MARK ANDREW KELLY

RECONSTRUCTION IN HAITI AFTER JANUARY 12TH 2010:

A GUIDE FOR NGO’S, SELF-BUILDERS AND AID AGENCIES

University of California, BERKELEY

Arch 253 - Seismic Design and Construction

December 16th 2010

2

Contents

3 Guidelines for NGOs

4 Earthquake Description

5 Timber or Brick?: Seismic, Ecological and Economic in� uences�

6 Earthquake Recovery

7 The Human Cost

8 Assessment of Damage

9 Soft Storeys

10 Design of reinforced masonry

12 Selecting a Site

13 Wood Buildings

14 Masonry Wall Skirt

15 Design: The Plan

16 Non-Structural Damage and Concrete Frames

17 Timber connections

18 Foundations

20 Buildings which survived

21 Case Study: Builders without Borders

22 Permanent housing for Haiti

23 Respecting cultural differences

25 Conclusion

27 Bibliography

3

Guidelines for NGO organisations when using this Manualg g

Construction after a disaster is an important area to explain to builders,

particularly when housing is urgently required. This illustrated guide could be

given to a construction layman in Haiti, to describe how to safely build a new

home for his family. The aim is to produce a handbook containing clear,

illustrations to explain techniques for seismic mitigation of structural problems.

These design guidelines are for Haitians who would like to build their own

homes, to understand structural principles which can provide the minimum

standard to keep their families safe during earthquakes. I made reference to a

variety of FEMA documents and numerous documents, in the Bibliography.

As a word of Introduction the following report outlines work needed to form

a permanent sanitary rehabilitation and housing reconstruction strategy for the

people of Haiti.

Thanks goes to the Paci� c Earthquake Engineering Research group at �

University of California at Berkeley, where I have been working for Professor

Khalid Mosalam on post-earthquake reconnaissance efforts in Haiti. The pho-

tography from Haiti is credited to Berkeley Earthquake Engineering Research

Institute (EERI) in January 2010 during earthquake reconnaissance.

In the reconstruction of Haiti, if earthquake-resistant bulilding practices can

be promoted and emphasised, the standards of construction and safety will

improve.

Block of Flats in Port-au-Prince, Haiti January 2010

Emergency temporary housing

4

Haiti January 12th 2010 Earthquake

Haiti is located off the south-eastern tip of Florida, where a very large Strike-

Slip earthquake hit on January 12th 2010, measuring 7.0 on the Richter scale.

The epicenter was near the town of Léogâne, approximately 25 km (16 miles)

west of Port-au-Prince, Haiti’s capital. The earthquake occurred at 16:53 local

time (21:53 UTC) on Tuesday, 12 January 2010. In 12 days after the

earthquake, there were 52 aftershocks measuring 4.5 or greater. The

Haitian people were severely affected with nearly 200,000 lives lost. The

Haitian authorities said the powerful quake destroyed most of the capital city of

Port-au-Prince. The Red Cross estimate 3 million people - one-third of Haiti’s

population were affected and 1,000,000 people were left homeless. Haitians

mainly live in shantytown dwellings, constructed from cheap locally-quarried

limestone, which were badly hit by the quake and this housing was levelled.

The Haitian Government estimated 250,000 residences and 30,000 commercial

buildings had collapsed or were severely damaged. The emergency services

were unable to cope in the event of a major disaster. Haiti is the poorest country

in the Western Hemisphere, worldwide Haiti is ranked 149th in 182 countries

on the Human Development Index. The damage and destruction caused by the

earthquake was exacerbated by Haiti’s dense population and lack of adequate

building standards.

The rebuilding period offers a great opportunity to protect lives and

communities from future disasters. Disaster relief organisations which supply

food, temporary shelter and healthcare in a time of crisis, are meant to be

temporary solutions. Although these shelters meet the urgent needs of today,

these short term solutions will not provide safe, secure and inhabitable

buildings. This paper touches on these temporary solutions, delivered by the

Haitian government which are likely to be in place for longer than intended.

ILLUSTRATIONS

Cover - Photo taken by Eduardo Fierra and Eduardo Miranda.

a Location and Plate Illustrations from C.V.R. Murty at Indian Institute of Technology

in Kanpur, India and NICEE - National Indian Center for Earthquake Engineering 04/02

b Photo taken by Eduardo Fierra and Eduardo Miranda. Copyright of NEES

FOOTNOTES

USGS – Earthquake Hazards Program http://earthquake.usgs.gov

Millar, Lisa (17 January 2010) “Tens of thousands isolated at epicentre” ABC News

“Red Cross: 3M Haitians Affected by Quake”. CBS News. 01/13/10

Red Cross Report. Quoted form a Red Cross report on January 15th 2010 Red Cross: 3M

Haitians Affected by Quake” CBS News. 13 January 2010.

Clarens Renois (5 February 2010). “Haitians angry over slow aid”. ‘The Age’ Journal

(Melbourne). 5 February 2010.

“Human Development Report 2009 Haiti”, United Nations Development Program- 13

January 2010.”UNICEF appeals for aid for Haiti following devastating earthquake”

“Human Development Report 2009 Haiti”, United Nations Development- 01/13/10.

Illustrations from C.V.R. Murty at IIT, India (a)

Photo taken by Eduardo Fierra and Eduardo Miranda (b)

5

Timber of Brick?

Choosing the appropriate material depends on the building purpose, budget,

soil type, occupancy and quality of the workmanship. In most cases lightweight

construction is safer than heavy modular building construction, for the

following reasons:

1) Single storey con� ned masonry houses with lightweight and � exible roofs,

can be well designed con� ned masonry buildings, which perform well in

earthquakes. However if brick buildings are designed and built poorly, they

can be deadly. Even a well built con� ned masonry building will probably have

cracks in a strong earthquake. Advice from a civil engineer for con� ned ma-

sonry buildings is advisable.

2) Gable wall construction is safer with timber or a hipped roof. Avoid masonry

in� ll which may easily crack, dislodge and crack during an earthquake.

3) In reinforced brick walls put horizontal steel reinforcement in every 7 course

bricks on top and below the frame. Brick walls also require minor concrete

columns on either side of the frame, which connects to the lintel beam on top

and below the frame. Timber houses need secure connections but require less

reinforcement because the lightweight material holds itself together more easily.

4) Foundations can be made from a heavy material like concrete, brick or stone.

But above 3 feet, it is strongly recommended to use a lightweight material,

particularly on gable walls, which are likely to collapse.

Environmental and Economic Factors in� uencing building material choices

From an economic perspective, timber houses make more sense in Haiti than

masonry. At the moment nearly 80% of the population live under poverty,

earning less than $2 per day. (CIA 2010). Food security is a chronic problem.

Environmental degradation exacerbates these troubles as deforestation of 98%

of the land area has left Haiti’s landscape eroded and its soil quality inadequate

for large-scale agricultural production. In 1925 there was 60% surface in forest,

in 1952 there was 18% left, and in 2006 there was 1.5% forest. From deforesta-

tion there is soil erosion, which reduces agricultural production and the ability

to grow food. Deforestation also causes soil sedimentation in the Lac de Peligre

reservoir and lost 30% of the drinking water capacity. In Gonaives City in

Haiti there was a tropical hurricane which caused mud sliding. Natural energy

resources are 75% Wood, 15% Petroleum and 5% hydroelectric power. There

have been ecological impacts from large scale deforestation.

FOOTNOTE

CIA. 2010. “Haiti.” The World Factbook. Retrieved April 19, 2010

(https://www.cia.gov/library/publications/the-world-factbook/geos/ha.html).

Guidelines for seismic-resistant building methods

Forces affesting a unreinforced brick masonry wall

How a masonry wall breaks

Forces affecting buildings in earthquakes: L,S, and P waves

6

The Earthquake Recovery

Since the Haiti Earthquake on January 12th 2010, there has been a coordinated

short-term aid effort. In the long-term NGOs have been working to restore the

country by building better infrastructure including water, power, roads,

buildings, schools and hospitals. Development in Haiti should incorporate in

sustainable energy, better government and policies, a functional healthcare,

education system and an improved economy. One NGO ‘Rebuilding Haiti

Now’ focuses on rebuilding Educational institutions. ‘Rebuilding Haiti now’

organisation selects school projects in Haiti further from Port-au-Prince, hard

to reach, and therefore last to receive help. There is social and economic impact

from these projects to rebuild schools, with a long-term impact on the local

community. Improvement of know-how in building techniques under the

leadership of recognized Haïtian professionals. Buildings should use local

workmanship and local materials for each site repaired.

Challenges to Rebuilding

Leadership and Government

The earthquake completely destroyed 13 of the 15 main government buildings,

leaving the country’s leadership without a � rm place to govern from. Politicians

were displaced and they had lost all of the demographic population data,

geographical maps, census records, records of other of� cials and policy

documents. People were left without a government at the time when they

required leadership the most.

Homelessness

One million people were left homeless without their possessions.

Camping grounds were erected by international aid agencies, to provide

immediate temporary housing. There is a drastic need to rebuild houses, to

provide shelter from tropical storms and to prevent disease from spreading.

Healthcare

There were 300,000 injuries and 220,000-250,000 casualties. Most of the

Haitian hospitals had collapsed with all patient documents inside (dental

records, blood type, age, immunode� ciency records, vaccination and insulin).

The existing healthcare infrastructure was in a very poor situation before the

earthquake. In the rescue plan there should be adequate help for orphans,

who may have last their parents and have been separated from their immediate

family.

7

The Human Cost

Aside from the economic impact which can be overwhelming, the human

impact is all to often not adequately accounted for in policy and accountable

government actions. The disaster damaged food kitchens, hospitals, police,

� re engines, which has a recurring human impact one year later. Fresh water

becomes contaminated quickly and on the small Haitian island surrounded by

oceanic salt water, dehydration can quickly lead to further casualties.

Immediate care is needed to stop wounds becoming infected, bone fractures to

be cast and adequate services for longer term concussion.

Fatalities are often collected on lorries and deposited in large un-named graves.

Some casualties were unrecognisable and the dental records had been lost

leaving no means to identify those lost. Haitian people have showed

tremendous resilience to carry on without their loved ones. School children

loose out on their education or face considerable delays in completion of their

course. Often these children have lost one or both of their parents, so their

family life is often in domestic turmoil. Aid agencies may provide a service for

young people to have a friend to talk to or be supported by.

If someone is injured in an accident, they may not be able to work in their

former occupation and be made unemployed. For a father an occupational

disability, can be devastating for his family. Social security from the public

government has been neglected by political instability, poor leadership and a

lack of personal accountability at the top.

Sanitation and toilets are important considerations for a sensible

reconstruction. People need clean water and composting toilets, to stop disease

spreading in overcrowded refugee facilities. Composting toilets are relatively

simple to build and maintain. The safe use of human waste as agricultural

fertiliser is strongly encouraged. This practice has been widely used in Sweden,

China and parts of Africa.

The government needs to commit to educating Haitian citizens in the

long term to allow their people to enter formal work, with basic analytical,

writing and word processing skills. The United Nations has tried to foster

a self-sustaining state in Haiti, between 1994-2004 before the departure of

President Jean-Bertrand Aristide on 29th February 2004. Policy remains

detrimental to the immediate needs. The international community wants a fair

democratically elected government, to reduce corruption and embezzlement of

aid money. Meanwhile the people most in need remain forgotten.

UN Peace Operations: A case study of Haiti(New York;2009:UN Press)C.T.Call

Red Cross Hospital Building in Port-au-Prince

Car trapped under a soft story

Child separated from her family

8

Assessment of Damage

Residents often fear reoccupying their home after the structure has been

compromised by and earthquake. Damage is best measured by inspection form

a team of building engineers and architects, to determine the damage and

column de� ection. A recently issued report notes the “complete absence of

seismic detailing in Haitian construction, from informal housing to recent

multi-storey buildings in downtown Port-au-Prince” (Fierro and Perry 2010:4).

The report concisely explains how much damage was avoidable if standard

concrete codes were followed to greatly acceptable rigidity in moment frames.

Debris and Rubble Clearance

There is a considerable amount of waste aggregate, broken street furniture

and roof tiles which need to be removed, for space for new houses to be built.

International aid would prefer not to fund this less glamorous rubble-clearance

activity although it is essential, to simply provide a high numbers of houses.

Accountable development is not just linked to the number of houses built, but

how they are built and intelligent reuse of left over material.

Leadership without infrastructure

The central Haitian government was equally unprepared for the earthquake,

which had catastrophic impacts on rescue efforts, communication and

international aid coordination. The bottom-left image shows the Parliament

where the President normally organises the country. On January 12th 2010,

when the country was in need of hard decisions being made, the government

could not give the necessary leadership. Searches for survivors, drinking water

and medical services were dif� cult to address.

The role of the NGO

Non-governmental organisations are powerful groups who can avoid

bureaucracy and build homes for Haitian people in need. Clean sanitary housing

is a priority, with an emphasis on implementing safe seismic-resistant codes to

prevent unavoidable future earthquakes. NGOs are independent from the

corrupt government, so international � nancial donations are safer when send

directly to an NGO registered with Habitat for Humanity.

Historic damaged structures: Repair or Rebuild?

Damaged architecture with cultural signi� cance should not be pulled down

immediately but reserved until after the urgent rebuilding and human

necessities are taken care of. At a later time with stable leaders, conservation

or demolition can be discussed and decided by the people.

Ministry of Justice Courthouse

Historic Building Damage

Ministry of Agriculture

Parliament of Haiti in ruins

9

Soft storeys

Soft and weak stories in houses, are often used in domestic parking spaces. The

primary cause of collapse is broken structural load paths between the ground

and upper storeys. Lower storeys are particularly prone to collapse, if proper

reinforcements are not installed. Heavy base materials can be used, with lighter

materials higher up the building. Foundations and the lower portion of the

� rst � oor can be made from a heavy concrete or masonry material. For low to

middle rise un-reinforced masonry (URM) buildings without vertical stiffness

or strength discontinuity, � rst story in� ll walls are expected to be damaged � rst,

since they are subjected to the highest sheer forces. In some cases, collapse of

the whole story may occur, if the columns were damaged and reoccupied with-

out a comprehensive survey taking place � rst.

Rebuilding the damage and length of time to reoccupancy

Rebuilding in Haiti is dif� cult to approximate. After the Loma Prieta (1989)

and Northridge (1994) earthquakes, “the typical repair of damaged... wood-

framed residential multi-family residential buildings required two years and

building replacement required almost four years.”(8) Reorganising the

rebuilding effort, requires considerable organisation from the top to achieve

success like the Mexico 1985 earthquake (8.1M) where there was a uprising by

Lembrino, spurred the Mexican government, aid groups and activists to build

100,000 housing units and rehabilitate the domestic infrastructure in less than

two years.(9)

Rehabilitation of Existing buildings in Haiti

Rebuilding is often cost prohibitive for many Haitians. Existing infrastructure

can be rehabilitated without comprehensive demolition. New building is

necessary in many cases, where the poor construction let to high out-of-plane

de� ection.

8. ‘Estimated Downtime from Data on Residential buildings after the Northridge and

Loma Prieta Earthquakes’ Earthquake Spectra Volume 26, Issue 4, pp. 951-965

(November 2010) Written by Prof. M.C. Comerio & H.E. Blecher, with PEER

9. David Ovalle writing for the Miami Herald ‘Mexico’s earthquake recovery could be a

model for Haiti’ 02.17.10

Heavy building collapsed ontop of a soft story in Port-au-Prince

Discontinuous sheer walls are weak in lateral forces.

Drawn by M. Kelly

Occupying the lower soft story � oor is very dangerous

10

Design of masonry blocks - how to avoid Unreinforced Masonry Walls (URM)

The design of a wall in a seismic area requires some connections between

elements, for lateral stability. Loads are transferred between structural elements

which could become displaced by sheer. In concrete blocks the reinforcements

can be concealed inside the concrete cavity.

Roof principles in earthquakes

The design of roofs is important for the safety of occupants. Light roofs on

higher levels are less dangerous in the event of a collapse. Heavy roof materials

should be avoided.

Connections between � oor and ceiling

Secure attachment of roofs to walls, and walls to � oors successfully transfer

forces between building elements. Reinforcement bar-bending and anchoring

should � rmly connect the columns and beams together, especially at the top of

the column and the ring beam. Use steel reinforcement to connect the masonry

wall to the column tie. Strong connections between the structural elements and

� rm tectonic attachments are the key to a successful seismic frame.

Attachment of roof to wall

Lateral forces from a slip-slide earthquake can be ef� ciently tackled by

attaching the roof � rmly to the perimeter walls. Horizontal forces are

transferred into the building elements, with connected load paths. Elements

attached: roof and wall. Continuous, properly connected load paths are

essential for good vertical and lateral loads on housing structures. Steel

connections are used between building elements to tie trusses to cavity walls.

Coordination between seismic researchers and workmen to share information

on stable structures and work together to build safely. In Haiti the majority of

the buildings were constructed out of necessity.

Steel bar in concrete, if it is tied together properly can be very effecient at

creating a moment frame. The � oor and wall reinforcement should be bonded

together at the same wime for a strong connection.

Pencil drawing by Mark Kelly

The

The

“Careful thought to the plan and layout can improve

earthquake resistance at little or no extra cost.”

Elizabeth Hausler, PhD 2006: Build Change Build Earthquake Resistant Houses; change Construction Practice

12

Selecting a Site

Liquefaction of the soil under the building, is one of the largest contribut-

ing factors to building collapse. Liquefaction is caused when the strength or

stiffness of soil is reduced by high water saturation in soil, sand and clay. Poor

drainage and � ooding on the soil around a building, often weakens the

structural capacity of load bearing walls. When selecting a site, avoid weak

soil which is loosely compacted with high sand content and land where the

water table is higher than average. When the house shakes on lique� ed soil, the

foundations which are responsible for resisting the ground shaking, cause

settlement of the house, which can result in cracking or collapse. Find a new

site for your new home with solid earth.

Timber is a good material because it is � exible and lightweight. Weak soil can

be improved with a cement addition, known as ‘densi� cation’ which is costly

and material intensive. Distribute the building load evenly and span loose spots

using a reinforced concrete raft foundation to avoid weak isolated pile footings.

The Nigata earthquake in Japan (1964) caused serious collapse because the soil

was weak and sandy.

It is strongly recommended to get a detailed soil investigation, before starting

any building construction. In Haiti, where there are stringent economic

constraints, there are simple tests builders and NGOs can perform prior to

construction.

1) Dig a hole on the site, large enough for a septic tank to determine the depth

of the water table and the soil type.

2) To check the soil sedimentation to estimate soil content of clay, sand or silt;

simply upturn a � lled a bucket of soil and measure the slump. Similar tests

should be carried out on soil in several sites before a decision is made.

3) An expansion test can measure how much the clay shrinks when it dries. To

perform this expansion test, simply collect a container of soil and measure the

volume at the beginning and then re-measure the volume after seven days. If

the soil volume measurements are similar, then the soil is good to build upon.

However if there is a reduced soil volume in the container, the clay moisture in

the soil has evaporated and cracking around the foundations is highly probable

due to moisture expansion.

Liquefaction

Diagram of Liquefaction by Benjamin Schlue, PhD, Marine Engineering

Geology, University of Bremen

In Oakland and San Francisco, liquefaction occured in 1989 Lona Prieta E.Q.

Non-structural damage often occurs with liquefaction

13

Wood Buildings

Wood buildings are known to perform well during earthquakes. Wood has a

high strength to weight ratio and therefore wood buildings tend to be lighter

than other building types. Lightness is an advantage during an earthquake. Of-

ten connections in wood houses are nailed together which allows the building to

� ex. Movement allows the building to absorb and dissipating energy during an

earthquake. Some plywood structural panels create sheer walls in combination

with studs and joists to form a diaphragm, which is very effective at resisting

lateral forces and gravity loads.

Ground movement caused the most failure in timber buildings, the follow-

ing components of wood-frame construction are critical to help resist against

seismic forces:

1) Anchorage to the foundation

2) Strength and ductility of the walls

3) Strength and continuity of the horizontal � oors, roof and ceilings

4) Interconnections of all the framing elements

Timber walls should be designed to resist lateral loading in earthquake forces.

Stud walls can be braced with diagonals and board to provide sheer resist-

ance. Plywood laid over the top of stud walls should be thick enough to resist

calculated forces. Ensure there is adequate nailing (at 50mm centres and over

intersections) ti transfer the sheer forces in the sheathing to the roof, � oor and

wall framing. The framing members around the perimeter of the diaphragms

should be strong enough to resist calculated tension and compression forces

with base shear anchor bolds into the � oor.

To prevent the collapse of timber houses like in Northridge and Loma Prieta,

the Canadian Engineered Wood Association (APA) recommend using base

shear anchor holts and a thick wood board over the timber stud wall to create

a self-bracing shear wall, for lateral and gravity load resistance.

FOOTNOTE

Canadian Wood Council (2003: Ontario; CWC) Wood frame Construction:

Meeting the challenges of Earthquakes. Building Performance Series No. 5

14

Masonry Wall Skirt

Above the foundations of a timber building, the base can be made from

masonry. Up to around 80 cm, bricks can be laid above the foundation for a

solid building base. One advantage of this masonry skirt strategy is to reduce

damp from entering the building and wall construction, where puddles may

otherwise enter the building from capillary action. Extending the foundation

above ground, does not compromise the seismic properties of the lightweight

structure above. It is important to keep the timber structure dry and protect it

from the open wind and rain which may compromise the structural

characteristics. Hybrid construction with wood-masonry skirts, combines the

material advantages of a solid masonry base for the lightweight timber house to

rest upon.

The sturdy timber frame which rests on the masonry wall skirt needs a selection

of good quality wood. The carpenters in Haiti should visit the timber yard to

select straight wood without knots, splits and avoid warped and twisted wood.

The joints between the lengths of wood should be fastened with two pins. Using

a masonry skirt lifts the building off the ground and away from water. Paint the

entire frame with preservative before installing walls and windows.

Use bricks, blocks or stone masonry to build a masonry skirt wall. The timber

should be connected to the masonry wall with nails. The walls can be rendered

with plaster (one part plaster and three parts water), and tightly attached to

timber backing boards.

The second photo on your left, shows a hipped roof (a square-based pyramid)

which does not need a gable wall, which can easily be damaged in an

earthquake.

FOOTNOTE

Canadian Wood Council (2003: Ontario; CWC) Wood frame Construction:

Meeting the challenges of Earthquakes. Building Performance Series No. 5

Masonry wall skirt with timber widows

Cheap hoouse with masonry wall skirt to 80cm

Sturdy wood joints � xed with two pins

Connection with wood joint

15

DESIGN: The Plan

Simple building plans, with ample sheer walls to provide strong resistance

against lateral loads behave well in earthquakes. Design of houses should be

kept simple, for three main reasons, it is cheap, standard sized pieces are easier

to � nd and housing will be easier to build which means more people will build

permanent houses for themselves and their families. Small and often

inexpensive design adaptations in design, can make a structure resilient. As

Haiti looks at how it may begin rebuilding its towns and cities, concern arises

on how to best design to resist these immanent and inevitable natural disasters.

Plan the con� guration to build a house in a common shape, like a square, short

rectangle or circle. In the gable wall avoid using brick, use either timber or

another lightweight material instead. Above openings use a beam or lintel and

reduce openings with regular support. Roughly equal plan dimensions increase

lateral stability. Avoid long narrow structures with a low surface area, and try to

think about where the center of gravity lies and design accordingly.

Bungalows fare better than multi-story dwellings, try to reduce height and

connect the columns together. Ideally the building should behave as one body,

with tectonic elements closely linked together.

Every length of wall more than 4 meters should be a cross wall or brace. It is

recommended to avoid using heavy material and using a simple, square

symmetrical layout. Avoid using long narrow structures, where the length is

longer than three times the width of the building. Walls longer than 4 meters

should be crossbraced with steel reinforcement.

Continuous long sheer walls connecting exterior faces are better than bent short

walls, with unsupported clear spans. Regular support along long spans adds to

lateral stability in strike-slip earthquakes with bidirectional seiemic activity.

Simple isometric by M. Kelly showing � oor, gable, wall and roof

Poor concrete connections behave poorly in Haiti

Optimum seismic-resistant � oor plans table. (Sheer walls in heavy)

16

Non-Structural Damage and Concrete Frames

After an earthquake, the recovery time is closely linked to the non-structural

damage in housing, shops, transport hubs and of� ces. Fittings, ceiling tiles,

bookshelves, glass and � nishes are often completely destroyed by the lateral

shaking, even though the concrete structure may not have sustained damage.

There can be considerable expense linked to broken building � nishes and for

commercial properties there is also down-time in trading to be accounted for,

when wages and overheads may loom over the owner. In a reconstruction strat-

egy for Haiti, I think we should pause brie� y to talk about � xing of furniture

and non-structural elements which are at high risk, for example bookshelves

and laboratory glass tubes could break.

Museum items and vulnerable objects can be � xed to a solid surface to reduce

unnecessary breakages.

Openings around the exterior of houses reduce the overall stability in an

earthquake. Walls with openings which are not con� ned masonry reinforced by

concrete columns and beams, are very vulnerable. Regular or large openings

make walls much more vulnerable than walls without windows and doors.

Reducing weight and improving connections

The reasons for failure often include a heavy masonry gable which collapses.

Connections between the column and beam are not strong enough. Avoid using

prefabricated columns which may be strong but cannot connect well to the rest

of the structure. Prefabricated elements are individual rigid components which

often do not connect well ring beams. Beams should be � rmly connected to the

main building and tied often, wherever possible.

c

m

R

Reinforced Concrete frame in Port-au-Prince suffered joint damage

Wall and roof elements need to be securely attached. Illustrations by Mark Kelly

An intact frame sustained only non-structural damage from good connections

17

Timber Connections

Timber connections and anchoring are very important for seismic resistance

against lateral forces. The choice of timber has a big impact for the quality of

the building construction and must be matched to the function of the timber

building element. Choosing timber effeciently and sized for the right purpose

can save money and make the building much safer. The best timber

characteristics to look out for are wood with no splits or cracks, no knots, no

warped or purved pieces and preferably Timber Grade I or II.

Timber should be weatherproofed to increase the lifespan and structural

performance of the structural members. I recommend two coats of a tested

wood seal.

Minimum standards for Building a Timber House

1) Choose good quality timber

2) Dimensions of foundation: 25 x 40 x 50 cm

3) Use preservative paint

4) Pour concrete on column footing and give anchor

5) Use anchor on wall masonry

6) Every timber connection should have a proper joint

7) Every connection should have a wooden peg or nail

to secure joint

8) Must have diagonal bracing on every corner

9) Scarf joint for beams

10) Nail the wire to the frame � rmly and stretch tight

11) Plaster and mortar mix 1:3

12) Truss Connection

13) Wind Bracing 40 4” nails Tenon

FOOTNOTES

Earthquake Resistant Design and Construction Guideline, 31st May 2006.

Elizabeth Hausler, PhD 2006: Build Change

Wood corner connection showing a ‘dowel pin’ to secure each intersection

The author building a horizontal seismic wood brace in Northern India, to

prevent against lateral shaking in a con� ned masonry wall with a square plan

with Tibet Heritage fund NGO, sponsored by the AIA Noel Hill travel award.

1. Simple scarf joint connection used for the purlin, it can only resist com-

pression (pushing) load but cannot resist tension (pulling) load

2. Hooked Scarf Joint is better because it can resist both compression (push-

ing and tension (pulling) load.

3. Hooked (Half Lap) Scarf joint is also good because it can resist both

compression and tension and it is easy to make.

4. Flared Tennon Butt Joint is common in fascia board because it can hold

compression (pushing) and tension (pulling) loads.

5. Scarfed Butt Joint is also common in fascia boards because it can resist

compression (pushing) and tension (pulling) loads.

18

Foundations

To build foundations correctly to code, Haitian self-builders need to follow

some basic rules. I am writing on the premise that base isolators are too

expensive for the average home, so I am describing a good rigid foundation

with well bonded connections to the rest of the house.

Make the bottom � at and level and remove any organics like tree branches from

the foundation trench. Remove loose soil and rainwater. Avoid building below

the water table and keep away from expansive soil

For a stone masonry strip footing the builder should lay the stones � at and

� ll the gaps completely with mortar (sand and gravel mix). Craftsmanship is

important, so if good masonry workmanship cannot be ensured, consider using

a reinforced concrete strip footing.

The aggregate should not be too � ne or too rough, a sand like consistency is

preferred. If the stones are clean, without organic waste in the mixture, the bond

will be improved in the cement.

The rebar steel anchors should be placed in the foundation at intervals of 1.5

meters and at the locations of all columns. It is okay to use recycled rebar,

without too much rust, if the bars are at least 10mm diameter and ribbed, for

better adhesion to the concrete mix. The bend should be at least 10cm from

the end of the reinforcement bar. It is important not to leave the column bars

exposed to the air, where they can corrode and become rusty which can spread

through the column and weaken the structure.

The minimum depth of foundation trench excavation should be 80cm. If weak

soil is common in the area, the foundations should go deeper as the depth

depends on the soil type.

The concrete mix should be lean to make the screed � oor (1 cement: 3 sand:

6 gravel). the screed � oor will create a solid even surface. The thickness of the

� rst layer of screed should be 10cm.

FOOTNOTES

Earthquake Resistant Design and Construction Guideline, 31st May 2006.

Elizabeth Hausler, PhD 2006: Build Change

“For decades, structures have been built throughout the country

without regard for the simple, often inexpensive design features that

would make them more resilient to these inevitable disasters..”

Michelle Flagg “Strengthening Foundations: The Sustainable Design of a Youth Center in Haiti”

20

Buildings in Haiti which survived

It is useful to mention buildings which behaved well in Haiti, as well as those

which collapsed. A single story building is safer than a two story buildings.

Higher buildings generally are less stable, due to the higher center of gravity.

The church on the left is a light weight timber structure which survived in good

condition. The red concrete of� ce building below is roughly the same height,

but built from heavy rigid materials with less ductile connections, higher joint

stress, redundancy of concrete or poor concrete mixes and maybe poor

quality construction. These factors may have caused the split columns. The

middle building has an overhanging story which is not advised. The rubble you

can see on the street is likely to be from another nearby building, which nobody

is taking responsibility to clean up. Steel reinforced brick buildings have a

higher construction quality, with higher grade materials and knowledgeable

craftsmen. Shown in the fourth photo, this reinforced-brick house sustained

very little damage.

Two story houses should include the following earthquake proof measures

- Build the second story out of timber

-Use con� ned masonry with strong connections

- Use lightweight in� ll for the walls, especially the upper sections

- Join all elements of the frame together

- Columns and Sheer walls should tough the ground, to prevent weak storeys

- Masonry in� ll on reinforced concrete frames can create falling street material

- Parapets above the gutter can fall and hurt people, adequate support is needed

- Avoid URMs (un-reinforced masonry buildings)

Lowering the buildings’ center of gravity is

important in an earthquake, when base isolation

is too expensive. Taller buildings generally

behave poorly with lateral forces, when structural

members are subjected to tension and compression. 2 storey building

Simple, symmetrical low square plan buildings

behave well. Mosques are excellent because they

are symmetrical and their clearstory are lightweight.

1 storey building

FOOTNOTES

Earthquake Resistant Design and Construction Guideline, 31st May 2006.

Elizabeth Hausler, PhD 2006: Build Change

l

on. 2 storey building

y

ght.

1 storey building

21

Case Study : Builders without Borders and Build Change

Building within local resources, technology and means is perhaps the most

challenging aspect of rebuilding Haiti. In brick buildings, use a minor concrete

column on either side of the frame. Make sure the brick wall and column are

connected well to the plinth beam and ring beam. Where possible use a

reinforced concrete lintel beam on top and below the frame, connected to the

columns.

In strawbale houses, timber performs the same role as concrete frame in brick

walls, providing stiffness and connecting all the strawbale elements together.

From an engineering perspective (Henri Mannik P.E.: Builders without Borders;

2010) a plastered strawbale wall is a composite system in which the strawbales

are only one component. “The inner strawbale core, the outer stiff plaster with

reinforcing and wall ties all work together as a structural assembly. One that

yields impressive results as a gravity loadbearing and lateral load resisting

system, all from simple and accessible materials such as earth, straw, twine

and wire.” A plastered strawbale is both a “stressed skin panel” and a “natural

structural insulated panel.” Timber frames are used not to suspend the strawbale

but to form a connected frame tied to the lightweight roof purlins.

Creating a market for rice-straw as a building material in Haiti, would create

jobs and avoid burning the straw every year which is the currently the practice

in Haiti.

Plastered strawbales offer an optimal balance of thermal insulation,

mass and comfort. In the daytime Haiti’s tropical climate requires little

insulation against heatloss, yet the straw shades the interior and keeps excessive

heat away from the interior. At night the temperature swing can be limited by

strawbale insulation and a light clay-straw layer above the tin ceiling, provides

an insulating barrier against radiant heat from the roof. A plastered strawbale

can be treated and rendered with a clay-cement plaster to be � re-resistant

enough to withstand 1-hour to 2-hour � re tests at ecobuildnetwork.org.

The purpose of this section, is to suggest innovative materials which may be

climatically appropriate, affordable and available. Permanent housing is a

number one priority in Haiti, to create a ‘new normal way of life’ because

things will never quite return to the way they were before the earthquake.

FOOTNOTE

A Straw Bale Rebuilding Solution for Haiti; Building Back Better Communities

Under the Auspices of Builders Without Borders. Martin Hammer

22

Permanent housing for Haiti

There is an NGO called Builders without Borders, who drew the designs on

the left for a straw-bail house for Haiti. Straw was chosen because is widely

available and it naturally will be � exible in biaxial earthquake forces. The

technology is straightforward enough for a Haitian to construct his own house.

Strawbale construction offers many signi� cant advantages as a semi-urban

building system in Haiti. Housing needs to protect the building from direct sun

radiation, avoid creating additional humidity and create natural ventilation for

air movement. The advantages of using stawbale housing in Haiti are:

1) Low Cost. The design drawings on the bottom-left show a 3 meter by 5 me-

ter (interior dimensions) cost $1500 for materials plus 20% for labour. A larger

house with two bedrooms costs approximately $2400 plus 20% labour. which

is $5USD per sq.ft. or $53USD oer sq.m. The � gures are taken from Pakistan ,

were a similar-sized reinforced concrete block building cost approximately two

times more than a strawbale house.

2) Earthquake resistant results have been successful in laboratory testing (12),

with an internal plaster render and wall ties (large steel pins) to connect faces of

the construction closely together.

Simple construction techniques and good buildability is important, to create

many simple modular houses to replace the tent camps where people have

been living. Fresh air, clean water and sanitation help considerably in reducing

diseases like Cholera from spreading.

FOOTNOTE

Ti Kay Pay: A Straw Bale Rebuilding Solution for Haiti; Building Back Better

Communities. Research refered to at University of Illinois, California State

Polytechnic and University of Nevada.

Existing Reinforced Concrete frame in Port-au-Prince suffered joint damage

Straw houses in Haiti will naturally be ductile and � exible enough in an E.Q.

In Pakistan a new straw house being built

Straw houses in California

23

Respecting cultural differences

Let us not forget we should respect the local people’s culture, customs and

traditions. In Creole building design, bright pastel colours are accepted and

identify the place. Home builders will � nd their houses work, when they adopt

characteristics which identify the place. Sustainable building in Haiti, will be

kept for generations to come, tradition should not be trivialised. If Haitians

build or paint their houses for themselves, people become encouraged to build

more and recover faster in the face of adversity. “Certain colours and

decorative elements can have speci� c meanings and signi� cance. Consciously

and skillfully employed, they can enhance the legibility of the environment”

(Martin Hammer; San Francisco: 2010 Writing on Haitian Creole). The opti-

mism of the Haitian people is strength, these types of cultural designs create

encouragement and help the people re-imagining their own cities future.

Individuality and the ability to customise a simple house with coulourful paint,

may give encouragment to continue to rebuild more and spark momentum.

If Haitian people build their own future homes, pride in their family’s future can

re-grow and the community can rebuild itself. Habitat for Humanity has

developed a standard house, without local materials which will probably be

there for longer than expected. I advocate using Haitian timber and local

strawbales, to create jobs and use a local material which people can reproduce

themselves at a very low cost.

FOOTNOTE

Building Back Better Communities

Under the Auspices of Builders Without Borders. Martin Hammer

Photo by Hydro Cabos

Cao Hatian Doors, photos by mary Ellen Andrews

“Every dollar spent on mitigation can result in a saving of 4 dollars in

recovery cost.”

Henry L. Green, Hon.AIA President writing to Secretary of State, Hilary Clinton

Information from the National Institute of Building Sciences, Washington D.C.

25

Conclusion

Haitian people face an uncertain future. Permanent housing development should

remain at the top of the agenda, to allow people to settle into a new permanent

way of life. The primary aim is to provide a resilient community, constructed

by the Haitian people using indigenous materials and knowledge dissemination,

so the housing is ultimately sustainable. In an EERI-NSF rapid and research

needs workshop, an interesting obstacle to rebuilding arose: “Understanding

the particular motivations behind corruption and developing innovative incen-

tives to prevent it, is another highly important research topic that can help lift

many of the barriers for sustainable rebuilding of Haiti.” Haiti’s built

environment, speci� cally its lack of adequate building materials, practices and

codes to endure severe natural disasters and complacency about earthquakes,

led a perilous chain reaction.

Rebuilding the country and creating jobs to sustain the infrastructure some

major challenges: Haitian leadership to create and implement a regeneration

plan, building houses and clearing the rubble, containing Cholera outbreak,

fresh water delivery, encouraging education and making jobs. The international

aid is temporary, permanent infrastructure needs to begin immediately with

local materials and local labour. NGOs can play excellent roles as building

educators to teach local people good practices in the built environment.

The Haitian people have shown temendous resilience and strength of character,

during the disaster. The aim of this paper has been to raise key building issues

which can increase the safely at little or no extra cost, early in the

reconstruction process.

26

Bibliography

FEMA document ‘Homebuilders’ Guide to Earthquake Resistant Design and

Construction’ FEMA232 – June 2006 US Dept of Homeland Security; National

Institute of Building Sciences Washington D.C.

‘Estimated Downtime from Data on Residential buildings after the Northridge

and Loma Prieta Eaarthquakes’ Earthquake Spectra Volume 26, Issue 4, pp.

951-965 (November 2010) Wtitten by Prof. M.C. Comerio & H.E. Blecher, with

PEER

Masonry Details, FEMA499 ‘Home builders’ guide to Coastal Construction’

August 2005 Technical Fact Sheet No.16

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ings’ Federal Emergency Management Agency May 1999 Applied Technology

Council: California

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Successful Risk Reduction Programs’ October 2009

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ENGINEERING IN INDIA” Written by Sudhir K JAIN and Navin (2000) C

NIGAM Professor, Department of Civil Engineering, Indian Institute of Technol-

ogy, India, Email:skjain@iitk.ac.in

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Architecture for Humanity

The 2010 Haiti Earthquake: Challenges and Opportunities for a Resilient Sus-

tainable Haiti. Professor Reginald DesRoches, PhD. Georgia Institute of Tech-

nology (2010: Georgia)

Earthquake Resistant Design and Construction Guideline, 31st May 2006.

Elizabeth Hausler, PhD 2006: Build Change Build Earthquake Resistant Houses;

change Construction Practice Permanently

Earthquake Resistant Design and Construction Guideline, 31st May 2006.

Elizabeth Hausler, PhD 2006: Build Change Build Earthquake Resistant Houses;

change Construction Practice Permanently

Ti Kay Pay: A Straw Bale Rebuilding Solution for Haiti; Building Back Better

Communities. Under the Auspices of Builders Without Borders. Martin Hammer

27

Bibliography

Haiti Regeneration: Creating an exemplar community of cottages and townhous-

es, Utilizing Haitian Creole environmental patterns. (Published in July 19th 2010

in San Francisco: Builders without Borders) Alliance of Haitian and International

environmental design professionals led by Frederick Mangones Architect

Henry L. Green, Hon.AIA President Letter to Secretary of State, Hilary Clinton

Information from the National Institute of Building Sciences, Washington D.C.

Meeting minutes from EERI-NSF rapid and research needs workshop;

Sustainability and Capacity Building led by K. Mosalam and A. Ta� anidis 2010

Fierro, Eduardo and Cynthia Perry. 2010. Preliminary Reconnaissance Report-

12 January 2010 Haiti Earthquake. Retrieved April 20, 2010

(supersites.unavco.org/Haiti_Reconnaissance.pdf).

UN Peace Operations: A case study of Haiti (New York;2009:UN Press)

Charles T. Call: New York University

CIA. 2010. “Haiti.” The World Factbook. Retrieved April 19, 2010

(https://www.cia.gov/library/publications/the-world-factbook/geos/ha.html).

Damage Assessment Using Laser Scanning after the January, 12, 2010 Haiti Earthquake

Khalid M. Mosalam,a) M.EERI, Shakhzod M. Takhirov,b) and Mark Kellyc)

This paper focuses on using laser scanners capable of measuring large objects.

High definition laser scans have many advantages and have been successfully

used to assess structural damage in earthquake engineering laboratories. This

paper is the first attempt to demonstrate the use of this technology in the field. On

July, 2010, a reconnaissance team to Port au Prince, Haiti, scanned an array of

structures, mostly buildings, at different states of damage and obtained laser scans

together with conventional and panorama photo imagery, to allow the creation of

a combined database of photo images and laser scans. This unique deployment of

field measurements using laser scanning provided a benchmark for image-based

remote sensing evaluation and future advancement in damage assessment of

structural systems. The techniques of gathering and disseminating critical

information employed in this paper is expected to have a major impact on future

earthquake engineering reconnaissance in the US and worldwide.

INTRODUCTION

Haiti is located off the south-eastern tip of Florida. A very large earthquake hit Haiti on

January 12th 2010, Moment Magnitude Mw = 7.0 (USGS 2010). The epicenter was near the

town of Léogâne, approximately 25 km (16 miles) west of Port au Prince, Haiti's capital. The

earthquake occurred at 16:53 local time (21:53 UTC) on Tuesday, 12 January 2010 (Millar

2010). In 12 days after the earthquake, there were 52 aftershocks measuring 4.5 or greater

(Red Cross Report 2010). The Haitian people were severely affected with more than 200,000

lives lost. The Haitian authorities said the powerful quake destroyed most of the capital city

of Port au Prince. The Red Cross estimated 3 million people, one-third of Haiti’s population,

were affected and 1,000,000 people were left homeless (Red Cross Report 2010). Haitians

mainly live in shantytown dwellings, constructed from cheap locally-quarried limestone,

which were badly hit by the quake and this housing was leveled. The Haitian Government

a) Professor & Vice Chair, 733 Davis Hall, Civil & Env. Eng. Dept., Univ. of Calif., Berkeley, CA 94720-1710 b) Senior Development Engineer, Pacific Earthquake Eng. Research Center, Univ. of Calif., Berkeley c) Graduate Student, Architecture Dept., University of California, Berkeley

estimated 250,000 residences and 30,000 commercial buildings had collapsed or were

severely damaged (Renois 2010). The emergency services were unable to cope in the event

of a major disaster. Haiti is the poorest country in the Western Hemisphere, worldwide Haiti

is ranked 149th in 182 countries on the Human Development Index (UNDP 2009).

The cause of the earthquake is based on the strike-slip fault system which has two

branches in Haiti, in relation to the North American plate and the Caribbean tectonic plate.

The strike-slip fault system occurred between the Septentrional fault in the north and the

Enriquillo-Plaintain Garden fault to the south, which had been locked for 250 years and

gathering stress. The rupture was roughly 65 kilometers (40 miles) long with a mean slip of

1.8 meters (5.9 feet) (CIRES 2010).

After the Haiti earthquake on January 12th 2010, a team of engineers from the University

of California, Berkeley, Stanford University, and BFP Engineers, Inc. visited Port au Prince,

Haiti to record the building damage using laser scanning technology. This is the first time this

laser scanning technology has been used for post-earthquake data collection. After the

earthquake several structures were in different states of damage with varying residual

deformation. The team focused on some of these structures to record their residual

deformation using a laser scanner, which estimates position of surface points and allows

creating a three-dimensional (3D) point cloud for subsequent analysis, to calculate these

residual deformations. The ScanStation2 laser scanner can record data to an accuracy of 4.0

mm from up to 100 meters away. The 3D point cloud data has been analyzed in Cyclone

(Leica 2006) and Matlab (MathWorks 2007) followed by mapping into Google Earth (KML

Reference, 2010) where results can be made public and accessible. The reconnaissance team

collected data in a combined database of photos and laser scans. In addition to the laser

scanning tasks, the reconnaissance effort included high resolution image acquisition

including 3D panoramic view of the damage sites. All information is analyzed and organized

in a searchable database and is available to the engineering community on the Internet.

The team traveled with the laser scanning equipment to scan an array of buildings in

different damage states. While collapse is obvious to the naked eye, it is often difficult to

discriminate between lesser damage states. The team scanned the structures in one city block

of Port au Prince previously surveyed by taking aerial photos and by members of the team

who used on-the-ground surveillance immediately after the earthquake. In the course of five-

days of field work, many types of structures, mostly buildings, were scanned, including a

residential building, a hospital, a school, a church, a commercial building used by a bank, a

hotel, a bridge and many others. The total number of scanned objects exceeded 20 with

various damage states. One of the objectives was to demonstrate that the high-definition

laser scanning would be an appropriate way to correlate damage from aerial or land surveys,

using conventional (photography and other visual) methods.

LASER SCANNING OVERVIEW

For the first time, this paper provides original information application, using advanced

high-definition laser scanning (HDS) technology from the reconnaissance effort after the

Haiti Earthquake. This paper focuses on using laser scanners capable of measuring large

objects in space, an important attribute for structural assessment. The use of such HDS has

many advantages and has been successfully applied to assess and document structural

damage in earthquake engineering. Several of these earthquake engineering applications were

conducted in laboratories (Mosalam et al. 2009) and this paper aims at demonstrating the use

of this technology in the field. A 3D point cloud representing the structure’s surface is

delivered as the final result.

Laser scanning technology is rapidly expanding into many fields and is becoming an

essential tool for accurate non-destructive 3D measurements of structures. This technology

enables users to capture millions of points from the subject structure with high accuracy. This

accuracy depends on the size of the structure, its proximity to the scanner and its type. A

laser scanner can deliver results with an accuracy ranging from 0.05 mm to 4.00 mm. 3D

point cloud representing the structure’s surface is delivered as the final result. The HDS

technology rapidly expands beyond the limits of its traditional usage (topographical

surveying, reverse engineering, etc.) and finds excellent applications in many other fields.

For instance, scanning surfaces of visible faults in earthquake-prone regions and analysis of

their roughness can lead to new developments in seismology (Sagy et al. 2007). Extensive

studies of heritage buildings are being conducted at many historic places throughout the

world, e.g. (Spring and Wetherelt 2007). The HDS have been extensively used for

documentation and damage assessment of test structures subjected to earthquake loads at the

University of California, Berkeley (Takhirov 2008).

Nowadays, there are several types of laser scanners targeting various applications. The

laser scanning concept of the scanner used in this paper is based on measuring distances

using the travel duration of a short laser pulse from a source back to a receiver. The laser

scanner sends a short duration laser pulse to an object and receives a reflected light. The

measured duration of the light travel is used in the estimation of the coordinates of each

point, relative to the scanner location. Moreover, the recorded intensity of the reflected light

by the scanner can be closely correlated to color of the object. ScanStation2 used in this study

is shown in Figure 1 and has a maximum 270°×360° field-of-view with a single-point range

and angular accuracies of ±4 mm (±0.16 in) and ±60 micro-radians, respectively. The beam

spot size is only 6 mm (0.24 in) from 0-50 m (0-164 ft) range. With these specifications, the

ScanStation2 delivers survey-grade accuracy while providing a versatile platform for data

capture. A major advantage of ScanStation2 is the leveling feature which provides a reliable

vertical reference axis that is extremely important in structural assessment.

Figure 1. ScanStation2 from Leica Geosystems, Inc. used in this study.

In general, each scanner location generates a database of points called a point cloud. The

point clouds can be generated from many locations around objects. These point clouds can be

stitched together through a process called “registration” where all common HDS targets

between several scan worlds are matched to each other. HDS targets are necessary for

referencing and stitching scan worlds together to combine them into one database with all the

details of the component point clouds. Correct selection of the target locations is important to

simplify data reduction and to increase accuracy of the combined scans into one registration.

The registration can be referenced to any known global (geo-referencing) or any local

coordinate system convenient for analysis. Cyclone version 5.8 (Leica 2006), a software

developed by Leica Geosystems, Inc. is used in this study for points acquisition, data

reduction and presentation. A complete point cloud of a registration or selections of it can be

exported in many formats for further reduction. In this study, several slices of the point

clouds were exported in ASCII format, reduced and presented in Matlab (MathWorks 2007).

ACCURACY STUDY OF LASER SCANNING

The accuracy study of the laser scanner was conducted in a laboratory environment. A

laser scanner was used in the shaking table experiments of a wood-frame building conducted

at the University of California, Berkeley (Mosalam et al. 2009). A 13.5-ft×19.5-ft two-story

wood-frame building representing San Francisco 1940’s design of a residential building with

a garage space on the first story (house-over-garage) was tested. The test building was

subjected to scaled ground motion based on Los Gatos record from Loma Prieta 1989

earthquake. The strong motion time history was scaled to match design spectra of a site in

Richmond district of San Francisco. The test results demonstrated the seismic vulnerability of

the test building due to soft story mechanism and significant twisting when shaken in two

horizontal directions. In addition to conventional instrumentation for measuring acceleration

and position of selected points of the test building, HDS technology was employed to assess

global and local anomalies of the building after the shaking table tests. The analysis

conducted in this study showed very good correlation between conventional data recorded

from position transducers and the laser scans. These laser scans expanded limits of

conventional data at discrete points and allowed analyzing the whole building after shaking.

The building was scanned from many locations in ‘before’ and ‘after’ conditions. The

point clouds were stitched into two registrations called ‘before’ and ‘after’, respectively.

Since the foundation of the building did not experience any damage or slip with respect to the

shaking table during seismic tests, the local coordinate system for both registrations was

selected on the foundation. Figures 2 and 3 show residual deformation of one of the walls of

the building as a contour plot and as a vertical slice parallel to the wall with the garage door

opening from the ‘before’ and ‘after’ scans, respectively. The slice was taken 0.3 m (1 ft)

from the east face of the foundation, into the test building. Clearly Figure 3 shows excellent

correlation between the HDS results and those from conventional measurements as indicated

by the superposed wire potentiometer (WP) readings on the south side of the vertical slice.

In another study, a corner reinforced concrete (RC) column is evaluated using

conventional measurements and HDS. The evaluated specimen is one of eight specimens

tested as part of the NEES Grand Challenge Project on Mitigation of Collapse Risk in Older

Concrete Buildings (PEER 2010). Details of the objectives and results of the first phase of

the experimental program can be found in (Park and Mosalam 2010a, b). The specimen was

replicating a corner column-to-beam joint in a non-ductile RC frame building, Figure 4a. The

specimen was tested under large column axial load and simulated beam shears up to collapse,

Figure 4b. Laser scans of the tested specimen were taken after the test and horizontal slices

for the bottom column right above the bottom 2D clevis and 0.5 m (1.64 ft) higher, Figure 5,

and for the top column right below the top 2D clevis and 0.5 m (1.64 ft) lower, Figure 6,

were analyzed and results were compared with conventional measurements. Drift was

defined as the ratio of the relative horizontal displacement of the column’s corner, at the two

horizontal slices to the difference of their elevation, i.e. 0.5 m (1.64 ft), as shown in Figures

5a and 6a (amplified 5 times). For small angles, this drift is close to the inclination of the

column’s edge relative to vertical axis measured in radians. To examine the accuracy of the

drift estimation, a digital level was used to measure the same inclination, Figures 5b and 6b,

and perfect match between the digital level readings and the HDS points cloud was obtained.

Z

Y

X

Note: North direction is along the x-axis

Final deformation after shaking table test

Final 3D point cloud Residual out-of-plane deformation of the

longitudinal (north) wall Figure 2. Out-of-plane deformation of a wood wall from shaking table tests and from HDS.

Figure 3. Residual NS deformation of a vertical slice parallel to the east wall one foot away

from the east face of the test building for the before and after configurations.

(a) Schematic of the test setup (b) Photograph of specimen after testing Figure 4. One of the corner beam-column specimens for a study on non-ductile RC frames.

100‐83.4=6.6oDrift=6.6π/180×100≈11.5%

(a) (b) Figure 5. (a) Plot of drift estimate from two horizontal slices, 0.5 m apart, of HDS of the bottom portion of the column, (b) Photo of digital level for inclination of bottom column.

100‐83.8=6.2oDrift=6.2π/180×100≈10.8%

(a) (b) Figure 6. (a) Plot of drift estimate from two horizontal slices, 0.5 m apart, of HDS of the top

portion of the column, (b) Photo of digital level for inclination of top column.

DESCRIPTION OF FIELD WORK AND STUDY CASES

As discussed earlier more than 20 structures were scanned in Haiti. The structures varied

in their damage states. Figures 7 and 8 show images of the main 20 structures considered in

this study. These structures are the ones that had successful and informative laser scanning

information. Also shown in these figures, below each photograph, are the GPS coordinates,

ordered as (west, north), of the location of the scanner. Five of these structures, shown in

Figure 8, are analyzed in details as four study cases (I to IV) where study case III represents

two adjacent buildings in the same city block of Port au Prince.

-72.32044176, 18.53552457 -72.34362064, 18.54741786 -72.34354011, 18.54747617

-72.32881736, 18.53444119 -72.33950604, 18.54007549 -72.34558123, 18.54969582

-72.34470146, 18.54924107 -72.34575219, 18.54977005 -72.34529644, 18.54929674

-72.34488522, 18.54904096 -72.34566362, 18.54968055 -72.34578763, 18.54966409

-72.33825071, 18.54968029 -72.3382724, 18.54957487 -72.33866162, 18.54945608

Figure 7. Fifteen structures with different states of damage successfully scanned.

(a) -72.41656808, 18.54983675 (Case I) (b) -72.34358178, 18.54743108 (Case II)

(c) -72.34498263, 18.54908690 (Case III) (d) -72.34362030, 18.54902101 (Case IV) Figure 8. Five structures considered in this paper for four in-depth study cases.

The goals of the study included: 1) To provide information for the first time on the use of

high definition laser scanning and the merits and difficulties of using this advanced

technology in a reconnaissance effort after a major disaster; 2) To evaluate if the scanning

would be an appropriate way to corroborate damage from aerial surveys; 3) To use this

unique deployment of field measurements to provide an important benchmark for image-

based remote sensing evaluation and future advancement of our capabilities for damage

assessment of structural systems using the collected detailed data in this study; 4) To improve

our preparedness in situations of similar disasters in the US and worldwide.

Study Case I: Bridge located near Léogâne, Haiti

The reconnaissance team surveyed a bridge located near the epicenter, Figure 8(a), which

was in the vicinity of Léogâne town, approximately 25 km (16 miles) west of Port au Prince,

Haiti's capital. The laser scan of the bridge has provided interesting information for structural

damage assessment. This study case provides a representative example of the scan work as it

relates to bridge structures. The bridge was scanned from two locations called Location 1 and

Location 2. The global view from Location 1 using coarse scan is shown in Figure 9. The

fine and course laser scans were performed from Location 2 where the fine scan, performed

on a damaged shear key, is shown in Figure 10a. The cross sections of the shear key along

the transverse direction of the bridge and parallel to the shear key’s face near its face and at

the mid-plane are shown in Figures 10b and 10c, respectively. The measurements performed

on the zoomed version of the scan section in Figure 10c is shown in Figure 10d indicating

residual deformation of that portion of the key of 9.2 mm.

Figure 9. Course global scan from Location 1 for the bridge in study case I.

9.2 mm

(a) (b) (c) (d) Figure 10. (a) Fine local scan from location 2 and photo; (b) Section at face of the shear key;

(c) Section at mid-plane of the shear key; (d) Zoomed in view of the section in part (c).

Study Case II: Asscotia Hotel

The building identified as Asscotia Hotel, Figure 8b, has GPS coordinates -72.343590

west and 18.547742 north. This building is a RC frame with masonry infill located at the

east-north corner of Boulevard Jean-Jacques Dessalines and Rue Pavee (street names are

taken from Google maps). The building was significantly damaged during the earthquake and

at the time of the field work was not occupied. The building was scanned from two positions,

namely from south side and the center of the nearby intersection of Boulevard Jean-Jacques

Dessalines and Rue Pavee. The scans were stitched based on 2 targets with one common

vertical reference axis in both positions. The fully stitched registration is shown in Figure 11.

N

Figure 11. Combined scan of the Asscotia Hotel from two point clouds generated at two

positions (view from west-south).

The local coordinate system of the registration was selected to have the south building

side (see the north (N) direction in Figure 11) aligned with Rue Pavee going from west to

east coinciding with the X-axis of the coordinate system. In this case, the Y-axis closely

matches the direction of the street going from south to north, i.e. Boulevard Jean-Jacques

Dessalines. In two horizontal slices of the point cloud, 1 m (3.28 ft) apart in elevation, the fist

story level was analyzed as discussed in the following paragraph. The first story of the

building represented a soft story, consisting of several columns built around the perimeter of

the building without shear walls. Since the building was scanned from two positions, the

majority of columns were captured from three sides as shown in Figure 11.

All the columns in the horizontal slices were selected to assess residual drift at the first

story of the building. For each column, the drift was estimated by the following procedure.

The points on two adjacent sides of each column slice were fitted by a straight line using the

least squares method. The intersection point was assumed to be at the corner of the column,

in this elevation corresponding to the particular slice in question. This operation was repeated

for all column sections and for the two horizontal slices. The vector connecting the corners of

a particular column sections at the two elevations corresponding to the two horizontal slices

was assumed to represent the residual deflection of that particular column after the

earthquake, as shown in Figure 12. The percentage drift shown was estimated from the ratio

of this residual deflection to the difference in elevation between these two horizontal slices.

The column drift vector is amplified 40 times in this plot. The residual drifts were estimated

at all columns with the results shown in Figure 13 showing significant twisting of the

building as reflected by the 40 times amplified rotated and translated bottom slice with

respect to the top one.

Figure 12. Example of drift calculation for one of the Asscotia Hotel’s columns (2nd column on east side counted from the south-west corner); Left: horizontal slices of first story at two elevations; Right: zoomed view of column (dashed box on the left) with drift vector shown.

Figure 13. Columns drift vectors of the Hotel as they relate to point cloud registration.

Study Case III: Two Adjacent Buildings in a City Block

The map of Port au Prince Downtown was divided into blocks which were investigated

by various teams. One of the blocks called Block 7 was assessed by E. Fierro immediately

after the earthquake. As previously stated, one of the goals of this study was to compare

common methods of surveying based on photographic images to surveying performed by the

laser scanner. There were 17 buildings in Block 7 where damage in this block was

significant. Figure 14 shows the Google Earth map of Block 7, highlighted by a rectangle.

Also Figure 14 shows the results of conventional surveying and structural damage

assessment, perfumed previously by the reconnaissance team member Mr. E. Fierro.

A B

Figure 14. Block 7 investigated earlier by E. Fierro; Left: Google earth image for the

location of the block; Right: damage assessment results from ground survey.

Two buildings in this block are identified as the focus of study case III, Figure 8c, and

they are labeled as A and B in figure 14. According to ground surveying, buildings A and B

suffered from moderate and heavy damages, respectively. Figure 15a shows building B at the

south-west corner of Block 7. It had been damaged heavily during the earthquake and it was

unoccupied at the time of laser scan surveying. It is a two storey building with a soft storey at

the first level. Figure 15b shows drift vectors for each column of the building indicating

values as high as 4.9% which are consistent with the observed “heavy” damage. On the other

hand, Figure 16a shows building A at the south-west corner of Block 7. It had been damaged

moderately during the earthquake and it was also unoccupied at the time of laser scan

surveying. It is a small two storey RC frame building with unreinforced masonry infill.

Figure 16b shows drift vectors for each corner of the building indicating much lower values

than those of building B which are consistent with the observed “moderate” damage.

(a) (b) Figure 15. Photograph (a) and structural damage assessment results produced from laser

scans (b) of building B identified in Figure 14 at the south-east corner of Block 7.

(a) (b)

Figure 16. Photograph (a) and structural damage assessment results produced from laser scans (b) of building A identified in Figure 14 at the south-west corner of Block 7.

Study Case IV: Mon Parfum Building

The same manipulation of point cloud was performed on the point cloud of a building

with round façade located on the next intersection north of the Asscotia Hotel. For the

purpose of this paper, the building is referred to as the ‘Mon Parfum’ Building, which is the

name of the business displayed on the building. The GPS coordinates of the building are

presented in Figure 8d. The coordinate system of the scan was transformed in such a way that

the east side of the building was aligned with Boulevard Jean-Jacques Dessalines going from

south to north and coinciding with X-axis of the coordinate system. Similar to the Asscotia

Hotel case, the Y-axis of the coordinate system closely matches the direction of the street

going from east to west, i.e. Rue Des Miracles. The first story of the building represented a

soft story consisting of many columns on the perimeter of the building without shear walls.

The building was scanned from one position only that explains the limitation that the

majority of columns were captured from two adjacent sides only as shown in Figure 17. The

figure shows two horizontal slices of the point cloud, 1 meter apart in elevation, at the fist

story level that was analyzed in the same manner as described above for study case II.

Clearly significant damage took place in this building where some columns reached as large

values of drift ratio as 9.9% which can be related to localized damage in that column.

0 5 10 15 20 25

-5

0

5

10

15

3.4%

5.0%

4.5%

4.7%

4.9% 4.3%9.9%

1.2%

East-West Coordinate (m)

Nor

th-S

outh

Coo

rdin

ate

(m)

Bottom Slice

Top SliceRotated&Translated Bottom

Figure 17. Residual drift calculated for all columns in study case IV.

Work in Progress

The reconnaissance team was able to acquire enormous amount of information, e.g. the

registration of the Asscotia Hotel alone consisted of 9 billion points. The detailed data

reduction requires some time. Table 1 is a representative example of work in progress. The

translational and rotational motions in the two buildings in study cases II and IV are

compared in the table. The computation of these components demonstrate the unique

capabilities in manipulating 3D point clouds from scanning group of buildings to understand

the global effect of earthquake shaking, i.e. on a group of buildings not just a single building.

The rotations and translations for all buildings captured during the field work are planned to

be summarized in a form similar to that table and this data will be overlaid over Haiti map in

Google Earth to capture global directivity of the strong motion.

Table 1. Rotation and translation of the bottom slice with respect to the top slice. Study Case

Rotation [radians]

X-translation [mm]

Y-Translation [mm]

Drift translation vector [%]

Drift angle to X [degrees]

II 0.0013 -14.4 -27.5 3.1 207.60 IV 0.0015 -14.7 46.0 4.8 162.25

CONCLUDING REMARKS

From the presented research in this paper, the following concluding remarks can be made:

1) The laser scanning and other conventional data collected from the earthquake in Haiti can

improve our preparedness in situations of similar disasters in the US and worldwide. It is

anticipated that techniques employed in this study in gathering and disseminating critical

information will have a major impact on future reconnaissance efforts.

2) A laser scanner used in the study delivers accuracy of individual point acquisition of 4.0

mm. This accuracy can be significantly increased by best fitting a point cloud to a surface

it is representing. In-house study at the University of California showed that the error of

tracking points of a surface can be reduced in this case to less than 1 mm.

3) The laser scans used in the scope of this paper showed good correlation of the quantitative

damage assessment based on the point clouds and that from qualitative visual damage

assessment or using conventional quantitative reconnaissance approaches.

4) Main limitations of the laser scanning are: a) it can only acquire visible surfaces due to the

nature of the laser technology, and b) it is relatively slow to use in real time structural

testing or rapid reconnaissance, which is a limitation that will most likely be resolved in

the future due to development of laser technology to increase speed of point acquisition.

5) The conventional and panoramic photographic images and the laser scans incorporated

into Google Earth allow prompt sharing the damage assessment data on the Internet

amongst the engineering community, emergency services and other quick response

agencies. With programming scripts in place, the reduction of laser scan data can be

accomplished within days and uploaded onto a server to be accessed on the Internet. By

means of the interactive panorama, users can look around the camera location and zoom

into building details. The laser scans can be conveniently viewed in a browser with options

to make any measurements and notes to be shared with others.

ACKNOLEDGEMENTS

The authors acknowledge the financial support, Award # 1034808, from the National Science

Foundation through the RAPID Program. Thanks are due to Mr. E. Fierro and Prof. E.

Miranda for being members of the reconnaissance team. The following PEER/nees@berkeley

summer interns: Victoria Servin, Clay Sorensen, and Sean Wade, contributed to the pre- and

post-filed work using the laser scanners. Their help is gratefully acknowledged.

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