Considerable progress has been made on the research of non-rectangular reinforced concrete (RC) squat walls over the past decades. However, the experimental data of L-shaped RC squat walls remain limited, especially for their seismic behaviors under non-principal bending actions. This paper presents an experimental and numerical investigation on L-shaped RC squat structural walls with an emphasis on how varying the directions of lateral cyclic loading influences the seismic responses of these walls. Four L-shaped specimens are tested under lateral cyclic displacements and low levels of axial compression The variables are axial loads and lateral loading directions. The performance of specimens is discussed in terms of cracking patterns, failure mechanisms, hysteretic responses, deformation components and strain profiles. Furthermore, three-dimensional finite element models are developed to supplement the experimental results. The direction of lateral loading is found to have a significant effect on the peak shear strength of L-shaped RC squat walls.

Flanged RC squat walls, defined by a shear span ratio less than two, are widely used in conventional buildings and nuclear facilities. However, due to the mechanical defects and insufficient parameters included, equations available in building codes and the literature exhibit significant scatter in predicting the peak shear strength of such walls. In this paper, a modified strut-and-tie model, including effects of flanges, was developed to account for the force-resisting mechanism in flanged RC squat walls and to derive the function form of the peak shear strength equation. Nonlinear regression was conducted to obtain the magnitude of unknown coefficients in the function form using a database containing 119 walls. The finalized equation was simplified and evaluated with models available in the literature. Results revealed that the proposed equation performs much better than current methods and provides guidance for the design of flanged RC squat walls.