Research has repeatedly pointed out the suitability of adhesive bonding to substitute to “traditional” joining techniques for numerous materials and loads, including timber to glass. Practitioners, however, are still reluctant to implement them into their designs. Adhesion as a method of joining, particularly in the context of hybrid structures, presupposes knowledge of all involved materials, including codes and procedures; most practitioners however tend to be focused on just a subset of materials. While such specialization is not unusual, it makes it challenging to implement novelty (i.e. new materials or techniques). Additionally, when it comes to adhesion where most of the knowledge has been generated by chemists, the lines become even more blurred. Taking the example of a pedestrian timber-glass bridge, this research shows how design and dimensioning of complex bonded hybrid structures can be performed in accordance with “traditional” engineering practice. The paper guides through every step, from the first concepts to the final design, including the manufacturing, of a relatively complex structure, in which timber and glass act together as equivalent members. The compliance of this process with engineering models is emphasized, and the embedment into existing codes and standards is sought after to ensure acceptancy by practitioners.
The connectors for the CLT shear wall with drift pin joint were suggested. The wall composed of five layers Japanese cedar CLT, steel connectors and drift pins (diameter d = 16mm). The horizontal shear performances of the walls were evaluated by static experiment and 2D frame analysis. The experimental parameter was number and position of drift pins. Characteristic failure was shear failure on the border of the laminae. There were good agreement on initial stiffness, yield load and second stiffness between experiment and calculation.
Lag screw bolt (LSB) has been used widely for composing glulam moment resisting column-leg as well as beam-column joints for constructing semi-rigid wooden frame structures. A serious problem on the existing LSB joint, however, was its brittle failure mode. In order to avoid this characteristic, Slotted Bolted Connection (SBC) systems, which is a kind of the friction damper for steel truss structure, was introduced to the existing glulam LSB joint system serially. Experiments on full-scale column-leg joint and beam-column joint, which were intended to be used in a three storey glulam school building, showed satisfactory performance on the requirements for the stiffness, yielding and ultimate performance. By this innovative investigation, a glulam semi-rigid portal frame, which has high initial stiffness, clear yielding capacity, rich ductility, and free from glulam brittle fractures, might be possible to be realized.
Damage in recent major earthquakes has resulted in engineers' effort on the development of techniques which not only provide life-safety, but also aim to minimise damage so that buildings could be reoccupied quickly with minimal business interruption and repair costs. In this paper, the new developments on the innovative Resilient Slip Friction Joint (RSFJ) technology are introduced which provide an advanced engineering solution for seismic damage avoidance design of structures. Given the significance of the deformation compatibility in the connections of rocking structures to fully satisfy the low-damage design concept, the performance of the RSFJ under in-and out-of-plane rotations has been investigated analytically and experimentally. The results demonstrate the RSFJ rotational flexibility in addition to the main translational deformability, owing to the discs springs providing the chance for the separation and prying of the RSFJ clamped plates without losing the joint integrity. The comparison between the predictions and the test results verifies the accuracy of the model developed. Also, different applications of the RSFJ technology have been presented adoptable for new structures as well as retrofitting of earthquake-prone buildings.
The Japanese domestic forests have never been maintained enough, and it was a great fear that the multiple functions of the forest such as watershed conservation, the land conservation, and so on has been declined. The construction employing the cross laminates timber (CLT) panels was offered as a method of large scale building in domestic and foreign countries. However, the seismic design method of CLT panel construction has never completed. So, in order to consider the seismic design method, the shaking table tests and static lateral load tests were conducted to the modelized CLT panel construction.
A reduction coefficient is applied in usual design of multiple dowels type connections. The numbers of stiffeners in row is one of important factor to decide this coefficient. CLT drift pinned joint showed small orthotropy against in plane tensile load. Tensile tests of multiple drift pins joints were performed to evaluate the effect of array. Numbers of drift pins n in each specimen were same (n=12), but the arrangements were different (2 x 6, 3 x 4, 4 x 3, 6 x 2). Also the grain directions were parameters (0, 90 degrees). The reduction of initial stiffness and proportional limit load showed good agreement between theoretical prediction and experimental results.
Cross-laminated timber panels offer an effective option for timber structures; they allow biaxial load transfer and have good dimensional stability. However, practical transportation and handling limits size of the panel and a stiff connection between the panels is required to effectively utilise biaxial properties. In this paper, a dovetail splice joint for timber panels is presented using cross-banded LVL with cast concrete grout interlayer. The interlayer allows a tight fit, which is important for stiffness, but also avoiding installation problems due to manufacturing tolerances and moisture-induced dimensional changes. The mechanical behaviour of the dovetail joint was investigated experimentally for various geometries. Furthermore, a numerical model was developed that shows a wide agreement with the experiments, especially in the cases with governing failure in the LVL. Using the numerical model, a parameter study was performed where the influence of the connection length (number of dovetails) and the joint geometry on the strength and stiffness properties was investigated. Besides the optimal geometrical configurations of the dovetail joint, also a significant increase of the strength and stiffness properties with increasing connection length was identified.
This paper presents an experimental evaluation of the fire resistance of glued-in rod timber joints using epoxy resin, with and without modification. A heat-resistant modified resin was designed by adding inorganic additives into the epoxy resin, aiming to improve the heat resistance. Joints that were made using the modified epoxy resin at room temperature showed a bearing capacity comparable to those with commercial epoxy resin. Twenty-one joint specimens with the modified epoxy resin and six with a commercial epoxy resin were tested in a fire furnace to evaluate the fire resistance. The main failure mode was the pull-out of the rod, which is typical in fire tests of this type of joints. As to the effects of the test parameters, this study considered the effects of adhesive types, sectional sizes, stress levels, and fireproof coatings. The test results showed that the fire resistance period of a joint can be evidently improved by modifying the resin and using the fireproof coating, as the improvements reached 73% and 35%, respectively, compared with the joint specimens with commercial epoxy resin. It was also found that, for all specimens, the fire resistance period decreased with an increase in the stress level and increased with an increase in the sectional sizes.