Element 1 - Testing & Analysis
Task 1.4.4 Behavior of Shear Walls
PI: Gerard Pardoen (University of California, Irvine)
The extensive damage to wood frame construction during recent earthquakes has shown that the current design codes have not met expectations. In an effort to characterize the load deformation behavior of 8’ x 8’ shear walls, the City of LA-UCI project recently completed the testing of 36 shear wall configurations using the SEAOSC sequentially phased displacement protocol.
Task 1.4.4 of the CUREE-Caltech Woodframe project is intended to -
• complement the CoLA shear wall project,
• provide a comparison to the behavior of the UCSD two-story house’s shear walls,
• evaluate the hysteretic behavior designed to current code requirements,
• evaluate the effects of perforations, composite behavior, and aspect ratio.
Task 1.4.4 consists of 25 shear wall configurations of one-story or two-story height with a common 16’ length. The one-story shear walls are either fully sheathed, have a 3’ x 6’-8 person door opening or have a 10’ x 7’ garage door opening. The two-story configurations are either fully sheathed on both floors or fully sheathed on the first floor and perforated with two 4’-6" x 4’ window openings. Most shear walls will be fastened with gun-driven nails. With the exception of three configurations subjected to a ‘slow, UCSD shake table’ displacement time history, the shear walls will be tested in accordance with the reversed cyclic CUREE test protocol.
The 25 configurations include shear walls with and without gravity loads, walls with stucco and/or oriented strand board, walls with gypsum wallboard interior, walls with common nails, and walls with the sheathing attached with staples. Each shear wall will be instrumented to measure the force in the anchor bolts, the diagonal deformation (racking), the uplift of the hold-down studs, the sill plate slippage, and the uplift of the sill plate. The displacements will be measured with linear potentiometers whereas the forces will be measured with load cells.
The CUREE test protocol requires a monotonic load pattern prior to testing the shear walls to the reversed cyclic load test protocol. Accordingly the monotonic tests for the three representative, one-story configurations (fully sheathed, sheathed with person door, sheathed with garage door) with oriented strand board sheathing have been completed. The load-deformation behavior of these shear walls due to the monotonic load condition provides the reference displacement needed for the ensuing CUREE test protocol using reversed cyclic loads.