Analysis and Design of Pierced Deep Beams and Shear Walls

Pierced deep beams and shear walls are widely used in the construction industry. For utility and ease of construction, most openings are rectangular in shape. This leads to stress concentrations which cause cracks to extend from the corners of the openings. The width of the cracks often exceeds the serviceability limits indicated by the code, and in many cases the resulting distortion of the opening causes serviceability problems, resulting in unnecessary maintenance costs. This project aims to develop methods of analysis and design rules for pierced deep beams and shear walls which will permit determination and limitation of serviceability cracking together with ultimate strength, allowing rational design of such components. The aims of the project will be accomplished by first developing a novel numerical model capable of simulating the behaviour of openings in these components under a variety of loading conditions. This numerical model will employ an exciting new computational technique, the scaled boundary finite element method, to permit efficient modelling of the stress concentration, crack initiation and crack propagation from the corners of the openings. The model will be verified by application to full-scale deep beam tests and scale model shear wall tests. This detailed numerical model will be used to evaluate and refine existing consistent strut-tie models for ultimate strength design of pierced deep beams. At the same time simplified approaches for the prediction of crack widths will be formulated. For deep beams with penetrations simple design tables for satisfaction of serviceability criteria will be developed. For shear walls, two approaches will be developed and investigated. The first will be based on pseudo-empirical correlation of moment and shear in the equivalent link beams over the opening (based on the linear elastic frame-type analysis typically used in practice). In the second approach a simplified element suitable for inclusion in frame analysis packages will be constructed. This will permit prediction of crack openings directly and allow more accurate analysis of the global effects of reduced stiffness on the structural response. Typical configurations will be investigated and suitable code provisions will be proposed to ensure that existing serviceability criteria are satisfied.