In consideration of the deficiencies of quadratic-function-response-surface method in structural reliability analysis

an improved response surface method is presented based on high-order-response-surface function and iterative rule with the geometry principle of JC method to decide center point. Reliability analysis of piles under inclined loads is done by the improved response surface method; reliability indices of piles with excessive top horizontal displacement and of piles with material yielding are calculated; and comparisons between results by the improved method presented and results by Monte-Carlo method and quadratic-function-response-surface method are done. The calculation demonstrates that iterative loops are reduced; precision of results and stability of numerical experiments are improved in the application of the improved response surface method; and the improved method is suitable for the reliability analysis of large-scale complicated structures.