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This paper presents the long-term experimental behavior of timber-concrete composite (TCC) floor systems with cross laminated timber (CLT) as the timber component. In TCC, the steel plates are installed between concrete and timber with adhesive. This floor system was confirmed to have high bending stiffness according to the conducted short-term bending test using the full-scale specimen. In this paper, the long-term behavior of such TCC floor was evaluated in 1270-day experiments using a full-scale specimen with a length of 6 m. The experiment was conducted in a room with uncontrolled temperature and relative humidity. As a result, it was found that the creep behavior showed a good correlation with temperature and relative humidity variations. Moreover, the amount of increase displacement during the summer tends to decrease year by year. The deflection after 1,270-day was 45.5 mm, and the creep displacement after 50 years predicted by using the power law model was 61.0 mm with a creep coefficient less than 3.60. In addition, in static bending test after long-term bending test, no performance degradation due to creep was observed. • Experimental investigation on long-term bending behavior of TCC-floor with CLT and steel plates in joint. • The creep coefficient is 3.60 or less by calculated Power low model. • There was no performance deterioration of stiffness and strength by unloaded and static bending test after 1270 days long-term bending test. [ABSTRACT FROM AUTHOR]

This paper presents the experimental results of squat mud infill walls with three different height aspect ratios in the timber frames of traditional Japanese residential houses. The deformation and failure characteristics, lateral load-carrying mechanism, and influence of the height aspect ratio on the lateral behavior of squat mud walls are investigated. We observed that when the height aspect ratio of the mud wall is less than 0.5, the initial failure is dominated by corner crushing rather than by shear failure. The lateral stiffness of the squat mud wall is positively correlated with the wall height, whereas the drift angle corresponding to the bearing capacity exhibits an inverse relationship with the wall height. For a height aspect ratio less than 0.3, the internal deformation of the squat mud wall is primarily driven by the deformation angle related to corner crushing and sliding. However, when the height aspect ratio increases to 0.5, the rotation angle increases significantly. The transformation of the deformation characteristics and internal force distribution of the squat mud wall depends on the interplay between the wall height aspect ratio and friction coefficient between the mud wall and timber frame. Drawing from comparative experiments and internal force analysis, the lateral resistance of the squat mud infill wall can be separated into two groups of elements: Q c and Q c ' , stemming from the corner compression between the mud wall and adjacent timber frame or internal timber laths, respectively, which exhibits a significant positive correlation with the wall height; Q f and Q g , attributed to the frictional force of the protruding ends of bamboo laths and the gravitational force of the squat mud wall, respectively, which exhibit a consistent behavior unaffected by alterations in the wall height. • Experimental clarification of lateral load-carrying mechanism of squat mud walls infilled in the timber frame. • Internal force and deformation analysis of the squat mud infill wall subjected to lateral force. • Impact of height aspect ratio on the lateral behavior of the squat mud infill wall. [ABSTRACT FROM AUTHOR]

• Resistance mechanisms of structural elements in a traditional timber frame. • Diagonal effect of the deep beam and interaction with beam-end joints. • Influence of structural elements on the force distribution and bending of columns. This paper presents a structural analysis of a frame with deep beams and hanging mud walls in traditional Japanese residential houses. Based on experimental investigations of a frame with deep beams and mud walls, as well as a series of substrate tests of a bare timber frame, mud wall, and mortise-tenon joints, it was shown that the resistance generated by the mortise-tenon joints, deep beams and hanging mud walls contributed to the lateral resistance mechanism of the entire structure. Furthermore, the interaction between the deep beam and beam-end joints in the frame was discussed, and it was confirmed that the diagonal effect of the deep beam was not only reflecting in the resistance provided by the deep beam, but also a positive influence on the maintaining the moment of the beam-end joints under large rotation. The superimposed resistance of all the components and the frame test results were found to be consistent. In addition, because the resistances of joints, deep beams and hanging mud walls were all transmitted by columns, the bending of the columns caused by the moment of joints as well as the shear force of the mud walls was considered. [ABSTRACT FROM AUTHOR]

Prestressing in wood connection, due to frictional forces, improves mechanical properties of the connection. This paper presents novel friction-based connectors, and corresponding tests at the connection and system levels. The friction-base connector is composed of a softwood or hardwood dowels inserted into the wood-based material and tightened to generate frictional force. Long-term performance was evaluated by stress relaxation tests and time-dependent connection tests. To evaluate dynamic performance of shear walls with friction-based connectors, shake table tests were conducted. The shake table tests showed that the restoring force characteristics of the wood friction shear walls were bilinear reflecting the behaviors of the friction-based connectors. The strength degradation of the wood friction shear walls due to cyclic input was small that more seismic inputs could be applied before any significant damage to the wood friction shear wall. Results of stress relaxation tests, for periods of 1 to 3 years, showed that the stresses were maintained at 70–90% under uncontrolled environment. On the other hand, the results of time-dependent connection tests, for 1 to 6 years, showed high initial clamping stresses caused large performance loss, but high performance could be maintained when tightened below the allowable stress for sustained loading. • Experimental studies of friction connectors using wooden dowels were conducted. • Shear walls with the connectors showed high seismic performance in shake table tests. • Long-term performance was evaluated by stress relaxation and time-dependent connection tests. • Experimental results suggest the connectors have a high potential for practical use. [ABSTRACT FROM AUTHOR]

• The dynamic and long-term performance of a connector using a wood friction is investigated. • The dynamic performance of shear walls with the connectors was compared with that of conventional shear walls in shake table tests. • Friction tests of the connections and the wall were periodically conducted along with stress relaxation tests of wood. • Experimental results suggest that the connectors have a high potential for practical use in indoor environments. This paper presents the results of shake table tests and periodical friction tests to evaluate the dynamic and long-term performance of a novel connector using a wood friction (friction-based connectors). The friction-based connectors are a quite simple system in which the wood is bolted transversely to generate friction force. The shake table tests showed that the type of hysteresis loop of the wall with the friction-based connectors exhibited a bilinear, and significantly reduced the maximum response displacement even when the conventional walls were combined. In addition, more than 60% of the total energy was absorbed by the wall with friction-based connectors, even the load bearing ratio of the wall was about 30%. The periodical friction tests of the connectors and the wall with the friction-based connectors indicated that the friction forces were mostly linked to the relaxation behavior of wood, and although the friction forces were significantly affected by humidity fluctuations, long-term friction forces were expected to be maintained. [ABSTRACT FROM AUTHOR]