| In recent years,accidental explosion accidents have occurred frequently in China and abroad,which caused serious damage to the building or even made it collapsed.It is necessary to carry out research on the anti-explosion performance of building structures and improve their anti-explosion capabilities.The wall and slab are the main resistant member in the building structures,which are easily damaged under blast load due to its large size.The traditional reinforced concrete slabs have a disadvantage of insufficient anti-blast performance,which reflects the shortage in their protective capabilities.Therefore,it is of great significance and value to propose and study the damage mechanism and anti-explosion performance of new structures under the action of explosive load.Steel-concrete composite slab is a new type of composite structure.It has the characteristics of high shear strength,high ductility,and high energy consumption compared with traditional reinforced concrete slabs,which has been widely used in highrise and super high-rise buildings.Steel-concrete composite slabs can be divided into single side steel-concrete(SC)composite slabs,concrete-steel-concrete(CSC)composite slabs,and steel-concrete-steel(SCS)composite slabs based on the structural form.However,the anti-explosion performance of steel-concrete composite slabs has not been fully studied and revealed.This paper discussed and analyzed the influences on their antiexplosion performance and its laws of parameters such as the amount of explosive,concrete strength,steel plate thickness,and the size of the joints.At last,a simplified calculation formula of anti-explosion performance of steel-concrete composite slab was proposed based on the dynamic response and damage analysis of the three types of steelconcrete composite slabs under contact explosion.The main research work of this article is as follows:(1)3 scaled specimens of single side steel-concrete(SC)composite slabs,concretesteel-concrete(CSC)composite slabs,and steel-concrete-steel(SCS)composite slabs were designed and manufactured.3 composite slabs and 1 ordinary reinforced concrete slab under contact explosion load were carried out to study the anti-explosion performance of the composite slab through damage analysis,comparison of displacements and accelerations at the bottom of the slab,and maximum deflection in the mid-span through the experimental and numerical method.(2)Based on the ANSYS / LS-DYNA nonlinear finite element program,three types of steel-concrete composite slabs were numerically analyzed to study the damage mode,maximum deflection of the mid-span,and peak acceleration of the measurement point,which were compared with the test results to verify the accuracy and applicability of the finite element model.(3)The parametrical analysis was conducted to study the influence of parameters such as explosive quantity,concrete strength,steel plate thickness and joint size on the antiexplosion performance of the steel-concrete composite slab.The results showed that: increasing the concrete strength can reduce the plastic damage of the structure;increasing the thickness of the steel plate can effectively reduce the maximum mid-span deflection of the composite plate,but this phenomenon is not obvious in the single-sided steelconcrete;the increase of the length of the connecting piece can reduce the separation phenomenon of the steel plate and the concrete plate,which is more obvious in the singlesided steel-concrete composite slab.(4)Based on the data of the relation between explosive charge and mid-span deflection obtained from the parametric analysis,the empirical formulas for the deflection of the span of the three types of composite plates were obtained through multiple nonlinear regression.The results showed that the fitting formula can reasonably predict the midspan deflection of the composite plate under the action of an explosion. |
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