Forensic Assessment of Performance Deficiencies of a New Department Store

Load bearing structure of a new department store consists of flat (double ribbed) reinforced concrete slabs supported directly on columns within span distances 12 x 12 m. Slabs above the first and second storey cantilever out beyond the edge columns by 3 m. After few years in service, serious performance deficiencies concerning cladding as well as interior partitions and other secondary elements were observed. Analysis of load effects showed that although the structure was safe (with respect to the ultimate limit states), the large span cantilevered slabs had insufficient stiffness. Serviceability deficiencies of the department store were primarily caused in design by lack of consideration of deflection due to permanent load and shrinkage. Several construction faults and overloading of the structure enhanced unfavorable deformation defects. It appears that causal (Bayesian) network may provide valuable insights into causal links between observed deficiencies, overall performance and utility of the building.