Damage Effect Of Concrete T-Beam Bridge Subjected To Blast Load

At present,bridge explosion accidents have happened occasionally.Structure damage and heavy casualties have been caused by explosion seriously,as a result,the normal using of bridges and the safety of people have been affected.Dynamic problem of bridge structure have been little researching which should pay more attention to the bridge design specifications.In addition,numerical simulation have been providing theoretical while they lack experimental studies.Therefore,combining the experiment with numerical simulation is beneficial to investigate the dynamic response,damage effect and constitutive relation of the bridge.Based on the basic theory of explosion,this paper designs the concrete simple T-beam bridge models,and explosion tests were made under different explosion height,diversified explosion locations(cross section)and various quantity of TNT.In these tests,SR-RCT was used to probe the concrete cracks development,and Utekl was used to collect Wing plate and Rib’s strains and accelerations.With the data from the tests,the dynamic response of T-beam bridge model under different explosion height,diversified explosion locations(cross section)and various quantity of TNT was analyzed.The dynamic response law of T-beam bridge model was simulated by the ANSYS/LS-DYNA software which found that if the quantity and height of TNT were at the same level,the change of loading position would lead to a certain change of strain of wing plate and ribbed plate.The stimulation tells that,changing the height of loading while keep the quantity of TNT and the location of loading,if the height is lower,the strain of wing plate and ribbed plate will increase,while the increase is not obvious.Ensuring loading height and position unchanged,the increase of the quantity of TNT will lead to the obvious increase of the strain of wing plate and ribbed plate with a fast curve growth.The the maximum strain value growth of wing plate growth is faster than that of the ribbed plate,which means that under the explosive load,the wing plate will get damaged before the ribbed plate.The reinforcement of girder bridges wing plate and roof can increase its property of anti-explosion.Experiment data were used to analyze the dynamic response.The comparative analysis of the simulation results and the experiment results shows.(1)The reduction of the height of the explosion may lead to the increase of the damage area of bridge and the amount of damage positions,while the bridge is still stable,telling that the set explosion height is safe.(2)With the increase of quantity of TNT,the damage of bridge becomes more obvious,leaving the whole bridge beam is mainly broken and lost stability which shows that the bridge beam is more sensitive to the quantity of TNT.(3)The change of the explosion location had no influence on the state and position of the bridge beam,which shows that the explosion position make little influence on its property of anti-explosion.(4)The bridge explosion,In the word,its wing plate and bottom edge position of ribbed plate,featuring highest sensitivity,are the most easily damaged areas.