Abstract: The loading uncertainties of bridge and structure ma y be expressed by the upper and lower boundaries of an interval.The interval Fin i te Element Method(FEM) is used to obtain the conservative bounds for the displac ement and force response quantities.The linear elastic beam elements are applied in the discretization of a real bridge.The bounded intervals are used in express i ng the load vector with unertainties.The conservative bounds for the response qu antities are determined by the theory of interval algebra and linear elastic pro g ramming.Then,the conservative bounds for the response can be obtained.The propos ed formulation is applied to the practical design of bridge and structure loadin g combinations.The results of an example indicate that the method used here is c onvenient and simple.This method also has small calculation work and is suitable to calculate the loading combinations of bridges and structures in the practica l design.

Key words: interval algebra, finite element method, bridge and structure, loading combinations, load uncertainties

摘要： 不确定的桥梁结构荷载,可以用上、下限的区间来表示,用区间有限元 (FEM)方法可以求得结构位移和内力响应的包络界限.用线弹性梁单元对实际桥梁结构进行离散化,并用确定的区间值表示不确定的荷载向量,根据区间代数原理和线性有限元程序求解响应量的界限,从而得到结构响应量不确定性的界限.用该方法计算桥梁结构设计中的荷载工况组合效应,算例表明该方法具有使用简便、计算量小的特点,适合实际桥梁结构设计的荷载组合计算

关键词: 区间代数, 有限元法, 桥梁结构, 荷载组合, 荷载不确定性