For demanding applications with increased requirements in terms of load-carrying capacity and long spans, the HighTech Timber Beam® (HTB) – a hybrid composite beam made of glulam and high-performance materials – was developed at the Bauhaus University in cooperation with a local SME . The applicability of the High-Tech Timber Beam® for TCC constructions (Timber-ConcreteComposite) is examined in ongoing research. In former investigations several studies with new technologies and materials for rehabilitation and strengthening of historic timber structures were carried out at the Bauhaus University . Within those studies, several formulations of glue-mortar based on epoxy resin and mineral fillings (hereinafter also referred to as PC – polymer concrete) were developed to implement a direct and continuous bond between timber and reinforcing materials or elements (for instance LVL, CFRP lamellas, bars made of GFRP or steel). The different mixtures of PC were adjusted to their application purposes through a range of modifications to the composition and detailed material analysis.
Wood in Europe, especially in Germany, is a good available row material. It has a high load capacity and stiffness in comparison to the low death weight. Timber is traditionally used for bending beams and columns with low processing. Since it is a natural material, there are variations in properties and quality. There is a demand for homogenisation for using in modern engineering and for the exploitation of the good properties of timber. Therefore, the timber is sliced, sorted and remounted as glued laminated timber or even as veneer lumber, to eliminate defects, knots or cracks. For increased requirements in terms of load-carrying capacity and long spans, a hybrid composite beam made of glulam and highperformance materials was developed at the Bauhaus University Weimar in cooperation with a local SME.
The main material of the developed High-Tech Timber Beam is still glulam with more than 90 % of the girders volume. Replacing one or two lamellas at the bottom side of the glulam by laminated veneer lumber (LVL) allows a significant homogenization of the timber beams properties.
For upgrading the compression zone of the bending beam, the upper lamella of the glulam is replaced by a decking of polymer concrete (PC). This is made of a mineral mixture with a special grain-size distribution and a binder on base a of 2-component epoxy resin. The PC has a high compression strength and also a high stiffness because of its high rate of filling with mineral grits.