A literature survey was conducted on the transition of standards and test methods of lightweight aggregates for concrete. Until 1950, the main types of lightweight aggregate were cinder, volcanic lapilli, and volcanic sand. Regulations were established as lightweight concrete, and were intended for non-structural concrete. In 1952, the quality of the aggregate itself was regulated. Starting in the 1960s, standards for artificial lightweight aggregates were created. Characteristic test methods that are different from those for normal-weight aggregates include testing methods for density, water absorption, floating particle ratio, and percentage of solid volume for lightweight fine aggregate.

The effect of gypsum on the fluidity and strength development of mortar using recycled cement and ground granulated blast furnace slag was investigated. The conclusions are as follows. 1) It was considered that an increase in the mass replacement rate of SO₃ in ground granulated blast furnace slag had a negative effect on the fluidity of fresh mortar. 2) In addition, it was considered that an increase in the mass replacement rate of SO₃ in ground granulated blast furnace slag had a negative effect on the strength development of hardened mortar.

The buried arc welding process offers deep penetration and high efficiency but faces issues like arc instability and excessive spatter. Recently, a welding technique to solve these issues has been developed. However, using buried arc welding in narrow gap welding raises concerns about the occurrence of hot cracking. In this report, we propose a semi-automatic high-efficiency welding method for small diameter columns that consider hot cracking using this technique and confirm through various tests that it has performance equivalent to standard methods.

The use of building parts made by additive manufacturing technology as support members for a complex-shaped glass exterior was investigated. To clarify the mechanical properties of the materials, static tests and rotating bending fatigue tests were conducted using test specimens. It was revealed that the material is isotropic, and its fatigue properties were determined. Furthermore, fatigue tests were conducted using actual specimens. Although it was not possible to predict the fatigue failure of the actual specimen from the fatigue properties obtained, some issues that need to be clarified were identified.

We have been developing a coating process to make flame retardation of timber. As a result of improving the coating amount of undercoat and the coating specifications of the undercoat and middle coat to achieve stable flame retardation, we found some of the coating specifications were effective in reducing total heat release and swelling of the coating film. The performance evaluation tests were conducted using the improved coating specifications by a performance evaluation organization, and it was confirmed that the performance met the evaluation criteria for quasi-noncombustible material.

This report is an experimental study to compare the lateral pressure acting on formwork using a pressure gauge and that obtained from the strain of the separator, and to clarify their characteristics. As a result, it was clarified that the method using a pressure gauge can measure lateral pressure with high accuracy. On the other hand, the method using the strain of the separator shows a slightly larger variance than the lateral pressure using a pressure gauge, but it is considered that the lateral pressure can be easily measured at the end of pouring.

To evaluate the thermal insulation performance of TS560MPa steel studs with web slots, material test, exterior wall panel experiment and corresponding numerical analysis are conducted. Thorough these test and analysis, it is confirmed that studs with 3 5 rows of web slots tend to have lower apparent thermal conductivity. Also it is confirmed that panels using studs with 5 rows of web slots tend to have lower thermal transmittance. Furthermore, it is indicated by numerical analysis that these results are because steel studs can create a large and non-linear gradient of temperature changing on web in-plane especially around web slots.

The previous study developed a framework for estimating the probabilistic seismic demand of a steel moment-resisting frame for seismic performance assessment. The framework is based on the prediction of the maximum displacement response, d_max, of the inelastic oscillator equivalent to the first mode. This research enhances the practical applicability of the framework by simplifying the formulae and introducing new graphical solutions for estimating d_max. An example of the assessment of building responses demonstrates the effectiveness of the proposed methods, considering regional differences in seismic hazard.

The friction coefficient of elastic sliding bearings varies under various conditions. Therefore, dynamic force tests were conducted on the elastic sliding bearings under loading conditions that can be compared with previous studies. As a result, the tendency of the friction coefficient to change with compressive stress and loading velocity and the limit deformation performance were confirmed. However, some behaviors different from those in previous studies were observed, and it is necessary to verify the effects of frictional heat and other factors by conducting dynamic loading tests in the future.

The authors developed a damper system combining steel dampers with gaps and oil dampers to harden story stiffness under large seismic motions. Chapter 2 outlines the system, Chapter 3 presents quasi-static tests on the steel dampers, and Chapter 4 reports high-speed tests evaluating sliding, elongation, and stable hysteresis loops. The system prevents deformation concentration in weak stories, enhances building ductility by distributing deformation, and efficiently resists seismic forces, offering a compact and cost-effective solution.

The seismic safety of the seismic resistance entrance steel doors (SDs) and non-seismic SDs installed on the ALC exterior wall was verified by three-dimensional shaking table tests on a full-scale 10-story reinforced concrete building conducted at E-defense in 2018 and 2019. The results suggest that the seismic resistance SDs had a larger in-place deformation angle and more damage than the non-seismic SDs. The in-place deformation angle of both the seismic resistance and non-seismic SDs were greater than the allowable deformation angle, but the damage was minor and all doors could be opened and closed after the tests.

Structural health monitoring has been attracting attention because of the need to quickly determine the degree of building damage immediately after an earthquake. In a previous study, a simple damage assessment method for RC buildings assuming the installation of next-generation gas meters was proposed using the change rate of the natural period when the velocity response spectrum reaches its maximum value. In this study, a shear model was analyzed using only unidirectional input ground. In this paper, the applicability of the damage assessment method is investigated using a frame model considering under two directions of ground motion.

In the Guidelines for Wind-Resistant Design of Base-Isolated Buildings, the rank of the seismic isolation layer is evaluated using the combined wind loads. In particular, when the seismic isolation layer behaves elastically against the wind load, the wind response can be calculated using The Recommendation for Loads on Building (RLB). RLB uses a method to evaluate wind loads based on the spectral modal method by setting modal parameters, but the setting method is unclear. Therefore, this study sets modal parameters for a super-high-rise base-isolated building and evaluates the combined wind loads calculated using the spectral modal method.

Based on seismic observation records of mid- to high-rise RC residential buildings with open corridor type, the natural periods and damping ratios were identified using the ARX model to analyze the vibration characteristics. As a result, compared to the conventional empirical formulas, shorter natural periods and smaller damping ratios were identified. Additionally, the amplitude dependency of the first and second damping ratio was observed from both acceleration and displacement perspectives.

The MPS and the HMPS methods are numerical calculation techniques that calculate objects as a collection of particles. Because they do not use meshes, they can robustly handle large deformation analyses. However, the analytical accuracy of these methods in static analysis of elastic bodies has not been verified in detail. In this study, we verify the effectiveness of the MPS and HMPS methods for small and large deformations. The analysis example compares and verifies a cantilever beam bending problem using a stress tensor consistent with continuum mechanics.

A horizontal cyclic loading test was conducted on the Uplift Column Damping System with Disc Springs inserted between the base plate and the footing foundation. The results clarify that stable response characteristics are observed when sufficient lubricant is applied onto guide steel. Meanwhile, the tendencies of its stiffness in both elastic zones and uplift behavior ranges where the spring material would be separated from the base plate, have been confirmed from the obtained relationships between applied loads and displacements. The analysis suggested that the characteristic of the system is to describe bi-linear model.

The proposed joint is a timber single-layer lattice shell joint designed to effectively absorb torsion specific to single-layer shells. It can accommodate various shapes by adjusting the plate bending process and the composition of its members. To protect the timber and prevent brittle fracture, the steel members are designed to yield first. The joints underwent thorough analysis to assess their stiffness and strength capacities, with their reliability validated through loading tests. Furthermore, demonstration tests were carried out to verify both constructability and deformability.

This paper reports on tests to confirm the elastic deformation of wall columns, in the research of Cross Laminated Timber (CLT) rocking wall columns conducted by the authors. We conducted monotonic compression experiments to understand the elastic behavior of CLT wall columns. We also calculated only the compressive deformation in part of the CLT for strong axis and compared the experimental values with the calculated values. As a result, when the wall height was sufficiently high compared to the wall width, the elastic deformation of the wall column could be roughly evaluated by calculating only the compressive deformation.

In this study, we presented the experimental results of four kinds of 2P mud walls, which two damage levels of the walls, the experienced maximum deformation angle and the accumulated one, are known. The strength characteristics after the restoration were examined, based on the results of the cyclic loading test of these walls. In the restorations, we took care to ensure that there was no gap between the practice and the research. The experimental formulas for the stiffness and the strength reduction factor after restoration compared to before restoration were shown by comparing the envelopes of the strength characteristics.

To preserve and inherit traditional wooden houses in Kyoto, Kyoto City conducts a program to provide seismic performance diagnosis and seismic retrofitting plans for those houses. This paper analyzes the seismic retrofit plans of 138 houses which were conducted by the Kyoto City program to understand what is proposed as seismic retrofitting of traditional wooden houses in Kyoto. We compare before and after seismic retrofitting in terms of their weight and base shear coefficients, and so on. We also analyze retrofit costs and cost-effectiveness in the seismic retrofitting plans.

This study proposed a new timber frame structural system for mid- to high-rise wooden building to enhance the strength and ductility using a new steel rod insertion and adhesive bonding joint construction and steel beam-column connection. To verify the effectiveness of proposed structural system, cyclic loading tests of full scaled specimen were conducted and also conducted lateral load-carrying capacity calculation. As a result, it was confirmed that the calculated values corresponded well with the experimental values. Furthermore, time history response analysis was conducted to verify that the design values for the structural coefficient were appropriate.

Lumbers composing the layers of NLT are often butt jointed at the longitudinal direction. These joints cause a reduction in bending strength. Load carrying capacity of NLT depends on the load distributing mechanism at the butt joints. Load carrying capacity of NLT composed of butt jointed lumbers was estimated by modeling lumbers as finite line elements jointed by shear springs. Butt joints were modeled as gaps between the line elements and the time history of the load distribution was calculated up to NLT failure. The calculated load carrying capacity was almost 85 to 90% of that of the measured one.

Currently, Japan is one of the world’s leading countries in forest resources, yet its timber has not been effectively utilized. Log construction offers a potential solution. The project-type, featuring protruding corners, is common in Japan, while the flush-type, without protruding corners, is prevalent in Finland. This study aims to clarify the structural performance of flush-type joints, comparing them with project-type joints through testing and analysis. Through testing and analysis, the stresses at the joints are reduced due to stress redistribution through the dowel. And it is found that joints do not need to have high performance.

To expand the use of JAS structural cedar lumber, basic data for the design of wooden trusses for medium-scale buildings made of lumber jointed by MPC was verified. As a result of tensile test of lumber from western Japan, it was confirmed that the lumber from any region performed satisfactorily compared with standard tensile strength and Young’s modulus. Furthermore, several variety connection tests were conducted to obtain the connector performance of two MPCs. As a result, strength performances for structural design were obtained for MPC types and each angle of lumber and MPC.

This paper presents a novel structural system developed to enhance the seismic performance of low-rise timber frame buildings. The system comprises a continuous wall made of a cross laminated timber (CLT) panel and friction dampers installed between the CLT panel and columns. Full-scale shaking table tests were conducted on a two-story timber frame structure with/without the proposed system, revealing that the CLT panel prevents damage concentration to a specific story and the dampers improve energy dissipation capacity of the timber structure.

Conventional CLT panel construction methods have many complex joining methods, creating complications in both structural design and on-site construction. In this study, a CLT unit with a simplified joining method using large diameter screws was proposed, and tensile and shear element tests of the screws and full-scale shear tests of the unit walls were conducted. As a result, it was confirmed that high bearing capacity could be achieved even with the simplified joining method. In addition, two types of usage were demonstrated: strength type and toughness type, depending on the screw joining method.

A design method that leverages the structural characteristics of both CLT and steel frames is proposed to develop a hybrid structural system combining these two materials. First, a target structural performance is assumed, and the CLT’s wall volume and deformation performance are determined accordingly. Finally, the steel frame is designed to compensate for any performance shortfalls relative to the target. The results of a trial design using this method confirmed that the required seismic performance is achieved.

Concrete must be placed at a site within the time interval prescribed in the code, so that several batches of concrete must be integrated after hardened. However, continuous placement of concrete could be difficult, a defect of the concrete joint, what we called, “Cold joint” could be occurred. In this study, concrete with a retarded water reducer and slump retention agent was placed in the middle layer to improve the integrity of the concrete. The specimens were made and loading test was performed. The shear strength at the concrete joint was improved, and the shear strength evaluation equation was suggested.

This study focused on bond degradation in cracked concrete due to rebar corrosion. Monotonic and cyclic pull-out tests were conducted on concrete specimens using EAFP to simulate cracking due to rebar corrosion. The test results confirm that the maximum bond stress decreased with the increase of induced crack width. For specimens with short bond length, hysteresis models were developed, which generally well represented the bond stress-slip behavior in the test results. For specimens with long bond length, bond analysis was conducted using the proposed models and the analytical results showed good agreements with the test results.

To evaluate the structural performance of geopolymer concrete beam with FRP rods as main reinforcement, flexural load tests were conducted. The findings obtained from the tests are summarized as follows: 1) The failure mode varied depending on the main reinforcement and concrete type. 2) The ultimate flexural strength can be calculated more accurately using the ACI equation for specimens with Ordinary Portland Cement concrete and Tran et al.’s equation for specimens with Geopolymer concrete. 3) FRP rods have different bond characteristics depending on their surface shape, so for FRP rod specimen, it is necessary to calculate the flexural strength based on the bond strength.

A seismic reinforcement efficiency evaluation index is proposed to select the optimal seismic reinforcement plan considering seismic performance, construction costs, and environmental impact. Focusing on seismic reinforcement of existing RC buildings, construction costs and environmental impacts are normalized to those related to reconstruction. Three types of common strengthening techniques were studied: RC shear walls, steel braces, and CLT walls. The evaluation results showed that using RC shear walls was the most cost-efficient, while CLT walls had the smallest environmental impact, suggesting that the most efficient retrofitting plan depends on the weighting assigned to costs and environmental impact.

An advanced evaluation method of the skeleton curve of unbonded PCaPC beams was investigated, to reproduce their load-deformation relationship more accurately. A new characteristic point where the concrete compressive stress at the extreme compression fiber reaches 0.9 times its compressive strength, 0.9_σB point, was incorporated on the skeletal curve, and its evaluation method, iterative and simplified calculation methods, was proposed based on a macro model. The skeleton curve with the new characteristic point confirmed that experimental results could be more accurately reproduced than previous estimation methods. Also, the simplified calculation results showed good agreement with the iterative calculation results.

To further understand structural performance of unbonded PCaPC walls, experimental investigations with different ratio of wall-height to wall-depth and tendon arrangement, from the previous test, were conducted. Showing rigid-body rotation behavior, even when the wall-depth increased, the walls had great superiority, such as high residual strength and almost origin-oriented resilience characteristics. When tendons were partially fixed, shear cracks tended to increase, but the maximum residual crack width remained less than 0.1 mm. The simplified estimation method of maximum strength was also proposed, based on the iterative method by the author. Simplified calculations showed good agreement with iterative calculations and experiments.

This paper proposed a dry construction method for RC slab to connect with unbonded PCaPC frame structure, which is considered to extend reuse of structural members after earthquake damage. Then, a static loading test was conducted on unbonded PCaPC frame with RC slab assembled by dry construction method. As a result, the effects of slab on the stiffness and strength of beam were quantitatively grasped, and an evaluation method considering this effect was proposed. In addition, the possibility of reusing RC slab was confirmed by employing residual crack width, which is significant engineering quantity to evaluate repairability performance.

The experiment of beam-column joint subassemblages post-tensioned by unbonded PT bars at widened beam end was conducted. The crack width and the residual drift angle were reduced and the equivalent viscous damping ratio became less by mixing steel fibers into the concrete. There were no significant differences in the stiffness, bearing capacity, and hysteretic restoring force characteristics between the virgin and reused members. By designing the PT bars of the beams to yield first and not to damage other parts of the beam, the structural performance of the reused members can be considered equivalent to that of the virgin members.

Partial induction hardening realizes the different strengths in the longitudinal direction of the steel bar. This study investigate the material property of the strength transition region, which is located between the two different strength regions. The strength transition region connecting the regions with the target yield strengths of 800 and 1200 MPa, shows a smooth strength variation without any metal phase changes. However, the strength transition region connecting the 600 and 1200 MPa-regions is tempered martensite outside but ferrite-pearlite inside. It results from insufficient core temperature during the heat treatment, and eventually makes it the origin of the tensile fracture.

Non-welded seismic retrofitting methods have been employed to ensure operational continuity and mitigate fire risks. This study investigates stiffness and strength of wide-flange column web - brace joints used in a retrofitting method that involves attaching supplementary braces to existing structures with high-strength bolts, thereby avoiding welding. Experiments and finite element analyses were carried out. The results indicate that the yield strength of the joints is influenced by bending and torsional yielding of the column flanges, and the out-of-plane strength of the wide-flange column webs can be evaluated using yield line theory.

In the event of a major earthquake, administrative facilities and hospitals should possess the technique to assess the structural integrity of the building themselves. In this study, relations between the damage probability for each damage state and the maximum inter-story drift angle or residual deformation angle are calculated. These relations are based on earthquake response analysis results conducted for mid-rise buildings under 115 sets of two consecutive earthquake ground motions of seismic intensity six or larger in the JMA scale. The quick inspection evaluation criteria are investigated in terms of damage probabilities based on these relations.

It is known that circular hollow section members used in truss towers are subjected to cyclic loading after bending buckling, which leads to early member failure. In this paper, cyclic loading tests of circular hollow section members are conducted to verify the applicability of the buckling behavior. In addition, a replication analysis is performed by FEM analysis to verify the applicability of the prediction method for the rupture timing.

It is known that circular hollow section members used in towers pylons are subjected to cyclic loading after bending buckling, which leads to early member failure. In this paper, a series of incremental dynamic analysis was performed to investigate the effect of the two different hysteresis rules on the collapse mechanism of steel chimney tower considering bucking and rupture of circular hollow sections with small slenderness ratio.

In this study, axial static loading tests for CFT column specimens connected with seismic isolator were conducted to grasp sustained load transfer mechanism of the composite structural system. The test results confirmed the effectiveness of diaphragm installed in CFT column which transferred axial force to the infilled concrete. In addition, the effect of rib plate attached to diaphragm was clarified which suppressed its deformation. Furthermore, axial force distribution of steel tube and infilled concrete in CFT column was accurately evaluated by considering bearing pressure behavior of infilled concrete due to diaphragm.

There are three damage assessment methods used after a severe earthquake. Although the content of these judgments is similar, investigators from different organizations go to the affected site and visually judge the damage state of the building. Performing these damage assessments quickly will contribute to early reconstruction, but the interrelationship of each method is currently unclear. Therefore, this paper aims to clarify the mutual relationship, we investigate the three assessment methods, and compared the results of each disaster assessment calculated with the results of the RC full-scale frame test, to understand the characteristics of each judgment method.

To develop the novel system for post-quake damage investigation using digital image processing technique, it is important to classify the real seismic damage and the pattern similar to cracks which is generated by traces of ivy vines, traces spider webs, artificial devices, and so on. In this research, deep-learning classification of seismic damage and artificial cracking pattern is constructed. Artificial cracking pattern is generated by mechanical pencils, ballpoint pens, oil-based markers. Through data argumentation, deep learning-based classification system can classify the seismic damage and artificial cracking pattern.

In this report, an experimental study was conducted on floor impact sound insulation performance when tatami mats with anti-vibration proposed in the previous reports were constructed on a floating floor system with damping sheets. As a result, from the results of the car-tire source, when tatami mats with anti-vibration are installed, the reduction of transmitted impact sound is 6 to 7 dB for the 63 Hz band, and floor impact sound insulation performance using the car-tire source is better than that of the bare surface.

The “Light and Color Education Design Working Group” of the Architectural Institute of Japan is conducting a survey to understand how content in the field of light and color is being provided as part of a study to develop educational materials useful for architectural practice. In this report, the current status and issues in university education around the light and color field of building environmental engineering are discussed, based on the results of a survey of universities offering the designated courses required to qualify to sit for the Qualified Architect of the first class.

This paper developed an educational program for architectural undergraduate students and examined the effectiveness. Firstly, the tracing works, practiced in the early stages of design and drafting classes, were explained to the students from the viewpoint of thermal environment, and deepened their understanding. After the field measurement of the thermal environment, proposed in the previous author’s study, the students redesigned their works, designed in the previous design and drafting class, taking thermal environment into consideration. Through these series of works, the students were encouraged to think about the relationship between architectural design and the environmental elements of the site.

This study investigates the energy consumption of electrode steam humidifiers through measurement survey. Energy calculations indicate that approximately 86% of the consumed energy is essential for humidification, while the remaining 14% is lost. To improve energy efficiency, heat loss under different steam cylinder thicknesses is examined, and the energy-saving potential of enhanced insulation is evaluated. These findings serve as a foundation for optimizing electrode steam humidifiers and developing more energy-efficient humidification systems.

This paper examines hybrid ground-source and air-source heat pump systems through empirical data and presents the findings. 1) Geothermal-only systems lost rainwater tank cooling ability within 3 days, whereas hybrid systems stayed effective for 5 days. 2) Rainwater from a 5m-deep tank circulated through a radiator at the outdoor unit’s inlet, cooling air by 10°C and maintaining inlet temperatures at 24–31°C in summer. 3) Unlike constant-pumping geothermal systems, hybrid systems activate water flow only when outside temperatures exceed 30°C, significantly reducing pump runtime while ensuring rainwater in tanks is naturally cooled by the soil during idle periods.

This study aims to visualize the effects of building envelope retrofitting using 3D point cloud data and augmented reality (AR). By integrating 3D scanning, computational fluid dynamics (CFD) analysis, and AR technology, the method enables an intuitive understanding of changes in thermal and airflow conditions before and after retrofitting. The proposed visualization improves decision-making for building owners, facilitating energy-efficient renovations and indoor environment enhancements. Results demonstrate that combining point cloud data with CFD optimizes simulation efficiency and accuracy, while AR provides an interactive visualization of retrofit benefits. This approach contributes to promoting sustainable building practices in aging structures.

In recent years, output suppression has occurred due to the increase in solar power generation facilities. In addition, natural disasters in Japan have become much more severe than ever. In this study, machine learning and optimization regarding the capacity and control of solar power generation facilities and storage batteries for detached houses are conducted. The results indicate that the early introduction of solar power generation facilities should be promoted, and at the same time, storage batteries are effective measures to respond to disasters. However, it is currently difficult for homeowners to recover their investment in storage batteries.