| Anchor bolt steel plate reinforcement is a reinforcement technology by drilling holes in the reinforced matrix and implanting anchor bolts,and then connecting the steel plate with the anchor bolts,so that the steel plate and the reinforced member can bear load together.The technology that has high reliability is easy to construct and can avoid the bonding failure between steel plate and matrix.As the core component of the reinforcement system,the shear performance of the anchor bolt will have the most direct impact on the effectiveness and safety of the reinforcement.Therefore,it is particularly necessary to study the shear performance of the anchor bolt and influencing factors.The special structure of the direct shear anchor bolts can effectively eliminate the installation gap and solve the problem of uncoordinated load of the group anchors.At present,there are many researches on the shear performance of group anchors,but few researches on the shear performance and its constitutive relationship of single anchor,especially the direct shearing type.In this paper,the shear test of single anchor bolt was carried out at first,and then the model verification and parameter analysis were carried out with the help of the finite element analysis software ABAQUS on the basis of the test results.Finally,an attempt is made to quantitatively express the shear displacement curve formula of the direct shear anchor bolt.The main research contents and conclusions of this paper are as follows:(1)Single bolt shear test was carried out for three different diameters of anchor bolts,in which variables such as anchoring depth and loading plate thickness were set.The shear performance of direct shear anchor bolts was compared with that of single anchor of common anchor bolts.Through the analysis of the shear force displacement curve and deformation form,the results show that: Firstly,in the case of single anchor,both the direct shear anchor and the common anchor can give full play to their respective bearing capacity,but the advantage of the shear performance of the former are not notable in this case;Secondly,for the direct shear anchor with three diameters,there is no obvious difference in the shear performance between the buried depth of 6times diameter and 8 times diameter;Thirdly,the increase of the thickness of the loading plate makes the restraint effect on the anchor bolt better,so that the anchor bolt is closer to the pure shear stress state during the shear process.(2)Based on the ABAQUS finite element analysis software,the anchor bolt steel plate members were modeled under each variable,and the simulation results were verified one by one.The results show that the finite element model of anchor bolt shear resistance established by the modeling method in this paper can simulate the load displacement curve and deformation characteristics of anchor bolt under shear more realistically.(3)Based on the finite element model verification,the simulation parameters of the direct shear bolt shear test were analyzed,and the influence of the diameter of the bolt,the strength of the concrete substrate,the embedded depth of the bolt and the thickness of the loading plate on the shear performance of the bolt was investigated.The results showed that: Firstly,the diameter of the anchor bolt is the most significant factor affecting its shear performance,and increasing the diameter can significantly improve its shear rigidity and bearing capacity;Secondly,the increase of concrete strength can enhance the shear rigidity of the direct shear anchor bolt,but the effect is not obvious;Thirdly,the embedding depth mainly affects the rigidity of the direct shear anchor bolt after shear yield,and the effect of rigidity increase becomes insignificant when the anchoring depth is greater than 6d;Fourthly,initial shear rigidity,yield rigidity and ultimate shear capacity and displacement was notably affected by the increase of thickness of the steel plate,and there is a critical value of steel plate thickness when the thickness is greater than the value enhancement effect will be not obvious;Fifthly,the shear performance of the single anchor between the direct shear anchor and the common anchor is not significantly different,but the restraint effect of the steel plate on the direct shear anchor is stronger than that of the common anchor,so the initial shear rigidity of the direct shear anchor is slightly greater than that of the common anchor.(4)Based on the curves under different variables obtained from tests and simulations,an attempt is made to quantitatively express the shear displacement curve formula of the direct shear anchor bolt. |
PDF Full Text Request