Condition Assessment of Prestressed Concrete Beams Using Cyclic and Monotonic Load Tests

Eight prestressed T-shaped beams were tested using the cyclic load test (CLT) method as proposed by ACI 437-12 followed by the ACI 318-11 monotonic (24-hour) load test method. The objective of the study is to assess the ability of these methods to evaluate damage in prestressed concrete (PC) beams. The test matrix included both pristine beams (subjected to no prior loading) as well as beams that were cracked and artificially predamaged using accelerated corrosion techniques, impressed current, and wet/dry cycles, prior to load testing. Deflections, crack widths, and slipping of the prestressing strands were recorded during the load tests. The load at which the monotonic test was conducted was chosen to be greater than the service load of Class U PC members, which does not allow cracking. This ensured that at the time of the monotonic load test the specimens were significantly damaged. However, the acceptance criteria associated with this test methodology were still met. Only one index in the CLT acceptance criteria (deviation from linearity) identified the condition of the specimens. The deviation from linearity index is found to correlate to the opening and widening of cracks.