This study aims at evaluating deterministic and probabilistic approaches for an analysis of the bearing capacity of a highway bridge foundation on undrained clay soil. The analysis of a rectangular concrete footing was presented for the ultimate strength limit state of the bearing resistance according to the formulation in ES EN 1991:2015 and ERA-Bridge Design Manual, which are the Ethiopian design codes for foundation structures. In the deterministic analysis, the traditional total safety factor method recommended by the ES EN 1991:2015, ERA and AASHTO LRFD method was implemented. It was assumed that design variables such as the soil parameters and loads would follow normal and lognormal distribution functions. With regard to the probabilistic methods, NESSUS-9.8 software, a statistical computer program, was used for the analysis. Comparisons were made between the results obtained from the traditional deterministic method and the reliability-based design approach. The evaluation asserts that the probabilistic approach is a better tool than the deterministic one for assessing the safety and reliability of geotechnical structures. The probabilistic design method rationally accounts for uncertainties more than the conventional deterministic method does. Thus, the author recommends that the National Design Codes of Ethiopia need to be revised and calibrated based on a reliability design format.
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机译:本研究旨在评估分析公路桥梁基础对不灌溉粘土土壤的承载力的确定性和概率方法。根据ES EN 1991:2015和ERA-Bridge设计手册的配方,提出了对轴承电阻的最终强度极限状态的矩形混凝土脚的分析,是基础结构的埃塞俄比亚设计规范。在确定性分析中,实施了ES EN 1991:2015,ERA和AASHTO LRFD方法推荐的传统安全因子方法。假设设计变量,如土壤参数和负载将遵循正常和逻辑分布功能。关于概率方法,NESSUS-9.8软件,统计计算机程序用于分析。在传统的确定性方法和基于可靠性的设计方法获得的结果之间进行了比较。评估断言,概率方法是用于评估岩土结构的安全性和可靠性的确定性的更好的工具。概率设计方法合理地占不确定性的不确定性,而不是传统的确定性方法。因此,作者建议基于可靠性设计格式进行修改和校准埃塞俄比亚国家设计代码。
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