Influence of Prestressing Force on Performance of Prestressed Concrete

In the present study, the performance of square prestressed concrete plates was investigated against drop impact. All the plate specimens were cast using the same concrete having 28 day’s strength of 48 N/mm2. The span length of the plates and thickness was kept the same for all the plates as 0.80 m and 0.10 m, respectively. The level of prestress in the plates varied between 0 and 30%. A known mass of 242.8 kg was lifted to 0.5 m and 1.0 m height and dropped freely to hit the target plates. The deflection, impact force, reaction, damage and energy absorbed were obtained through different sensors and studied. The finite element (FE) simulation of the problem was also carried out to understand the mechanics of deformation and for the reproduction of experimental findings. The metal plasticity and Holmquist-Johnson-Cook (HJC) models were used for steel (for tendon and reinforcement) and concrete, respectively. The prestress in the plates was noticed to have reduced the magnitude of deflection such that the highest deflection was noticed in plates with 0% prestress followed by 20% prestress and 30% prestress. The flexural deformation was dominant in plate having 0% prestress, while plates with 20% and 30% prestress have pronounced splitting damage. The energy absorbed by the plates induced with 20 and 30% prestress was found 5.4 and 6.3% higher compared to the plate with 0% prestress. The finite element simulation reproduced the response of the plates with a good correlation.