Reliability Analysis Of Sheet Pile Quaywalls And Pile Foundations Of Harbour Engineering

Sheet pile quaywalls and pile foundations of harbour engineering shall be designed, constructed and maintained in such a way that they are suited for their use during the design working life and in an economical way.The rationality of design method is implied in the safety level prescribed in design code.Thus,the rationality may be considered as the basis of structure design.For revising the design code of sheet pile quaywalls and code of pile foundations of harbour engineering,the reliability of sheet pile quaywalls and pile foundations is studied in this paper.The main contents are summarized as follows:(1) A new method called "virtual simply supported beam" method is presented in this paper,in which only the soil layer is necessary to divide.A set of equations are set up based on deformation compatibility principles and the boundary equilibrium conditions of sheet pile. The solution of the equations gives the results of deformations and internal forces of sheet pile, and the tension of tie rod.Forteen sheet pile quaywalls are selected from practice to check the validation of the new method.It is indicated that there is a good agreement between the results analyzed using the new method and those obtained from software ANSYS.The results show that the new method can be used in the design of sheet pile.(2) Factors influencing the reliability of sheet pile quaywalls are discussed and limit state functions are established for different failure modes.Based on the analysis results in this paper and target reliability indexes prescribed in various reliability based design codes,the target reliability indexes are presented for structural design of sheet pile quaywalls in China. The partial factors for resistance in design equations are presented in order to ensure the reliability indexes resulting from design equations approach the target ones.(3) An analytical method is developed to predict the responses of laterally loaded pile in layered soils.The method uses fundamental basis of structural mechanics to obtain the governing equations of the soil and pile systems.Both free head and fixed head piles are considered in this method.The pile deflections,bending moments and soil reactions can be calculated using this method.Deflections and bending moments calculated using this method are found to be in good agreement with those obtained from ANSYS,thus verifying the reliability of the proposed method.Based on the presented method,the reliability of pile subjected to lateral load is analyzed. (4) The measured ultimate shaft resistances and point resistances of soil are compared with those given in Code for Pile Foundation of Harbor Engineering based on collected static load test data.The reliability of axially loaded single pile designed in accordance with formula prescribed in the code is analyzed.(5) The probability density functions of the statistics related to the best linear unbiased estimate method are derived,allowing for the small sample properties of static load test data. The confirmation of analytical results is accomplished by the use of Monte-Carlo simulations. The characteristic value determination of ultimate bearing capacity of piles from static load test data is discussed.Furthermore,a method is presented for analyzing the reliability of pile designed based on static load test data.