承插式连接桩基承台冲切性能试验

Experimental Study on Punching Shear Behavior of Pile Caps with Socket Connections

摘要:

为了探究承插式连接对桩基承台冲切力学行为的影响，设计并进行了1个现浇承台和3个不同承插深度和配筋形式的承插式连接承台的竖向冲切性能试验，比较了承插式连接桩基承台和现浇桩基承台冲切性能的差异，并探讨了承插深度和U形钢筋设置对冲切承载力的影响，对现有规范中承插式连接桩基承台冲切承载力计算公式进行了评估和改进。结果表明：承插式连接桩基承台与现浇承台的损伤发展过程相似，其冲切承载力较现浇试件小6.75%~7.85%；增加承插深度和设置U形钢筋对承插式连接桩基承台的竖向传力和冲切承载力影响很小；现有规范公式不能合理反映出承插式连接桩基承台的冲切承载力随承插深度和配筋形式变化的规律，基于试验结果修正的拉压杆模型可以合理预测承插式连接桩基承台的冲切承载力。

Abstract:

To investigate the influence of socket connections on the punching shear behavior of pile caps. Experimental tests were conducted on 1 cast-in-place （CIP） pile cap and 3 socket connection （SC） pile caps with varying embedment depths and reinforcement configurations. The punching shear performance of SC pile caps was compared with that of the CIP counterpart， and the effects of embedment depth and U-shaped reinforcement on punching shear capacity were examined. Additionally， the existing code formulas for estimating the punching shear capacity of SC pile caps were evaluated and modified based on the test results. The results indicate that SC pile caps exhibit a damage development similar to that of the CIP， albeit with a 6.75% to 7.85% reduction in punching shear capacity. Increasing the embedment depth and incorporating U-shaped reinforcement have minimal impact on vertical load-displacement behavior and punching shear strength of SC pile caps. The study highlights the inadequacy of existing code formulas in capturing the variation of punching shear strength with respect to different embedment depths and reinforcement arrangements. A modified strut-and-tie model is proposed， demonstrating its ability to provide reasonable predictions of the punching shear strength for SC pile caps.