Bearing Capacitystudy Of Q690Tubular Jointused In Herringbone Column And Cross-brace

Herringbone column chord and horizontal supports pipe-pipe intersection joint isone kind of major joint in the steel structure. Though there has relatively muchtheoretical studies and experimental studies on pipe-pipe intersection joint at home andabroad, but most of the studies are about joints’ ultimate bearing capacity under theaxial force on chord and branch. There has some studies about branches’ mechanicalproperties subjected to complex loadings such as in-plane bending moment、bendingmoment、shear force、axial forceand the out-of-plane bending moment,etc. However it’snot comprehensive enough.In additionwhen the bearing capacity of the joints can notachieve the requirements of the overall structure or joints are required to be rigidlyconnected in the actual project, strengthen measures will have to be taken on thejoints.In one hand, once there have some strengthen measures been taken, formulas forcalculating the bearing capacity which applicable before become not applicable anymore. In the other hand, the specification of the both at home and abroad rarelyinvolved design formulas for joints that have taken strengthen measures,steel Q690hasnot been widely applied in the practical engineering yet, the mechanical performanceand failure mechanism of herringbone column chord and horizontal supports pipe-pipeintersection joint made of steel Q690is not clear at present.Thence,carrying on someexperimental studies on the performance and systematic numerical analysis on anexperimental basis of this kind of Q690high strength steel joints is necessary.This article take the method of combining the numerical calculation andexperimental means.Loading tests forfour groups eight full scale specimen are carriedout, mechanical performance、damage phenomenon and ultimate bearing capacity ofQ690herringbone column chord and horizontal supports pipe-pipe intersection Joint areobtained by analyzing experiment phenomena and data. Based on experimental results,a reasonable finite element model is established. Through a large number of finite elementcalculation of Q690herringbone column chord and horizontal supports pipe-pipeintersection joint, systematic analysis can be carried on. Research the mechanicalproperties of the joints with kinds of strengthening measureswhen they are in differentgeometric parameters, as well as the actual effects of strengthening measures.Analysis found that: when the nodes taking three different kinds of strengthenmeasures，there are varying degrees of improvement for bearing capacity of each kindsof nodes.What’s more the effect of the improvement of the three kinds of strengthenmeasures is basic quite.But on the other hand the impact of the plastic properties of thethree strengthen measures has a different effect:the form of the destruction of the innersleeve strengthen node completely passed from plastic failure to brittle failure;theplastic performance of nodes within the spacer ring retain well;the plastic performanceof nodes with tile-shaped plate becomes lower, but still has good plastic deformationcapacity.Besides, the article also studies the effects on the ultimate bearing capacity andmechanical performance when changing related parameters of the nodes.