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T-shaped slender reinforced concrete (RC) structural walls are commonly used in medium-rise and high-rise buildings as part of lateral force resisting system. Compared to its popularity, experimental results on seismic performance of these walls are relatively sparse, especially for data regarding these walls in the non-principal bending directions. This article aims at providing additional experimental evidence on seismic performance of T-shaped RC structural walls. Experimental results of six T-shaped RC walls were presented. These walls resemble the structural walls found in existing buildings in Singapore and possess slightly inferior details compared to the requirements of modern design codes. The test variables were the loading direction and the axial load ratio. The experimental results were discussed in terms of the failure mechanisms, cracking patterns, hysteretic responses, curvature distributions, displacement components, and strain profiles. In addition, the experimental results were compared with methods commonly adopted in current design practice including the nonlinear section analyses, shear strength models and effective width of the tension flange. The experimental data illustrate that the shear lag effect not only was not accurately accounted for by the effective width method but also significantly affected the strength and stiffness of the tested specimens.

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This paper evaluates the three-dimensional (3D) or slab effects on reinforced concrete (RC) buildings to mitigate progressive collapse, which is caused by the loss of an interior column. Six one-quarter scaled beam-column, or beam-column-slab substructures are tested. These six specimens are categorised into three series (P-, T-and S-series).The test results confirm that transverse beams and RC slabs can reduce the collapse vulnerability of RC buildings effectively. In addition, it is quantified that 3D effects without slab can increase the yield load of the frame by up to 100%, while 3D effects including slab can increase the yield load up by 246 . 2%. This is because the slabs not only increase the bending moment capacity of beam sections working as flanges, but also provide more alternative load paths for load redistribution. RC slab can upgrade the first peak load of the buildings by developing compressive membrane actions, and upgrade the ultimate load capacity of the building during the large deformation stage by developing a tensile membrane action. As the number of tested specimens is relatively small, a series of numerical and parametric studies are carried out to further quantify the 3D or slab effects on RC buildings in resisting progressive collapse.

Reinforced concrete (RC) T-shaped walls have been studied by many researchers over the past decades due to their popularity. Among them, however, few investigations are conducted regarding T-shaped squat walls, especially for their seismic behaviors under nonprincipal bending action. To build the database and improve the understanding of structural walls, reversed cyclic tests of four RC T-shaped squat walls were conducted under displacement control. The variables were axial loads and lateral loading directions. Seismic responses of specimens were presented and assessed in detail from various aspects. Nonlinear section analyses and finite element modeling were also performed to facilitate investigations. The results indicated a significant shear lag effect exited in some T-shaped squat walls, which distinctly affected the strength and stiffness of test specimens. It was also found the impact of the shear lag effect increased with additional axial loads, and decreased as the test progressed.