unusual buildings and vulnerability in earthquakes

UNUSUAL BUILDINGS AND VULNERABILITY IN

EARTHQUAKES

Walter Hays, Global Alliance for Disaster Reduction, Vienna, Virginia,

USA 

BACKGROUND

INADEQUATE RESISTANCE TO HORIZONTAL GROUND SHAKING

EARTHQUAKES

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

CASE HISTORIES

BUILDING ELEVATIONS

• FACT: Unnecessary FACT: Unnecessary horizontal and vertical horizontal and vertical changes in symmetry, mass, changes in symmetry, mass, and stiffness will increase a and stiffness will increase a building’s vulnerability to building’s vulnerability to strong ground shakingstrong ground shaking. .

FACT: UNUSUAL BUILDINGS ARE LIKELY TO BE MORE

VULNERABLE IN AN EARTHQUAKE

A CHURCH: REYKJAVEK, ICELAND

ATLANTIS HOTEL: DUBAI, UAE

EMP MUSEUM: SEATTLE, WASHINGTON (USA)

A LIBRARY: KANSAS CITY, MISSOURI (USA)

A HOTEL: PYONGYANG, NORTH KOREA

“THE GHERKIN,” AN OFFICE BUILDING: LONDON

SKY CITY (2,749 FEET--NOT YET FINISHED) : CHANGSHA, CHINA

REGULARITY IN A BUILDING’S ELEVATION REDUCES ITS

VULNERABILITY TO STRONG GROUND SHAKING

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

BoxBox

DAMAGED HOUSE:CHINA

ASYMMETRY AND LATERAL CHANGES: CHINA

RELATIVE VULERABILITY

[1 (Best) to 10 (Worst)]

11

ANALYSIS OF VULNERABILITY

LOCATIONS OF POTENTIAL FAILURE

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

BUILDING ELEVATION

PyramidPyramid

RELATIVE VULERABILITY

[1 (Best) to 10 (Worst)]

4 - 64 - 6

ANALYSIS OF VULNERABILITY

LOCATIONS OF POTENTIAL FAILURE

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

BUILDING ELEVATION

Inverted PyramidInverted Pyramid

RELATIVE VULERABILITY

[1 (Best) to 10 (Worst)]

5 - 65 - 6

ANALYSIS OF VULNERABILITY

LOCATIONS OF POTENTIAL FAILURE

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

BUILDING ELEVATION

““L”- Shaped L”- Shaped BuildingBuilding

RELATIVE VULERABILITY

[1 (Best) to 10 (Worst)]

3 - 53 - 5

ANALYSIS OF VULNERABILITY

LOCATIONS OF POTENTIAL FAILURE

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

BUILDING ELEVATION

Inverted “T”Inverted “T”

RELATIVE VULERABILITY

[1 (Best) to 10 (Worst)]

2 - 32 - 3

ANALYSIS OF VULNERABILITY

LOCATIONS OF POTENTIAL FAILURE

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

BUILDING ELEVATION

Multiple SetbacksMultiple Setbacks

RELATIVE VULERABILITY

[1 (Best) to 10 (Worst)]

4 - 54 - 5

ANALYSIS OF VULNERABILITY

LOCATIONS OF POTENTIAL FAILURE

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

BUILDING ELEVATION

OverhangOverhang

RELATIVE VULERABILITY

[1 (Best) to 10 (Worst)]

6 - 76 - 7

ANALYSIS OF VULNERABILITY

LOCATIONS OF POTENTIAL FAILURE

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

BUILDING ELEVATION

Partial “Soft” StoryPartial “Soft” Story

RELATIVE VULERABILITY

[1 (Best) to 10 (Worst)]

8 - 108 - 10

ANALYSIS OF VULNERABILITY

LOCATIONS OF POTENTIAL FAILURE

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

BUILDING ELEVATION

““Soft” First FloorSoft” First Floor

THE TYPICAL SOFT-STOREY BUILDING IN TURKEY

RELATIVE VULERABILITY

[1 (Best) to 10 (Worst)]

9 - 109 - 10

ANALYSIS OF VULNERABILITY

LOCATIONS OF POTENTIAL FAILURE

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

BUILDING ELEVATION

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

OverhangOverhang

RELATIVE VULERABILITY

[1 (Best) to 10 (Worst)]

1010

ANALYSIS OF VULNERABILITY

LOCATIONS OF POTENTIAL FAILURE

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

BUILDING ELEVATION

Building on Building on Sloping GroundSloping Ground

SOFT STORY BUILDING ON SLOPING GROUND: CHINA TRIGGERED LANDSLIDES

RELATIVE VULERABILITY

[1 (Best) to 10 (Worst)]

8 - 98 - 9

ANALYSIS OF VULNERABILITY

LOCATIONS OF POTENTIAL FAILURE

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

BUILDING ELEVATION

Theaters and Theaters and Assembly HallsAssembly Halls

RELATIVE VULERABILITY

[1 (Best) to 10 (Worst)]

9 - 109 - 10

ANALYSIS OF VULNERABILITY

LOCATIONS OF POTENTIAL FAILURE

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

BUILDING ELEVATION

Sports StadiumsSports Stadiums

SIMPLICITY IN A BUILDING’S FLOOR PLAN REDUCES ITS

VULNERABILITY TO STRONG GROUND SHAKING

BUILDING FLOOR PLANS

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

RELATIVE VULERABILITY

[1 (Best) to 10 (Worst)]

11

ANALYSIS OF VULNERABILITY

POTENTIAL PROBLEMS

None, if symmetrical layout maintained.

FLOOR PLAN

BoxBox

RELATIVE VULERABILITY

[1 (Best) to 10 (Worst)]

2 - 42 - 4

ANALYSIS OF VULNERABILITY

POTENTIAL PROBLEMS

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

FLOOR PLAN

RectangleRectangle

RELATIVE VULERABILITY

[1 (Best) to 10 (Worst)]

2 - 42 - 4

ANALYSIS OF VULNERABILITY

POTENTIAL PROBLEMS

Asymmetry will cause torsion and enhance damage at corners.

FLOOR PLAN

Street CornerStreet Corner

RELATIVE VULERABILITY

[1 (Best) to 10 (Worst)]

5 - 105 - 10

ANALYSIS OF VULNERABILITY

POTENTIAL PROBLEMS

Asymmetry will enhance damage at corner regions.

FLOOR PLAN

““U” - ShapeU” - Shape

RELATIVE VULERABILITY

[1 (Best) to 10 (Worst)]

44

ANALYSIS OF VULNERABILITY

POTENTIAL PROBLEMS

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

FLOOR PLAN

Courtyard in CornerCourtyard in Corner

RELATIVE VULERABILITY

[1 (Best) to 10 (Worst)]

88

ANALYSIS OF VULNERABILITY

POTENTIAL PROBLEMS

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

FLOOR PLAN

““L” - ShapeL” - Shape

TORSION: CHINA

RELATIVE VULERABILITY

[1 (Best) to 10 (Worst)]

5 - 75 - 7

ANALYSIS OF VULNERABILITY

POTENTIAL PROBLEMS

Directional variation in stiffness will enhance damage at intersecting corner.

FLOOR PLAN

““H” - ShapeH” - Shape

RELATIVE VULERABILITY

[1 (Best) to 10 (Worst)]

8 - 108 - 10

ANALYSIS OF VULNERABILITY

POTENTIAL PROBLEMS

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

FLOOR PLAN

Complex Floor PlanComplex Floor Plan

RELATIVE VULERABILITY

[1 (Best) to 10 (Worst)]

5- 95- 9

ANALYSIS OF VULNERABILITY

POTENTIAL PROBLEMS

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

FLOOR PLAN

Curved PlanCurved Plan