Nonlinear Analysis for Masonry under Monotonic and Low Cyclic Loading

Confined masonry with tie columns and ring-beams was adopted during the reconstruction in the rural and suburban areas in Sichuan Province after the 2008 Wenchuan Earthquake. Based on the results of the sample tests of building material such as clay brick, cement mortar, steel and concrete in reconstruction and the analysis on the characteristics and features using Solid65 elements in ANSYS, the shear property of joints in masonry structures under different vertical load (σ∕fm) is numerically simulated. Comparing the experimental results with the numerical ones, the proposed values for the shear transfer coefficients for open and closed crack of Solid65 elements for simulating masonry structures are given. The seismic performance of confined masonry walls (strengthened by tie column and ring-beam, etc.) and unconfined masonry walls with different stress condition (σ∕fm) under low cyclic load are discussed. Results show that, under monotonic loading, confined masonry walls have better performance for displacement and load corresponding to the occurrence of the first crack as well as for the ultimate load and ductility, although the energy dissipating ability of unconfined walls under low cyclic loading increases with vertical load (σ∕fm) at low stress level. The results demonstrate that confined walls are greatly enhanced by strengthening measures such as tie column and ring-beams.