VULNERABILITY OF BUILDINGS TO EARTHQUAKE GROUND SHAKING GENERALIZED
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
ELEMENTS OF RISK HAZARDS EXPOSURE RISK VULNERABIL ITY LOCATION
BUILDING DAMAGE: DEATH TOLL REACHED 230, , 000
CAUSES OF DAMAGE INADEQUATE RESISTANCE TO HORIZONTAL GROUND SHAKING SOIL AMPLIFICATION PERMANENT DISPLACEMENT (SURFACE FAULTING & GROUND FAILURE) EARTHQUAKES IRREGULARITIES IN ELEVATION AND PLAN CASE HISTORIES TSUNAMI WAVE RUNUP LACK OF DETAILING AND POOR CONSTRUCTION MATERIALS LACK OF ATTENTION TO NON-STRUCTURAL ELEMENTS
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
ANY COMMUNITY CAN ASSESS THE VULNERABILITY OF ITS BUILDINGS BY EXAMINING EACH BUILDING’S ELEVATION AND FLOOR PLAN • An Incremental Process CLARIFY VULNERABILTIES INDENTIFY OPTIONS IMPLEMENT BEST SOLUTION INITATE ACTIONS OPTIMIZE EVALUATE
SOURCE OF INFORMATION • The following graphic assessments of building vulnerability to earthquake ground shaking were developed by an insurance company and provided to other organizations for educational uses.
BUILDING ELEVATIONS • Horizontal and vertical changes in symmetry, mass, and stiffness—deviations from regularity--- will increase a building’s vulnerability to damage from ground shaking.
AN IMPORTANT NOTE • NOTE: Analysis of the effects of changes in the local site geology and the construction materials, key parameters in controlling a building’s performance, are NOT considered here.
ANALYSIS OF VULNERABILITY BUILDING ELEVATION LOCATIONS OF POTENTIAL FAILURE RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] 1 -2 Box None, if attention given to foundation and non-structural elements. Rocking may crack foundation and structure. XCracks around windows.
DAMAGED HOUSE: CHINA
ASYMMETRY AND LATERAL CHANGES: CHINA
ANALYSIS OF VULNERABILITY BUILDING ELEVATION LOCATIONS OF POTENTIAL FAILURE RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] 1 Pyramid None, if attention given to foundation and non structural elements. Rocking may crack foundation.
ANALYSIS OF VULNERABILITY BUILDING ELEVATION LOCATIONS OF POTENTIAL FAILURE RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] 4 -6 Inverted Pyramid Top heavy, asymmetrical structure may fail at foundation due to rocking and overturning.
ANALYSIS OF VULNERABILITY BUILDING ELEVATION LOCATIONS OF POTENTIAL FAILURE RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] 5 -6 “L”- Shaped Building Asymmetry and horizontal transition in mass, stiffness and damping may cause failure where lower and upper structures join.
ANALYSIS OF VULNERABILITY BUILDING ELEVATION LOCATIONS OF POTENTIAL FAILURE RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] 3 -5 Inverted “T” Vertical transition and asymmetry may cause failure where lower part is attached to tower.
ANALYSIS OF VULNERABILITY BUILDING ELEVATION LOCATIONS OF POTENTIAL FAILURE RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] 2 -3 Multiple Setbacks Vertical transition in mass, stiffness, and damping may cause failure at foundation and transition points at each floor.
ANALYSIS OF VULNERABILITY BUILDING ELEVATION LOCATIONS OF POTENTIAL FAILURE RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] 4 -5 Overhang Top heavy asymmetrical structure may fail at transition point and foundation due to rocking and overturning.
ANALYSIS OF VULNERABILITY BUILDING ELEVATION LOCATIONS OF POTENTIAL FAILURE RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] 6 -7 Partial “Soft” Story Horizontal and vertical transitions in mass and stiffness may cause failure on soft side of first floor; rocking and overturning.
ANALYSIS OF VULNERABILITY BUILDING ELEVATION LOCATIONS OF POTENTIAL FAILURE RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] 8 - 10 “Soft” First Floor Vertical transitions in mass and stiffness may cause failure on transition points between first and second floors.
THE TYPICAL SOFT-STOREY BUILDING IN TURKEY
ANALYSIS OF VULNERABILITY BUILDING ELEVATION LOCATIONS OF POTENTIAL FAILURE RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] 9 - 10 Combination of “Soft” Story and Overhang Horizontal and vertical transitions in mass and stiffness may cause failure at transition points and possible overturning.
ANALYSIS OF VULNERABILITY BUILDING ELEVATION LOCATIONS OF POTENTIAL FAILURE RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] 10 Building on Sloping Ground Horizontal transition in stiffness of soft story columns may cause failure of columns at foundation and/or contact points with structure.
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)] 8 -9 Theaters and Assembly Halls Horizontal and vertical transition in stiffness and cause failure of individual members.
ANALYSIS OF VULNERABILITY BUILDING ELEVATION LOCATIONS OF POTENTIAL FAILURE RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] 9 - 10 Sports Stadiums Horizontal and vertical transition in mass and stiffness may cause failure columns.
BUILDING FLOOR PLANS • CHANGING FLOOR PLANS FROM SIMPLE TO COMPLEX AND FROM SYMMETRICAL TO ASYMMETRICAL WILL INCREASE A BUILDING’S VULNERABILITY TO GROUND SHAKING.
ANALYSIS OF VULNERABILITY POTENTIAL PROBLEMS FLOOR PLAN RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] 1 Box None, if symmetrical layout maintained.
ANALYSIS OF VULNERABILITY POTENTIAL PROBLEMS FLOOR PLAN RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] 2 -4 Rectangle Differences in length and width will cause differences in strength, differential movement, and possible overturning.
ANALYSIS OF VULNERABILITY POTENTIAL PROBLEMS FLOOR PLAN RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] 2 -4 Street Corner Asymmetry will cause torsion and enhance damage at corners.
ANALYSIS OF VULNERABILITY POTENTIAL PROBLEMS FLOOR PLAN RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] 5 - 10 “U” - Shape Asymmetry will enhance damage at corner regions.
ANALYSIS OF VULNERABILITY POTENTIAL PROBLEMS FLOOR PLAN RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] 4 Courtyard in Corner Open space in center reduces resistance and enhance damage at corner regions.
ANALYSIS OF VULNERABILITY POTENTIAL PROBLEMS FLOOR PLAN RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] 8 “L” - Shape Asymmetry will cause torsion and enhance damage at intersection and corners.
TORSION: CHINA
ANALYSIS OF VULNERABILITY POTENTIAL PROBLEMS FLOOR PLAN RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] 5 -7 “H” - Shape Directional variation in stiffness will enhance damage at intersecting corner.
ANALYSIS OF VULNERABILITY POTENTIAL PROBLEMS FLOOR PLAN RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] 8 - 10 Complex Floor Plan Asymmetry and directional variation in stiffness will enhance torsion and damage at intersecting.
ANALYSIS OF VULNERABILITY POTENTIAL PROBLEMS FLOOR PLAN RELATIVE VULERABILITY [1 (Best) to 10 (Worst)] 5 - 9 Curved Plan Asymmetry and irregularities will cause torsion and enhance damage along boundaries and at corners.
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