Experimental research on pinned connections in aluminium truss girders

Aluminium truss girders are widely used in the entertainment industry. The loads on these girders, representing systems for sound and lighting, are standardised in uniform loads and/or concentrated loads. Focusing on larger spans, standard connections, i.e. welded joints between chords and braces and mechanical fasteners between girder sections, may limit the design strength of these girders. In this publication the experimental research on pinned girder section connections, which allow for an easy assembly and disassembly of the truss girders, is described and discussed. The experiments have been carried out using two different boundary conditions as well as two different securing methods. The results show a design strength which is not limited by the shear and bearing mechanism of the pinned connection. Failure is induced by cracking of a centerpoint, which is applied for easy welding procedures

Load sharing in insulated double glass units : determination of the air pressure in the cavity due to mechanical and thermo-mechanical loads

Glass is an indispensable building material because of the special properties. Glass has a low heat resistance and therefore it is a thermal leakage in the outer wall. Insulated double glass reduces the heat transfer tremendously. The closed air in the hermetically closed cavity is a good insulator. The magnitude of the pressure in a hermetically closed cavity is an unknown parameter. What is the cavity pressure if the temperature changed, ambient pressure changed, under a uniformly distributed load, under a concentrated load and the like? These influences were investigated by an analytical model and were verified by experimental research

Optimization of aluminium stressed skin panels in offshore applications

Since the introduction of Eurocode 9 specific design rules for the calculation of aluminium stressed skin panels are available. These design rules have been used for optimization of two extrusions: one for explosions and wind loading governing and one for explosions and floor loading governing. The optimized extrusions are fulfilling class 3 section properties leading to weight reductions up to 25% of regularly used shear panel sections. When the design would have been based on class 4 section properties even more weight reduction might have been reached. The failure mode depends on the height of the hat stiffeners. For sections using relatively high hat stiffeners failure is introduced by yielding of the heat affected zone. For these kind of cross sections the Eurocode 9 design rules and numerical calculations show very good agreement. For sections using relatively low hat stiffeners failure is introduced by global buckling. For these kind of cross sections Eurocode 9 gives rather conservative results

Structural application of perforated aluminium plates in a footbridge canopy

A recently designed footbridge canopy covering a concrete bridge at the Eindhoven University of Technology campus is build up by aluminium plates containing perforations. The perforations differ in concentrations, diameter and pattern. The aluminium structure was adapted to improve global behaviour especially in relation with deformation requirements. Further experimental and numerical research was carried out to investigate the failure behaviour of perforated plates loaded by compression. It is concluded that the failure behaviour of relatively thin aluminium plates in compression is very complex, even for non-perforated plates (see [8]). Further fundamental research is needed to investigate failure modes and failure loads of the perforated plates

Load sharing in insulated double glass units : determination of the air pressure in the cavity due to mechanical and thermo-mechanical loads

Glass is an indispensable building material because of the special properties. Glass has a low heat resistance and therefore it is a thermal leakage in the outer wall. Insulated double glass reduces the heat transfer tremendously. The closed air in the hermetically closed cavity is a good insulator. The magnitude of the pressure in a hermetically closed cavity is an unknown parameter. What is the cavity pressure if the temperature changed, ambient pressure changed, under a uniformly distributed load, under a concentrated load and the like? These influences were investigated by an analytical model and were verified by experimental research

Fire exposed aluminium structures

Material properties and mechanical response models for fire design of steel structures are based on extensive research and experience. Contrarily, the behaviour of aluminium load bearing structures exposed to fire is relatively unexplored. This article gives an overview of physical and mechanical properties at elevated temperature of frequently applied aluminium alloys, found in relevant literature and discusses mechanical response models currently applied for fire exposed aluminium structures. A comparison is made with steel structures exposed to fire

Bracing Steel Frames with Adhesively Bonded Glass Panes - Mechanic Models

Circumferentially adhesive bonded glass panes in steel frames of facades can take over the structural function of steel braces for the stabilization of one-storey buildings. A system, built up of a steel frame, a single glass pane and a flexible adhesive bonded joint across the full thickness of the glass pane was subjected to a concentrated horizontal in-plane load at the top. Experiments with square glass pane sizes showed that the system had a very small inplane stiffness, a glass-steel contact at large horizontal in-plane loads and a good residual capacity. The parametric studies by means of finite element models only focused on the variation of the geometry of the glass pane. The behaviour of the system mainly depends on the stiffness of the adhesive bonded joint. At larger horizontal in-plane displacements, systems with rectangular glass pane sizes have two glass-steel contacts. The mechanic models well predict the in-plane stiffness of the system, the largest maximum principle stress and the maximum normal and shear stresses in the adhesive bonded joint. The horizontal in-plane load and the horizontal in-plane displacement at the top at the first glass-steel contact are also well predicted. The criteria are the limitation of the horizontal in-plane displacement at the top (serviceability) or the strain rate of the adhesive bonded joint (strength). To guarantee the stability of a building all glass panes in the facade have to be mobilized to transfer in-plane load