Experimental Investigation of Glued Laminated Timber Beam-to-beam Connection / Klijuotosios Medienos Sijos Elementu Tarpusavio Jungties Eksperimentinis Tyrimas

Semi rigid mounting joints of glued laminated timber elements are connections that are fully assembled on construction site and capable to handle bending moments, axial and shear forces. The need for new type of semi rigid timber elements' connection is obvious. The manufacturing possibilities of glued laminated timber elements' are wide: straight element's length may extend up to 40 m or curved axis elements with dimensions of up to 10 meters in height, therefore, manufacturers, erectors and others face with transportation problems of non-standard, oversized elements. Semi-rigid mounting joints are used to solve this problem. In factory non-standard, oversized, glued, laminated timber elements are cut into standard transportation dimensions and fully mounted into integral element on construction site, using semi rigid mounting joints. In this article semi-rigid, glued, laminated timber elements' joints which are used as beam to beam, beam to column and column to foundation connections are analysed. Also the main design principles of semi-rigid joints are discussed. The new type of semi rigid beam to beam connection is proposed and experimentally analysed. The experimentally and theoretically analysed connection is composed of welded steel details which are anchored into timber element. The main experiment is four point bending; the analysed connection is in the middle of the span. The beam's span is 3.20 m; the dimensions of the timber element's cross section are: width 200 mm; height 400 mm; mounting bolts are M16. Glued laminated timber strength class is GL24h. The tight contact between timber element and steel detail is created by anchoring steel detail's T shape part into timber element. The initial movement between timber element and steel detail is eliminated using fillers. Two types of fillers are used in these experiments: two component polyurethane and cement based filler with polymer fibres. Two joints with different fillers are tested in laboratory experiments. Bending bearing capacity and stiffness (displacements) of the joints' are determined in laboratory. Experimental bearing capacities are compared with theoretical calculations according to European (EC5) and Lithuanian timber structures design codes. Conclusions and recommendations are presented for further experiments and computer simulations.