The 2-story classroom structure is part of a multi-building school campus that was severely damaged during the earthquake. The structure was approximately 20000 gsf with 8 bays in the longitudinal direction and a single bay in the transverse direction. Al...

Prepared By: Quinn Peck
Occupancy: Education
Year Built:
Height: 28 ft
Number of stories: 2
Stories below ground: 0
Size: 20000 gsf
Original Code:
Modification: Unknown
Year Modified:
Code of Modification:
Lateral Load System: Frames with Masonry Infill
Other Load System:
Vertical Load System: Slabl_Beams_Columns
Other Vertical Load System:
Foundation : Unknown
Other Foundation :
Country: Haiti
State:
City: Port-au-Prince
Street: Delmas 33, Port-au-Prince, Haiti
Latitude: 18.5545
Longitude: -72.3034


 

2-Story Classroom

Earthquake Information

 

 

Earthquake Date 1/12/2010
Moment Magnitude 7
Epicentral Distance 27
Local Intensity VIII MMI
Site Description Most of Port-au-Prince sits in the southwest corner of the Cul de Sac depression and is primarily underlain by Mio-Pliocene sedimentary deposits, relatively stiff soils with low impedance. It has been suggested that the low-lying Mio-Pliocene deposits in central Port-au-Prince may have amplified peak ground acceleration values by an approximate value of 1.8 . (Hough et al., 2011) A 2011 analysis of the site conditions throughout Port-au-Prince indicated that away from the foothills, the soil conditions largely coincide with NEHRP site class C. (Cox et al., 2011)
PGA Lateral None (g)
PGA Vertical None (g)
SaT
Ground motion recording stations
Distance to station None
Station Latitude None
Station Longitude None
Ground Motion Summary The main shock of the 2010 Haiti earthquake occurred along the Enriquillo Fault at a depth of approximately 13 km and a location of 18.457, -72.533. The focal mechanism indicates left-lateral oblique-slip motion on an east-west oriented fault with a fault rupture from east to west. The source zone had a down-dip dimension of approximately 15 km and an along-strike dimension of about 30 km - a source area about one third the size of a typical 7.0 magnitude earthquake. There were no active strong-motion instruments in Haiti so macroseismic observations offer the best estimation of shaking intensity during the main shock. Additionally, local geologic structure heavily influences the degree of ground motion amplification, further obscuring potential ground motion estimates.

 

Damage Information

 

 

Performance summary

The structure was severely damaged during the earthquake, including the partial to total collapse of the cantilevered stairways and canopies, shear cracking of captive columns and out-of-plane toppling of masonry infill walls.

Damage state description

Portions of the stairways partially collapsed, apparently because of the impact of the falling canopies. The partial-height masonry infill walls on the east side of the structure reduced the clear height of adjacent columns, resulting in shear-governed or flexure-shear behavior. The worst shear failures occurred where partial-height masonry infills were taller than normal because of a restroom. Columns next to partial-lenth masonry infill walls tended to develop flexural hinges at the top and bottom of the first floor. Full-height and full-length masonry walls tended to perform adequately, with only minor cracking in the corners from induced compression struts. The significantly deep beam sections created the beginning of a story mechanism at the first floor. Columns at various locations throughout the structure exhibited severe spalling and exposed reinforcing.

Summary of causes of damage

1. The presence of partial-height masonry infill walls along the perimeter of the building forced the columns into shear-governed or flexure-shear behavior. In the worst cases, these masonry infills resulted in shear failures. 2. Concrete canopies above stairways were supported on weak columns, resulting in their collapse. 3. The combination of nearly identical detailing in first floor and second floor columns and relatively deep beams resulted in the beginning of a story mechanism. 4. Partial-height and/or partial-length masonry infill walls tended to fail out-of-plane, creating falling hazards.

Observed Design and Construction Characteristics

 

Construction Quality

MaterialsNotesContribution to Damage
Concrete
Reinforcing steel

ExecutionNotesContribution to Damage
Conveyance/placement of concrete
Rebar
Field variance with design documents
OtherNotesContribution to Damage
Other Factors Construction Quality

Configuration

Plan IrregularitiesNotesContribution to Damage
Torsion
Perimeter boundary
Diaphragm
Out-of-plane offsets in lateral resisting system
Non-orthogonal systems

Vertical IrregularitiesNotesContribution to Damage
Soft story
Weak story
Geometric variablility of lateral resisting system
In-plane discontinuity of lateral resisting system
Mass distribution
Setback
Change in stiffness

OtherNotesContribution to Damage
Other Factors Configuration

Lateral Load Resisting System‐General

StrengthNotesContribution to Damage
Overall lack of strength

StiffnessNotesContribution to Damage
Extreme Flexibility

Load PathNotesContribution to Damage
Collectors/Struts
Anchorage of nonstructural elements
Out-of-plane capacity of walls
Diaphragm chords
Diaphragm openings

OtherNotesContribution to Damage
Other Factors Lateral Load Resisting System-General

Lateral Load Resisting System‐Frames

ColumnsNotesContribution to Damage
Shear strength
Flexural strength
Axial load ratio
Vertical load columns drift capacity
Interference of frame action by infill

BeamsNotesContribution to Damage
Strength relative to columns
Shear controlled behavior
Continuity of longitudinal reinforcing
Loss of vertical capacity
Interference of frame action by infill beams

JointsNotesContribution to Damage
Interior
Exterior
Corner

OtherNotesContribution to Damage
Other Factors Lateral Load Resisting System-Frames

Lateral Load Resisting System‐Shear Walls

ShearNotesContribution to Damage
Diagonal tension/compression
Sliding Shear
Flexure/shear

FlexureNotesContribution to Damage
Compression zone buckling capacity
Discontinuity of wall
Boundary reinforcing fracture/buckling
Boundary Reinforcing at openings

OtherNotesContribution to Damage
Other Factors Lateral Load Resisting System-Shear Walls

Lateral Load Resisting System‐Infills

InfillsNotesContribution to Damage
Unreinforced
Interference with frame action
Out of plane
Attachment to framing

OtherNotesContribution to Damage
Other Factors Lateral Load Resisting Systems-Infills

Lateral Load Resisting System‐Other

FoundationsNotesContribution to Damage
Liquefaction
Pounding
Surface Rupture

OtherNotesContribution to Damage
Pile/Pier tension capacity

MiscellaneousNotesContribution to Damage
Spread footing capacity
Other Factors Lateral Load Resisting Systems-Other-Foundations

OtherNotesContribution to Damage
Other Factors Lateral Load Resisting Systems-Other-Misc

Repair and Retrofit Information

 

Type of Retrofit or Repair

Unknown

Other Retrofit or Repair

Performance Level

Unknown

Hazard Level

Unknown

Retrofit or Repair Code

Unknown

Other Retrofit or Repair Code

Lateral Analysis

Unknown

Other Lateral Analysis

Design Strategy

Retrofit Summary

References

 

http://eqs.eeri.org/resource/1/easpef/v27/iS1/pS137_s1
Hough, S. E., Young, A., Altidor, J. R., Anglade, D., Given, D., Mildor, S., 2011. Site characterization and site response in Port-au-Prince, Haiti,Earthquake Spectra,27, S137S155.


http://eqs.eeri.org/resource/1/easpef/v27/iS1/pS67_s1
Cox, B. R., Bachhuber, J., Rathje, E., Wood, C. M., Kottke, A., Green, R., and Olson, S., 2011. Shear-wave-velocity and geology-based seismic microzonation of Port-au-Prince, Haiti,Earthquake Spectra27, S67S92.


United States Geological Survey (USGS), 2010a.USGS ShakeMap: Haiti Region,http://earthquake.usgs.gov/earthquakes/shakemap/global/shake/2010rja6/ (16 July 2012).


United States Geological Survey (USGS), 2010b.USGS Peak Ground Accel. Map (in %g): Haiti Region,http://earthquake.usgs.gov/earthquakes/shakemap/global/shake/2010rja6/#Peak_Ground_Acceleration (16 July 2012).


Telleen, K., 2012. "January 12, 2010 Haiti Earthquake: Post-earthquake reconnaissance." Earthquake Engineering Research Institute. Oakland, California. 25 June 2012.


http://ascelibrary.org/doi/abs/10.1061/41171(401)198
Zhang, D., Federico, G., Telleen, K., Schellenberg, A., Fleishman, R., and Maffei, J., 2011. Structural analyses to replicate the observed damage to engineered buildings from the January 2010 Haiti Earthquake, inProceedings, Structures Concress 2011.