Ultimate Load Behaviour of Concrete Wall Panels with Varying Opening Configurations

Abstract

Currently the wall panel design equations given in the Australian Standard and the American Institute Code give no guidelines for the inclusion of side restraints, openings, or for a slenderness ratio (H/t) greater than 32. Empirical formulae have been derived based upon limited test data, in which the size and location of openings are accounted for with a dimensionless alpha parameter (a). In this study the Layered Finite Element Method (LFEM) is used to undertake three parametric studies investigating the influence of opening size, length and height on the ultimate load and deflection of wall panels performing in one-way and two-way action. A total of 20 wall models with varying opening configurations are analysed. Comparisons of the numerical results to established formula for walls with openings validated the accuracy of the LFEM predictions. Results indicate that increasing the height together with the length of the opening has the most critical effect, decreasing the axial strength ratio to different degrees for one-way and two-way walls with an increase in opening size. Increasing only the length of the opening also significantly decreases the axial strength ratio. Increasing only the opening height has little impact on the ultimate load capacity. Walls analysed in two-way action have an increased strength compared to the one-way counterparts due to the provision of side restraints, however such improved strength becomes insignificant for large sized openings. To ensure safe design, the combined effects of increasing both the height and length of an opening should be incorporated into the alpha parameter formula.