Experimental and numerical study on the mechanical behavior of Q460D high-strength steel bolted connections

Based on static tensile test of 20 Q460D high-strength steel bolted connection joints, influences of high-strength steel material strength and bolt arrangement pattern on bearing capacity and deformation of connections were analyzed. According to differences of end distance, edge distance, and pitch between bolts, finite element modeling, theoretical calculation, and test results were compared, a quantitative analysis was carried out for mechanical property of high-strength steel bolted connections, and applicability of relevant standards was investigated. The study showed that bearing capacity and deformation of specimens for Q460D high-strength steel increased as pitch increased when bolts were under transversal arrangement. Influence of increased edge and end distance on bearing capacity of the connection was minimal after standard value of the structure was reached. Stress nephogram obtained from numerical analysis and plastic region presented symmetrical distribution with two holes bearing balanced stress, fitted curve points were dispersedly distributed, and margin of theoretically calculated value was large when EC3 standard was used. When bolts were under longitudinal arrangement, bearing capacity of the specimens only presented a linearly increasing trend as pitch increased, two holes bore unbalanced stress in stress distribution, stress borne by bolt hole at end part and its deformation were both large, and bearing capacities of end and middle bolts calculated according to the EC3 standard were relatively accurate. This study can provide a theoretical basis for design and connection structure of Q460D high-strength steel bolted connection joints.