Limit State Design to Eurocode – Methodology, Design Procedure and Application

The design of a structure must ensure that under the worst loadings the structure is safe, so that during normal working conditions the deformation of the members does not detract from the appearance, durability or performance of the structure. Despite the difficulty in assessing the precise loading and variations in the strength of concrete and steel, these requirements have to be met. Three basic methods using factors of safety have been developed; (1) The permissible stress method in which ultimate strengths of the materials are divided by a factor of safety; (2) The load factor method in which the working loads are multiplied by a factor of safety, and (3) The limit state method which multiplies the working loads by partial factors of safety and also divides the materials ultimate strengths by further partial factors of safety. Various design methods and operational techniques, which take these uncertainties into account, have been developed and used. At present, the most advanced operational methods of structural design accept the partial factor format in conjunction with the concept of limit states. The Eurocode is often used along with numerical analysis procedures for a broad range of situations, and provides a unified approach to structural and geotechnical design with partial factors allowing uncertainty to be accounted for at source that often results in serious inconsistencies. The lack of available theoretical tools and knowledge is obvious in the case of gross errors, which are often the decisive causes of structural failures.

کلیدواژه ها:

Eurocode ، non-linearity ، limit state ، design ، method