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UNUSUAL BUILDINGS AND VULNERABILITY IN EARTHQUAKES. Walter Hays, Global Alliance for Disaster Reduction, Vienna, Virginia, USA . BACKGROUND. CAUSES OF DAMAGE. INADEQUATE RESISTANCE TO HORIZONTAL GROUND SHAKING. SOIL AMPLIFICATION. PERMANENT DISPLACEMENT (SURFACE FAULTING & GROUND FAILURE).
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UNUSUAL BUILDINGS AND VULNERABILITY IN EARTHQUAKES Walter Hays, Global Alliance for Disaster Reduction, Vienna, Virginia, USA
CAUSES OF DAMAGE INADEQUATE RESISTANCE TO HORIZONTAL GROUND SHAKING SOIL AMPLIFICATION PERMANENT DISPLACEMENT (SURFACE FAULTING & GROUND FAILURE) IRREGULARITIES IN ELEVATION AND PLAN EARTHQUAKES TSUNAMI WAVE RUNUP CASE HISTORIES LACK OF DETAILING AND POOR CONSTRUCTION MATERIALS LACK OF ATTENTION TO NON-STRUCTURAL ELEMENTS
BUILDING ELEVATIONS • FACT: Unnecessary horizontal and vertical changes in symmetry, mass, and stiffness will increase a building’s vulnerability to strong ground shaking.
FACT: UNUSUAL BUILDINGS ARE LIKELY TO BE MORE VULNERABLE IN AN EARTHQUAKE
REGULARITY IN A BUILDING’S ELEVATION REDUCES ITS VULNERABILITY TO STRONG GROUND SHAKING
ANALYSIS OF VULNERABILITY BUILDING ELEVATION LOCATIONS OF POTENTIAL FAILURE RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] None, if attention given to foundation and non-structural elements. Rocking may crack foundation and structure. X-Cracks around windows. 1-2 Box
ANALYSIS OF VULNERABILITY BUILDING ELEVATION LOCATIONS OF POTENTIAL FAILURE RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] None, if attention given to foundation and non structural elements. Rocking may crack foundation. 1 Pyramid
ANALYSIS OF VULNERABILITY BUILDING ELEVATION LOCATIONS OF POTENTIAL FAILURE RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] Top heavy, asymmetrical structure may fail at foundation due to rocking and overturning. 4 - 6 Inverted Pyramid
ANALYSIS OF VULNERABILITY BUILDING ELEVATION LOCATIONS OF POTENTIAL FAILURE RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] Asymmetry and horizontal transition in mass, stiffness and damping may cause failure where lower and upper structures join. 5 - 6 “L”- Shaped Building
ANALYSIS OF VULNERABILITY BUILDING ELEVATION LOCATIONS OF POTENTIAL FAILURE RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] Vertical transition and asymmetry may cause failure where lower part is attached to tower. 3 - 5 Inverted “T”
ANALYSIS OF VULNERABILITY BUILDING ELEVATION LOCATIONS OF POTENTIAL FAILURE RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] Vertical transition in mass, stiffness, and damping may cause failure at foundation and transition points at each floor. 2 - 3 Multiple Setbacks
ANALYSIS OF VULNERABILITY BUILDING ELEVATION LOCATIONS OF POTENTIAL FAILURE RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] Top heavy asymmetrical structure may fail at transition point and foundation due to rocking and overturning. 4 - 5 Overhang
ANALYSIS OF VULNERABILITY BUILDING ELEVATION LOCATIONS OF POTENTIAL FAILURE RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] Horizontal and vertical transitions in mass and stiffness may cause failure on soft side of first floor; rocking and overturning. 6 - 7 Partial “Soft” Story
ANALYSIS OF VULNERABILITY BUILDING ELEVATION LOCATIONS OF POTENTIAL FAILURE RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] Vertical transitions in mass and stiffness may cause failure on transition points between first and second floors. 8 - 10 “Soft” First Floor
ANALYSIS OF VULNERABILITY BUILDING ELEVATION LOCATIONS OF POTENTIAL FAILURE RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] Horizontal and vertical transitions in mass and stiffness may cause failure at transition points and possible overturning. 9 - 10 Combination of “Soft” Story and Overhang
ANALYSIS OF VULNERABILITY BUILDING ELEVATION LOCATIONS OF POTENTIAL FAILURE RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] Horizontal transition in stiffness of soft story columns may cause failure of columns at foundation and/or contact points with structure. 10 Building on Sloping Ground
SOFT STORY BUILDING ON SLOPING GROUND: CHINA TRIGGERED LANDSLIDES
ANALYSIS OF VULNERABILITY BUILDING ELEVATION LOCATIONS OF POTENTIAL FAILURE RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] Horizontal and vertical transition in stiffness and cause failure of individual members. 8 - 9 Theaters and Assembly Halls
ANALYSIS OF VULNERABILITY BUILDING ELEVATION LOCATIONS OF POTENTIAL FAILURE RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] Horizontal and vertical transition in mass and stiffness may cause failure columns. 9 - 10 Sports Stadiums
SIMPLICITY IN A BUILDING’S FLOOR PLAN REDUCES ITS VULNERABILITY TO STRONG GROUND SHAKING
BUILDING FLOOR PLANS • FACT: CHANGING FLOOR PLANS FROM SIMPLE TO COMPLEX AND FROM SYMMETRICAL TO ASYMMETRICAL WILL INCREASE A BUILDING’S VULNERABILITY TO GROUND SHAKING.
ANALYSIS OF VULNERABILITY FLOOR PLAN POTENTIAL PROBLEMS RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] None, if symmetrical layout maintained. 1 Box
ANALYSIS OF VULNERABILITY FLOOR PLAN POTENTIAL PROBLEMS RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] Differences in length and width will cause differences in strength, differential movement, and possible overturning. 2 - 4 Rectangle
ANALYSIS OF VULNERABILITY FLOOR PLAN POTENTIAL PROBLEMS RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] Asymmetry will cause torsion and enhance damage at corners. 2 - 4 Street Corner
ANALYSIS OF VULNERABILITY FLOOR PLAN POTENTIAL PROBLEMS RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] Asymmetry will enhance damage at corner regions. 5 - 10 “U” - Shape
ANALYSIS OF VULNERABILITY FLOOR PLAN POTENTIAL PROBLEMS RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] Open space in center reduces resistance and enhance damage at corner regions. 4 Courtyard in Corner
ANALYSIS OF VULNERABILITY FLOOR PLAN POTENTIAL PROBLEMS RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] Asymmetry will cause torsion and enhance damage at intersection and corners. 8 “L” - Shape
ANALYSIS OF VULNERABILITY FLOOR PLAN POTENTIAL PROBLEMS RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] Directional variation in stiffness will enhance damage at intersecting corner. 5 - 7 “H” - Shape
ANALYSIS OF VULNERABILITY FLOOR PLAN POTENTIAL PROBLEMS RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] Asymmetry and directional variation in stiffness will enhance torsion and damage at intersecting. 8 - 10 Complex Floor Plan
ANALYSIS OF VULNERABILITY FLOOR PLAN POTENTIAL PROBLEMS RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] Asymmetry and irregularities will cause torsion and enhance damage along boundaries and at corners. 5- 9 Curved Plan