Study On Blast Resistant Performance Of Reinforced Concrete Slabs Strengthened With High Strength Steel Wire Mesh And Polymer Mortar

In recent years,the explosion occurred around the common events,including residential gas pipeline explosion and residential near the dangerous goods warehouse explosion,including extremists on the crowded public buildings of the terrorist bombing,resulting in a large number of personnel casualties.With the terrorist attacks and accidental bombings continuing to increase,the issue of explosion safety is also becoming more and more prominent.The reinforced concrete slab is an important force component in the building structure,and its anti-blast impact level has a key role in the explosion safety of the whole building structure.Therefore,in order to improve the anti-explosion design level of the important building structure,it needs to be retrofitted.At present,it is possible to improve the anti-blast performance of the original specimens by sticking steel,clad steel,and FRP reinforcement to the reinforced concrete slab.However,since the reinforcement method involves the use of organic structural adhesives,applied in High Temperature Environment.High strength steel wire mesh-Polymer mortar reinforcement technology is a new type of reinforcement technology.Compared with the traditional reinforcement measures,it has better fire resistance,corrosion resistance and durability,and has been used in the building structure and bridge seismic reinforcement widely,but there is no relevant research on this reinforcement technology applying in the field of anti-blast protection.Therefore,it is very important to explore the anti-blast performance of reinforced concrete slabs with high strength steel wire mesh-polymer mortar under the impact of explosion.In this paper,the anti-blast performance of reinforced concrete slabs reinforced with high-strength steel wire mesh-polymer mortar under explosive load is studied by numerical simulation.On the basis of validating the simulation results of the finite element software ANSYS / LS-DYNA,the influence of the strength of the mortar,the thickness of the mortar and the spacing of the wire rope on the reinforcement effect were analyzed,and the effect of the reinforcement parameters on the reinforcement effect was analyzed.This is the preparatory work for the explosion test.Later,7 different reinforced concrete slabs under the parameters of explosion test,comparison and analysis of the test results of reinforced and unreinforced slab,reinforcement factors test take into consideration the strength of mortar,steel wire rope,wire rope and pin spacing of prestressing,and from the failure mode,specimens crack development and steel strain and the displacement time curves were compared.The main conclusions are as follows:(1)Using finite element software LS-DYNA to simulate the dynamic performance of the reinforced concrete slab under explosion load,we proved that the finite element model and material properties of the rationality and validity of and the comparison of the parameters are analyzed in detail.Simulation results show that the double reinforcement effect and anti explosion the performance is better than that of single reinforced mortar;but also found that the reinforcement effect of layer thickness and mortar strength of reinforced concrete plate is significant.(2)According to the experimental phenomena and data,high-strength steel wire mesh and polymer mortar anti explosion effect of reinforced concrete plate is very significant,the extent of damage of the slab significantly reduced.The explosion load ratio distance were 0.94 m/kg1/3,0.84 m/kg1/3,0.70 m/kg1/3,the whole slab bending failure,strengthening peak displacement and residual displacement of the plate were greatly reduced,reinforcement strain was also decreased,and no overall peeling failure of reinforced layer.(3)Through the comparison and analysis of test,the results show that the reinforcement layer of wire rope spacing(short side*long edge is 30 mm * 50mm)than the wire rope spacing(short side*long edge is 60mm*100mm)has better reinforcement effect and the reinforcement layer energy dissipation capacity significantly improved,and effectively reduce the extent of damage low plate under blast loading.(4)Can also be found from the test results that prestressing steel wire rope can effectively reduce the maximum displacement and the maximum strain at the bottom of the plate tensile reinforcement;increasing the strength of mortar can enhance the bonding ability between rope and mortar and the overall reinforcement deformation capacity and stiffness of the reinforced layer,but there could existing a stiffness coordination problem.Using the pin can effectively prevent the blast loading reinforcement layer and the original concrete slab shedding,but the impact is unlikely to improve the antiknock performance of the original specimens.(5)The reinforced concrete slabs strengthened with high-strength steel wire mesh and polymer mortar reinforcement design proposal: 1)According to the level of anti-explosion design specimens,reasonable selection of wire rope reinforcement layer spacing increased energy dissipation capacity,in order to reduce the degree of damage to reinforced concrete slab.2)It is suggested that some shear pins should be set in the middle position of the RC plate to increase the interface bearing capacity of the strengthened layer and the original specimens.3)The strength of reinforcement layer and the the stiffness of original reinforced concrete slab should be matched,in order to achieve better anti explosion reinforcement effect.