Numerical investigation of precast RC beam with unbonded prestressing tendon under impact loads

Abstract

In this work, dynamic performance of precast reinforced concrete beam connected by unbonded prestressing tendon under impact loads was conducted using the numerical simulations. First, a detailed numerical model for cast-in-place beam was established, and the simulation method was verified with the available test observations. Then, the numerical model of precast beam connected by unbonded prestressing tendon was established. The parameters of impact velocity, impact position, concrete strength and prestressing level were investigated, respectively. The results show that the failure modes of precast beam with prestressing tendon is shear failure mode which is similar to that of cast-in-place beam under impact loads, and a large number of shear cracks are formed in the mid-span impact location. The interface of precast beam is the weak area, and it is easy to form through shear cracks under impact loads. The residual displacement of precast beam is smaller than cast-in-place beam due to its good self-resetting ability. It should be noted that with the decrease of prestressing level, peak displacement, residual displacement and damage degree of precast beam increase gradually. Additionally, with the increase of concrete strength, the peak displacement of precast beam decreases gradually.