| Summary: | 碩士 === 國立臺灣科技大學 === 營建工程系 === 93 === The purpose of this study is to apply the reliability concept to study the ultimate vertical bearing capacity of prestressed concrete driven pile. Two tasks conducted in this study are: (1) using the First Order Second Moment (FOSM) method of CalREL to analyze the relationship between the safety factor and the probability of overestimation, (2) application of the Load and Resistant Factor Design (LRFD) method on driven pile design.
This study uses the pile test results of prestressed concrete driven pile of No. 6 Naphtha Cracker in Me-Liao for the reliability analysis. The analytical results can be summarized as follows. (1) While safety factor is 3.0, the probability of overestimation is 0.00001~0.000001 when using three estimating methods investigated in this study to design the pile. (2) When the dominant soil layer is noncohesive soils and the safety factor is 3.0, if the standard deviation of the parameter of soil (SPT-N value, effective friction angle) increase one time, the probability of overestimation can increase 100 times at most. (3) For prestressed concrete driven pile designed by the SPT-N method of general building (the ratio of live load to dead load is 0.5 to 2.0), the resistant factor suggested is 0.33 to 0.50, the dead load factor is 1.02 to 1.07, and the live load factor is 1.27 to 1.52. On the other hand, the resistant factor suggested is 0.27 to 0.55, the dead load factor is 1.02 to 1.07, and the live load factor is 1.25 to 1.54 if we use static method to estimate pile capacity. (4) With the conditions of this study, the resistant factor will reduce 0.69 times and live load factor will increase 1.08 times when the reliability index is increased from 2.326 to 3.09. On the other hand, the resistant factor will decrease 0.70 times when the coefficient of variation of the soil resistant increase 1.11 times.
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