核电工程双钢板组合墙-筏板基础插筋式锚固节点拉拔性能试验研究

EXPERIMENTAL STUDY ON PULLOUT BEHAVIOR OF LAP SPLICE CONNECTIONS BETWEEN DOUBLE-STEEL-PLATE COMPOSITE WALLS AND RC RAFT FOUNDATION IN NUCLEAR ENGINEERING

双钢板混凝土组合结构结合了钢与混凝土两种材料的优势、力学性能以及耐久性优越,且施工快速便捷,正越来越广泛地应用于核电工程中。双钢板混凝土组合墙与钢筋混凝土筏板基础的锚固节点是其优越性能充分发挥的关键之一。插筋式节点相较于传统嵌入式节点和埋件式节点可以显著提高施工效率,从而得到更多青睐,但是目前关于该类节点锚固性能的研究较少。该文设计了4个1∶2缩尺的双钢板混凝土组合墙-钢筋混凝土基础插筋锚固节点,对其进行静力单调拉伸试验。通过对试件承载力、刚度、裂缝形态、钢筋及钢板应变等开展分析,探究了搭接钢筋布置方式以及对拉钢筋配置对于节点锚固性能的影响规律,并针对可能的破坏模式提出了相应的设计方法。试验结果表明:该类节点可以实现等强连接,且延性较好;对拉钢筋对控制裂缝发展,提高节点整体性具有重要作用,且沿长度方向对拉钢筋应变呈非线性分布;随着搭接钢筋与钢板距离的增大,钢筋与钢板间的不平衡力矩增加,导致对拉钢筋应变增大,但搭接钢筋的滑移有所降低。该文研究结果为插筋式节点的锚固设计提供了重要依据。

Combining the advantages of steel and concrete, the double–steel-plate composite(DSC) structures exhibit the advantages of high bearing capacity, good seismic performance and durability, and convenient construction, and they have been increasingly used in nuclear engineering projects. The connection between DSC walls and reinforced concrete raft foundation is the key to make full use of the aforementioned advantages.Compared with the traditional embedding connection and anchoring connection, the lap splice connection can greatly improve the construction efficiency, which gains more and more attention. However, there is few research on such connection. Therefore, in this paper, four 1∶2 scaled lap splice connections between double-steel-plate composite wall and RC foundation are designed, and the static monotonic loading tests are carried out. Through the observation of bearing capacity, stiffness, crack pattern and strains of steel plate and rebar, the influences of the arrangement of lapped bars and tie bars on the mechanical performance of the connections are explored. The test results show that this kind of connection can achieve equal strength and shows satisfactory ductility.Transverse bars can control the crack development effectively and improve the integrity of the connection greatly;in addition, the tie bar strain along the lap length is not linearly distributed. The higher eccentricity of the lapped bars, which means larger unbalanced moment between the reinforcement and the steel plate, will result in lager strains of the transverse bars and lower slip of lapped bars. This paper provides experimental basis for the design of lap splice connections.