Felix Nicklisch

Outline of Testing and Evaluation Program Used in Selection of Adhesives for Transparent Adhesive Joints in All-Glass Load-Bearing Structures

Architects are increasingly demanding all-glass load-bearing structures with fully transparent adhesive joints. Usually, such structures are classed as nonregulated forms of construction. The Institute of Building Construction at Dresden’s Technische Universitat has now obtained the first individual approvals in Germany for all-glass structures with transparent adhesive joints for two buildings in Dresden and Grimma. In these cases, the loads are carried via load-bearing glued frames that rely on a material bond between the individual parts without any metal fixings. This solution is based on the results of many years of development. Currently, various frame corners covering a wide range of parameters are being studied in a follow-up project. The aim is to optimize the adhesive joints and the bonding technology. The requirements placed on the joint are being identified and corresponding adhesive systems researched. Preliminary studies of numerous material specimens form the starting point for determining the material parameters. Small-scale specimens are being tested under various boundary conditions and aging scenarios to establish the strengths of a number of suitable adhesives. These results will enable prototypes to be designed for numerical simulation. Numerical calculations and experimental investigations are being carried out in parallel to optimize the geometry, load-carrying capacity, long-term reliability, and durability of the glued all-glass frame corners. Specimen components are loaded in a testing machine to study the structural effect of these glued glass frame corners. The findings will be incorporated in the design of the adhesive joint and in the development of a numerical simulation for the glued connection. Data for executing an adhesive joint, specific to each adhesive and crucial for the quality of the transparency, conclude the project.

Evaluation of joining methods for novel timber–aluminum composite profiles for innovative louver windows and facade elements

ABSTRACT The demand for efficient buildings requires improvement in window and facade design. Aluminum and steel dominate the solutions for large facades while wood is used on a much smaller scale. In order to widen the scope of wood application in facades, this paper assessed novel timber–aluminum composite profiles which have been developed for louver windows. The research focused on two different technologies suitable for joining wood to other parts of the louver window. First, the study assessed the adhesive bond between the glass unit and the wooden part of the profile. The evaluation focused on seven different wood substrates ranging from solid softwoods and hardwoods to wood-based products and modified wood. Second, a specific rolling technique was applied to join the wooden section to the aluminum component. The technology was taken from the prefabrication process of conventional composite profiles. There, plastic insulating bars are clamped onto the aluminum profiles. This joining method had not been applied to timber so far. The results show that beech wood has the most suitable properties for use in such composite profiles. The composite frames examined provide a lower energy footprint compared to standard solutions. They enable a sustainable yet durable solution for the building envelope.