LONG-TERM DEFLECTION OF HIGH-STRENGTH LIGHTWEIGHT AGGREGATE CONCRETE BEAMS

Three high-strength lightweight aggregate concrete (LWAC) beams were experimented for long-term deflections,which lasted for nearly 1 year, with the average 28-day compressive strength 601 8MPa and 6414MPa. From the test results it is observed that long-term deflections developed quickly at early ages and reinforcement ratio for compression steel had a significant effect on time-dependent deflections. Finite element methods had been developed to account for time-dependent deflections of reinforced concrete members and a good agreement was achieved. It isfound that ACI318 and ACI435methodshad resulted in good estimates for the time-dependent deformation and the design methods of current Chinese codes may be unsafe.