Pile Group Under Transient Impact Loading

摘要奖：CMS 97 - 13951 P. K. Banerjee等人，SUNY布法罗"瞬态冲击荷载下的桩群" 本研究主要探讨交通与滨水建筑物在冲击作用下的主要受力经验，即瞬时水平荷载。 这种载荷通常传递到支撑在桩组和/或钻孔轴上的结构基础。 桩和钻孔竖井基础的横向荷载的实用设计采用弹性地基梁分析来模拟这种动态荷载。 在该分析中，从桩到土壤的载荷脱落由"p-y"弹簧表示，其中土壤响应（p-y或力与挠度曲线）被建模为一系列离散的非线性弹簧。虽然p-y曲线已经根据经验进行了修改，以考虑到许多观察到的现象，如非线性，慢循环响应，阴影区和群体相互作用因素等，动力扰动在群桩间的传播从未被考虑过。 因此，使用这些弹簧进行动态加载有! 通过实验和分析研究相结合，可以显著改善和合理验证。 本研究的目的是开发和验证一种改进的分析方法，群桩（包括钻孔桩）的设计受到瞬态横向冲击荷载。 研究任务包括：a）从分析和实验两方面对层状介质中桩群的瞬态冲击行为进行了批判性研究; B）改进分析方法的开发; c）测试和验证所提出的新方法; d）在数值代码中实施改进方法。 实验研究将涉及现有的负载测试数据的分析，以及为测试和验证改进的分析方法创建新的测试数据。 这项工作将在全国范围内适用并产生直接影响。 根据本研究的结果，可以向AASHTO推荐修订版，以便纳入合理适用的设计规范，用于设计承受船舶冲击载荷的新结构。 ****

Abstract Award: CMS 97-13951 P. K. Banerjee et al., SUNY Buffalo "Pile Group Under Transient-Impact Loading" This research focuses on the principal force experiences in transportation and waterfront structures during impact which is transient horizontal loading. Such loads are often transmitted to the structure's foundation supported on groups of piles and/or drilled shafts. State-of-practice design for lateral loading of pile and drilled shaft foundations used beam-on-elastic-foundation analysis to model this dynamic loading. In this analysis, load shedding from a pile to the soil is represented by "p-y" springs in which the soil response (p-y or force versus deflection curves) is modeled as a series of discrete nonlinear springs. Although p-y curves have been empirically modified to take into account many of the observed phenomena such as non-linearity, slow cyclic response, shadow zones and group interaction factors, etc., the propagation of dynamic disturbance from pile-to-pile in a group has never been considered. Therefore, the use of these springs for dynamic loading has ! to be significantly improved and soundly validated by combined experimental and analytical research. The objective of this research is to develop and validate an improved method of analysis for the design of pile groups (including drilled shafts) subjected to transient lateral impact loads. The research tasks encompass: a) a critical study of the transient impact behavior of pile groups founded in layered media, both analytically and experimentally, b) development of improved methods of analysis; c) testing and validation of the proposed new methods; and d) implementation of the improved methods in a numerical code. Experimental research will involve analysis of existing load test data as well as creation of new test data for testing and validation of the improved analytical method. The work will have national applicability as well as an immediate impact. From the re sults of this study, revisions can be recommended to AASHTO for inclusion in rationally applicable design specifications for the design of new structures subjected to vessel impact loading. ****