The design and dimensioning of pile cap is a challenging task depending upon shape and thickness of cap, soil strata, pile dimension and their locations in plan. A pile cap is a reinforced concrete structural rigid slab, which distributes column forces to a group of individual piles as per rivet formula. The main assumption in rivet formula is that the pile cap should be rigid enough to distribute load uniformly. Most of the pile cap are designed by short-cut or thumb rule procedures for spacing of piles, thickness of pile cap and minimum edge distance of pile cap from pile center or edge. In the present paper, finite element analysis of pile cap is performed to capture the behavior of pile cap under axial load and moment. The focus of this study is to find adequacy of the clear edge distance for pile cap, as there are very few guidelines available. In case of minimum clear edge distance, a large amount of tensile stresses are developed at edge of pile cap, which may not acceptable. It is observed that providing 100 mm or 150 mm or 250 mm as clear edge distance suggested by most of the codes is inappropriate. However, it should be at least half of the diameter of pile used to accommodate the stresses developed at the edge as proposed in this paper depending upon the mathematical model of structure. Moreover, the proposed suggestions are well agreement with the experimental results.

中文翻译：

---

桩身净边距和间距对桩帽失效的影响

桩帽的设计和尺寸确定是一项具有挑战性的任务，取决于帽的形状和厚度、土层、桩尺寸及其在计划中的位置。桩帽是一种钢筋混凝土结构刚性板，它按照铆钉公式将柱力分配给一组单独的桩。铆钉公式中的主要假设是桩帽应具有足够的刚度以均匀分布载荷。大多数桩帽是通过桩间距、桩帽厚度和桩帽距桩中心或边缘的最小边距的捷径或拇指规则程序设计的。在本文中，桩帽的有限元分析被执行以捕捉桩帽在轴向载荷和力矩下的行为。本研究的重点是寻找桩帽的净边距是否足够，因为可用的指南很少。在最小净边距的情况下，桩帽边缘会产生大量拉应力，这可能是不可接受的。据观察，提供 100 毫米或 150 毫米或 250 毫米作为大多数规范建议的清晰边缘距离是不合适的。然而，根据结构的数学模型，它应该至少是桩直径的一半，用于适应本文提出的边缘产生的应力。此外，所提出的建议与实验结果非常吻合。然而，根据结构的数学模型，它应该至少是桩直径的一半，用于适应本文提出的边缘产生的应力。此外，所提出的建议与实验结果非常吻合。然而，根据结构的数学模型，它应该至少是桩直径的一半，用于适应本文提出的边缘产生的应力。此外，所提出的建议与实验结果非常吻合。