一、前言可靠性设计的概念和优点已越来越多地被世界各国土木工程界所认识和接受,近十几年来得到了广泛的应用。目前发达国家的工程建设标准、规范都在向可靠度设计过渡,以建立在可靠度理论基础上。为适应世界这一潮流,提高我国标准、规范的水平,、各工程部门都开展了这方面的研究工作,并取得了一定的成果。建筑部门率先于1 976年开始可靠性研究,并于1978年着手编写“建筑结构设计统一标准”其后水工、铁道、港口、公路等部门也针对某些结构开展了工作。1989年g月,各部门共同完成了第一层次的“工程结构可 I. INTRODUCTION The concepts and advantages of reliability design have been increasingly recognized and accepted by civil engineering circles all over the world and have been widely applied in the past ten years. At present, the engineering construction standards and norms of developed countries are all transitioning to reliability design based on the reliability theory. In order to adapt to the trend of the world and improve the standards of our country, the engineering departments have carried out research in this field and have achieved certain results. The construction department took the lead in reliability studies in 1976 and began writing 1978 ”Uniform Standards for Design of Building Structures". Later, the departments of hydraulics, railways, ports and highways also carried out work on certain structures. In the month of 1989, all the departments jointly completed the first-level project structure