Timber Glass Research Articles

Novel composite connection for timber–glass composite structures

This study presents a newly developed timber–glass point connection intended to strengthen existing timber elements in a reversible and visually unobtrusive manner. The new connection consists of an aluminium insertion, two-component structural bonding epoxy resin adhesive, and self-tapping screws. The connection offers the possibility of easy attachment and detachment of the glass element from the strengthened timber element. Seven timber–glass specimens were constructed to perform an experimental investigation of the shear load-bearing capacity and load-slip behaviour of the connection. The aluminium insertion is bonded to a tempered glass strip with a hole and is screwed to the spruce timber block. The timber–glass connection preparation process is thoroughly presented. A special testing apparatus was developed to perform the experiments on a hydraulic universal testing machine. The experimental results are evaluated using analytical expressions and a finite-element simulation. The average connection load-bearing capacity obtained from the experiments of the analysed specimen was 13.31 kN, and the average slip modulus was 20.48 kN/mm. All connections failed on account of self-tapping screw failure, whereas the tempered glass strips remained undamaged.

Flexural Behaviour of Timber Glass Composite Beams using Various Adhesives

This paper mainly deals with providing a clear understanding of the bonding nature of various adhesives as a structural connection in timber glass composite beams and investigates the flexural behaviour of the same. This paper depicts the clear idea of the critical factors to be considered for the application of adhesives as a structural connection in timber glass composite beams. The timber glass composite beams will be a significant alternative for the conventional beams, which are currently used in the beams in temporary structures. Apart from being a significant replacement for the conventional beams, the glass web portion permits the light to pass through it. Thus, the artificial light energy required inside the structure will be reduced. This makes the composite beams to be energy efficient structural component in the temporary structures. In this research, the flexural behaviour of the composite beams made using various adhesives such as Acrylic, Epoxy and Silicone were studied. The result shows that epoxy adhesive connection behaves much better when compared with silicone and acrylic adhesives.

Cyclic and shaking-table tests of timber–glass buildings

Cyclic and shaking-table tests of timber–glass buildings

Timber–Glass Composites Used for Bracing of Mid-Rise Timber Buildings

Various façade-glazing systems have long been in use and are generally considered state of the art. However, with these solutions, the glass serves no stiffening function. The objective of several research projects was to investigate alternative systems that could replace costly frameworks and/or St. Andrew’s cross bracings. For this purpose, the Department of Structural Design and Timber Engineering (ITI) studied and optimized the load-bearing capacity of existing timber–glass composite (TGC) constructions and subsequently developed new TGC constructions. Based on the results of these research projects, the ITI coordinated the follow-up international joint research project “Load bearing timber–glass composites (LBTGC) ” within the framework WoodWisdom-Net. Since TGC elements were just used in one or two storey buildings, the objective of the research project LBTGC was to develop “stiffening” TGC elements for mid-rise buildings considering their long-term behaviour and practical application. Investigations were made to evaluate the possibilities and limits of such systems. Different types of TGC façades were compared with each other. The results showed that all structural systems have sufficient stiffness against horizontal displacement. The executed calculations proved the efficiency of newly developed TGC structures. The results provide a marketable component system for mid-rise timber buildings.

Experimental testing of load-bearing timber–glass composite shear walls and beams

The paper presents results from the experimental testing of load-bearing timber–glass composite shear walls and beams.Shear wall specimens measuring 1200 × 2400 mm2 manufactured with three adhesives of varying stiffness were tested. Twelve specimens with a single 10 mm thick glass pane and one specimen with an additional insulating glass unit were produced. The testing procedures involved various loading conditions: pure vertical load and different combinations of shear and vertical loading. The test results showed that the adhesive had only a minor influence on the buckling load which was the main failure mechanism.240 mm high and 4800 mm long timber–glass beams manufactured with adhesives of different stiffness were tested. For the webs, two types of glass were used: annealed float and heat-strengthened glass, in both cases 8 mm thick panes were used. In total, 12 beams were tested in four-point bending until failure. Despite the considerable difference in adhesive stiffness, beam bending stiffness was similar. Concerning load-bearing capacity, the beams with heat-strengthened glass were approximately 50% stronger than the beams made using annealed float glass.

Testing of timber–glass composite walls

This paper deals with monotonous, quasistatic cyclic and dynamic testing of timber–glass composite wall panels. The goal of the testing was to analyse the general behaviour of timber–glass walls and the failure mechanisms that occur in such structures. First the basic properties of the adhesives (used to connect the timber and glass) were investigated. Experiments were performed on epoxy-, silicone- and polyurethane-based adhesives. These were followed by tests on timber–glass walls, which consisted of 2·4 × 2·4 m timber frames and insulating glass units glued to the timber frame with a polyurethane adhesive. Two types of such walls were used: (a) frames with one large glass panel or (b) two smaller glass panels with one timber post in-between. The wall panels were subjected to monotonous tests, according to EN 594, and quasi-static cyclic tests, according to ISO 16670, in order to analyse the wall's ductility, strength and stiffness degradation. Various combinations of one- and two-storey building set-ups were also tested on the shaking table and subjected to recorded and modified accelerograms. The tested set-ups present a starting point for finite-element modelling that will result in a more comprehensive parametric study.

Experimental investigations of timber–glass composite wall panels

The importance of building large-size glazing into timber structures has significantly grown over the last decade due to the enhanced physical characteristics of glass panels and owing to the fact that proper integration of both materials, timber and glass, has a positive impact on the energy efficiency of buildings, which was one of the major reasons for carrying out our investigation. This paper presents the results of the experimental research on timber–glass wall elements where glass panes are directly bonded to the timber frame, leading to a load-bearing and visually interesting wall element which is suitable for lightweight timber structures.

Glass, timber and adhesive joints – Innovative load bearing building components

Structural glass–timber composite beams and shear wall elements were investigated in terms of their mechanical behaviour, energy performance and their LCA performance. The load bearing components were manufactured using annealed float glass which was adhesively bonded to the timber with different adhesives. The results show, among other things, that is is possible to join the two materials glass and timber and obtaining a non-brittle failure of the beams. The shear wall elements have the potential of being used as stabilising elements and load bearing walls in buildings of up to 4 storeys height. It is possible to combine glass and timber in a load bearing shear wall without loss of energy performance of a building or without loosing LCA performance. In addition to these benefits, the timber glass composite wall has, of course the benefit of being transparent.