Modified fly ash (MFA) is defined as FA treated by thermal processing. It is well known that excessive unburned carbon adversely affects the air entrainment performance of concrete. MFA has a consistent LOI of 1% or less. First, the characteristics of unburned carbon in FA and the quality of FA before and after thermal processing were studied, and then, the quality variation of MFA collected periodically were investigated. It was found that MFA with uniformity of characteristics can be produced stably, and one of the obstacles in the promotion of effective utilization of FA seems to have been overcome.

Binder using ground granulated blast-furnace slag with specific surface area 20000cm²/g (GGBS20000) for ultra-high strength concrete were examined. As a result, it was possible to improve flowability of ultra-high strength mortar by use of proposal binder using GGBS20000. And proposal binder using GGBS20000 also had the effect on improvement of early-age strength of mortar. However, binder which used silica fume was more effective than proposal binder using GGBS20000 to produce mortar with high long-term strength.

In this study, the basic properties of polymer-modified mortar using cement clinkers as fine aggregates were evaluated. As a result, it was confirmed that the mortar using cement clinker had excellent strength development and durability. It is considered that this is because the interface between the cement clinker and cement paste become dense due to the hydration reaction of the cement clinker. In addition, the polymer film was formed around the cement clinker, which also contributed to the improvement of physical properties.

Grading of crushed sand is different from that of natural sand. In this report, in order to simplify the expression method of grading of crushed sand, modified Rosin-Rammler’s equation was studied instead of Mimura’s one with five experimental constants. It was found that the grading of crushed sand can be expressed with modified Rosin-Rammler’s equation using two experimental constants and introduction of fineness modulus to the equation was considered. Based on the existing data and the provided equation in this study, it is suggested that one of the stipulations on crushed sand of JIS A 5005 may be reconsidered.

The purpose of this study is to clarify the carbonation progress of precast concrete to get knowledge for suggestion of evaluation and prediction method of the carbonation. The measured data of the compressive strength and the carbonation depth of core specimens sampled from 495 actual precast concrete buildings were analyzed. As a result of the data analysis, the indoor side of precast concrete showed a higher carbonation rate coefficient than outdoor side of precast concrete and both indoor and outdoor sides of cast-in-place concrete.

In this study, 10-year outdoor exposure test was conducted to confirm the durability of bamboo reinforced concrete exposed for a long period of time. Concrete specimens with the same composition and bamboo reinforced concrete members with the same shape and reinforcement were placed in the outdoor and underground environment for 10 years. The strength tests of these specimens were carried out at the 1st month, 3rd month, and 10th years. The results of examining the effects of differences in environmental conditions on the quality of concrete, the corrosion of bamboo reinforcement, and the aging deterioration are described.

In this study, we examined the effect of increasing the diameter of the CFRP strand on the structural performance of the end fixing structure with the aim of further expanding the application of the end fixing structure in the CFRP strand (6φ). For verification, the end fixing structure of CFRP strand (9φ) was formed, and a pull-out test and cross-sectional observation by X-ray CT were performed. As a result, 9φ and 6φ showed the same structural performance by increasing the shortest distance from the through hole of the CFRP socket to the outermost end of the socket.

Some of the watertight members of exterior wall joints have a double-layered structure for redundancy, and gaskets, watertight rubber seals, are used for the inner watertight members. In recent years, new materials such as improved urethane are used for gaskets in addition to the conventional materials such as PVC, TPE, CR, EPDM and SR. In this study, we compared the durability of each gasket in a wet heat test. The results showed that there is no significant difference in performance. In the future, it is necessary to compare each material based on the parameter of construction performance.

In this report, we conducted a questionnaire survey targeting contractors who perform placing and compaction of concrete, and investigated the actual conditions of placing and compaction. As a result, the description of compaction in JASS 5 is the standard for compaction of ordinary concrete, so the number of workers, the number and the rod diameter of internal vibrators, etc. been determined according to the construction conditions. In addition, there were many opinions that it was expected that the possibility of problems such as poor filling could be reduced with the spread of high fluidity concrete.

Renovation work on train station platforms requires removing the protective covering of half-finished work and then putting it back again at the end of each day. However, the time allotted for renovation work in station buildings is limited. Reducing the time for removing and putting back coverings is therefore expected to help shorten the working time. We developed a light, high-strength covering plate consisting of resin-impregnated glass cloth, foam, and a thin steel plate. This paper discusses the results of construction experiments conducted on a model to study the work efficiency improvements by using the developed light covering plates.

We proposed an improved evaluation process for the quantitative nondestructive evaluation of anchorage zone of post-installed anchor by using electromagnetic pulse method. We changed the method of assigning NG points for each index value so that there is a difference depending on the amount that deviates from the judgment threshold. The improved process can evaluate the degree of the defectiveness, and the effectiveness was demonstrated by comparing with the conventional one.

The amount of delay in rainwater storage and runoff in green roof depends on the type of soil, thickness, water content, type of plant, growth condition, and roof slope, etc., but the effect of soil is large. In this study, we focused on the soil, and examined a simple method to estimate the delay of rainwater storage and runoff. The method is to determine the macropore volume involved in drainage from the transition of the water content of the soil during rainfall and the moisture characteristic curve, and to determine that the macropore volume equals the amount of rainwater storage.

For proffer the authorization standard of the act on facilitation reconstruction of deteriorated RC condominium buildings, studied on evaluation methods and criteria about buildings having the risk of falling cover concrete caused by rebar corrosion that exist in a wide. The approach is integrating the deterioration grade of the member of the buildings by visual examination. Through trial and case study used real aging RC condominium buildings, suggested evaluation methods could estimate the grade of rebar corrosion occurred on the exterior of the RC buildings.

In this study, we survey on ready-mixed concrete shipped in Okinawa prefecture, including material temperature, concrete temperature at the time of kneading and unloading, and outside temperature. As a result, It was found that the concrete temperature at the time of unloading must be about 33℃ or less so that the concrete temperature at the time of kneading does not exceed 35℃. We also showed that random forest and LightGBM, which are a type of machine learning, can estimate concrete temperature at the time of kneading and unloading with high accuracy from the unit quantity of material, material and outside temperature.

47 years long creep characteristics of thick natural rubber bearings could be estimated by using the existing measured creep displacement data of an actual vibration isolation building, which was established in 1966. From the estimated creep characteristics, it was confirmed that increment rate of creep displacement is gradually decreased with time. Therefore the time dependent formula for creep recommend in JIS K6410-2:2015 was applied to the estimated creep characteristics. As the formula matched the actual creep characteristics, so it was possible to predict the creep displacement 60 years after the start of measurement using this formula.

Base-isolation system is designed to lengthen the period of the building. However, this can also increase wind-induced responses of the structure since wind forces have long duration and predominant energy on long periods. Furthermore, the mean component in the along-wind direction also causes certain base-isolation components, such as sliding bearings to become prone to creep phenomenon. Despite of this, evaluation methods of wind-induced response considering creep property on high-rise base-isolated buildings with sliding bearings has not yet been fully investigated. Therefore, this paper examines the evaluation method on those buildings and clarifies the effect of creep property using time-history analysis.

In this paper, the safety margin of seismically isolated buildings (SIBs) is probabilistically evaluated using Incremental Dynamic Analysis (IDA), and the effect of laminated rubber bearing’s hardening characteristics on the safety margin of SIBs is also verified quantitatively. As a result, since the non-consideration of hardening characteristics overestimates the safety margin, it is important to consider the hardening characteristics in the evaluation of superstructure’s safety margin. Also, tendency of the safety margin probabilistically evaluated by IDA under numbers of actual ground motions is showing high consistency with tendency of that under general design ground motions.

This paper presents a simple displacement-based seismic design method for RC frames with steel damper column. As a numerical example, two 10-story RC frame building models are shown. The results of nonlinear time-history analysis show that the peak displacement at the equivalent height of the building models is close to the target displacement. The strength demand of the beam ends connected to the steel damper columns, and that of RC beam-damper column joints, are calculated from the nonlinear static analysis and compared to the nonlinear time-history analysis results. Then the proper overstrength ratio is discussed.

In recent years modeling methods of equivalent shear spring models for passive control structures have been proposed. However, no methods are available for configurations with multiple kinds of dampers in parallel. Thus, in this paper, a method is proposed to create an equivalent shear spring model of passive control structures with parallel configurations of stud-type viscoelastic dampers and hysteretic dampers. The parameters of the proposed model are calculated by considering the response of the structure in four states. This paper shows that the proposed modelling method can accurately reproduce the results of time-history analysis of member models.

Dynamic behavior of glass screen of low-rise steel frame building has been examined by earthquake response observations and simulation analysis. Strong-motion earthquake measurement was conducted at damaged a low-rise steel-frame building with glass screens to examine its vibration characteristics that could generate force on the glass screens. From the analysis and an earthquake observation done, it was confirmed that the Glass Screen at the corner of the building tends to be easily destroyed due to the influence of coupling with the torsional vibrations in addition to the large vibrations in out-of-plane direction.

The authors have developed a new simple tuned mass damper (TMD) system, which can be applied to buildings with different natural periods in horizontal two directions. In this paper, the principle of the tuning mechanism and a simple method for determining the parameters of the system is shown, and the superiority of the control performance to that of a conventional TMD is demonstrated by resonance curves and seismic response analyses. In addition, shaking table tests using a 1/10 scaled specimen are conducted, then its dynamic performance and an accurate trace using a simple analytical model are confirmed.

This paper describes development of substructure real-time online response testing system (SROLT) for seismically isolated building with a small response delay using existing experimental equipment. Authors made analytical examinations of the influence of response delay to the test results caused by using existing experimental equipment, and developed a control method to minimize the problem. It was demonstrated by various test results that the developed system has sufficient accuracy as SROLT for seismically isolated buildings.

In this paper, a new type of air beam system named “semi-rigid air beam” is proposed. This system is made by adhering a plate material having semi-rigidity to the upper surface of the tie-type air beam with diagonal cords. The feature of this system is to show higher stability and rigidity under low air pressure. In this study, the effectiveness of this system was clarified by numerical analysis and simple loading tests. By producing full-size test pieces by hand, it was confirmed that the manufacturing process of this structure is comparatively easy.

Extraction of significant data and data reduction are desired in the 3D measurement of existing buildings. In this research, two methods were applied to interpolate and thin out the point clouds. One is the weighted least squares method which can create a surface that is not affected by outliers. The other is the simple shape extraction method using principal component analysis. This method is suitable for point clouds of directional members such as columns.

In this paper, I present the experimental results of traditional mud-hanging walls subjected to constant amplitude multi-cycle loading. The number of the lording times were considered the results of the earthquake response analysis. From the experimental results, I examined the strength deterioration factor and the change of the hysteresis loop. I discussed the strength deterioration factor and the equivalent viscous damping coefficient, which are considered the effect of the multi-cycle loading.

In a land of earthquakes like Japan, one of the most common cause for collapse of wooden houses is the story collapse on the first floor. In this paper, a new method to control seismic response of wooden houses using rocking walls was proposed. By redistributing the reserve strength of upper floor to the first floor that is short of sufficient seismic performance in most cases, it is possible to improve the safety of the entire building. Through time history response analysis, it was confirmed that the seismic response of the first floor was reduced very effectively by this method.

The purpose of this study is to establish the design method of the splitting reinforcement for the glulam beam-end joint by drift-pined joint with inserted steel plate to improve the plastic deformability. In this paper, we conducted the cyclic loading test for the moment resisting joints with the reinforcement by the full-thread screws embedded in the glulam to restrain the splitting failure to confirm the failure behaviors, the reinforcement efficacy by the full-thread screws and the interaction relation of the reinforcement strength of the full-thread screws and the plastic deformability of the moment resisting joint.

We have developed the wooden framed structure with knee brace that has superior performance for application to middle or large scale wooden structures, and verified its seismic performance. For the knee brace, the buckling restrained brace was used to restraint buckling by sandwiching flat steel with wood. As a result, it was confirmed that the framed structure has a high energy absorption effect due to its spindle-shaped hysteresis characteristic. It was also confirmed that the standard shear strength is 4.8 kN per a column, which is equivalent to 7.6 times wall magnification.

In order to realize high-rise wood building, structural design of column base joint is one of the most difficult issues. Generally, failure of timber member, which brittlely fractures, should be prevented. M-N interaction relation is a useful tool to understand the structural characteristic in a practical design. In this paper, M-N interaction relation of base joint of glulam column and CLT wall was investigated by conducting full-scale experiment and numerical analysis using multiple-spring model. It was found that bearing strength of timber is a key parameter to determine the accuracy of the simulation under high intensity of compression force.

Fatigue behavior of glulam moment resisting joint subjected to repeated cyclic loading has not been well clarified. In addition, the accuracy of conventional design formulae for rotational stiffness and yield/ultimate moment should be discussed especially related to the method to obtain material properties. In this research, repeated cyclic loading tests were conducted for drift pined joints with insert-steel gusset plate and tensile-bolted joint. Deterioration of strength and energy dissipation is focused on. The dependency of the performance on the material properties is also investigated through sensitivity analysis.

This paper proposes a series of so-called stud type passive control systems, each of which consists of an oil-damper and vertical support members, in order to effectively reduce seismic response and damage of wooden houses. The feature of the systems is pre-stressed support members and the pre-stress is able to prevent the support member from local slip and deformation. Static and dynamic loading tests of the systems are carried out and the mechanical behavior such as hysteretic curves, deformation contribution of local member, dynamic properties are discussed.

Glued build-up members (GBM) are structural building members that are developed as an application to effectively utilize box-heart timbers. The purpose of this study is to establish a method for evaluating the bending performance of a GBM. In this paper, we analyze the effect of stress distribution and dimensions (Size effect) on the bending strength of GBM. As a result, in the evaluation of the bending strength of GBM, the tensile strength and bending strength of the bottom timber are reduced according to the dimensions, and the combined stress method is appropriate.

To clarify the difference in the structural performance of the plate-type-connector, the box-type-connector, and the L-shaped-connector, the static shear loading tests of tensile brace shear walls were performed. From the tests, it was found that the plate-type-connector provides high lateral stiffness, while the structural performance of the L-shaped-connector was lower than the ones of the plate-type-connector and the box-type-connector. Regarding the relationship between the axial load of a brace and the diagonal displacement of a wood frame, the difference in initial stiffness was not detected in the specimens with 1P, 1.5P, and 2P of wall length.

In recent years, wooden houses may be required higher seismic performance than before. Installing isolation system can be considered as one of the solution, whereas its cost prevents the promotion. This study presents a new isolation system without steel framed foundation by using continued columns and steels shaped like a dish; formed in a recess shape at the center which generates the force putting the structure back to there. This paper describes findings from both numerical simulation and basic experiments, and the behavior of new system can be explained.

The present study focuses on the pull-out behavior of beam longitudinal rebar with bending and mechanical anchorage from a typical reinforced concrete (RC) exterior beam-column joint. In particular, an optical fiber sensing using the fiber bragg grating (FBG) sensors was applied to experimentally measure the strain behavior of reinforcing bars pulled out. Consequently, the bond behavior between the reinforcing bars and concrete measured by the FBG sensors was significantly different from that by conventional strain gauges. The obtained test results can contribute to clarify the anchorage mechanisms.

In recent years, due to environmental considerations and design requirements, there are increasing opportunities to use timber members for nonresidential buildings. Therefore the authors have proposed a moment frame that uses steel materials for columns, and timber materials for beams, as well as its joining method. In this paper, the static and dynamic analyzes are performed by using the school and hotel column beam structure using timber-steel hybrid structure with dog bone as a model during a large earthquake. And a feasibility cost study was conducted of timber-steel hybrid structure and other structures to verify the practical application.

Shake table tests were conducted to examine the seismic performance of unit houses (prefabricated metal houses). The specimens comprised 4 unit-house units connected vertically and horizontally. After experiencing the JMA Kobe record twice, welded connections at the base beam had fractured, and local buckling had occurred in some beams. Bolted beam-to-column connections dissipated substantial energy by slipping repeatedly. Non-structural wall panels were damaged around openings and near columns. Nonetheless the specimens exhibited excellent performance beyond the current Japanese code requirements for ordinary, non-temporary buildings

Concrete filled steel tubular (CFT) columns have become popular as structural member used for buildings. In this paper, theoretical studies are presented on the prediction of bending strength of a concrete filled rectangular tube subjected to uni-axial or bi-axial bending. The main objective of this study is to refine the AIJ design formula which is based on the modified superposed strength method. Bending strength of a column is calculated as the full plastic moment, which is obtained by the generalized-superposed strength method. Proposed formula shows a good agreement with precise numerical solutions.

In recent years, flood damage has been extensive, and therefore building codes in Japan are being strengthened. In view of this, we propose a novel full-scale flooding test system for the purpose of better understanding flood damage and developing flood-proofing technology for wooden houses. It utilizes a simple large-scale excavation water tank built with sheet piles, with temporary equipment to create rising water and rushing water conditions. A full-scale test system was built and tested for two flood levels. The construction process and measurement and camera recording methods are described. The effectiveness of the test system is demonstrated.

Reducing dead load of buildings helps to decrease seismic design force and shrink the sections of structural members, leading to reasonable construction time and cost. This study is focusing on hybrid FRP slabs which is proposed as a replacement of reinforced concrete slabs. Experimental and analytical studies were conducted to investigate structural behavior of the FRP slab. The results show that structural performance of the FRP slab is enough to replace conventional concrete slabs and that the strength capacity can be increased by improving laminate design.

In this article, as one of the development studies of the structure utilizing the characteristics of bamboo, we report on the formulation of the cross-sectional dimension of long natural bamboo.

Bamboo varies in diameter and wall thickness over its entire length, and it is not realistic to measure all of them when designing. It will be formulated by measuring those changes over the material length, and will be used as materials for design. Parameters include type (Moso-chiku or Madake), area (Miyagi Prefecture or Shiga Prefecture), and root diameter.

In this study, we propose simple temperature evaluation models for an unprotected steel beam placed inside drywall assemblies consisted of gypsum boards in a case of fire, which can be used for practical fire resistant design for steel structures. From the comparison with the calculation and the past experimental results, it was clarified that the safe side estimation on the steel temperature was obtained by the proposed calculation model.

We developed a hybrid SWP with organic and inorganic heat insulating materials as the core material and verified the performance of fire resistance and mechanics during the development process. By using both inorganic and organic materials together, it exhibits better fire resistance than organic materials alone. In particular, the specifications using fiber-reinforced plaster board plate, which was superior to the specifications using rockwool in terms of mechanics, also showed excellent fire resistance in the ISO 13784-1 test.

Numerical simulation of the laboratory measurement of sound transmission loss in rectangular test rooms is realized up to high frequency bands, using the fast multipole boundary element method. Setting membrane materials as reference samples, numerical results with fine and simplified room models are validated in comparison with measured and theoretical values. In addition to the sound-pressure-based method, another sound-intensity-based method is numerically simulated. It is demonstrated that the former method overestimates transmission loss at low frequency bands, while the latter method gives the values in relatively good accordance with theoretical ones.

Considering the reduction measures for floor impact noise, it is widely known the increasing the thickness of floor slabs and a method of using a sound insulating material as a finishing material shown the improvement. In this study, a dynamic damper using asphalt damping material is proposed as another new floor impact noise reduction method. We report the change in characteristic vibration during damper adjustment and the floor impact noise reduction effect when installed on a floor in 2×4 structure as an example of damper installation.

A gymnasium with small LED luminaires and daylighting was completed. This gymnasium uses small LED luminaires to reduce glare. Also, this gymnasium has mirror duct system and automatic lighting control system. Measurement of luminance distribution and glare evaluation experiment were conducted. The result of measurement of luminance distribution showed that daylighting reduced luminous flux from the luminaire which in turn reduced the high luminance area. In addition, the result of the subjective experiment showed that glare could be reduced in the gymnasium where small LED lighting luminaires were distributed as shown in previous studies.

A measuring instrument for indoor thermal environment has been developed. It can measure dry-bulb temperature, relative humidity, globe temperature, and wind speed for comprehensive thermal environment evaluation. An illuminance sensor was also added to estimate the behavior of office workers. The cost per unit is about 5,000 yen, and the size is palmsized to make it easier to increase the number of measurements. By reducing the power consumption, it is possible to make continuous measurements for about 25 days using only batteries. It is an open source hardware with all design documents made public.

This study aimed to clarify the method to compute response factors of temperature response. At the beginning, representative wall compositions were investigated. Subsequently, appropriate root sequence and weight ratio for the least-squares method were investigated concerning representative walls. The results confirmed that the error of computed response factor is small if the minimum value, maximum value, numbers of the sequence, and index number for weight ratio are 1/(86400×15)[s^-1], 1/60[s^-1], 10 and 2, respectively.

Phase change materials (PCM) are expected to be indoor thermal environmental control materials in a residential house. In this paper, experiment for effect of introducing PCM was conducted in test chamber with PCM wall. The relationship between difference of melting point of PCM and indoor thermal environment were analyzed by CFD. As a result, the difference of indoor temperature fluctuation was small due to different pasting positions of PCM. It was suggested that energy saving effect and good indoor thermal environment may be formed by expanding PCM area and applying melting point of PCM equivalent to air-conditioning control temperature.

The potential of using Phase Change Material (PCM) in wooden house has been investigated. Since the cost of the PCM is high, searching for a laying position with high heat absorption and dissipation efficiency has been shown as a problem to solve. In this study, we focused on the distribution of the efficiency of heat absorption of PCM laid in the floor or in the ceiling or both in the floor and ceiling of real scale experimental room in winter.