Publication

Abstract : Structural walls are subjected to axial load with bi-axial bending. Despite this, structural walls are designed considering the demand along the strong axis. However, to minimize damage to structural wall it is necessary to design structural walls considering P–Mx–My interaction. Currently, IS 456:2000 recommends design P–Mx–My interaction for columns using a non-dimensional parameter (𝛼𝑛). In theory, the recommended 𝛼𝑛 are meant for symmetric column sections with uniform distribution of longitudinal reinforcement. Consequently, it is necessary to verify the applicability of the design P–Mx–My interaction equation for structural walls. Furthermore, the 𝛼𝑛 values recommended in the design code are shown to underestimate the flexural capacity of columns, particularly at lower axial load ratios (i.e., Pu/Puz; where Pu is the axial load demand and Puz is the maximum compressive load capacity of the column). To address these issues, the paper recommends design 𝛼𝑛 values for rectangular RC structural walls. Additionally, the paper presents simplified design equations to develop bi-axial interaction for structural walls. The simplified equations present in this paper are developed using regression analyses of rectangular structural walls with: (a) aspect ratios ranging between 4 and 25, (b) longitudinal reinforcement ratios from 0.5% to 1.5%, (c) reinforcement grades of 415 and 500 MPa, and (d) grade of concrete between M20 and M55. The proposed bi-axial interaction for structural walls will help designers to assess the adequacy of wall with relative ease.