Experimental Investigation on the Load-Carrying Capacity of Steel-to-Laminated Bamboo Dowel Connection I: Single Fastener with Slotted-In Steel Plate under Tension

The dowel-type connection is widely applied in timber and bamboo structures. It is ambiguous regarding the calculation method of engineered bamboo connections completely referred to the timber design codes. The steel-to-laminated bamboo dowel connections with slotted-in steel plate tests were conducted to investigate the mechanical performance under tension based on the ASTM-D5652-15. The effects of the thickness, dowel diameter, and end distance on the yield load, ultimate load, initial stiffness, and ductility of the connections were studied. The difference in the yield load for different end distance is negligible. With the same thickness of the connections, the lower the thickness to dowel diameter, the larger the load-carrying capacity. The three typical yield modes and corresponding load-displacement curves of the connections are observed. By considering the rigid-plastic model, the theoretical equation for the connections is proposed and proven to fit well with the experimental results. It presents a better prediction for the load-carrying capacity of steel-to-laminated bamboo dowel connections with slotted-in steel plate.

Determination of the load-bearing capacity of «steel-wood» connections of LVL structures under tension

The article presents the results of calculation of the load-bearing capacity of connections of LVL structures under tension using cylindrical dowels in trusses and frames. The description of calculation schemes for determining the load-bearing capacity of connections with different location and sizes of steel plates in the connection is given. The influence of steel plate placement on the distribution of forces in the cross-section of samples is investigated. Based on the results of analytical and experimental studies, the load-bearing capacity of dowels during bending is considered, as well as the mechanism of wooden structures` fracture during chipping. A comparative analysis of the effectiveness of different schemes of dowel connections with three steel plates under tension is carried out.

Investigation of linear stiffnessin the connection with claw washers in the LVL beam

The study considers the performance of double-cut dowel connections with the use of claw washers in the LVL beam. The authors present a method of testing the double-cut wood connection performance under compression, the angle of forces application in regard to the fibers being 45°. There has been carried out an experimental study of the connection with claw washers in the LVL beam for a 45°angle between the direction of the fibers in the outer and middle elements under the action compressive load. The testing results allow assessing the deformation value in the connection and the experimental values of the linear stiffness coefficient. There has been implemented an evaluation of results, and the nature of the connection`s fracture is considered.

Analysis of various failure models of steel-wood connections with self-drilling dowels

The load-bearing capacity of the dowel connections of wooden structures is determined by two limiting states, namely, by the failure of wood (crumpling) or deformation of steel dowel (bending). Both failure models are plastic. In some cases, brittle failure is possible, which will determine the load-bearing capacity of the connection. However, the regulations in the Russian Federation do not consider the brittle failure of dowel connections because this type of failure is excluded by the rules for placing dowels. Appendix A of Eurocode 5 includes types of brittle failure caused by chipping of a block or slipping of wood in connection. In [10, 11], the authors consider various fracture models for connections with large-diameter dowels (over 12 mm). In the present study, the author evaluates and classifies calculation models for brittle failure in connections of wooden structures using self-drilling dowels of small diameter (less than 12 mm), which are not presented in the Eurocode 5 and SP 64.13330.2017 standards. Solutions are proposed for reducing the probability of brittle failure propagation in such connections.

Experimental Investigation and FEM Modeling of Glued Timber Connections with Slotted-In Steel Plates

The study is focused on the mechanical behavior and finite element method (FEM) modeling of glued timber dowel connections with slotted-in steel plates. Standard tests accompanied by a physical optics investigation method were used in order to obtain information about the mechanical properties and stress-strain behavior of glued timber dowel connections with slotted-in steel plates. As such a methodology provides information on the stress-strain state over the surface of a connection, it was used as a verification criterion for a 3D finite-element model. Small-scale glued timber dowel connections with slotted-in steel plates were tested in parallel-to-grain tension to investigate their load-carrying capacity and the load-slip performance of the connection. A three-dimensional finite-element model of the glued timber dowel connections with slotted-in steel plates was developed using existing FE software and verified using the holographic interferograms obtained during step-by-step loading as well as the test results.

Predicting Behavior of Grouted Dowel Connections Using Interfacial Cohesive Elements

Grouted dowel connections are used extensively in precast load bearing walls owing to their simple construction and forgiving tolerances. Current design guidelines do not adequately consider the composite nature of such connections. Moreover, robust numerical models for these connections are yet to be developed. Therefore, a finite element model of grouted dowel connections was developed in this paper. The model adopts a phenomenological bond–slip constitutive law to predict the load versus slip response of grouted bars and considers tensile yielding of the reinforcement. The local bond–slip law used was generated from carefully designed experiments to eliminate spurious effects associated with bond testing. The model was validated using experimental results on grouted connections, as well as data retrieved from the open literature. Excellent agreement between experimental and numerical results was observed, highlighting the accuracy of the model in depicting interfacial stresses of the assembly. The model requires simple calibration, is computationally efficient, and can accurately simulate the failure behavior of bars embedded in grouted connections.