Dynamic Response Study Of Prestressed T-beams Under Blasting Loads

As an important infrastructure in road traffic,bridges play an important role in the national economy.Bridge may bear all kinds of blasting loads such as terrorist attacks and transportation accidents blasts within its life-cycle.PRC-T beams are widely used in bridge engineering,therefore,the risk of terrorist attacks are high.Focusing on terrorist attacks above the bridge surface,this paper designed the PRC-T beams blasting experiment program and carried out 3 PRC-T beams model experiments,the effectiveness of numerical simulation were verified by experiments results,through the experiment and numerical simulation,the damage modes and mechanisms of the PRC-T beams are studied in this paper.The main contents are as follows:(1)Design the experiment program of contact blasting loads on PRC-T beams.Firstly,the model size and steel bar are designed,and three specimens are built according to the design.Secondly,the tests of concrete basic mechanical properties are proformed.Finally,the data acquisition system and experiment condition are designed.(2)Conduct the experiments of PRC-T beams under contact blasting loads,the damage modes of PRC-T beams under different blasting loads are analyzed.Firstly,three working conditions were determined based on the design condition and the actual situation.Then,the experiment phenomena,damage morphology of T beam and overpressure data of specimens under each working condition were collected and analyzed.Finally,according to the failure region,the local failure characteristics of the specimens are analyzed,and the overall failure modes are studied through the flexural capacity of the middle normal section.(3)Carry out thr numerical simulation on mechanisms of PRC-T beams under contact blasting loads,the damage mechanisms of the PRC-T beams are analyzed.Firstly the finite element model of PRC-T beams under contact blasting loads are established and the process of blasting and PRC-T beams' destruction are simulated.After that the feasibility of the numerical calculation model of PRC-T beams under contact blasting loads are verified.Secondly,according to the simulation of PRC-T beams' face destruction process,opposite-face destruction process on the specimens and the prestressed steels' loss,the damage mechanism of PRC-T beams under blasting load and the failure process of prestress are analyzed.Finally,the influence of explosive equivalent on the failure degree of T beam is studied through numerical simulation.