Seismic performance of reinforced concrete squat walls with embedded cold-formed and thin walled steel truss

To investigate the seismic performance of squat reinforced concrete (RC) walls with embedded cold-formed and thin walled (CFTW) steel truss, experimental and analytical studies were conducted. Four one-third scaled composite wall specimens were tested to failure subjected to cyclic load reversals under constant axial load. The experimental behaviors of test specimens including damage development process, load-deformation responses, stiffness degradation, energy dissipation capacity, failure pattern and ductility were discussed. Test results indicate that the embedded CFTW steel truss web braces can effectively avoid web concrete crushing and improve the energy dissipation capacity of shear walls with low aspect ratios, resulting in a more ductile failure pattern due to the failure of boundary elements. Nonlinear finite element analysis (FEA) on test specimens was carried out based on suggested modeling techniques and the accuracy of the numerical method was verified. Influences of critical parameters such as axial load ratio, amounts of embedded CFTW steel truss chord and web braces on the performance of the composite shear walls were further examined through comprehensive parametric analysis. It shows that the axial load ratio has a significant impact on the post-yielding behavior of composite shear walls. Good displacement ductility can be achieved under medium level of axial load ratio. Increasing the amount of embedded truss chord cannot significantly improve the performance of composite walls. The embedded truss web braces are noticeably beneficial to the energy dissipation capacity and ductility behavior of squat composite walls.