Seismic Shear Forces in Post-Tensioned Hybrid Precast Concrete Walls: Fid-Bau Portal

Seismic Shear Forces in Post-Tensioned Hybrid Precast Concrete Walls

Buddika, H. A. D. Samith / Wijeyewickrema, Anil C.

A method to accurately calculate seismic shear forces in post-tensioned hybrid (PH) precast concrete walls under risk-targeted maximum considered earthquake ( ${MCE}_{R}$ ) level ground motions is essential to avoid unexpected damage or possibly failure. Although extensive research on seismic performance evaluation of PH precast concrete walls has been carried out previously, the postelastic amplification of shear forces due to higher-mode effects, relative to the design shear forces computed using the equivalent lateral force (ELF) procedure, has been addressed only in a limited manner. In the present study, first the equations to calculate shear forces in PH precast concrete walls, post-tensioned rocking (PR) precast concrete walls, and reinforced concrete (RC) shear walls are examined and their limitations discussed. Then an extensive numerical study of PH precast concrete walls designed using the equivalent lateral force procedure is carried out. The applicability of currently available equations to calculate seismic base shear forces in PH precast concrete walls are evaluated by comparing them with the results of nonlinear response history analysis (NLRHA) using a suite of 40 ground motions. Next, the shear force distribution over the wall height in PH precast concrete walls is also investigated. Regarding the base shear force, it is found that the existing methods developed for PR precast concrete walls and RC shear walls can produce reasonable estimates of the base shear. In the case of the wall shear force along the height of the wall, existing methods for RC shear walls are found to provide good estimates. Based on the results obtained, (1) an equation to calculate the peak base shear force and (2) a multilinear shear force design envelope to calculate wall shear forces along the height of the PH precast concrete walls are proposed under ${MCE}_{R}$ -level.