Analytical and finite element modelling of long plate mode jumping behaviour

Trapezoidal sheeting of thin-walled steel is applied frequently for roofing and cladding. As such, it is loaded by a concentrated load (at the support) and a bending moment. A recently developed model to predict the sheeting's failure behaviour leaves the question open whether mode jumping (the phenomenon that a plate dynamically changes its buckling mode during an increasing load) should be taken into account in the model. This article presents the analytical and finite element modelling of square and long plates, which, depending on the boundary conditions, may represent the compressed flange of trapezoidal sheeting. The analytical modelling is based on the combination of several displacement functions and using the principle of minimal potential energy. Hereafter the stability of each part of the resulting equilibrium curves is determined. A spin-off of the analytical model is an analytical expression for a current curve-fitted based prediction formula for the post/pre buckling stiffness ratio by Rhodes. Furthermore, the accuracy range of a solution by Williams and Walker for the far-post buckling behaviour can be confirmed. The finite element modelling has been carried out by implicit dynamic, and explicit (dynamic) simulations. Both for the load levels and the buckling mode sequences, the analytical and finite element models give equivalent results. It is concluded that for the specific boundary conditions that represent the situation of a compressed flange for trapezoidal sheeting, it is very likely that mode jumping will not occur

Composite Behaviour of Steel Frames with Precast Concrete Infill Panels

This paper presents preliminary experimental and numerical results of an investigation into the composite behaviour of a steel frame with a precast concrete infill panel (S-PCP) subject to a lateral load. The steel-concrete connections consist of two plates connected with two bolts which are loaded in shear only. The connections are designed for a failure mechanism consisting of ovalisation in the bolt holes due to bearing of the bolts to avoid brittle failure. Experimental pull-out and shear tests on individual frame-panel connections were performed to establish their stiffness and failure load. A full scale experiment was performed on a onestorey one-bay 3 by 3m infilled frame structure horizontally loaded at the top. With the known characteristics of the frame-panel joints from the experiments on individual connections, a numerical analysis was performed on the infilled frame structure taking nonlinear behaviour of the structural components into account. The finite element model yields reasonably accurate results and indicates a connection failure sequence similar to experimental failure

Experiments investigating concrete floor punching using specific reinforcement

To reduce the surface crack width and to optimize the ultimate punching load of warehouse concrete floors, fibre reinforcement and special reinforcement mats above piles are used. Due to the special reinforcement mats, current design rules cannot be used to correctly predict the surface crack width and the ultimate punching load. Therefore, full-scale experiments have been carried out for six different reinforcement types. A fibre-reinforced floor with circular pile mat is the best solution, both for reducing the surface crack width and for optimizing the ultimate punching load

Elastic post-buckling behaviour of uniformly compressed plates

In this paper it is discussed how existing analytical and semi-analytical formulas for describing the elastic-post-buckling behavior of uniformly compressed square plates with initial imperfections, for loads up to three times the buckling load can be simplified and improved. For loads larger than about twice the buckling load the influence of changes in the buckling shape, assumed sinusoidal, cannot be neglected anymore. These changes can be taken into account by using the perturbation approach. The existing and improved formulas are compared to the results of finite element simulations

Parameter Study for First-Generation Sheeting Failure using a Theoretical and FE Model

First-generation sheeting is sheeting without longitudinal and transversal stiffeners. For the prediction of failure of this sheeting type, if loaded by j concentrated load and bending moment, several theoretical models and design codes exist. One of these theoretical models was developed recently and predicts failure by using a derivative of the web-crippling deformation due to the concentrated load as an imperfection for the compressed flange for which the behaviour is predicted by Marguerre's simultaneous differential plate equations. The quality of the model has been checked with a whole range of experiments, however, the experiments did not have such a variation of variables that the model could be checked systematically. In this paper, a FE model is used to predict failure for a systematic variation of sheeting variables and the failure loads are used to check the theoretical model. For varying web width, angle between web and flange, corner radius, yield strength, plate thickness, and span length, the theoretical model performs well, qualitatively and quantitatively, compared to the finite element model. For the compressed flange width and load bearing plate width, the theoretical model results show some divergence from the FE model results, although absolute differences remain acceptable

Ultimate Failure Behaviour of Second-generation Sheeting Subjected to Combined Bending Moment and Concentrated Load

Second-generation sheeting is widely used for cladding and roof construction. At interior supports, it is subjected to combined bending moment and concentrated load. Unfortunately, design rules for this loading are complicated and do not provide insight in the sheeting\u27s failure behaviour. This means there is a need for a new, insight providing design rule. For first-generation sheeting, a similar problem did exist. The Technische Universiteit Eindhoven (TUE) carried out three research projects [Bakk92a,Vaes95a,Hofm00a] that provided insight in the first-generation sheeting behaviour and resulted in a new, insight providing design rule. The TUE now uses the strategy of these three research projects for a new project on second-generation sheeting [Kasp01a], with the final aim of a new design rule for second-generation sheeting. In this new project, experiments on commonly used (in the Netherlands) second-generation sheeting were carried out. Second-generation sheeting behaviour was compared with first-generation sheeting behaviour. For sheeting with only stiffeners in flange, load falls occur before ultimate load. Stiffeners in the web only result in load falls after the ultimate load. For an experiment with only stiffeners in the web, a finite element simulation was made. The simulation predicts the sheeting behaviour fairly well and indicates how a stiffener affects the sheeting behaviour

Experimental Research on the Behaviour of Combined Web Crippling and Bending of Steel Deck Sections

At an interior support, sections of cold-formed steel are subjected to a concentrated load and a bending moment Existing design rules describing the section failure at an interior support are subject to improvement and are not based on the section\u27s physical failure behaviour. In the last decade, several analytical models have been developed that predict the section ultimate concentrated load and directly include the influence of the bending moment, so that an empirical interaction method is not needed. However, the authors believe that these models are correct only for a concentrated load and a small bending moment In practice large bending moments occur. Therefore, the aim of the current research project is to develop an analytical model for trapezoidal hat sections subjected to a concentrated load and a bending moment as occurring in practice. The development of this model will be based on both experimental and numerical research will be carried out. In this article, a part of the experimental research will be presented