The strength development of 300N/mm² class ultra-high strength grout by heat-controlled curing was investigated. The strength development at 80-180 ℃ becomes higher than that at a constant temperature of 5-35 ℃, and can be expressed by an effective age based on the same manner. This is because the reactions of C₂S, C₃A, and C₄AF are promoted, and the capillary pores are reduced by heat-controlled curing. Furthermore, it was clarified that heat-controlled curing with a heating wire system and/or surface heating elements achieved the same strength level as that by heat-controlled curing under sealed conditions due to similar water content.

This paper investigates the effect of the span of cantilevered RC wall, the in-plane stiffness of the roof, the layout of friction damper support on both the response control of cantilevered RC walls in RC gymnasiums with metal spatial roofs and the proposed response evaluation method. According to the response history analysis results, the proposed method was proved to be available on various RC gymnasiums and the evaluation formula of the column base moment of the cantilevered RC walls was modified following the appropriate moment diagram.

This paper reports the results of our research on bending and pull-out behavior of the wooden joint reinforced by aramid fiber sheet. First, conducting some element tests of sheet pasting forms, we understood the fundamental mechanical properties and some problems: the breakage of fiber-reinforced plastic by concentrated compressive force, the detachment prompted by non-adhered sheet to woods, etc. Then, we proposed some solution to the former problems. Next, we understood material characteristics of sheet on some material tests. Lastly, building analytical model of joint, we could simulate element tests by increment analysis with high precision.

This paper reports the results of our research on change of mechanical characteristics of existing wooden structures with jointed column. First, taking the questionnaire survey for carpenters or workers, and conducting measurement survey on a temple, it’s found that Kanawa-tsugi is used a lot for repair. Next, based on displacement incremental analysis on plane frame models with jointed column, shear force and initial stiffness deteriorate with jointed column number. Lastly, based on eigenvalue analysis on solid frame model, it’s found that, in case of jount near inflection point of column, or high bending rigidity of joint, the natural frequency rise.

The authors developed the seismic damping retrofitting method by installing energy absorbing devices on the outside of reinforced concrete buildings. The devices are composed of steel braces and independently developed ring mechanism type friction dampers. In a stage of development, the load generating mechanism and dependence on various vibration conditions were clarified. In addition, age-related changes of friction load were verified by testing friction dampers used on buildings for 20 years subsequent to the application of the seismic retrofitting. In this paper, the performance of friction dampers was clarified, and also the efficacy as earthquake resistant retrofitting devices was verified.

This paper proposes a sequential approximate multi-objective optimization method and its application to the hysteresis and viscous damper placement problem of elasto-plastic multi-story structures. The objective and constraint functions are approximated by using machine-learning techniques. Search for the optimal solutions, or the Pareto frontier, is conducted mostly in the approximated response space and only promising solutions are forwarded to true function evaluations with costly time-history analysis. The validity of the method is shown in a 10-story lumped mass shear spring model subjected to earthquake input.

A numerical analysis is conducted for the load-bearing fire test of flooring system composed of deck composite slabs and an unprotected secondary beam, and the test results and numerical analysis results are compared. The main aims are to verify the validity of the analytical model and to analyze the stress distribution inside the composite slab, which is difficult to obtain experimentally. In addition, the influence of the effective depth of the welding wire mesh on the deflection behavior of the slab is discussed.

In this study, fire resistance tests of glulam timber frames were conducted to investigate the influence of rotational resistance of dowel-type connections at the beam ends on the failure time of the beams. The failure time of the simply supported beam specimen exposed to 60 min standard fire was 152 min during the cooling phase, while the failure times of the frame specimens under the same condition were 165 min and 211 min. Based on the fire resistance test results, the bending resistance of the beam with the dowel-type connections was discussed.