European Convention For Constructional Steelwork Research Articles

Fatigue Reliability: ECCS Safety Factors

A simple reliability analysis for limit-state (load and resistance factor) fatigue assessments is presented. This analysis was recently proposed in guidelines published by the European Convention for Constructional Steelwork (ECCS). Partial safety factors are related directly to the safety index by means of a simple formula, and examples are shown graphically for typical target values of the safety index. Further work is needed to investigate the importance of parameters such as quality assurance and in-service inspection for a range of practical problems.

Simplified Interaction Method for Sway Frames

A number of simplifying assumptions are applied to a previously developed multi‐curve interaction method that determines the failure load of sway frames. These simplifications consider the establishment of the required parameters from a subassemblage analysis, the replacement of a rigorous second‐order analysis by a magnified first‐order solution and the determination of the “limiting slenderness ratio” from a single‐cycle approach. Furthermore, a graphical presentation of the major parameters is demonstrated. In all instances, the procedures are illustrated by examples. The results obtained by the simplified techniques indicate a good correlation with more rigorous approaches thus confirming that the presented procedures are suitable as a substitute for full‐scale elasto‐plastic computer solutions. They also produce results which are superior to the Merchant‐Rankine rule, which was proposed by the European Convention for Constructional Steelwork (ECCS) and is intended for inclusion in the new British Spe...

CEPAO—an automatic program for rigid-plastic and elastic-plastic analysis and optimization of frame structures

The computer program CEPAO handles the plastic design and analysis of plane frame structures. Classical finite element techniques combined with linear programming are used. In the plastic limit analysis, the program gives the collapsed load, the distribution of the bending moments, the normal forces, the shear forces, and the collapsed mechanisms of structures with proportional loading. Concerning stable design, the program finds the practical discrete profiles existing in Euronorm or American norm of different elements of the structure with minimum weight. The force distributions and the mechanism of the optimum state are given. The different stability conditions proposed by the European Convention for Constructional Steelwork (ECCS) are verified a posteriori to obtain, finally, a safe structure. From the fact that the European Convention recommends a limitation of elasto-plastic deflections, a step-by-step program is combined with the optimization procedure to obtain an elasto-plastic analysis of the stable structure. The program may also consider the analysis and design of frame structures under variable loadings. Efficient linear programming formulations are adopted in such a way that all necessary information, such as residual stresses, plastic deformations and optimum mechanisms, are obtained directly in the output. CEPAO may also design concrete reinforced structures (optimal limit design) where full redistribution of moments serviceability and rotation capacity of critical sections are taken into account.