| Compared with normal-strength steel,high-strength steel with higher strength can significantly reduce the size of structural components,lighten structural self-weight and save steel quantities,which has been increasingly used in steel structures.However,with the improvement of steel strength,the yielding to tensile strength ratio of steel is increased and its ductility becomes worse,the effect of which on the design of highstrength steel structures needs to be further studied.The application of high-strength steel structures needs to ensure high-strength steel components are effectively connected,and bolted connection is one of the main connections of steel structures.In order to study the block shear failure behavior of high-strength steel bolted angles and further extend the application of high-strength steel structure,the full-scale test and numerical analysis on the block shear failure behavior of Q690 high-strength steel double-row bolted angles have been conducted by this paper.The main studies and results were concluded as follows:(1)The static tensile test of Q690 high-strength steel double-row bolted angles was conducted and the block shear failure mode of Q690 high-strength steel doublerow bolted angles was identified.The load-displacement and load-strain curves of the bolted angles failed by block shear were obtained.The test results showed that the double-row bolted angles exhibited two kinds of block shear failure modes(i.e.BS1 and BS2 mode).Compared with Q275 angles,the ductility of Q690 angles is relatively lower,but they still exhibit evident characteristics of ductile failure.The increases of bolt number,pitch distance and edge distance contributed to the enhanced block shear strength of the angles,but the length of the unconnected leg had no significant influence on the angles’ block shear strength.(2)Nonlinear finite element numerical models of double-row bolted angle specimens using ABAQUS software were established.The accuracy of the finite element numerical model was validated by comparing the failure mode,loaddisplacement curves and ultimate strength of numerical analysis with the test results.Based on the validated finite element model,the stress on block shear failure planes of angles was extracted and then the stress distribution and evolution on these planes were analyzed.The results showed that when the angles failed by block shear,the tensile stress of net tensile section was mainly developed on the connected leg section,and the tensile stress on the unconnected leg section was distributed nonuniformly.The shear stress on the active shear plane was distributed more uniformly than that on the gross shear plane.(3)A fast finite element parametric modeling technology for the double-row bolted angles was developed based on Python language which is a secondary development tool provided by ABAQUS.Then,parametric studies on the block shear behavior of Q690 high-strength steel double-row bolted angles were developed.The analysis results showed that the increases of end distance and bolt number contribute to improving the block shear resistance,but their influences are limited.As for the angles with relatively shorter connection length and longer net tensile section length,increasing their transverse pitch distance was more effective to improve their block shear strength than increasing their edge distance.The eccentricity of different connection types of steel angles has no obvious effect on the block shear strength.An increasing connected leg length of angles can slightly enhance their block shear strength and ductility when the unconnected leg length is kept identical.(4)The test and numerical parameter analysis results of Q690 high-strength steel double-row bolted angles were compared with that predicted by the equation in various design standards and proposed by literature.The results showed that the predictions for the block shear strength of Q690 high-strength steel double-row bolted angles given by GB50017-2017 were more conservative than other equations. |
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