| Because of the advantages of simple structure and low cost,reinforced concrete beamless floor has been widely used in commercial and residential buildings.However,because the RC slab-column connections are prone to brittle punching shear failure,and easy to cause the collapse of the entire structure.In order to improve the bearing capacity and deformation performance of RC slab-column connections,the current configuration often take stirrups,bent-up bars,studs,but these cutting resistance measures to improve the cutting resistance of slab-column connections is limited,therefore,research and development of superior resistance to new cutting measures to improve the security of this kind of structure has an important theoretical significance and practical value in engineering.This article first on the punching shear capacity calculation method is not unified and difference is big,analyzing slab-column connections by the punching shear capacity calculation model of uncertainty in current design code:GB50010-2010,ACI318-19,EN1992,JSCE15,CSA A23.3-14 and BS 8100,the code of the K-S test can be compared to the national standard of RC slab-column connections punching node degree of deviation with the test data,determine the model calculation model uncertainty of probability statistics.The results show that the accuracy of EN1992 and JSCE15 is high.To effectively improve plate column node cutting resistance,for the purpose,put forward by the longitudinal chord and oblique abdominal rod welded together space steel truss as the new cutting measures,using the finite element software ABAQUS,the built-in steel truss RC slab-column connections under the vertical load cutting resistance,analyses the failure mode,concrete,steel,steel truss,etc.,revealing the built-in steel truss punching failure mechanism of slab-column connections,deeply analyzes the form of steel truss structure parameters such as against the influence of cutting performance.The results show that the section size of the web bar with steel truss can effectively improve the punching capacity and anti-punching performance of slab-column connections,and the abutment bar can limit the development of cracks and strengthen the aggregate bite action of concrete at cracks.System in this paper the scholars at home and abroad in recent years,according to different theoretical background plate by punching shear bearing capacity calculation method,put forward by the analysis of the concrete strength,ratio of reinforcement,effective depth,column length,longitudinal reinforcement yielding strength and so on main factors that affect punching plate,the results show that the critical shear crack caution of theoretical derivation,calculation accuracy is higher,is a relatively ideal model for calculating the punching shear capacity.In turn,based on the critical shear crack theory model,combined with the finite element simulation analysis,through the strict derivation set up internal punching steel truss concrete slab-column connections model and a simplified and practical calculation method,this method can accurately calculate the web member in stress under different working conditions,the punching shear capacity calculation results are in good agreement with the test data,and has good reference value to guide the engineering practice. |
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