Earthquake Readiness Capacity Building Project 2009

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BUILDERS TOOLKIT

WHAT TO DO WHEN PLANNING TO BUILD

This presentation is part of the DEVELOPERS, DESIGNERS & BUILDERS TOOLKIT of the CDEMA Earthquake Readiness Public Awareness & Education Campaign in the Caribbean

2009

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This toolkit is downloadable from http://www.weready.org

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WHAT WE WILL LEARN Best Practices For:

Site Selection & Construction Planning

Building and Designing

Strengthening Schemes in construction

Construction along a coastline

Building in Tsunami-prone areas

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FACT

Every year, earthquakes take the lives of thousands, and destroy property. It is imperative that structures are designed to resist earthquake forces, in order to reduce the loss of life. Structural design plays an important role.

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FACT

Ground shaking from earthquakes can collapse structures;

Buildings not seismically sound or placed on unsuitable soil are at risk of collapsing;

When an earthquake occurs in a populated area, it may cause deaths, injuries and extensive property damage.      

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Hence the claim that

"Earthquake don't kill people, buildings do."

 

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THINGS TO CONSIDER

The size of the earthquake does not mean there will be more damage and destruction. Rather, it is how well informed people are at responding to earthquakes and how much money can be spent on making structures able to respond to the ground movements.

Design a Building to withstand Earthquakes tutorial http://www.geointeractive.co.uk/

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BUILDING CLASSIFICATIONS

Seismic intensity of zone where building will be constructed;

Importance of the building

Stiffness of the foundation soil http://www.nicee.org/iaee/E_Chapter3.pdf

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SEISMIC ZONES

Zone A: Risk of widespread collapse and destruction -MSK 1X or greater)

Zone B: Risk of collapse and heavy damage (MSK V111 likely)

Zone C: Risk of damage – (MSK V11 likely)

Zone D: Risk of minor damage (MSK V1 maximum) http://www.nicee.org/iaee/E_Chapter3.pdf

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CATEGORISING BUILDINGS

oHospitals & ClinicsoSchools/ Universities, ChurchesoPolice & Fire stationsoCinemas & TheatresoStadiums, museumsoMeeting hallsoHomes, OfficesoFactories and warehousesoHotels

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CATEGORIES OF BUILDINGS FOR STRENGTHENING PURPOSES

Categories Combination of conditions for categories1 Important buildings on soft soil in zone A

11 Important buildings on firm soil in zone BImportant buildings on soft soil in zone BOrdinary building on soft soil in zone A

111 Important buildings on firm soil in zone BImportant buildings on soft soil in zone COrdinary buildings on firm soil in zone AOrdinary building on soft soil in zone B

1V Important buildings on firm soil in zone COrdinary buildings on firm soil in zone BOrdinary building on firm soil in zone B

Firm soils refer to those have safe bearing value;Weak soils are liable to compaction and liquefaction under earthquake

conditions

All structures should be designed and built to stand up to

earthquakes.

Ensure that the land to be developed is suitable and the proposed building is adequately designed to survive an earthquake.

The more you know, the better prepared you are. Knowing … that’s where

reducing vulnerability starts.

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Investigate

Find out whether

the area in which you intend to build is susceptible to rockslides or land slippage

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TALK

TO OLD-TIMERS

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CONSULT

ZONAL MAPS AVAILABLE THROUGH THE PUBLIC SERVICE

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RESEARCH BUILDING CODES

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EMPLOY BEST PRACTICE BUILDING AND DESIGN STANDARDS

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Consult a qualified engineer, architect or other authority to find out how safe your location is.

Build on stable soil in an area not prone to natural hazards.

Construct only in approved Construction zones.

WHEN PLANNING TO BUILDSite selection

GET APPROVALSite selection…

Get planning approval in principle/outline approval.

Coastal areas are vulnerable to tsunamis. Set back to higher ground where possible.

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DESIGN

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Design in accordance with the recommended building codes. *

Ensure that “seismic-proofing” takes into account the need to secure critical equipment.

Design connections of building elements (footings, floor, wall, roof, etc) properly.

DESIGN

Select favourable building envelope geometry.

DESIGN

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23Source: Ebook – General concepts of Earthquake resistant design

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3 D CONCEPTS

Interrelated, refers to buildings ability to suffer extensive deformation without collapsing

Buildings ability to suffer extensive damage without partial or complete collapse

Ductability /Deformability

Damageability

http://www.nicee.org/iaee/E_Chapter3.pdf

Set back at least 6 m from the back/crest of terrace, and 6m from the back of the slope.

Build away from large, mature trees approx. 6 m away or a distance equal to the tree height. 27

CONSTRUCTON

CONSTRUCTION

Brace building elements properly. Design the columns to be stronger

than the beams

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CONSTRUCTION

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CONSTRUCTION

Use quake-resistant building techniques Use correct quality construction materials

Store construction materials properly

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Protect window and door openings to keep the envelope watertight.

Protect foundations from scour, build the ground

floor above flood water level.

Locate top of footings 600 mm (2’) minimum below the external ground.

Position the ground floor 300 mm (12”) minimum above the external ground.

CONSTRUCTION

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FOUNDATIONS

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SOME REQUIREMENTS FOR STRUCTURAL SAFETY

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SOME REQUIREMENTS FOR STRUCTURAL SAFETY

Design free standing walls to be as safe as a vertical cantilever.

Horizontal reinforcement is necessary to transfer load

Walls should be tied.

Place shear walls on both axes of the building

http://www.nicee.org/iaee/E_Chapter3.pdf

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SOME REQUIREMENTS FOR STRUCTURAL SAFETY

A shear wall must be capable of resisting all horizontal forces.

Roof and floor elements tied and able to exhibit diaphragm action

Trusses must be anchored to the supporting walls and have an arrangement for transferring their own inertia force to the end walls

http://www.nicee.org/iaee/E_Chapter3.pdf

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FOUNDATIONS

DOWNLOAD INFORMATIONwww.cdera.org

Safer Building Handbook for Homeowners in the Caribbean also

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www.cdera.org/projects/champ/docs/FinalCDERACodeofPracticeforConstrofHouses.pdf

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Common seismic problems

IN WOOD FRAME BUILDINGS

38Lack of foundation bolts

39Cripple wall collapse

IN WOOD FRAME BUILDINGS

COMMON SEISMIC PROBLEMS

40Soft storey park under parking

REDUCING DAMAGE

THROUGH STRUCTURAL MODIFICATION

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STRENGTHENING SCHEMES

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– Water tanks– Water heaters– Gas cylinders– Storage wall units

IF IT CAN FALL/OPEN – VOLT BRACE OR FASTEN!

Brace or fasten - Heavy furniture - Mirrors- Light fixtures- Shelves - TVs

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OTHER STRENGTHENING SCHEMES

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Add plywood sheathing to soft storyManufactured strong-wallsMechanical energy-dissipation devicesLots of measures for household contents

– Strap water heater to frame– Latches on cabinets– Strap tall furniture to frame– Shelf lips

REMEMBER ….. A high percentage of earthquake loss is caused by failure of :

o ceilings o windows o doors o partitions o cupboard and shelves o external cladding/sidingo electrical & mechanical systems o & other components of buildings

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OTHER STRENGTHENING SCHEMES

EARTHQUAKE ENGINEERING

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PERFORMANCE BASED

Source © Keith A. Porter, PE, PhD, GW Housner Senior ResearcherCalifornia Institute of Technology

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PERFORMANCE BASED EARTHQUAKEENGINEERING

(

Estimating the future seismic performance of buildings and other facilities in terms of repair costs, health impacts, and repair durations.

Dollars, deaths and downtime)”

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Step 1: DEFINE STRUCTURE TO BE BUILT

Hazard analysis

Structural analysis

Damage analysis

Loss analysis

Iterate to quantify uncertainty, vulnerability

Statewide hazard

Site ground motion

Location & design

Decision making

Structural model

Building response

Fragility information

Physical damage

Repair cost data

Cost in this earthquake

Building

Site, soil

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Step 2: HOW STRONGLY DOES THE GROUND SHAKE

Hazard analysis

Structural analysis

Damage analysis

Loss analysis

Iterate to quantify uncertainty, vulnerability

Statewide hazard

Site ground motion

Location & design

Decision making

Structural model

Building response

Fragility information

Physical damage

Repair cost data

Cost in this earthquake

Building

Site, soil

Fault

Rupture:magnitude,other features

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Step 3: HOW MUCH DOES BUILDING DEFORM

Hazard analysis

Structural analysis

Damage analysis

Loss analysis

Iterate to quantify uncertainty, vulnerability

Statewide hazard

Site ground motion

Location & design

Decision making

Structural model

Building response

Fragility information

Physical damage

Repair cost data

Cost in this earthquake

Building

Site, soil

Fault

Rupture:magnitude,other features

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Step 4: WHAT GETS BROKEN?

Hazard analysis

Structural analysis

Damage analysis

Loss analysis

Iterate to quantify uncertainty, vulnerability

Statewide hazard

Site ground motion

Location & design

Decision making

Structural model

Building response

Fragility information

Physical damage

Repair cost data

Cost in this earthquake

Building

Site, soil

Fault

Rupture:magnitude,other features

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Step 5: WHAT DOES IT COST TO FIX?

Hazard analysis

Structural analysis

Damage analysis

Loss analysis

Iterate to quantify uncertainty, vulnerability

Statewide hazard

Site ground motion

Location & design

Decision making

Structural model

Building response

Fragility information

Physical damage

Repair cost data

Cost in this earthquake

Building

Site, soil

Fault

Rupture:magnitude,other features

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In other words, where is it likely to be cost-effective to seismically strengthen a structure?

WHEN PLANNING TO BUILD >>>

TSUNAMIS & FLOOD PRONE AREAS

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Know the risk for tsunamis in the area.

Consider a Tsunami Evacuation Point higher than 35 metres above sea level.

Download Checklist for Designing to Counteract Natural Hazards from

Site Selection

http://weready.org/builders.php

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Design & Construction(Tsunami)

Elevate coastal buildings because most tsunamis waves are less than 30 metres high

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Install features to divert waves away from the property.

Tsunamis & Flood prone areasAdditional Shoreline protection

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Protect coral reefs.

Stabilise dunes

Maintain and/or build wetlands and mangroves and keep them healthy. These act as natural shock absorbers, soaking up destructive waves.

In the 2004 tsunamis in Asia, wetlands were believed to have protected lives and properties.

Mangroves can absorb 70-90% of the energy from a normal wave. http://news.bbc.co.uk/2/hi/science/nature/4547032.stm

BBC News 25 Dec 2005.

Tsunamis & Flood prone areasAdditional Shoreline protection

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Tsunamis & Flood prone areasAdditional Shoreline protection

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Shrubs, grasslands, and marshes will not provide adequate protection against tsunami waves, but will help to absorb flood water.

Tsunamis & Flood prone areasAdditional Shoreline protection

Where possible, build structures to help protect the shoreline from tsunami damage.

Build seawalls and revetment structures to help protect the shore from storm waves.

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And finally…A Caribbean Building Code?

There is currently no regional building standard to guide and enforce safe building.

The Caribbean Regional Organisation for Standards Quality (CROSQ) Regional Building Standard project is intended to review base codes, prepare Caribbean Application Documents, train users, strengthen building authorities and build consensus among key stakeholders.

For more information, visit http:// www.crosq.org

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