Howard D. Wright

The experimental behaviour of double skin composite elements

Double skin composite elements are formed from two steel skins connected to an infill of concrete with welded stud connectors. This paper describes scale model tests on beam, column and beam column specimens. Basic failure modes are defined for each load type and more detailed observations regarding the structural action of this form of construction are given. It is concluded that the structural system provides a suitable medium for construction with predictable and therefore safe characteristics.

The design of double skin composite elements

Abstract Double skin composite elements are formed from two steel skins connected to an infill of concrete with welded stud connectors. This paper describes design development and experimental studies on the system. A design model developed from previously reported scale model tests and similar to that used for reinforced concrete is proposed. A series of full scale tests is then used to verify the model. Comparisons show that the design model is suitable for most simple elements and gives a good prediction of behaviour.

The behaviour of composite walling under construction and service loading

Abstract Composite walling is defined for the purpose of this paper as a vertical load-bearing ] system formed from two skins of light gauge, profiled, steel sheeting infilled with concrete to create a composite section. The system is a natural development of composite flooring, which is now predominant in steel framed building structures. This paper describes the walling system, the proposed construction methodology and four full-scale pilot tests on axially-loaded wall elements. It will be shown that the main advantage is associated with ease of construction, however, the low interface bond strength obtained from commercially-available decking restricts the development of the full axial capacity.

The behaviour of through-deck welded shear connectors: an experimental and numerical study

Abstract This paper describes a study of the behaviour of shear connection between steel beams and composite slabs, which use through-deck welded shear connectors. An experimental study involving three push-out test specimens was carried out and these test results were discussed. A push-out test specimen was simulated and analysed in both two and three-dimensions. The effect of the inclusion of profiled steel sheeting, the effect of the width of a concrete slab, and the effect of different loading and support conditions have been discussed. The pull-out strength of the concrete has also been studied and compared with the experimental results of tests carried out by the authors and others. A new expression based on wedged cone failure has been developed for the effective width of a concrete slab in a two-dimensional numerical analysis.

The axial load behaviour of composite walling

Abstract Composite walling is a novel system comprising two skins of profiled steel sheeting with an infill of concrete. The axial load capacity of the walls is dependent upon the capacity of the concrete and steel and the transfer of load between the two. Full scale tests reported in the paper show that the full yield stress in steel and concrete is not achieved. This is thought to be due to buckling of the thin steel component plates of the sheeting and the inability of the cross section profiled shape of the concrete to carry eccentric moments caused by imperfections in the specimen and line of loading. Modifications based upon plate buckling theory for the steel and an empirical model for the concrete are proposed that provide closer agreement between experiment and the commonly used squash load design formula. A device to more equally divide load between steel and concrete is also described along with a discussion on the efficiency of embossments in the profile.

Experimental and finite element study of profiled steel sheet dry board folded plate structures

Folded plate structures constructed with profiled steel sheeting connected to dry boards by self drilling, self tapping screws (known as the PSSDB system) are being proposed as an alternative to traditional forms of roof construction. This paper describes the analysis, testing, and the structural behaviour of such kind of structures. The proposed efficient and load bearing structural system consists of an assembly of individual PSSDB panels connected by steel angle plates at the ridges, formed to the required shape, width and span. An analytical model using finite element method has been proposed. The profiled steel sheeting was idealised as an equivalent homogeneous orthotropic thin shell plate elements of constant thickness. Two directional plate elements were proposed in modelling the connection between profiled steel sheeting and dry board to include biaxial shear deformation. The proposed analytical method has been used to analyse the results of full-scale folded plate PSSDB tests and is found to give good results.

Two-way bending behavior of profiled steel sheet dry board composite panel system

Abstract This paper describes the structural behavior, analysis, and testing of a structural system known as the profiled steel sheeting dry board (PSSDB) system when applied as two-way floor panels subjected to out-of-plane loading. The system consists of profiled steel sheeting connected to dry boards by self-drilling, self-tapping screws. Analytical models employing the finite element method have been proposed to analyze the panel. This involved two types of modeling: first, the isotropic model, and secondly, the orthotropic equivalent model representing the geometrically orthotropic profiled steel sheeting. It is the simpler latter approach which is of main interest. However, comparison of theoretical to experimental results shows that the isotropic model is more accurate, within reasonable agreement with discrepancies ranging from 2.8% to 12.8%. The ‘orthotropic model’, on the other hand, shows a bigger discrepancy of more than 30%. This indicates that there is a need for improving further the orthotropic model as described in this paper. However, for practical design purposes, the orthotropic model is acceptable since it is more conservative in predicting deflection values of the two-way PSSDB panel. The orthotropic model is preferred over the isotropic model because it is less tedious, requiring less computer memory and computational time, and is more practical for design purposes.

Partial interaction analysis of double skin composite beams

Abstract Double skin composite beams are formed using steel plates connected to a concrete infill by means of welded stud shear connectors. This construction acts in a similar way to doubly reinforced concrete elements but the flexibility of connection between the steel plates and concrete gives rise to interface slip and additional overall element deflection. This paper presents a closed form solution for the analysis of simply-supported double skin composite beams. This method takes into account the flexibility of connection on both tension and compression faces and is extended to cover the effects of concrete cracking and non-linear connector behaviour using a step-wise linearisation technique. The analysis is compared against model and full scale experimental work that has been previously reported by the authors. It is concluded that the proposed method shows good correlation with real behaviour and may be reliably used for the analysis of simply supported double skin composite beams.

ICTs, videoconferencing and the construction industry: opportunity or threat?

The paper discusses the potential impact of videoconferencing on practices and processes within the construction industry, based on analyses carried out on its use and impact in the healthcare sector – which like construction involves technology‐intensive processes which are dependent upon cross‐professional and cross‐disciplinary relationships and communications, operate within an increasingly regulatory and litigious climate, and involve organizationally fluid, virtual, teams spanning several subindustries. Recently published research evidence from the healthcare sector suggests that whilst videoconferencing and other advanced information and communication technologies (ICTs) have pervasive capabilities, successes in their application may be shortlived and modest in achievement. In use, their actual uptake and application have been found to be fundamentally affected by a range of social and operational issues, such as fears over a new formalization and trackability of previously informal conversations; a rebalancing of power relationships (between professionals using the ICTs as well as between doctor and patient); pressures on social/cultural and procedural alignment between participants; and personal and corporate attitudes to the technologies (including simply disliking the ICT). There is also evidence from the healthcare sector to suggest that ICTs increase the complexity of the delivering healthcare, and that the limitations of the technologies emphasise an existing dependency of communications and processes on tacit knowledge which is not readily formalized for communication via ICTs. However, the paper also notes an increasing pressure on the construction industry to respond to the globalizing potential that ICTs offer for the supply and delivery of knowledge‐based services, and discusses the implications of the issues found in the healthcare sector for the use and potential abuse of ICTs in the construction industry that will have to be successfully addressed in order to avoid ICTs being perceived as threatening and to allow their use to help organizations address the globalising marketplace.

In-plane shear behaviour of profiled steel sheeting

This paper will describe the behaviour of profiled steel sheeting under inplane shear and its application in building frames. Analytical models for shear strength and stiffness of the profiled steel sheeting are developed and validated by small scale model tests and finite element analyses. The strength, stiffness, failure modes and strain conditions are found to be greatly influenced by the boundary condition of the sheeting. The values of several factors related to the mode of attachment of the sheeting to practical building frames are studied to verify the suitability of design equations.