Damage Effects Of Reinforced Concrete Beam&Slab Under The Combined Impact Of Blast And Fragments

Nowadays,because of the existence of terrorism,extremism and racism,people are still living in a dangerous environment.For terrorists,bombs are the most common and important weapons,including suicide bombs and car bombs.The majority considered only the damage caused by the blast wave,but the damage by the fragments is neglected.The structural damage by the fragments produced by close range explosion is serious.Therefore,the research on damage and deformation of reinforced concrete members under blast wave and the fragment is practical.In this paper,a discrete model of a reinforced concrete member is established by using LS-DYNA software.The steel bar and concrete are connected together by sharing nodes.The fragments are placed under the charge.The fragments can scatter and shock wave can propagate by detonating the explosives.The main works and results are as follows:(1)In this paper,the numerical simulation of the experiment of the reinforced concrete beam & slab subjected to close range explosion is carried out,which verifies the reliability of the parameters used in this paper.In this thesis,the different dynamic responses of the reinforced concrete beams under different loadings are studied.The effects of the standoff distance,concrete strength and stirrup reinforced ratio on the dynamic response of the reinforced concrete beams are analyzed.The failure mode of reinforced concrete beam under simultaneous blast and fragment loading is also discussed.The results show that: The dynamic response of the reinforced concrete beams under simultaneous blast and fragment loading is bigger than the sum of responses of the beam under blast loading and under fragment loading;With decreasing distance,the dynamic response of the beam is aggravated;The vertical displacement of the beam can’t be increased remarkably by increasing the concrete strength;The increase of the stirrup reinforced ratio can improve the blast-resistant capacity of the beam.In this thesis,the different dynamic responses of the reinforced concrete slabs under different loadings are studied.The effects of the standoff distance,spacing of reinforcing steel bars,slab thickness and supporting conditions on the dynamic response of the reinforced concrete slabs are analyzed.The results show that:The dynamic response of the reinforced concrete slabs under simultaneous blast and fragment loading is bigger than the sum of responses of the slab under blast loadingand under fragment loading;With decreasing distance,the dynamic response of the slab is aggravated;When increasing the slab thickness,the failure mode of reinforced concrete slab does not change,however,the dynamic response of the slab decreases;When the supporting condition is different,the failure mode is different;Decreasing the spacing of reinforcing steel bars can enhance its anti-explosion capacity.