Wooden constructions are on the rise again – encouraged by a strong trend towards sustainable and resource efficient buildings. Load-bearing timber-glass composite elements – a novel concept to use the in-plane loadbearing potential of glass – could contribute to a more efficient use of materials in façades. The current study relates to the adhesive bond between the glass pane and the timber substructure. The applicability of structural sealants such as silicones is limited due to their distinct flexibility which leads to large deformations of the joint. Further potential arises from the use of adhesives of medium and high stiffness. Their general performance as well as their durability have not yet been evaluated with respect to the proposed use in building constructions. This paper draws attention to the ageing stability of two promising adhesives. Small-scale adhesively bonded specimens which are composed of a wooden and a glass piece are exposed to different ageing scenarios which relate to the impacts typically encountered in façades. Based on the results it can be concluded that the considered high-modules adhesives enable an increase of characteristic failure loads and a reduction of joint deformation, but also reveal shortcomings regarding their ageing stability.
The thermal refurbishment of the building stock is one of the most fundamental challenges of sustainable urban development. Particularly the use of natural and local materials gets an increasing relevance, regarding the embodied energy. The focus of this work is the development of systematised solutions for thermal refurbishment with...
Fulfilment of conditions given by European design codes for structures in seismic regions presents a problem during the design of new and repairing of existing structures. Although there are various options, obvious choices are solutions which provide increase of rigidity and seismic capacity with minimal increase of structural mass. Current research at the University of Zagreb, performed in cooperation with the University of Ljubljana, is leading to the development of special kind of high-ductility hybrid panel made of timber frame with supporting laminated glass infill, which, in addition to strength and stiffness, is also characterized by high level of seismic energy dissipation. This paper objective is to give preliminary assessment of application of hybrid panel as seismic reinforcement in concrete, steel and timber frame structures. Finally, to provide more accurate input data, numerical results are compared for the structures tested in full-scale shaking table test.
The project included product development and materials research. The aim was to produce a wooden façade system with an attractive modern appearance and good constructive design with the help of modern woodworking technology. Important requirements to consider were that the system should have a contemporary, attractive expression and that the façade system should provide a product with high quality ambitions in terms of environmental impact. It should also be flexible and easy to use for architects and designers who want to create unique façades. The main focus in this study was about the visible wood surface appearance where the intention was to create a varied surface with interesting innovative designs, with a method that make it possible to always create new patterns. Two different façade cladding systems were developed by combining woodcraft tradition, new research, digital design tools and industrial processes in the wood construction industry. Prototypes with patterned surfaces on both individual boards joined together and on a system based on multi-layer solid wood panels were tested.
Structural solutions involving the mechanical interaction of timber and glass load-bearing members showed a progressive increase in the last decade. Among others, a multipurpose hybrid facade element composed of Cross-Laminated Timber (CLT) members and glass panels interacting by frictional contact mechanisms only was proposed ion the framework of the VETROLIGNUM project. While demonstrating enhanced load-bearing and deformation capacity performances under seismic loads, facade elements are known to represent a building component with multiple performance parameters to satisfy. These include energy efficiency, durability, lightening comfort and optimal thermal performance. In this paper, a special focus is dedicated to the thermal performance assessment of CLT-glass facade modules under ordinary operational conditions. Based on the thermal-chamber analysis of small-scale prototypes, reliable Finite Element numerical models are developed and applied to full-scale VETROLIGNUM solution. Sensitivity analyses are hence carried out to explore the actual thermal performance of these novel hybrid systems.
This study investigates five fire stop variants used to limit the spread of fire on wooden façades. For this purpose, five fire tests using various types of wooden façade claddings and different fire stops were conducted as full-scale tests and compared to the existing findings. The influences and interactions between the material qualities of the external wall behind the façade cladding, the construction type of the wooden façade cladding, the design of the substructure, the depth of the ventilation gap, and the design of the fire stops were investigated. In evaluating the fire stops, the design of the interior corners, the joint design, and the influence of thermal expansion were examined. Finally, design proposals for the design of fire stops at wooden façades in order to limit the spread of fire were derived based on this evaluation. The outlook presents further needs that need to be investigated in the future in order to clarify undiscussed aspects or points that were ultimately not evaluated within the scope of this study.
Canadian Conference on Building Science and Technology
Research Status
Complete
Summary
On tall wood buildings, mass timber elements including CLT, NLT, glulam, and other engineered
components absolutely need to be protected from excessive wetting during construction. This requirement precludes the use of many conventional cladding systems unless the building is fully hoarded during construction.
The building enclosure and façade of UBC Tallwood House consists of an innovative prefabricated steel stud rainscreen curtain-wall assembly that is pre-insulated, pre-clad, and has factory installed windows. Design of connections and air and water sealing of panel joints and interfaces was carefully considered given the tall wood structure they were designed to protect. While steel studs were utilized in the panelized structure, feasible curtain-wall designs were also developed and prototyped for wood-framing, CLT, and precast concrete as part of the project.
Looking ahead, there will continue to be innovation in design and construction of fast and durable facades for taller wood buildings. New prefabricated panel designs incorporating CLT panels and connection technologies from unitized curtainwall systems are already being developed for the “next tallest” wood buildings in North America.
Up to now, structural sealant glazing façades have been extensively applied. They are at the cutting edge of technology and meet the highest standards. The objective of several research projects was to develop stiffening glass fronts, which replace expensive frameworks or wind bracings behind the large glass windows. Thus, potential applications of timber-glass composites (TGC) as alternative stiffening constructions for multi-story façades were investigated. Based on the results of those previous research projects the Department of Structural Design and Timber Engineering (ITI) coordinated the follow-up international research project “Load bearing timber-glass composites (LBTGC)” within the framework WoodWisdom-Net. In consideration of long-term behavior and practical application, the objective of the joint research project LBTGC was to develop load-bearing and stiffening TGC structures. With the purpose to meet the highest standards of cost effectiveness and environmental compatibility, alternative stiffening TGC constructions for multi-story facades were investigated. This paper illustrates these developments and application of TGC multi-story façades.
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