钢-UHPC组合梁单钉连接件抗拔性能分析

Analysis on pull-out behaviors of single nail connection in steel-UHPC composite beams

为研究钢-UHPC组合梁单钉连接件的抗拔性能,通过6组UHPC中单钉连接件的拉拔试验和ANSYS软件数值计算,分析了栓钉直径、高度对抗拔承载力和破坏模式的影响.提出了钢-UHPC单钉连接件抗拔承载力计算公式,得到了不同UHPC和栓钉强度下栓钉钉杆拉断和UHPC开裂2种典型破坏模式的高径比界限.结果表明,若高径比大于界限值,抗拔试件破坏时栓钉钉杆被拉断,UHPC板完好,属于延性破坏;若高径比小于界限值,试件为UHPC开裂破坏,栓钉脱出,UHPC冲切破坏面与竖直面的夹角约为43°,属于脆性破坏.钢-UHPC单钉连接件抗拔承载力公式的计算值略低于模拟值,相对误差小于10%.

To study the pull-out behaviors of single-nail connections of steel-UHPC(ultra high performance concrete) composite beams, six pull-out tests of single nail connections of steel-UHPC composite beams and numerical calculation based on ANSYS software were carried out. The effects of the diameter and the height of the stud on the pull-out capacity and failure mode were analyzed. The calculation formula of the pull-out capacity of the steel-UHPC single nail connection was proposed. The limiting height-to-diameter ratios of two typical failure modes including the rod rupture of bolt nail and the cracking of UHPC were obtained under different UHPC and stud material strengths. The results show that when the ratio of height to diameter is greater than the limit value, the failure of the pull-out test piece presents with the pull-off failure of the bolt nail rod, and the UHPC is in good condition, belonging to the ductile failure. When the ratio of height to diameter is less than the limit value, the specimen present UHPC cracking failure with the stud completely out, and the angle between the punching failure surface of UHPC and the vertical surface is about 43°, which belongs to brittle failure. The calculated value of the pull-out capacity formula of the steel-UHPC single nail connection is slightly lower than the simulation value, and the relative error is less than 10%.