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.     

A plate model for composite slab analysis

Composite floor decks constructed with profiled steel sheeting acting as formwork and reinforcement to a concrete slab are increasing in popularity. In this paper an elastic folded palte method of analysis has been applied to model their behaviour. The analytical model idealises both the steel sheeting and the concrete as a collection of thin-walled plates and separates the bending and shear action between horizontal and vertical elements. The effects of concrete in tension and slip between the concrete and steel have been included. The method has been used to analyse the results of 32-full-scale slab tests and is found to give good results.     

Finite element prediction on the structural performance of profiled steel sheet dry board structural composite system proposed as a disaster relief shelter

Folded plate structures constructed from profiled steel sheeting connected to dry boards by self drilling, self tapping screws (known as profiled steel sheeting dry board (PSSDB) system) are being proposed as an alternative to traditional forms of roof construction. The proposed load bearing composite 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. This kind of structure has a significant advantage of removing the internal trussing and support that is normally required in a traditional trussed roof system, thus adding to livable space in a building. The introduction of this innovative system would eliminate the difficulty in constructing folded plate roof that is normally very troublesome, especially when they are made out of traditional reinforced concrete system, hence would help promote the folded plate technique of construction. This paper looks into the possibility of employing the PSSDB folded plate structure to provide an efficient emergency shelter, analysing it under the effect of static wind loading using the already established and verified Finite Element technique. Such a structure is quite conceivable in the likely event of a disaster. Firstly, its basic behaviour in the elastic range is studied checking for deflection as the main controlling design factor. Secondly, the method of enhancing the structural stiffness and performance of the system is proposed. It was found that this could be easily achieved by restraining the bottom longitudinal edges on both sides of the structure. A practical solution is proposed in this paper that can be implemented in real practice. It can be concluded that the proposed structure has a great potential to be exploited for the above-intended purpose.     

Analysis of deflections of composite slabs with profiled sheeting up to the ultimate moment

This paper deals with an investigation of the deflections of composite slabs. The deflection of composite slabs depends directly on the shear stiffness of the connection between profiled steel sheeting and concrete. A method for calculating deflections of slabs is presented in this paper. This method is based on a theory of built-up bars, which allows one to take into account directly the shear stiffness of the connection. Influences on the stiffness of the structure of normal cracks in the concrete layer and plastic deformations of concrete that has been subjected to compression are also taken into account in the analysis method. The method gives one an opportunity to assess variations of these factors at all stages of the slab’s behaviour from the start of loading up to the ultimate moment. Results of the experimental investigations of a connection (contact) between steel profiled sheeting (Holorib type) and concrete are presented in this paper. In the results of these investigations, three stages of behaviour of the contact are distinguished. A connection shear characteristic is determined for each stage, which is used for calculating the deflection of the slab.Experimental investigations were performed on deflections of composite slabs with a Holorib type of profiled sheeting. Variations in experimental deflections of slabs were explored from the beginning of loading up to the ultimate moment.Theoretical calculations of deflections for the experimental slabs were made. Calculations were performed according to the method proposed by the authors. A comparison of experimental and theoretical values of deflections revealed that agreement between these values was sufficiently good at all stages of the slab’s behaviour.     

自攻螺钉、拉铆钉连接的受力蒙皮抗剪性能试验研究

本文对111个自攻螺钉、拉铆钉连接及14块由这种连接件连接的蒙皮板进行了抗剪性能试验,并分析了其抗剪强度、抗剪刚度、工作特点、破坏模式以及变更连接件布置方式、压型板跨度对受力蒙皮性能的影响。试验结果与国外的试验和理论分析结果符合较好。文中还提出了将压型钢板等效为正交各向异性板,用有限元法分析蒙皮的抗剪性能,所得蒙皮连接件内力分布规律,有助于进一步研究建立我国的蒙皮设计计算方法。     

Analysis of longitudinal shear behaviour for composite steel and concrete slabs

The strength of composite slabs depends mainly on the strength of contact between the steel sheeting and concrete. In the article a method of analyses for strength of the horizontal section of the composite slabs based on the theory of built-up bars, which gives one an opportunity to assess strength and the rigidity of contact is presented. The proposed method evaluates the influence of both plastic deformations of the concrete layer and cracks in the concrete on the rigidity of this layer and of the whole slab as well. Performed investigations in deformations and strength of the contact between steel sheeting and concrete allowed one to explore the behaviour of the contact from the start of loading up to the failure. During contact testing, influence of pre-compression forces on deformations and strength of the contact were investigated. The strength of horizontal section in 6 fragments of composite slab with ‘Holorib’ type profiled steel sheeting was investigated experimentally. In tests the thickness of concrete layer of the slab and concrete strength varied. Theoretical calculations for the strength of a horizontal section of experimental slabs were made in this investigation. Calculations were performed according to the method proposed by us with the application of the method of built-up bars. In calculations, rigidity of the contact between steel profiled sheeting and concrete as well as equivalent rigidity of a concrete layer with cracks were evaluated. Experimental and theoretical results of the strength of the horizontal section in composite slabs were compared. Comparison of results revealed that their agreement was sufficiently good.     

Stiffness and critical buckling load of perforated sheeting

This paper deals with selected foundations of the design of perforated trapezoidal sheeting. Based on numerical analysis, graphs on effective stiffness values for perforated sheeting with different arrays of holes are provided. As an outlook on further research, the calculation of the buckling coefficient for a perforated plate under uniform in-plane compression loading and for an infinitely long perforated plate under shear loading is presented.     

各向异性拱型折板结构的分析

本在献[1]的基础上，提出各向异性拱型折板结构的分析与设计，并用单元板力法对它进行内力分析，解出三种不同情况下的内力挠度公式，从而获得折板棱边的连接弯矩。     

New prediction model for failure of steel sheeting subject to concentrated load (web crippling) and bending

Current design rules for steel sheeting do not give adequate insight in the sheeting's structural behaviour and are not always accurate. The current rules use three concepts: ultimate bending moment; ultimate concentrated load; and interaction. This paper presents a new analytical model to predict the ultimate load of first-generation sheeting under practical loading conditions. These practical conditions are defined by the ratios between bending moment and concentrated load as occurring in practice. Comparisons between the new model and experiments indicate that the new model reaches approximately the same accuracy as the design rules. The new model provides more insight in the structural behaviour of the sheeting and uses only one concept for determining failure. The new model is based on two existing models. Namely an analytical model developed in 1995 by Vaessen (On the elastic web crippling stiffness of thin-walled cold-formed steel sections, Graduate Thesis TUE-BKO-95-17, Eindhoven University of Technology, The Netherlands) to predict the local web crippling deformation and a solution of Marguerre's (Zur Theorie der gekrümmter Platte grosser Formänderung. Proc. Fifth. Int. Congress Appl. Mech., p. 93) simultaneous differential plate equations included in a book by Murray (Introduction to the Theory of Thin-walled Structures, Oxford Engineering Science Series 13, Clarendon Press, Oxford).     

Performance of shear connection in composite beams with profiled steel sheeting

This paper describes the structural performance of shear connection in composite beams with profiled steel sheeting. An accurate and efficient nonlinear finite element model was developed to study the behaviour of headed stud shear connectors welded through-deck. The profiled steel sheeting had transverse ribs perpendicular to the steel beam. The material nonlinearities of concrete, headed stud, profiled steel sheeting, reinforcement and steel beam were included in the finite element model. The capacity of shear connection, load-slip behaviour of the headed stud, and failure modes were predicted. The results obtained from the finite element analysis were verified against experimental results. An extensive parametric study was conducted to study the effects on the capacity and behaviour of shear connection by changing the profiled steel sheeting geometries, the diameter and height of the headed stud, as well as the strength of concrete. The capacities of shear connection obtained from the finite element analysis were compared with the design strengths calculated using the American Specification, British Standard and European Code for headed stud shear connectors in composite slabs with profiled steel sheeting perpendicular to the steel beam. It is found that the design rules specified in the American and British specifications overestimated the capacity of shear connection, but the design rules specified in the European Code were generally conservative.     

Numerical simulation of lap screw connections

The aim of the paper is to show that advanced finite element computer codes, able to take into account large inelastic strains and contact problems, can be used to simulate, numerically, the behaviour of connections in steel sheeting. The numerical results are validated by comparison to experimental results.     

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.     

雁形板及V形折板屋盖在水平集中荷载下的空间工作特性

根据文献［３］的理论,按文献［１,２］同样的方法,算出雁形板及Ｖ形折板纵向水平集中荷载的应力系数。同时,还用有限元法,对这种屋盖受横向水平集中荷载作用的情况进行了计算,计算结果表明,雁形板屋盖与Ｖ形折板屋盖相比,更能满足水平面内刚度无限大的假设,且其空间整体工作性能优于Ｖ型折板屋盖。     

Bracing of thin walled steel box columns during pumping of wet concrete in tall buildings

This paper considers the bracing of thin walled steel box columns during the wet concrete pumping procedure for the construction of concrete filled columns in a tall building. The wet concrete exerts a hydrostatic pressure in addition to the axial loads from floor construction on the column cross-section and this causes excessive lateral deflections. For economical construction the steel component plates of the column are required to be minimized in thickness and thus an effective bracing strategy is required to be developed to restrain these deformations. The bracing system presented is similar to that employed for formwork of rectangular reinforced concrete columns and has been used on various tall buildings throughout the world being particularly germane to steel columns which are composed of flat faceted plates such as rectangular and triangular sections. The analysis presented herein uses a linear folded plate finite element method developed elsewhere to study the effects of wet concrete being pumped into steel columns. The main parameters which are found to influence the results are the boundary conditions, column width and plate thickness and the number of braces provided between floor levels. A design example is given and further research, including experimental calibration, is then outlined.     

Structural behaviour of glass folded plate curtain walls

This article is concerned with the nonlinear behaviour of glass folded plate curtain walls as an application of folded plate structures. The finite element approach was adopted for the analysis of the glass folded plate curtain walls. A plate finite element model was developed based on the nonlinear Mindlin theory. Furthermore, the model was also modified for the extension of hinges parallel to one of the global axes of the plate to simulate the case of glass folded plate curtain walls. To study the behaviour of glass folded plate curtain walls, an experimental model was built at the Structural Laboratory of Texas Tech University, USA, using aluminium plates with different connections, such as hinged or welded, and with different boundary conditions. The model, with different setups, was tested under distributed loads using vacuum machine. The results obtained from the experimental study were compared with the corresponding finite element results and conclusions were drawn.     

Test of screw fastened profiled roofing sheets subject to simulated wind uplift

Screw fastened light gauge steel profiled roofing sheets are predominantly subjected to wind suction, i.e., wind uplift, and may fail locally in the vicinity of screw fasteners under strong or sustained fluctuating wind uplift. A series of static tests was performed on three types of profiled roofing sheets to investigate their structural behaviour and profile effects under simulated wind uplift. The considered sheeting profiles were arc-tangent, trapezoidal and ribbed, and an alternate (or equivalent alternate) sheeting crest fastening system was adopted. It was found that structural behaviour of the roofing sheets under uplift loads was greatly dependent on the sheeting profiles including the shape and height of the crest. Both arc-tangent and trapezoidal type roofing sheets exhibited a large cross-sectional distortion stage and a deflection hardening stage, following a local plastic collapse in the vicinity of the screw fasteners at the central support. The ribbed roofing sheet, however, had a final failure mode of sudden fracture with cracks under the screw fastener head at the central support. The use of cyclone washers with screw fasteners reduced local plastic deformations and, in general, increased initial failure loads of the roofing sheets. Increasing the roofing span only slightly reduced the limit values of the reaction force per fastener at the central support due to the local failure characteristic of the screw fastened profiled roofing sheets.     

Combined flexure and web crippling strength of a low-ductility high strength steel decking: experiment and a finite element model

Profiled decking or sheeting of high strength low-ductility steel (ASTM611 Grade E) is a relatively new development in building construction industry. Due to inadequate information, the major international codes of design practices are yet to include this steel, and apply additional restrictions on their design and use. This type of decking shows high sensitivity to distortional as well as local buckling. Strength of such decking under combined flexure and web crippling as well as moment–rotation capacity are of principal concern if such decking is to be designed as a continuous structure to achieve better economy. This paper describes an experimental study of the behaviour of re-entrant decking of low-ductility steel under combined web crippling and flexure. Based on this experimental study, a nonlinear finite element model has been proposed which can predict the moment–rotation characteristics of such decking with reasonable accuracy.     

A simplified method for elastic large deflection analysis of plates and stiffened panels due to local buckling

A computational model for analysis of local buckling and postbuckling of stiffened panels is derived. The model provides a tool that is more accurate than existing design codes, and more efficient than nonlinear finite element methods. Any combination of biaxial in-plane compression or tension, shear, and lateral pressure may be analysed. Deflections are assumed in the form of trigonometric function series. The deformations are coupled such that continuity of rotation between the plate and the stiffener web is ensured, as well as longitudinal continuity of displacement. The response history is traced using energy principles and perturbation theory. The procedure is semi-analytical in the sense that all energy formulations are derived analytically, while a numerical method is used for solving the resulting set of equations, and for incrementation of the solution. The stress in certain critical points are checked using the von Mises yield criterion, and the onset of yielding is taken as an estimate of ultimate strength for design purposes.     

Effective section method: A general direct method for the design of steel cold-formed members under local–global buckling interaction

Thin-walled steel cold-formed members usually display local–global buckling interaction which strongly affects the structural strength of columns and beams. The local bucking of slender folded sections develops in analogy with single plate buckling, including the interaction between the plate elements of the cross-section and can be identified with appropriate first-order stability analysis and the consequent results of the critical buckling loads and the associated modes. The effective section method, ESM, as an extension of the original effective area method, EAM, was conceived for the design of cold-formed members on the basis of the actual local buckling results of the section, together with calibrated formulations for column and beam resistance. The strength equations were taken from the direct strength method, DSM, as it is presented in the North American AISI standard. In addition, as a consequence of its proposed formulation the effective section method is able to be applied side-by-side with the traditional effective width method, EWM, allowing its inclusion in the main part of the codes and specifications for the design of cold-formed members and improving its dissemination. The ESM was proposed in combination with equations and tables that enables designers to directly access the critical local buckling compressive force and bending moment of usual sections, resulting in a contribution that improves the attractiveness of the method.     

折板形网壳结构的设计及研究

以某体育馆钢屋盖结构为实例 ,论述了折板网壳结构的选型、受力特点、水平推力的处理方法和模态分析。研究发现 ,该结构的自振频率呈密集型分布 ,结构的基本振动为水平振动 ,而不象平板网架那样以竖向振动为主 ,结构表现出良好的受力性能和抗震性能