Real-life monitoring of slab and beam deflection of a multi-level office building

Serviceability failure in buildings can occur when actual deflection exceeds an allowable deflection limit as a result of flexure. Excessive deflections may cause many serviceability problems to other parts of the building such as aesthetic, functional and structural problems. Over the past several years, numerous cases have been reported, in Australia and elsewhere, of flexural elements for which the calculated deflection is far less than the actual deflection. Hence, the primary objectives of this research are to develop an analytical model to evaluate the time-dependent deflections in post-tensioned concrete suspended slabs and validate this model by using real-life measurements of long-term slab deformations. For this purpose actual deflections of slabs and beams of a multi-level office building under construction are being measured. The building is a 11-storey office building with post-tensioned one way-spanning slabs and band beams. This paper presents a comparison between measured on site deflections of slabs and beams during construction with calculated deflections using the simplified method given in AS 3600.