Report from Structural Team 3/17/10

Report by Team Members Jack Moehle, Jeff Dragovich, Carlos Sempere, Juan Jose Besa, and Benjamin Westenenk

3/17/10

Department store in Concepcion after looting and being set afire.

Image 1687 below

Midrise concrete building in Concepcion. Significant damage to concrete walls over nearly entire height of building. Lateral system features two longitudinal walls running NW/NE with transverse walls. Transverse walls heavily damaged in at least first and second stories.

Images 1725, 1724 below

Highrise concrete core-wall building in Concepcion. Severe damage including axial shortening of stories on SW face, severe damage on NW face, insignificant damage visible on other two faces. View of north NW corner (1734). Collapsed story on NW face (1732). Damage to NE face (1762). Close-up of pier damage on NE face (1741). View of NE face (1766).

Images 1730, 1734, 1732, 1762, 1741, 1766

Midrise concrete building in Concepcion. Two towers arranged in L configuration, separated at intersection, where elevator shaft is located (1788). Note failure of penthouse spanning the elevator shaft and expansion joint. Subterranean parking adjacent to the towers. Towers themselves on unknown foundation. Damage to pavement surrounding Tower A suggests rocking (1823). Structural damage to Tower A (1798) mainly concentrated in transverse walls. Crushing and inclined cracking damage of end wall in Tower A (1811). Diaphragm cracking suggests transfer from discontinuous walls to continuous walls.  Tower B has only minor damage.

Images 1788, 1823, 1798, 1811

Group of several similar concrete midrises. One tower (the first constructed in the group, ca 2001) had balcony beams that apparently coupled walls out of plane; may be source of wall boundary damage (1943). Significant damage to one concrete wall (1947) led to axial subsidence that buckled adjacent partition wall (1948).

Images 1943, 1947, 1948

Concrete building on square in Concepcion (ca 1965). Unable to enter building. Portion extending horizontally beyond lower stories apparently has concrete columns with masonry infill. Substantial concrete walls reported to be inside the remainder. Note failure of columns at setback.

Image 1999