Torsional Response of a Two-Storey Low-Damage Concrete Wall Test Building

In recent earthquakes, poor performance and collapse of buildings attributed to inelastic torsion responses have been reported. The torsional responses of buildings have been extensively studied with analytical models, but large-scale experiments considering seismic-induced torsion demands on buildings are rare. A shake-table test of a two-storey, low-damage concrete wall building with strength asymmetry in the plan view was recently conducted, and the response of the building to both unidirectional and bi-directional loadings at the design-level earthquake intensity is presented. Analysis of the results includes the global responses of the structural components and the centre of mass for the test building, the strength response of unbonded post-tensioned walls, the interaction between the translational strengths and torque, the total absorbed energy related to the torsional rotation, and variations in the eccentricities of the centres of rigidity and strength. Furthermore, the seismic response of the test building is explained with a comparison to previously published torsional mechanisms. Key outcomes from the analysis of the test results included: (1) an increase in the strength asymmetry and bi-directional loading both amplifies the torsional rotations and effects the displacement and strength responses of the structural components along the perimeter of the diaphragm; (2) the comparison to previous torsional mechanisms shows a desirable level of agreement and supports the utilization of these mechanisms to assess the torsional performance of low-damage wall buildings with irregularities; and (3) despite exhibiting a strong torsional response, the test building with the asymmetric strength configurations still achieved the low-damage performance targets.