the roof is actually separate

from the rest of the building you see

the roof is sitting on the building so

during a seismic

event roof is not going to

be bringing a whole lot of mass to

what's happening there

because it's going to be be moving

separately

so i'm going to talk about the sito

gumpa

this is a this is a monastery

here is the uh here is the the temple

itself

and the monks quarters on either side

here you're looking at the mon

you're looking at the temple straight on

and here here is on the other side

um the temple has these beautiful uh

paintings on the inside that are painted

that are placed on paper

so this is what the the floor plan of

the entire

monastery was like and here is the

temple

the idea was to seismic rehabilitate the

temple

and these uh these areas here were

rehabilitated actually they were

reconstructed they pulled them down and

rebuilt them on site because you can do

that with rammed earth

one of the things we did was added a

separate

kitchen and dining room down here to

complete the courtyard

because they had the the kitchen was on

the second floor of this structure

we were really worried that they were

going to burn it down they have

they have problems with fires here so

this was the plan

for the entire one these are some of my

partners in crime

uh chung dorji and karma wang chuk

uh sonam tashi is not in this photograph

although i hope he has called in this

morning

he is a shout out to sonam and uh

and karma and this was the idea that we

came up with

for the temple um the temple did not

have any horizontal

members in it so we decided to introduce

them we uh these walls are about one

meter thick

and so we were actually carving into the

wall

and we're putting these wood members on

the outside

and on the interior we are connecting

them with

with metal ties it was fairly easy to do

with this rammed earth construction and

then we wanted to wrap the whole thing

with a band

and um beginning of the project we had a

a long four-hour ceremony

uh that included ritual dancing

and a feast where all the villagers came

in

and then we went to work here's the

inside of the temple

with all of the with all the paintings

removed

i believe those are some of the

paintings there that are wrapped up

in the paper and so you can see now that

a lot of this area has been

reconstructed and here is a temple

and here is where we're cutting in and

we're we're installing the wood

it's going in now and here is the entire

uh

group of people that were working on the

on them

on the monument here's sonam and

and here is my favorite plumber and

um and the entire group of villagers

that were working on this we had to wait

until

we were off season because all of the

villages are rice farmers

and the exterior of the of the temple

you can see that

and here's the last part where we're

actually wrapping it with a

polyethylene strap it's the same

material that is used for

seat belts in a car then they were

they were covered with the this is a

clay purging on the outside everything

is

everything is clay and you can see that

we are

actually leaving the uh the strap

exposed in these particular areas

because we want people to be able to see

what the actual intervention is and here

we're finishing up this project

the uh the paintings went back in place

um the the uh the

ritual we had to dedicate the new uh

the new temple and that's the completion

of the

of the sito gumpa monastery and

in the last one minute i'm going to

quickly show you

the wangdufa during zong this is an

administrative center

that has um has a series of courtyards

and the important aspect here is this

building here called the utsi you can

see that you'd see here

building unfortunately had a fire in

2013

and it was um the interior was destroyed

in this

particularly the utsi which is gone here

and we were there in 2013 trying to

uh tout uh traditional techniques for

the seismic retrofit

and professor mann talked a little bit

about that but

what i wanted to share with you is that

this particular otsi

what they did is the swiss

offered to give them the money to put in

a base isolation system

so the utc was completely reconstructed

it's got a base isolation system

underneath it

i was allowed to um to visit this

project

during its uh during its reconstruction

and i was also allowed to

climb underneath you would see to see

the base isolation system but it was

not allowed to take any photographs i

think it's the only base isolation

system that was put in

in the himalayas and so with that i'd

like to say

thank you and open the questions or

to go to the next speaker thank you very

much

you are you're muted tim

thank you that always has to happen once

during a webinar right so

um all the rest is now on notice um

thank you so much for your presentation

steve

we will not go to questions just yet you

can post your questions in the q a or in

the chat

also welcome to all the people who have

just joined

um i noticed some of you joined during

steve's presentation feel free to

introduce yourself in the chat we would

like this to

for this to be an active participation

webinar

and so we will move on to our next

presentation which i'm personally very

excited about

because meredith hijazi is going to

address one of my favorite traditional

structures

merdat is a professor of traditional

structures

in the faculty of civil engineering at

the university of isfahan

in iran he's an expert member of ikomas

iscarsa and the chief adviser to the

iranian ministry of cultural heritage

handicrafts and tourism he has been the

director

of structural restoration of a number of

national and world heritage sites

in iran he has published six books and

more than 46 journal papers and 116

conference papers mostly on

architectural heritage

welcome merdat

uh thank you very much tim i hope you

have my voice

yes we do

the subject that i'm going to explain is

about

traditional construction techniques in

perishier to mitigate

earthquake effects and my case study

is in pair space

first i will give you a short

introduction then we go to pairs police

then we go

to nearby ancient sites then we go

two or three hundred kilometers away to

susa and

again we return to paris valleys

well if you had have a look at the

uh at the map of the country at the

moment

but when you go for 25 centuries ago

the first persian empire was so

large and here

a sousa and pairs for us

where the capital of the empire

i'm going to make a talk about the paris

parish and then

i go to pasargadi and then to susa

to see what was the

construction methods in that era

if you have a look at the

micro zonation of

earthquake in iran you can see here that

shiraz and also susa

is located in a high

risk zone for earthquake

first let's have it look at pairs

for this it's quite a huge

site more than 120

000 square meter the area

and its construction took about

100 years and this is what we

see today

as you can see the uh site is

constructed

on a high platform just adjacent to a

mountain here and if we

go back a few centuries ago say

25 or 23 centuries ago this was the

situation it had

and it is very important that this

site was not a governmental site but it

was

a ritual site for celebrating the new

year

which we call no rules in iran and it

is on 21st of march

since then still we have the stem

ceremony and it's very important

ceremony for iranians

to celebrate that therefore the paris

police

is very important to persians

it's a situation at the moment

these are the remaining of the site

it is the word heritage site

it is very well preserved

and even there have been some um

researches to the building to this site

for example if you have a look at the

clan you can find the golden proportion

there

it means that the design of the

plan and other dimensions are based on

some

ratios mostly on golden ratio

let's go to see how was the foundation

built at that one as you can see the

foundation was built

in several layers of stone as you see

and these stones were connected with

flexible metal connectors

we see the same procedure the same

method

for other sites let me

well if you have a look here even at

present you can see the metal

connectors which uh connect the

stones together and still it works

uh let's go a few kilometers about 10

kilometer away from

paris police to pass our guardian nash

and natural stuff

here is persporius near shiraz then we

have an actual

roster of one kilometer and then about

nine kilometers again

away we have possibility here

this is the remaining of paso grady

palace

and this is the tomb that most of you

know it's the tomb of

cyrus the great

and if you go to narshirostan near the

dharjam

near paris paris you see some sort

of stone stone

[Music]

stone tower which worked as a calendar

for the new year and some sort of

ceremonies

let's have a look at the foundation uh

we start with the foundation of

the tomb of cyrus

as you can see they

dug the ground they went for

one or two meters down then they put the

first

layer of the foundation which was stone

and then they put the second layer

or the upper layer of the stone

they were just put together with no

connection

you see the same technique used

in in that power here

the first layer and the upper layer

on the ground ground level and also

on other other other buildings

as you see when you have earthquake here

you have some sort of some sort of

acceleration or some sort of movement if

you want to say

and when you have two layers of

two layers of foundation they can easily

slip against and somehow

they can dissipate the energy of

earthquake

it's the same rule in in in the

buildings in the south

in i commit period for more than

uh three or four centuries they ruled

the country

let's like too pearcefully again

if you have a look here at one of the

walls it is not a wall also

it it acts as a platform for the

superstructure here you see irregular

cuts have been used for the

for the for these stones and you have

irregular joints again the

architect has

this had this idea that give the

possibility of

of movement to the stones in this case

there are some movement of the ground

these stones

are free to move without damaging the

superstructure

let's go to the columns

if you have a look here

there is a special connection between

the

main part of the column and the support

part of the column

it's like this

again there has been a connection

between the two parts in order to make

it uh

possible to rotate somehow because it's

at the moment with this technique it is

not a

rigid connection anymore but it is

somehow semi-rigid it means that

if the top of the column would like to

move somehow it is possible at the

bottom that

you have some sort of rotation and it

prevents from

the cracking or the breaking of the

stone and again if we go for the beams

here

at the top if you look the the beams

wear wood and

it's like this okay and again

here you need some sort of

freedom for both movement and rotation

and therefore they didn't use a very

rigid connection here but they use some

sort of center-rich connection

in order to load the top

beam to rotate and move in case of

earthquake and

in this how they were able to dissipate

the energy of the

of the earthquake

and more important is the rigidity of

the whole roof

they use some sort of wooden roof in

order to make a rigid diaphragm at the

top

in order to make

all the columns have similar and

same movement at the top and they

they make it to move uh in a in

in in in in a similar way

for the all columns and having a

rigidly off strike or a rigid roof is

very important for those

tall columns

let's go two or three kilometers away to

the

uh west to susa

which is here it

used to be again

the the capital of the of the of the

empire in some time

uh here you see the

uh the one of the palaces here

this is the side here

is another palace

the one or two kilometers away and

in the middle is the mausoleum of

daniel

well this is the aerial photo here to

the right is the

apadena place of susa very over the tomb

of daniel and to the left

is the shahooz palace which

was built about 200 bc

this is again the situation and maybe

here

you can see this is the daniel monsolium

and here this upper and to the

bottom that you can see is the older

part

if you have a look at the

if you have a look at the topography of

this

system here uh to the right you see the

old talents here it was

very old it was 24 centuries ago it was

built if you have a look here the ground

level

was here but they decided to

to to to bring the level about

four meters up and from here you started

to

construct the new palace like this

if you have a look here

at the bottom very bottom you have the

remains of heroes from the

previous period and they add some sort

of sand

or gravel layer here for about

one or two meters and from here on the

top of the sand

layer they started constructing the

the site or the pilots with columns of

about 22 meters high

and again here when you have sand here

is some sort

of base isolation here in case you have

some sort of acceleration or movement in

the ground

these these this

sand or gravel layers prevent

the energy the total energy

going up to the to the to the main

building

let's come back again to paris police

i'm going to give some talk about the

sewage system because i think

the sewage system is somehow related to

the

foundation system of the of the site

if you have a look here this is the site

and when you have heavy rain

it's like this therefore for such a huge

uh huge huge site you need to

have some sort of some sort of sewage

system in order to

in order to drain and somehow convey the

rain and somehow the sewage and this is

what they found a few years ago

as you can see there is a underground

sewage system

as you can see it was discovered a few

years ago

and two years ago we had a very heavy

storm and rain fall there

and you can see it worked at that time

it means the uh the city the city of

shiraz and nearby maratha city

where were both flooded but it was

interesting that

that that pair space

was not flouted if i can show you this

you should see a movie which shows how

the water is running inside the soldier

system

this is at the same time that on the

floor of the site there is no water

but one kilometer away nearby city

they're just

flooded and many people have to leave

their homes it means that

it means that it is not it's just sort

of the

foundation for earthquake but also the

the design of uh of

foundation for the flood or for your

ceiling system is also

very important okay

let me finish my uh talk with uh

with the memory of skarsall visit to

paris police in 2018

and i should give you some references

here

there are five books that i with my

colleague have written and also there

are some

some papers that you can find also in

the references

and also it is my email address in case

anybody

would like to contact me it is possible

to contact me

i thank you very much and i hope you

have enjoyed my presentation

thank you so much for the wonderful

presentation merdat

again if you have questions you can post

them in the q a

or in the chat and we will discuss them

at the end after all presentations

and so now we will move on to the next

presentation which is by

fernando pena mondragon he is the head

of the structural engineering department

of the institute of engineering at unam

in mexico fernando received his

doctorate

in seismic engineering from the

polytechnico de milano in italy

and did a postdoc in at the university

of migno in portugal

he has published a multitude of

scientific articles on the seismic

vulnerability of historic masonry

and he is the treasurer of the council

of the mexican society of structural

engineering

welcome fernando thank you very much

i will talk to you about some lessons

that

we have uh obtaining from the

earthquakes that hit mexico

in september of 2017.

so uh but first i would like to

acknowledge

my team especially

my colleagues professor marcus chavez

and

professor natalia garcia and

our army of students and project

engineer

here is the last one squad

they participate with us but there are a

lot of

uh many students and engineers that

work with us

in september 7 and september

19 two large earthquakes hit

mexico and left

two thousand three hundred forty damage

architectural

heritage buildings throughout the

country especially

in the center and south of

the country so this is

really a huge number

of damage buildings

so um i would like to focus that

this number is only the listed buildings

that uh in mexico are considered

as architectural heritage but there are

a lot of

small houses and particular buildings

that are not counted in this number

but that

is they are part of our

um ancient uh

structures so uh this number

it's almost the six percent of all the

architectural heritage listed

in this region so it's really really

a huge number so

after that we made a

survey of trying to see

and understand the different dimensions

that occur

in these buildings for example this is

the common dimension in churches

so uh there are many churches of

these types so many small churches of

one name

and really practical

all the towns in mexico

and we found in general

this type of damage so in the first say

the facilities particular

only in playing the match practically

the out-of-plane damage is only a

see in the front space

due to the crying overturning of the

front in this

and this is a

really interesting picture for example

this is

a diagonal crack due to the shear

stresses

in the tower and this is

a front view and this is

the other part of the tower so

it's like that the tower has cut by a

knife

no so uh we don't understand why

don't uh collapse this part

of the tower and

besides there was a street

and the street was closed because the

vibration induced by cars and rocks that

are passing

it could collapse the tower so

this is a typical damage in a lot of

churches that we found another typical

uh damage in

doms and drums there was a

the typical uh cracking that we can see

in literature with radial and uh

meridional cracks some

dumbs were collapses or

shear stress damage the drum

[Music]

uh bolts have

also the typical the meshes that we can

found in literature

with this longitudinal cracks

especially do because the walls

that support the arcs and the balls

opening and that's

the reason to find these longitudinal

cracks after uh

in walls we can see the

typical diagonal cracks due to the shear

stresses

at the base of the walls we can see

these horizontal cracks due to the

flexural moment in the

outer plane of the wall and

we can see also these vertical cracks

that is due to the shear stresses and

these vertical cracks were found when

the

masonry was a very bad

quality especially when it was made but

peoples with people's stones

and earth more darks or very bad

mortar so

um another damage that we can found in

some buildings especially uh we focus

on the monasteries that

were attached to the churches that would

visit

so it's the of course the collapse of

the

roof so the overturning

of the center of the walls like

in this case and this particular case is

very interesting

because it was uh the cloister

of an ancient monastery and all the

second floor was collapsed

so uh we can see here all the average

of the second

floor but this is

how the material uh

go down to the yard so

in this particular case the mansuri

was very very poor

made by rounded stones

pivots and a very very weak

earth mortar so from its

origin the masonry was a very bad

quality

and we

when we have a very

bad quality masonry

we can found a

collapse mechanism the structure

disgrace completely so

when the second floor completely

collapsed

the material has uh behavior

like a fluid and all the material

was concentrated in this part

so this is how how they

the combine was after the earthquake

fortunately in this case was no

day any dead or some person endure it

but this is a very dangerous

behavior in because

in the earthquake this is a very fragile

behavior so

the conclusion of the observer the match

in this

survey that we made in the different

regions that

has struck by these two earthquakes

where the the mass patterns and

collapses that we found

were similar than those observed impacts

events

this is for me

very impressive conclusion so

we don't found new

behaviors in the

in the seismic behavior of the buildings

so we know the behaviors we know from

the past

events the different types of the mass

and the collapses so for example big

towers

balls and dawns continue to be the most

believable elements

so these three elements of the churches

is always the elements

that where we have a problems of damage

and special collapses and of course

like in the

in some cases the collapses were

due to poor quality of the masonry

so

from from this

in general in in mexico intervention

projects

are based of course in the icomo's and

escarsio recommendations

but authorities and practitioners

take four particular recommendations

from all the universe of e-commerce

and scarce principles and

recommendations so

especially authorities recommend minimal

interventions

non-invasive techniques use of

compatible materials and techniques

and of course traditional materials and

techniques

are preferred

but unfortunately this full

recommendation

has become as the best project is to

return the structure to

its original conditions

so the idea in general

in practically all

the intervention projects in these

dimension structures

is trying to return to original

condition

of the structures before the earthquake

so what can we expect from an

intervention whose objective is to

return the structure

to its original conditions

so

we have evidence of pass events

here i put only three

particular events that

damage a lot of structures for example

in 1973

1980 and 1999 we have

three earthquakes similar to those

that occur in 2017

and we have always the same

scenario so a lot of the match

a lot of collapses the same kind

of the matches the same kind of

collapses and

someone said

insanity is doing the same thing over

and over again

and expecting different results so

if we're trying to

restore the

destructor to its original conditions

we know what will happen with these

structures

in the next sysmic semicolon we will

have

the same dimensions we will have the

same

weak elements we will have the same

collapses

so now we are trying to change this

paradigm in mexico

actually the paradigm is the aim of the

project

is the conservation of the authenticity

of the architectural

heritage so uh

we don't have time to discuss

what authenticity it means

but this is the idea here in mexico

so the best project is

try to conserve the authenticity of the

architectural

heritage

however we need to change

this because

sometimes we forget

the most important aim of

the engineering structures so is that

the safe work of human life

in this particular

event scenic events we have really

few deaths and injury persons

because the earthquakes hit in an hour

of the day and in a week of the day

that there was not a concentration

of people in for example in the churches

but if this seismic event

hit in a sunday in the

uh at 12 o'clock when

almost all the churches are full

in the mess so

there was a really really tragedy in

mexico

because was collapsed and killed a lot

of people

so we cannot forget

that the most important aim of any

intervention

must be the same word of human life

those thinking about

this idea we need

that the criterion to be follow

is not just trying to return to the

authenticity and conservative

authenticity

of the structure instead

trying to use

a cost benefit criteria

so cost of course is not only

economic costs so what we can

lose if we choose some particular

technique or material in intervention of

course loss of authenticity

we cannot forget that in

any intervention project we need to

conserve

the architectural heritage all the

implicit

uh values in the that the building

contains

like history artistic

values architectural historic

etc and we must

put in a balance so this costs what we

will

lost with an intervention but

at the same time what will be the

benefit

so the benefit in the human life

safeguard of human life

of course conservation of the

authenticity

conservation of all the values of

the buildings benefits

in the structural behavior etc so

we need

as engineering projects just remember

that always the capacity

must be greater than the demand capacity

in the sense of strength of destructor

dutility

deformation etc and demand in the sense

of loads

displacement etc and

remember that the aim of any

intervention project

should be in the first place the safe

work of the human life

in the second place of course

preservation of the building value

artistic historic

architectural and of course we

should remember the match in the

structure

so if we change the paradigm

and we don't forget the human life

we will preserve the building value

because to preserve this

safe work human life is for example

that the structure will not collapse

if the structure will not collapse

the building value will conserve

unfortunately at least in mexico

and in many practitioners that

are involved in this

in this area they think that

it's mandatory

to try to conserve a structure

in its original conditions

[Music]

however it's a very often discussion

that what original condition means

so we know that any intervention that we

make in a building

even the small interventions will

change this idea of virginity

so we need change we are fighting

to change this idea and remember

that the most important is

the capacity much bigger than demand

of course

with trees aim

no don't forget of course the

preservation of the building value

so

how can we improve the performance of

the structure

we can improve increasing the capacity

decreasing the demand or at the same

time

increasing the capacity and decreasing

the demand

so in this context

of cost benefit criteria

so we need to focus on solving the

causes

and the problems and not only the

solving the symptoms

we can found a lot of intervention

projects

that we have some cracks in the

structures

and the practitioners just only want

to close the cracks with some

material and that's all and the

structure is

okay but this is

not to solve the problem because

we need to understand what was

the structural behavior to have these

crack patterns

so we need

to understand first the structural

behavior

and after try to

propose an intervention project of

course it must be based

on the current conservation criteria

but we must follow

almost the modern criteria of structural

analysis and design

we need to incorporate the new tools

that we have in

structural engineering in the seismic

engineering

to study and to conserve this kind of

structures so

a technique or some material

may be good for one case but not for

another one

and in this particular case in

for me it's i don't like to divide

the materials and techniques as

traditional or new

because this has

allowed this idea that only the

traditional

materials and techniques are good for

the intervention

in this kind of structures and

return to the previous

state before the earthquake

but if we use exactly the same materials

and the same techniques for example

in the case of of these cloister that

collapsed all the second floor because

the masonry was a very

bad quality now

in this particular case the authorities

and the engineering projects that

are involved

in the reconstruction of

the building wanted to use

the same kind of masonry because it was

its

original material and this is

a really bad mistake because

we will have the same problem in the

future

so if we will reconstruct

the second floor of the monastery we

should reconstruct

with a better performance than before

so the selection of the technique and

material

will depend on how we will improve the

structural behavior

we need just to remember this part

that sometimes we forget

because we are involved in in another

question

but sometimes in the interpretation

project

we forget this simple idea

always the capacity must

be greater than demand

so how we improve

the structural behavior is

what material and what technique we must

to use

of course taking in account all

the conservation criteria taking in

account the conservation of the

values of the structure but

improving the structural behavior

improving

the seismic behavior for don't have

first any collapse if the structure

collapse

means that the intervention project

was failed

so the first point that we

have in mind is that the structure

must not collapse

so

just uh as a summary of

this idea that i want to share

today with you is that in mexico

at least in mexico we need to change the

paradigm

and don't forget that the most important

aim is the safe word of the human life

and after that is the conservation of

the all

values of destructors so

the structural intervention must improve

structural response so if we have

collapse in the structure means that the

structure

have a very bad scenic behavior

so we need to improve this because

if we made exactly the same we will have

exactly

the same problem so

due to the two earthquakes that hit

mexico in

2017 we have really a lot

of damaged buildings and mexico

has not the resources to

uh uh to conserve all

that or to intervene and restore all

that uh buildings

after three years of the events

we have almost uh

one third part of the structures that

has not been intervented

today so this is a huge problem so

we need to improve the structural

behavior

of our structures and of course is not

to return the structure to this initial

condition

because means that the initial condition

is not

perhaps not good performance

and we need

remember that any intervention

will modify the original structure so

any intervention that we've made

we change the original structure so it's

really complicated

just this idea to return to the

structure to its original conditions

of course the intervention project must

be multi-disciplinary

because the structural engineering

is an important part to increase

fernando sorry to interrupt we're going

to have to move on very soon to the next

presentation in order

not to go okay i i will finish now this

is the last

slide so uh

the intervention project must be

interdisciplinary so of course to

uh trying to save work not only the

human life but

also the value of the

buildings and each problem is unique

so we can make some general rules that

this is another problem in the

practitioners that

once a general rule

to solve the problem and

we propose that a good benefit must be

followed

thank you very much thank you so much

fernando and i think you're raising

a bunch of really interesting topics

that we will touch on in the discussion

later

for example that your distinction

between traditional and modern

methods and especially when you bring up

authenticity and human life i would like

to point out to all the

attendees that escarsa will be putting

up

a specific webinar on authenticity and

reconstruction at the end of april you

will get the information about that

um in a few weeks i would also like to

encourage people who are watching our

webinar through facebook live to post

questions there we are monitoring your

questions and we'll address them at the

end

um that said we will move on to the next

speaker

amina abdesemet fufa is a professor of

build urban and natural cultural

heritage

with a particular focus on heritage at

risk due to earthquakes

landslides and flooding she is also the

director of the research sciences

laboratory of environmental and

technology

environment and technology for the

architecture and patrimony

at the universite de blind aside from

being a professor

amina is also an active professional

architect

of build cultural heritage and historic

sites at the ministry of culture in

algeria

she has supervised many restoration

projects and is currently in charge of

the restoration of the palace of the day

and palace of the base at the citadel of

algiers

which is a unesco world heritage site

welcome amina

thank you tim and

good evening everybody thank you very

much for the invitation and

i'm here i'm happy to share with you the

um experience of the

north african countries and the

particular the

magrav region so my talk today is about

earthquake resistant

techniques from action to 20th century

in the maghreb region

where i will present the case of algeria

tunisia and morocco

um well so all over the world

buildings located

in risk prone in seismic pro risk area

are almost

and exclusively constricted on the basis

of the experience and

observation of local builders the people

living in this uh

risk region has developed over time

many strategies to coexist with this

phenomena in particular social behavior

and constructive approach and at

preventing

and limiting the exposure of buildings

and inhabitants

the concept of local culture encompass

encompasses this social and technical

dimension dimension

of the act of building and the process

of developing the knowledge

and its skills the vernacular way uh

the vernacular as a way of living as a

characterization of construction

and self-protection methods turned out

to be a valuable

source of practices techniques and

measures

proven over the century and

to and and of the many of

hazard for the construction of a

sustainable built

environment accessible and secure

so this

this

that shows the distribution of

earthquake in the mediterranean

and we noticed that the most

the most event located

in the west central region

um when we have

the seismicity of the northern

lights right and those

moderate seismic countries except recent

earthquakes

which happened during the 21st century

maghrib countries has experienced

in the past several seismic event

that caused loss of human lives and

damage to property in different region

the historical earthquake knows uh

no since ancient ancient time to today

greatly increase

the probabilistic of an earthquake

occurring

and damage in the future so we have

three great earthquake that happened in

this

during the um past uh the 1716

earthquake of algiers the 16 25

24 of first and 1795

so um based on this information

fundamental question of interest for the

architect and

engineers are how did the local

population

build their houses resisting earthquake

loads

and what what structural techniques did

the local population

use for building their house to protect

themselves

against earthquake

of africa and

here in the algerian country and morocco

and fest and we have uh all the

techniques are located in the coastal

line

and some of them are located in the

highland

in the west island of algerian country

the techniques developed are of two

scales

the first are architectural and urban

concept

and the second are the construction so

we have

architectural design urban design human

design

such as the um

discharging discharging arches

voted basement linked by archers

and from the details we have the

reinforced

masonry with wooden logs reinforced must

only by layers of bricks and reinforced

rained

earth

during the um during the

autumn and in recent periods the three

cities big cities algiers tunisia and

fest

uh showed typical characteristics of

muslim cities their buildings blocks

are a lot of

various sizes

the plots are fully built and the houses

are leaning

against each other constitute

constituting or forming

a compact unit forming a narrow

street which are covered by galleries

sometimes they are built with

they are voted or

are called

and and they this

this different characteristic of urban

design constitutes a structural

continuum

so when

when

when when the uh passageway

are voted and they disconnect

between between the houses this is a

perfect

perspective

which is connected with two parts

of the two sides of the

houses and we have here in this picture

in this slide

different different case of

um connection between the battery

and the houses and this

structural continuum which dissipates

have different different cases uh we

um we just

a basement and in the higher part of the

building

we have three three three

um three votes

between the two part of the buildings

so there are two series

inside and outside the houses which

connect between

the two blocks

this has a different example of algae's

covered passageway with

roof

these charging arches we have

buttresses first or in this picture

the the different um

during the 20th century uh during the

french

colonization the recommendation

of the 18th 44 by the military engineers

for the construction of algaes they

pricks

they brexit bricks click shaped as well

for the private and public construction

the low buildings because of the seismic

risk

and to work the basement and to join the

building between them

by archives i'm sorry to not um present

i lost my photos

recently and unfortunate unfortunately i

did not

have time to go to the site to take

another picture

but it is uh it is written in the

military engineers

report that jesus has

has been built obtaining taking into

account this

so from the part of the

the constructive detail some of

techniques were discovered or was

highlighted

during the investigation institute

investigation in the territory in the

algerian

and the magribun territory so here we

have

um announcing time site

of caesarea cetera

located in albania

and these techniques

where we have a certain position

superposition of

two layers of spoon and

platinum is not too big but it is

a plate made of made of

blick which

is treated

or disposed of the depths of

and

because we have some problems hearing

you

maybe because turn off your video maybe

the audio quality

will be better thank you

[Music]

sorry

what's the problem you don't hear me we

don't hear you very well

your sound goes on and out so i'm i'm

worried it's the quality of your

internet

so maybe if you turn off your video

which should be on the

bottom left of your screen you can maybe

turn that off

if you don't find it we can just yes

perfect thank you can you continue

yeah uh did i repeat or i

continue no you can just continue okay

so this um

it's called um is an opis system

uh where we have two layers of different

materials

and this stone tables are

surrendered of the stone

stone masonry so um

this is uh this is not some

ancient techniques used by the past

during the medieval medieval period

we have the reigned earth reinforced by

wooden

this kind of

uh in the city where um

where

the moorish uh lived

because in the city we where we have

found these

techniques the moorish lives

during the summer and they have

blocked this

this technique

for the people who are living in the

city

and this is part of the walls the walls

the surroundings of the city and we can

see

red earth air force dialogues of

during the ottoman period and we found

the

we found the techniques of the

transmission of foundation

the foundation of the column we have

we have superposition of

two layers two perpendicular layers of

treyarch which is a which is

a cedar wood and these slots

would take has the role of

shock absorber and he

minimized the application of ground

acceleration

this is um this is one of the

techniques of the energy dissipation

of the in the foundation

vertical structures such as

walls we found um we

found that the wooden logs are inserted

in all the depths

of the walls

and this is uh in the site of

tunis these are in the site office

we have also the this kind of

uh this this kind of techniques

they reported in the

pillars in algiers and tunisia

we have also the training at the angle

uh

also in different in the different um

different cities so here we have the

training of the the wall we have

this this have they are um

this these techniques or these

logs are put

in this um in this in this manner

and they were where where the

greater fragility fragility fragility of

the world

is due to the combination between

bending effect and shear and torsion so

this technique this technique did

diminute the the effect of uh

and the angle did not collapse

algiers there is a particular techniques

in archers

in arches they are reinforced by logs of

yeah and we can find

sometimes one layers when we have only

the art

artists we can find also two layers

layers of logs of tria when the

column supported the

supported method revolved

only vault this

of two materials

one rigid and the other flexible

guarantee due to the slip movement or

rolling

which is a good resistance to share

during earthquake

and those the uh this system of archive

is contribute to the resistance of

earthquake of earthquake loads this is

particular to all this

um haven't found it in another site

this is the galleries of

houses

and the other one is

the site of tunis

blocks are also used in the

um and compula and you can find these

logs here and

this character they

they are they they are uh

playing the role also of a shock

absorbers

and

well the other techniques

which is different from the reinforced

reinforcements only with the logs of tui

and this says um techniques which

was used in the city built

built or constructed constructed by the

moorish

when they arrived at algeria's history

so uh during the 15th century we have

this uh earth and earth

and it was um this is called tapia

valenciana

and it was evaluated by christine in

spain

as a seismic resistant techniques and it

was uh

used at valencia after the great

earthquake of

13 50

uh 95 on 59

if yes 1359

earthquake later during the 19th century

this same the same techniques was used

in the colonial buildings

such as resistance

and at my at my city

because it is located in a very high

risk area we have fought the

beef

um so marbling and fault

which arrived and which arrived

until the uh the city and i was

destroyed

several times in the history the first

the first recognized

the first important earthquake was the

the one of uh 17

25

17 25 year earthquake where

all the city was destroyed and then the

reconstructions

was during their

constriction all the the houses were

built with the capital and siena

and when the when the french were

at in algeria they used this technique

because they

are because they they were

they were

because they know they they know during

this time that the city

is

this big area

and in the um different

in other region in the highland of

um in the in the west highland

we discovered a system which

is so we called um

traditional warning system this

uh this this is

made of it's built with the

beam of with with the logs of

trees and the hooking system of food

element

uh they detached the the

detached when soil movement happened

and this happened not only when the

earthquake happened but also when we

have a landslide

because the constriction are

sloping on sloping uh

soil so we have uh this techniques was

used

in the historical uh in historical

mosque during the 17th

century and this um

the in the this region was known

as the first known earthquake was

the earthquake of the 18th

um and during the

project uh as

as today

we are we are talking about the use of

compatible materials of

historical techniques we have

repealed we have reused the

techniques uh using the logs

of wood inserted in the masonry and in

the columns so we have here

for the restoration and here after the

restoration it was really difficult to

ask

to to reproduce and to reuse

the um the uh

these techniques because in algeria

our regulation is is still

dating from the 18th

from 1918 uh it was

the the regulation was made after the

al-aznab earthquake and

during this time the restoration was

made

over the world by the reinforced

concrete

so the techniques of the post

consolidation

are still today in our regulation with

the

still with the reinforced concrete but

but today the research has evolved and

with

our students we are now working on the

basis of the euro code 8

for the remason rebuilding while waiting

to develop

our own regulation for historical

building

so the citadel of algiers today

is restored according the european

code and not following the algerian one

but it is not easier because for us

because

the regulation the algerian regulation

is still applied today

and we must to see conventions

this is um this this is a picture

showing the

um shaking table

test that

which has been done during the

perpetuate project

seismic preservation of historical

building

where algeria contributes and

the uh and they

we have

they have a mosque

at algiers today is located at inside

the citadel of algiers

and the the

the prototype collapsed at the uh

acceleration of uh the recent earthquake

of

algiers yes it was collapsed

because uh the prototype was isolated it

was not uh

it was not um connected with

the other part of the building or the

other part of

the construction but we have just

simulated

a part of a part of the vault

of the mosque

i it is known that the man has always

know how to adapt to different natural

risk particularly earthquake

in the north african region and in

particular the magrav earthquake

resistant technique have been developed

also the moderate seismicity before the

regulation

from antiquity to the colonial period

earthquake resistant technique are

different from one region to another

they constitute today the transferable

indigenous knowledge

in the mediterranean being thank you

very much for your attention

thank you so much amina for this

wonderful presentation

it's also wonderful to see that

parallels are being

drawn in the chat between the techniques

in iran for example and then in the mag

weapon it's

something we can come back to when we um

start the discussion

um now i would like to introduce our

last speaker

jitendra bottara who's speaking to us

from new zealand where it's currently

almost 4 a.m in the morning so thank you

um chitandra for your

for your dedication so jitendra is in

nepali based in new zealand

he's a fellow of the um fellow of

engineering

new zealand and of the new zealand

society for earthquake engineering

he is director of recipro international

engineering a new zealand based company

and has

lectured and written extensively on

seismic engineering and disaster risk

mitigation

he has provided advisory services about

disaster risk reduction

earthquake recovery and reconstruction

to many governments and international

organizations

including the united nations and the

asian development bank

he is an ardent believer in identifying

strong linkages between social

and seismic engineering for seismic

safety welcome jitendra

what

see here so

you hear me yes we can okay

so give me a minute um

[Music]

it is recording my screen

and you can see my screen yes my project

all good to go

okay good

thank you team for the kind introduction

good morning from the country of sunrise

good day good afternoon good evening

to all from around the globe

in my today's presentation i will be

discussing about my experiences and

observations of

last two and a half decades and seismic

resilience of vernacular construction

along the himalayan arc i have two more

co-speakers professor jason ingham and

dr dimitrov

both from new zealand but i will be

presenting

this webinar thank you to ecomo

kamos for this opportunity to share my

observations

in my presentation today i'll be

discussing about

identifying seismic resilient vernacular

construction

missionary building systems along the

himalayan arc

and i'll evaluate their seismic

resilience

from uh from current engineering

perspective

my goal is not to romanticize or glorify

the vernacular construction but to

scrutinize

these because these are live

construction in himalayan region

but the fundamental question is why

should we study

this vernacular earthquake easily and

construct our vernacular construction at

all

because earthquake after earthquake it

has been proved

these are very weak highly vulnerable

construction

either you go to himalayas or anywhere

in the world

so why should we study them rather than

discarding them and bringing

something more modern which can provide

us better seismic safety

but in my opinion and my observations

in work in many countries i believe this

vernacular construction can provide

disaster risk reduction

in a sustainable way when i say

disaster risk reduction i am not talking

about only natural disasters

i am talking about cultural disaster and

i am also talking about

socio-economic disaster so they are

sustainable system because they

developed over the time

due to from the experience of the people

a large part of himalayas is still very

inaccessible

if we are talking about this vernacular

construction

the knowledge base is with the community

we don't need to bring

technical engineering knowledge from

outside

the material construction materials are

there

so people have no dependency and

importation of material

they are socioeconomically more amenable

they conserve culture and

environmentally

they are environmentally sustainable

because they require minimal

energy over their life cycle

but of course this building system have

their own problems

their own limitations that we need to

understand they can't fit everywhere

though they could be sustainable in

certain context

so we need to understand this but there

are certain

building types along the himalayas

with certain earthquake resilient

features

which has provided seismic safety over

the centuries

and in each earthquake they have proved

their

validity they are validated by

earthquakes

so let's look at the himalayas so from

east to east west it is something like

2400 kilometer long

and we all know himalayas are seat of

mega earthquakes many many magnitude

8 plus earthquakes but let's look at the

building types

so if you look from east to west from

bhutan to

almost close to palmyr west of pakistan

western pakistan

you see a lot of building types which

have

survived earthquakes after earthquakes

maybe some buildings are

weak some are stronger but the most

important thing is

how intuitively how intelligently

people have used whatever resources they

have

to make this building earthquake

resilient

so it is not a matter of weak or strong

it's a matter of

how intelligently the system has evolved

or developed if you look at these

building types

we can broadly classify these building

types in two groups

one is earthquake earthquake-less

mercenary buildings

where timber runners or bamboo runners

are laid along the length of the

building

and they are tied together by class

members

and these timber members these runners

tie whole building

together as a box and provide box action

these timber members subdivide masonry

in small parts

thereby it prevents widening of cracks

dangerously and then masonry

and timber work together

as a composite system to survive an

earthquake

or earthquake shaking the other system

if you look at

is basically timber framed masonry

buildings

good thing with this system is their

walls are very thin

something like four and a half inch to

18 depending on brick

or stone they have timber frames

with bracings but bracing doesn't need

to be accept

it could be any any configuration as you

can see

in the left photograph mercenary is

confined in

small compartments

and meso is held by timber and masonry

and timber work together

to develop a composite system

and these both systems have developed

over the time

through the experience and they have

survived well

but of course as i see along the

himalayas

there are more timberless system

than the timber frame system timber

frame system are muslian

western himalayas

time to look at their seismic uh safety

or to do assessment

if you look at earthquake engineering or

building safety

uh there are two ways for building

to be earthquake resilient either

building has to be very strong

or it must have deformation capacity

we all know these vernacular masonry

buildings are very weak

because the masonry is very weak because

of mud motor or many times there is no

more

motor we can't make strong

the motor we can't because there is no

alternative in many areas

or most of the areas i would say

connections of these buildings

are i would say cannot be made rigid

they are semi rigid we can't make them

rigid like welded or bolted connection

so they are relatively weaker than

industrialized modern materials

but the beautiful thing is the people

have turned these weakness into the

strength

so the building can survive earthquake

shaking

so basically people have adopted

deformation

route provide more and more deformation

capacity

to the system so they can survive an

earthquake it is something like saying

if i am flexible enough if you push me

i'll just deflect you can't push me any

further

because i am deflecting and that's how

these buildings

work but the important thing is

we lack understanding of these building

systems

this vernacular building system the

earthquake and resilient building

systems

work differently than the industrialized

modern materials

buildings constructed of cement

steel or reverse and our building cores

are written for these industrialized

modern materials

which are mostly monolithic

so we can't apply this building course

to this vernacular construction and

every time if you apply

what we find is these buildings are

unsafe or vulnerable

whereas this building has survived

earthquake after earthquake

so we need to rethink our strategy

or our approach to these buildings let's

take one example

on the left on the right there is a

building system

a base isolated building system and what

happens in base isolated building system

whole building remains as a rigid body

works as a rigid body without any

non-linearity

all the non-linearity or deformation

happens in the base and at the base

isolated system

in the base isolated system whereas if

you look at

this vernacular construction it's a

stone in one motor but with

reinforced concrete bends and you see

how it works because the motor has very

it doesn't have any strength practically

so

everything slides and rocks and that's

how it

works so let's see this

small video where did it go

so the consequences are because of our

lack of understanding

the consequences are of sorry

the consequences are here is a temple

from karphendo valley

is a five five-tier temple this temple

has survived

1833 earthquake 1934 earthquake

and recently 2015 earthquake with

minimal damage

all the studies completed until now i

have

seen so this building is this temple is

highly vulnerable to earthquakes

but no study i have seen it to indicate

why this building survived all the mega

earthquakes

that clearly shows we don't understand

these building systems

so we need to develop new strategy

to the understand this building system

the fundamental philosophy earthquake

safety is life safety

so we can't apply current building cores

or the standards

to evaluate these buildings so let's go

to the fundamentals

and look at these buildings from

fundamental principles

are these buildings really uh earthquake

shefa or they meet

earthquake resilient principles

so i evaluated these buildings from

configuration

integrity redundancy stiffness

deformability capability energy

dissipation and

reduced seismic weight

if you look at configuration point of

view these buildings are very simple

vertically and horizontally they are

very regular

their windows are very small the small

window means

there's a larger wall area to carry

seismic force

they have very well defined load paths

so the load can easily travel from

point of its origin to the ground if you

look at the

length to width ratio or lay height to

width ratio

it is a typically one to two and most of

the standards would

recommend this should be less than three

so this building from configuration

point of view are good buildings

if you look at the bottom left building

it is a circular building

and i am not sure if you are aware of

circular buildings

though indian force performed extremely

well

during gujarat earthquake in 2001

and this building is from west nepal

let's look at the integrity point of

view

my observation in many many earthquakes

is one of the

biggest reason of catastrophic failure

of vernacular construction or even any

building system

is loss of integrity

these earthquake resilient vernacular

construction system

have enhanced integrity

people have tried to use whatever they

have any resource

to improve integrity of these buildings

other thing is they are flexible joints

because they couldn't make rigid joints

but the beautiful thing with

flexible joint is they flex

thereby release energy but at the same

time they do not

over stress the connection or the

connecting elements

so the controlled movement helps

releasing energy but helps building to

deform

what about redundancy

any resilient system it could be even

our family

if our family is resilient that means it

must have a redundancy plan

it must have backup system these

building systems have

high redundancy because these buildings

have

multiple load paths

they have sacrificial elements so for

example if you look at the

left figure left image the part of wall

has collapsed

building is still standing well

so basically it is meeting the the its

requirement of

maintaining integrity if you look at the

central

miss you can see how badly walls have

deformed

due to 2005 pakistan earthquake or the

kashmir earthquake

and a few of the stones has already

fallen off

still wall is maintaining its integrity

so that means this system has very high

redundancy

and redundancy is one of the trait of

any

earthquake resilient system

what about stiffness one of the biggest

problem i have seen

in many many earthquakes is the

reinforced concrete frame building

barely suffer from soft history

mechanism

because of obvious reasons

though masonry buildings these

vernacular masonry buildings

are flexible in nature have enough

stiffness

to avoid such type of failure

of course this can happen to this build

these vernacular construction also

if earthquake is a very long

and very high intensity but

probabilistically that's

very unlikely to happen

so these buildings have enough stiffness

to survive earthquake though they are

very flexible

what about deformability these

vernacular construction systems

work on the deformability their capacity

to deform

but if many elements different elements

deform in different way

if and if they do not have compatibility

things would start breaking the moment

one element breaks

that chain of brave failure will start

and that would lead to catastrophic

failure

but the cool system good thing with

these systems is

they are very compatible different

elements are compatible

for example wall is sliding the motor

sorry missionary units are sliding past

each other they are rocking

like this the joints are flexible

or semi-rigid so all this control

movement avoids stress concentration

in particular elements thereby helps

building to survive

what about energy dissipation

as early as shown by many presenters

and you may have seen during many

earthquakes in the past earthquakes

masonry buildings are very large cracks

like this because these cracks have to

happen

to release energy because earthquake is

imparting energy to the building system

but what happens if there are seismic

bands

there are runners or frames let's look

at a video

here with timber frame

this test was completed in 2018 when we

completed a

very extensive test on masonry buildings

so

let's have a video

the acceleration of this video during

shaking was

1g that was the capacity of the table it

is 2 30 scale model

and you can see how mesonory is sliding

past

each other and units are rocking

so you can see through this sliding it

is releasing energy it's

like a friction damper or rocking damper

and the beautiful thing is in

the the left figure you see very large

cracks

but mud motor if there are timber bands

or the

some bands some form of tying elements

that the cracks are prevented

from widening dangerously

because these bands hold the masonry

together

and other thing is beautiful thing with

masonry in mud motor is because it is

always in cracked state

so that means degradation is very low

compared to high strength machinery

what about seismic mass people have

tried their best to reduce

mass for example in the central figure

bottom two stories are

masonry uh with timber bands but

one is a light structure same in that

this is

timber frame construction say from

pakistan

and just by doing this timber frame

people have reduced seismic weight by

almost one third to half so that's a

significance

reduction in seismic force that leads to

reduction in seismic force

what i mean is people have tried their

best

to improve the system if you put this

all seven attributes of seismic

resilience in

one figure together what we see

is more this shaded area better the

building is

so this is an unrained force machinery

building vernacular building again

but have very little

gray area that means this building is

highly vulnerable

but last building system

is a much much better than indian force

masonry

because very large shaded area

if you look at timber frame building

these are further

better

but we need to understand these timber

frames building are mostly one to two

story

whereas this timberless building can go

maybe three story

or even more

so each building type has their own

limitations

and there is strength and we need to

understand that

so the conclusion is

vernacular building systems are

sustainable building systems

and again i highlight when we look at

sustainability

it is not only earthquake or any natural

disaster

sustainability means cultural

sustainability

socioeconomic sustainability because

these

cars life these are important tenures of

life

not only the technology

barnacular earthquake resilient building

system can provide

earthquake safety sustainably so the

important thing is

to to mainstream

promote these strengths and mainstream

this construction system of course as i

mentioned earlier

these building systems are their own

weaknesses and strengths

and we need to study these weaknesses to

understand how we can improve them

using modern technologies

so that should be our goal

thank you very much ah this is all about

my presentation

and if you have any question please feel

free to

ask thank you thank you so much

chitandra for such a wonderful

presentations i

i particularly liked your um

your analogies trying to um

you know explain very difficult concepts

with very simple analogies and i think

it's

it gives us a great overview of why

traditional

um structures can work well so i would

like to pick up on that

now and if you could stop sharing your

screen so we can

get all of the panelists

on the screen then that would be great

thank you and so we will go on for about

another 15 minutes with discussion

based on the questions that were raised

and first of all i would like to um

go back to what you actually put on your

last slide jitendra and like the two

signs of change

versus go back to um the same old

and that that also brings me back to the

points that fernando raised about

traditional versus modern interventions

and rebuilding better

um and i was also really struggling

tendra by your comment there that we

should not glorify

um one slide back but better understand

traditional structures and so i wanted

to ask steve

to comment on that interaction of new

and old techniques in traditional

structures

based on different um approaches that

you presented steve

and maybe later jitendra you can uh

chime in on that as well

should i try steve okay i think we'll go

back to sleep first

um okay okay i i am here i

can't seem to turn on my video but um

i'm here

and um i'm interested in

the combat compatibility of

okay let's see start my video i'm

interested in the

um the issue of compatibility of

traditional and modern techniques i know

that

in the past uh materials such as

reinforced concrete reinforced concrete

is

concrete has become like the bad boy in

heritage conservation

and in many in many ways that

is that is earned but i don't think that

we should always just say

certain materials or certain techniques

um can't be used

it's really a question of compatibility

now in the presentations i

did i sh in haiti i showed that we

actually used

concrete in the foundations in bhutan

we got this uh horizontal uh tie

going like what jatendra was talking

about

using a uh using a polyethylene strap

and that is because

we couldn't go all the way around the

building and tie the wood in

the way that um the way that would have

been

deal based on the building that we had

but i think

that i think it is okay to look at

content materials and contemporary

techniques we should always start with

the guideline of

minimum intervention but

when we intervene on a building as

minimal as that intervention may be

it's going to be a change so there's

always going to be a change fernando was

talking about the change and the change

that we need to have

these are these are important topics but

we should always start with

what is minimum and the uh the

principles

that are there are scarce principles and

also the guidelines they're working

working with i like to look at these as

guidelines or road maps

is something that you can start with if

you're taking a trip you may look at a

roadmap but then you may decide to go a

different way

based on what based on what

road or sites that you want to see

so i think that we can have some

guidelines but we don't need to have

strict

rules i hope that that uh i hope that

that answers your question

it does it does any of the other

panelists chitandra for example wants to

chime in

you did you have a comment on that as

well

i would like to add to stephen

compatibility is important issue

and of course as i mentioned we need to

understand

limitations and strength of this

vernacular construction

and bring in modern science or modern

engineering

to improve them further rather than

discarding them and there is a lot of

opportunity to do that

because that time if you look at

historically

there are only five construction

materials along the himalayas

stone semi-burnt bricks mud

timber and bamboo but now we have more

materials

these buildings are very flexible and

they said stones or brick

so we can bring some confinement uh

polypropylene

or it could be wires or anything but

this

system should be compatible with the

existing system

so rather than destroying the philosophy

of existing system or the vernacular

construction system

we should be enhancing that properties

that characteristic

that's how i think and we did some

testing on that

some extensive set table testing that

could be one of the largest

testing program in this end time on

stone missionary and we found

fantastic results

i i think that's a great um that's a

great comment thank you um

i don't know fernando as this all

started with you i'm wondering if you

want to comment further or if we

should move on to the next one yes of

course i

i agree with stefan and

i like a definition of what means

minimum

intervention of philip garnier that

write in the chat i will read it that

he said that minimum intervention means

maximum

understanding so that is the idea

so uh when i talk

about the the change of of the idea

is that um we are

according with this karsa principle and

icomos

and of course the minimum intervention

is

uh a part of of of this

idea of intervention however uh

sometimes for professionals

involving the practitioners um and

unfortunately

at the same time in some part of the

authorities

they don't understand very well these

principles

so in the academia is well spread and

understanding

and etc so i try to

show how the practitioners are thinking

in mexico not not their academia so

when i say that we need to change the

idea is

the idea in the sense of

first we need to know the structure and

knowing the structure is how to

make the intervention of course taking

in account the minimum

intervention and when i said that uh

the general rules is not possible uh

i don't i don't say

that the guidelines is not okay

i i agree with stephen kelly that

it's a type of road map but

unfortunately the practitioners take

like a quick receipt that okay

the first step is this this this this

and i will

do these steps in all the cases

but without knowing the structure

without

knowing why the structure have

that damage so

i think that one

aim of the academy is to spread

this knowledge to the practitioners and

in the first place to the authorities

because uh when i talk to authorities

is in all levels of authorities in

general

the directors of uh the institute

that is uh regarding to conservation

of uh the architectural heritage in

mexico

they understand very well these concepts

and

these ideas how to conserve

but they is though authorities

that they are in field and

they are working with the practitioners

sometimes

they are not full understand these ideas

thank you so much um i would like to

move on to another point that was made

um a couple of times in the chat i think

um

it was very well voiced by fateme saraj

who said that

many of the construction techniques that

amina was showing

in algeria were very similar

to what was what you could find in iran

for example

and i was wondering if amina or merdot

could

maybe comment on that transfer of

technology and similarities

i think that yes

it's probable because

there is a transfer there is transfer of

technology i know that between the

uh um

the two side of the mediterranean basin

there is transfer

of different technologies or different

techniques of constriction

but and using the

logs of wood in the measuring

uh i think that the last um

the last country

or the um yes the country that i uh

i'm sure that there is this techniques

is syria because they discovered

during the um they they discovered

uh in lataki that the

historical building uh constructed after

the major earthquake historical mother

earthquake

uh with the earthen they they they

reinforced the earth and the rent

uh they ran the earth

constriction with the wood and it is

written

in logarithmic language

so i'm not for the

part of um from iran i'm not sure and i

don't know if there is this

similarity between the

magribun region and the eastern region

so if possible mayhem can say

can explain to us if there is this kind

of techniques in his country

yes actually i don't think that there is

a

need for a transmission

of techniques between the two countries

because

first the uh the climate

of algeria is very similar to the

climate of central iran which is

war and also the people

in these two countries had the same

problems

and also they had

both people in people in both countries

were

human beings and they had their own

knowledge and therefore

to solve the same problem they reach the

same

solution that's simple probably

sometimes there would be some

exchange of knowledge but between

algeria and iran i don't think there

have been such an exchange of knowledge

during the

history and therefore i think it's the

same

solution to the same problem and

that's it the material is the same the

climate is the same and also

the mentality of the two people two

nations are the same it is just the

matter of same problem same

solution i think that is a wonderful

comment

um to indeed like recognize that several

of these techniques

recur all around the world and often

people have arrived at the same

solution because it just makes sense

with that said i'm being mindful of the

time i would like to thank

all of our panelists once more for

making time to

attend the webinar i would also and

speak at the webinar i would also like

to remind everyone that there is a first

and final part to this webinar series on

thursday

april the 14th and with that i would

also

finally like to thank all the

participants for the active

participation

in the chat thank you so much