VULNERABILITY OF BUILDINGS TO EARTHQUAKE GROUND SHAKING GENERALIZED VULNERABILITY ASSESSMENTS BASED...

VULNERABILITY OF BUILDINGS TO EARTHQUAKE

GROUND SHAKING

GENERALIZED VULNERABILITY ASSESSMENTS BASED ON CHANGES IN

A BUILDING’S ELEVATION AND FLOOR PLAN

Walter Hays, Global Alliance for Disaster Reduction, University of

North Carolina, USA

HAZARDSHAZARDSHAZARDSHAZARDS

ELEMENTS OF RISKELEMENTS OF RISKELEMENTS OF RISKELEMENTS OF RISK

EXPOSUREEXPOSUREEXPOSUREEXPOSURE

VULNERABILVULNERABILITYITY

VULNERABILVULNERABILITYITY LOCATIONLOCATIONLOCATIONLOCATION

RISKRISKRISKRISK

BUILDING DAMAGE: DEATH TOLL REACHED 230,,000

INADEQUATE RESISTANCE TO HORIZONTAL GROUND SHAKING

EARTHQUAKESEARTHQUAKES

SOIL AMPLIFICATION

PERMANENT DISPLACEMENT (SURFACE FAULTING & GROUND

FAILURE)

IRREGULARITIES IN ELEVATION AND PLAN

TSUNAMI WAVE RUNUP

LACK OF DETAILING AND POOR CONSTRUCTION MATERIALS

LACK OF ATTENTION TO NON-STRUCTURAL ELEMENTS

CAUSES OF DAMAGE

CAUSES OF DAMAGE

CASE HISTORIESCASE HISTORIES

GOAL: REGULARITY IN BUILDING ELEVATIONS AND SIMPLICITY IN FLOOR PLANS

• EFFECTIVE WHEN IMPLEMENTED IN ACCORDANCE WITH BUILDING REGULATIONS DURING THE DESIGN AND CONSTRUCTION PHASES ---

• NOT AS EFFECTIVE WHEN ADDED BY RETROFIT OR BY STRENGTHENING

CLARIFY VULNERABILTIES

CLARIFY VULNERABILTIES

ANY COMMUNITY CAN ASSESS THE VULNERABILITY OF ITS BUILDINGS BY EXAMINING EACH BUILDING’S

ELEVATION AND FLOOR PLAN

EVALUATEEVALUATE

INITATE ACTIONSINITATE ACTIONS

INDENTIFY OPTIONS

INDENTIFY OPTIONS

OPTIMIZE OPTIMIZE

IMPLEMENT BEST SOLUTION

IMPLEMENT BEST SOLUTION

• An Incremental ProcessAn Incremental Process

SOURCE OF INFORMATION

• The following graphic assessments The following graphic assessments of building vulnerability to of building vulnerability to earthquake ground shaking were earthquake ground shaking were developed by an insurance company developed by an insurance company and provided to other organizations and provided to other organizations for educational uses.for educational uses.

BUILDING ELEVATIONS

• Horizontal and vertical changes Horizontal and vertical changes in symmetry, mass, and in symmetry, mass, and stiffness—deviations from stiffness—deviations from regularity--- regularity--- will increase a will increase a building’s vulnerability to building’s vulnerability to damage from ground shakingdamage from ground shaking. .

AN IMPORTANT NOTE

• NOTE: Analysis of the effects of NOTE: Analysis of the effects of changes in the changes in the local site geology local site geology and the construction materials, and the construction materials, key parameters in controlling a key parameters in controlling a building’s performance, are building’s performance, are NOTNOT considered here. considered here.

RELATIVE VULERABILITY

[1 (Best) to 10 (Worst)]



1-21-2

ANALYSIS OF VULNERABILITY

LOCATIONS OF POTENTIAL FAILURE


None, if attention given to foundation and non-structural elements. Rocking may crack foundation and structure. X-Cracks around windows.

BUILDING ELEVATION

BUILDING ELEVATION

BoxBox

DAMAGED HOUSE:CHINA

ASYMMETRY AND LATERAL CHANGES: CHINA





11




None, if attention given to foundation and non structural elements. Rocking may crack foundation.

BUILDING ELEVATION

BUILDING ELEVATION

PyramidPyramid





4 - 64 - 6




Top heavy, asymmetrical structure may fail at foundation due to rocking and overturning.

BUILDING ELEVATION

BUILDING ELEVATION

Inverted PyramidInverted Pyramid





5 - 65 - 6




Asymmetry and horizontal transition in mass, stiffness and damping may cause failure where lower and upper structures join.

BUILDING ELEVATION

BUILDING ELEVATION

““L”- Shaped L”- Shaped BuildingBuilding





3 - 53 - 5




Vertical transition and asymmetry may cause failure where lower part is attached to tower.

BUILDING ELEVATION

BUILDING ELEVATION

Inverted “T”Inverted “T”





2 - 32 - 3




Vertical transition in mass, stiffness, and damping may cause failure at foundation and transition points at each floor.

BUILDING ELEVATION

BUILDING ELEVATION

Multiple SetbacksMultiple Setbacks





4 - 54 - 5




Top heavy asymmetrical structure may fail at transition point and foundation due to rocking and overturning.

BUILDING ELEVATION

BUILDING ELEVATION

OverhangOverhang





6 - 76 - 7




Horizontal and vertical transitions in mass and stiffness may cause failure on soft side of first floor; rocking and overturning.

BUILDING ELEVATION

BUILDING ELEVATION

Partial “Soft” StoryPartial “Soft” Story





8 - 108 - 10




Vertical transitions in mass and stiffness may cause failure on transition points between first and second floors.

BUILDING ELEVATION

BUILDING ELEVATION

““Soft” First FloorSoft” First Floor

THE TYPICAL SOFT-STOREY BUILDING IN TURKEY

THE TYPICAL SOFT-STOREY BUILDING IN TURKEY





9 - 109 - 10




Horizontal and vertical transitions in mass and stiffness may cause failure at transition points and possible overturning.

BUILDING ELEVATION

BUILDING ELEVATION

Combination of Combination of “Soft” Story and “Soft” Story and

OverhangOverhang





1010




Horizontal transition in stiffness of soft story columns may cause failure of columns at foundation and/or contact points with structure.

BUILDING ELEVATION

BUILDING ELEVATION

Building on Building on Sloping GroundSloping Ground

SOFT STORY BUILDING ON

SLOPING GROUND: CHINA TRIGGERED LANDSLIDES





8 - 98 - 9




Horizontal and vertical transition in stiffness and cause failure of individual members.

BUILDING ELEVATION

BUILDING ELEVATION

Theaters and Theaters and Assembly HallsAssembly Halls





9 - 109 - 10




Horizontal and vertical transition in mass and stiffness may cause failure columns.

BUILDING ELEVATION

BUILDING ELEVATION

Sports StadiumsSports Stadiums

BUILDING FLOOR PLANS

• CHANGING FLOOR PLANS FROM SIMPLE TO COMPLEX AND FROM SYMMETRICAL TO ASYMMETRICAL WILL INCREASE A BUILDING’S VULNERABILITY TO GROUND SHAKING.





11


POTENTIAL PROBLEMS

POTENTIAL PROBLEMS

None, if symmetrical layout maintained.

FLOOR PLANFLOOR PLAN

BoxBox





2 - 42 - 4


POTENTIAL PROBLEMS

POTENTIAL PROBLEMS

Differences in length and width will cause differences in strength, differential movement, and possible overturning.


RectangleRectangle





2 - 42 - 4


POTENTIAL PROBLEMS

POTENTIAL PROBLEMS

Asymmetry will cause torsion and enhance damage at corners.


Street CornerStreet Corner





5 - 105 - 10


POTENTIAL PROBLEMS

POTENTIAL PROBLEMS

Asymmetry will enhance damage at corner regions.


““U” - ShapeU” - Shape





44


POTENTIAL PROBLEMS

POTENTIAL PROBLEMS

Open space in center reduces resistance and enhance damage at corner regions.


Courtyard in CornerCourtyard in Corner





88


POTENTIAL PROBLEMS

POTENTIAL PROBLEMS

Asymmetry will cause torsion and enhance damage at intersection and corners.


““L” - ShapeL” - Shape

TORSION: CHINA





5 - 75 - 7


POTENTIAL PROBLEMS

POTENTIAL PROBLEMS

Directional variation in stiffness will enhance damage at intersecting corner.


““H” - ShapeH” - Shape





8 - 108 - 10


POTENTIAL PROBLEMS

POTENTIAL PROBLEMS

Asymmetry and directional variation in stiffness will enhance torsion and damage at intersecting.


Complex Floor PlanComplex Floor Plan





5- 95- 9


POTENTIAL PROBLEMS

POTENTIAL PROBLEMS

Asymmetry and irregularities will cause torsion and enhance damage along boundaries and at corners.


Curved PlanCurved Plan

VULNERABILITY OF BUILDINGS TO EARTHQUAKE GROUND SHAKING GENERALIZED VULNERABILITY ASSESSMENTS BASED...

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