Calibration to Determine Load and Resistance Factors for Geotechnical and Structural Design
Calibration to Determine Load and Resistance Factors for Geotechnical and Structural Design
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通过校准确定岩土和结构设计的载荷和阻力系数
DOI：
10.17226/21978
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
R. Bathurst
中科院分区：
文献类型：
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作者：
T. Allen;A. Nowak;R. Bathurst
随着北美设计规范中极限状态设计方法的出现，越来越需要获取统计数据来评估结构和岩土设计的可靠性。可靠性取决于负载和电阻系数，这些系数是通过使用可用统计数据的校准程序确定的。本通函描述了可用于确定岩土和结构设计的载荷和阻力系数的方法。该通函首先介绍了基本的可靠性概念，然后介绍了可用于表征数据的详细程序，以开发可靠性分析所需的统计数据和函数，提供了详细的分步示例，最后在统计数据有限时提出了实际考虑。详细讨论了可用于简单情况的估计负载和阻力系数的封闭式解决方案，以及更严格的概率分析方法（例如蒙特卡罗方法）。针对必须考虑单个或多个负载的情况提供了程序。还提供了一个示例，演示了仅考虑给定设计方法的输入参数的可变性与考虑设计方法的整体可变性的效果。这种方法还可用于评估给定设计参数的可变性对设计可靠性的影响。本通告旨在向 AASHTO 或类似负载和阻力系数设计 (LRFD) 规范的用户介绍如何制定负载和阻力系数。此外，在某些情况下，必须开发新的负载和/或阻力系数，或者由于项目或区域特定问题而无法直接应用当前负载或阻力系数。本文提供的信息可用于估计负载和阻力系数，其中根据当地经验和数据调整这些系数是合理的。还提供了校准输入和结果的记录标准。撰写本通函的前提是读者对基本统计概念和工具有一定的了解。然而，为了方便那些不熟悉的人，附录中提供了基本统计概念的简要总结。
With the advent of limit states design methodology in North American design specifications, there has been increasing demand to obtain statistical data to assess the reliability of structural and geotechnical designs. Reliability depends on load and resistance factors that are determined through calibration procedures using available statistical data. This Circular describes methodologies that can be used to determine load and resistance factors for geotechnical and structural design. The Circular begins with basic reliability concepts, continues with detailed procedures that can be used to characterize data to develop the statistics and functions needed for reliability analysis, presents detailed step-by-step examples, and concludes with practical considerations when statistical data are limited. Closed-form solutions for estimating load and resistance factors that can be used for simple cases, as well as more rigorous probabilistic analysis methods such as the Monte Carlo method, are discussed in detail. Procedures are provided for situations where either single or multiple loads must be considered. An example is also provided that demonstrates the effect of considering only the variability of the input parameters for a given design methodology versus considering the overall variability of the design method. Such an approach can also be used to assess the effect of variability of a given design parameter on the reliability of the design. This Circular is written to educate users of AASHTO, or similar Load and Resistance Factor Design (LRFD) specifications, on how load and resistance factors are developed. Furthermore, there are some cases when new load and/or resistance factors must be developed, or when current load or resistance factors are not directly applicable due to project- or region-specific issues. The information provided herein can be used to estimate load and resistance factors where adjustment of these factors is justified based on local experience and data. Criteria for documentation of calibration input and results are also provided. This Circular has been written with the assumption that the reader has some familiarity with basic statistical concepts and tools. However, for the convenience of those lacking that familiarity, a brief summary of basic statistical concepts is provided in an appendix.