Reliability analysis of foundations accounting for parametric uncertainties
Aye, Lwin Nandar
Date of Issue2016
School of Civil and Environmental Engineering
The most important thing for engineers is the safety of the structure. To obtain safe structure, the design consideration is the most fundamental to deal with uncertainties. It can be said that the superstructure is not in safe condition without reliable foundation of the structure. The design of the foundation is to be able to transfer the loads from the structure without overloading of soil. The overloading of the soil can cause the soil’s shear failure or the excessive settlement that can destroy the structure. Foundation can be classified into shallow foundation and deep foundation based on the structure and soil condition. The main focus of this project is to design shallow foundations and deep foundations with two design methods: Eurocode 7 design approach and Reliability-Based Design. Eurocode 7 design is the limit state design approach and the design point is obtained from the characteristic values that are applied with partial factors. Increasing or decreasing the value of design point will cause the structure’s failure. Although Eurocode 7 is a reliable design approach, it cannot define the probability of failure. Reliability-Based Design is a design method based on reliability and engineers use it to analyze the structure. Unlike Eurocode 7, the design point is based on the mean value, standard deviation and correlation matrix. The reliability-based design is to indicate the most likely failure design point and it can automatically reveal sensitive parameters. The probability of failure can be estimated from the target reliability index. The result will be compared with Monte Carlo Simulation @RISK. It shows that the results obtained from reliability index are approximately similar to the results generated by Monte Carlo Simulation @RISK. Although Eurocode 7 design approach is a design method, there are some limitations. Firstly, the probability of failure cannot be obtained using Eurocode 7. Second, the partial factors proposed by Eurocode 7 are not able to cover uncertain parameters of different sensitivities in some conditions. Last but not least, Eurocode 7 cannot consider the correlation between parameters.
Final Year Project (FYP)
Nanyang Technological University