Efficient flat-slab post-tensioning layouts guided by Topology Optimization

Topology optimization with density methods has been applied to post-tensioned flat-plate slab framing considering common support configurations with the objective of reducing material and improving deflection performance. The optimization objective is the minimization of out compliance in a domain delimited by the concrete floor plate subjected to vertical gravity loads. The results are interpreted to give typical guidance of post-tensioned tendon layouts in the flat-slab. These methods have been applied to design of buildings, highly coordinated with contractor means and methods, and currently being constructed. Based on this practical and comprehensive research, two efficient post-tensioned tendon layout concepts are proposed named Rounded and Overlapping Circles. They proved to be more efficient and higher performing than traditional orthogonal post-tensioned tendon layouts resulting in savings of up to 25% on the post-tensioning weight required in the slab. In practice, savings are found to go up to 35%. This economy is achieved by reorienting the tendons to respond more efficiently to the gravity load experienced and is multiplied throughout all floors of the building. The authors validate the concept of stiffness-oriented post-tensioned tendons layout and conclude on the potential of defining typical patterns for the optimized layout of flat-slab post-tensioned systems for common support arrangements.