Time-Dependent Deflection and Deformation of Reinforced Concrete Flat Slabs - An Experimental Study

This article reports on an experimental program of long-term testing of large-scale reinforced concrete flat slab structures. The authors present the results from tests on seven continuous flat slab specimens. Each specimen was subjected to sustained service loads for periods up to 700 days and the deflection, strains, extent of cracking, and column loads were monitored throughout. The authors note that the defection and extent of cracking in reinforced concrete slabs are difficult to predict with confidence. The results showed that measured long-term deflection is many times the initial short-term deflection, due primarily to the loss of stiffness associated with time-dependent cracking under the combined influences of transverse load and drying shrinkage. Thus, time-dependent cracking greatly affects the serviceability of flat slabs. In all specimens, new cracking occurred with time and existing cracks extended and widened (usually on the top surface). The authors maintain that this effect is not accounted for adequately in the current code approaches for deflection calculation and control. The results form a benchmark set of data from which more reliable deflection calculation procedures can be developed and calibrated.


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  • Accession Number: 01000387
  • Record Type: Publication
  • Files: TRIS
  • Created Date: May 25 2005 7:21AM