The Ultimate State Design Principles And Some Applications On Highway Bridges Structure Based On Reliability

With Highway & Bridge Specifications re-issued on Oct. 1, 2004, the structure design theory on highway bridges is gradually changing and promoting "Constant design method" to "Probabilistic ultimate state design method" during highway bridges structure design. The paper mainly explores the Ultimate State design principles and some applications on highway bridges structure based on reliability1.Elaborate basic concepts of structure reliability theory with help of mathematics statistics and probability theory; point out a general method of structural reliability analysis (Monte-Carlo Simulation) and some practical analysis method in view of mathematics model and method of structure reliability. Meanwhile, some structure element and system methods used greatly in engineering field are discussed and compared; then take the first-order second-moment method for a example to establish optimizing model of structure reliability index according to geometric meaning of structure reliability index .It is reliable and advantageous for this solving method through calculating practical samples.2.Study and establish action (or load) of highway bridges structure and probability model of resisting force and analyze its statistics characteristics and further search action load needed and statistics information of resisting force about highway bridge structure design of reliability.3. Describe the Probabilistic ultimate State design method and practical design expression of highway bridge structure based on relations between structure ultimate state equation and probability theory of reliability , then decide each item factor and structural important factor and load effect combination factor . At last, introduce basic steps of the section design of structural members and the optimal design method of reliability.