火灾下钢结构和组合结构的非线性模拟

近年来Sheffield大学开发了一种计算机程序Vulcan，用来对火灾下组合结构的性能进行三维模拟。本简要叙述了程序的理论基础。1995—1996年在Cardington进行了三个组合框架的抗火试验，各试验中相邻结构所提供的平面内约束程度不同，通过模拟这三个试验来显示受热区域内约束对结构性能的影响。为了阐明薄膜作用的影响及其和边界约束的关系，所有的试验都分别用几何线性以及非线性的板单元进行了分析。为此，首先对引起这种作用的钢筋的性能做了一系列参数研究。很明显，板内的薄膜作用对隔间最终的完整性很重要，并且在模拟火灾下这种类型的结构时应加以考虑。

Non-Linear Modelling of Steel and Composite Structures in Fire

A computer program Vulcan has been progressively developed for some years at the University of Sheffield,with the objective of enabling three-dimensional modeling of the behavior of composite buildings in fire.In this paper the current theoretical basis of the program is very briefly outlined.Three of the fire tests carried out in 1995-96 on the composite frame at Cardington,representing cases in which different degrees of in-plane restraint are provided by the adjacent structure,are modeled to show how this restraint affects the structural behavior within the heated zone.In order to illustrate the influence of membrane action and its relationship with boundary restraint,all cases have been analyzed using both geometrically linear and non-linear slab elements.A series of parametric studies has been carried out as an initial investigation into the characteristics of steel reinforcement which allow this action to take place.It is evident that the influence of membrane action in slabs can be very important to the ultimate integrity of compartments,and should be taken into account in the modeling of this type of structure in fire conditions.