Progressive collapse of multi-storey buildings due to sudden column loss — Part I: Simplified assessment framework

Accepted versio

Progressive collapse of multi-storey buildings due to sudden column loss—Part II: Application

Accepted versio

A new look at Eurocode 3

This paper is concerned with the recently published Eurocode 3: Part 1.1: General Rules and Rules for Buildings, the introduction of which has highlighted a problem facing the structural design community: the ability of engineers to quickly locate relevant information from lengthy and seemingly complex codes. Two solutions are proposed: the first involves restructuring Eurocode 3 into sections dealing with specific design tasks; the second applies hypertext software. Hypertext is a facility for creating computer-based documents that contain sophisticated search and reference facilities.<br/

Finite element idealisation of a cold-formed steel portal frame

A simple linear beam idealization of a cold-formed steel portal frame is presented in which beam elements are used to idealize the column and rafter members, and rotational spring elements are used to represent the rotational flexibility of the joints. In addition, the beam idealization takes into account the finite connection length of the joints. Deflections predicted using the beam idealization are shown to be comparable to deflections obtained from both a linear finite element shell idealization and full-scale laboratory tests. Using the beam idealization, deflections under rafter load are divided into three components: Deflection due to flexure of the column and rafter members, deflection due to bolt-hole elongation, and deflection due to in-plane bracket deformation. Of these deflection components, the deflection due to bolt-hole elongation is the most significant and cannot, therefore, be ignored. Using the beam idealization, engineers can analyze and design cold-formed steel portal frames, including making appropriate allowances for connection effects, without the need to resort to expensive finite element shell analysis

Material and geometric properties of structural steel for use in design

This paper establishes an up-to-date measure of the variability of the material and geometric properties of commercial quality structural steel. A comprehensive set of measurements (over 7000 samples) was obtained and collated. The large data set was sufficient to evaluate the type of probability distribution characterising variability. The results provide the detailed statistical evidence essential for reliability analyses of the type needed to underpin the selection and calibration of new design rules for structural steel components. The statistical data reported are compared with the measures of variability assumed during the calibration of Eurocode 3 (EC3) partial safety factors; it is shown that some of these may safely be reduced.<br/

Design and development of a general cold-formed steel portal framing system

A general cold-formed steel portal framing system is proposed that uses simple bolted moment connections, formed through brackets, for the joints. Such brackets are easy to manufacture and the joints easy to assemble on site. The joints, however, are semi-rigid and the importance of this for the design of the frame is explored through a combination of numerical analysis and full-scale testing. A simple beam idealisation that accounts for the semi-rigidity of the joints in a frame analysis is described and verified using a combination of finite element shell analysis and laboratory tests. The efficiency of the proposed frame is compared to that of an equivalent rigid-jointed frame, including consideration of serviceability requirements and practical site constraints on the size of the brackets and number of bolts used for the joints. For certain combinations of frame geometry and imposed loading such frames are shown to provide very competitive alternatives to conventional rigid jointed hot-rolled steel construction