Chapter 4 - Limit state design

Abstract

The design of any structural system must withstand the loads imposed upon it and in addition must have adequate durability throughout its life. A limit state of a structure is a condition or design performance requirement, which the structure must satisfy to fulfill its structural function. A “conditional” or hazard limit state, which corresponds to a very infrequent extreme random event, is normally treated as an ultimate limit state with modified factors of safety. To design and build a cost-effective structure, an understanding of the properties and methods of manufacture of the composite material and knowledge of appropriate design analysis methods is necessary but not sufficient. The limit state design methodology for conventional structural materials has been developed in Europe on a National and International basis by the civil and structural engineering industries and is widely recognized as providing a sound basis for the design of steel and concrete structures. The methodology is ideally suited to dealing in a unified fashion with a large number of interactive design variables. Consequently, the availability of design codes of practice for composites would greatly simplify the complexity of the designers' task by providing a rational limit state design philosophy, which would greatly enhance the design procedures for composites.