Ductile End Connections for Glulam Beams

Abstract

Ductility, which is the capability of a structure to deform significantly beyond the elastic limit without brittle failure, is a fundamental property which can be an impor tant requirement in many instances. In particular, the behaviour of structures under seismic actions depends on the capacity to withstand large displacements in the plastic field without reaching the collapse. Wood suffers from the unfavourable material characteristic that exhibits no (tension) and limited (comp ression) post-elastic deformation capacity. Therefore timber structures rely on steel dowel-type connections to provide ductility and energy dissipation. In general, good performance can be achieved by light timber structures with a large amount of steel connectors, designed to favour steel yielding as the governing mechanism. For heavy timber structures, because of the lower redundancy of the structure, a more "engineered" joint design is needed to ensure a safe performance during seismic events. The research reported in the present paper has been devoted to the investigation of an innovative steel-to-timber joint suitable for different joint configurations within a frame, where a timber element is connected to a steel stub by means of an end-plate and glued-in steel rods. The proposed system has been investigated by means of numerical models and experimental tests, in order to determine strength values and moment-rotation relationships of the joint. Some interesting conclusions can already be drawn from the available experi mental tests, suggesting a possible full implementation of such techniques in seismic resistant timber structures, which is the ultimate goal of the research.

A component method for moment-resistant glulam beam–column connections with glued-in steel rods

“…Moment-resistant timber connections were investigated using the component method mentioned above in the literatures [13,19,20,24,25]. By using the component method, Tomasi et al [19] and Andreolli et al [20]. carried out detail investigation on ductile moment-resistant timber connections with the combination of glued-in rods and steel connecting studs.…”

“…5. Thus the stiffness for glulam column in transverse compression k cc becomes: According to Tomasi et al [19], the stiffness for glulam beam in compression k bc can be determined using Eq. (17).…”

“…(17). where E w,0 (N/mm 2 ): modulus of elasticity parallel to grain of glulam beam; β (dimensionless): coefficient, which can be approximated to the value 4 [19].…”

“…A great number of research has been carried out on pull-out behavior of glued-in rods joints [4][5][6][7][8] and a comprehensive review of early efforts involving it can be found in the literature [9]. Also some research was carried out on moment-resistant behavior of timber connections with glued-in rods [10][11][12][13][14][15][16][17][18][19][20], which is the focus of this paper.…”

Experimental investigation on the behavior of glued-in rod joints in timber beams subjected to monotonic and cyclic loading

“…Few test data on multiple rod connections are available in the literature, and they often concern pull-out tests. Studies on groups of rods were performed by Gehri [8], Broughton and Hutchison [9], Tomasi et al [10], Tlustochowicz et al [11], and Parida et al [12]. In addition to the previous failure modes, splitting failure due to a short rod distance and group pull-out is of interest for multiple rod connections.…”