Resistance of Long Adhesive Joints in Facade Applications Exposed to Negative Pressure Loads

abstrakt

angličtina

Façade joint strength is affected by a number of elementary influences, these are particularly temperature, humidity and wind. Wind is a complicated phenomenon, mainly because of its influence on the structures and situations that arise from these conflicts. Façade elements must withstand horizontal wind load, where high wind speeds can cause significant stress concentration in a building surface, as well as local stresses in the joints and anchoring areas. The paper is focused on the verification of the bonded façade joint resistance against negative pressure loads, i.e. wind suction. The steps of the test procedure were compiled according to the recommendations given in European guideline ETAG 034. The most critical case was tested, deformations due to temperature and humidity variations were taken into account in the numerical model. The test samples of the size 4.1 m2 were placed in a pressure/suction chamber allowing hermetic closure. The samples consisted of two rectangular cement-bonded particleboards, bonded along their edges in a vertical direction to a wooden load-bearing façade frame, which was attached to the bearing structure. The experiment focuses on four different adhesive systems intended for façade bonding with adhesives ranging from flexible high strength polyurethanes to one-component modified polymers. Two variants of the test samples were tested, where in the first case the instructions of the adhesive system manufacturer were followed, and in the second case no mounting tape was used. This step made it possible to assess the impact of the mounting tape on the physical and mechanical properties of the bond. In case of all test samples without the mounting tape, a higher failure load rate between 5% and 40% was recorded. Furthermore, it was possible to determine the influence of the tape on the elongation of the bonded joint, the elongation of the joint increased again by about 20 – 60% depending of the adhesive system stiffness. Finally, all test samples achieved a higher failure load rate than the numerical model by a maximum of 40%, while no predicted elongation was achieved for any of the studied combinations, with values varying by up to 30%.

Adhesive; Adhesion; Cohesion; Wind; Resistance; Pressure;

NEČASOVÁ, B.; LIŠKA, P.; ŠLANHOF, J.; SEDLÁK, P.; MOTYČKA, V.

24. 10. 2019

Publindústria, Produção de Comunicação, Lda.

Ponta Delgada

978-989-892-788-0

AJP2019 - 1st International Conference on Advanced Joining Processes - Book of Abstracts

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https://web.fe.up.pt/~ajp2019/AJP2019%20Prog.pdf