We analyzed the results of experiments on the strength development of structural concrete. We applied machine learning to construct a model that predicts core strength using the compressive strength of cylindrical specimens, such as standard cured specimens and simple adiabatic cured specimens. In addition, we analyzed the number of simple adiabatic curing specimens.

Explanatory variables were extracted from the prediction model obtained by random forest, and multiple regression was performed using the compressive strength of simple adiabatic cured and standard cured specimens as explanatory variables and strength prediction equations were proposed.

The influence of air content on compressive strength of concrete containing high strength area through literature survey. The findings are summarized as follows. Calculation method of strength reduction ratio varies depending on literatures, therefore the method must be clearly stated in the literature. The strength reduction ratio was 5 to 6% in normal strength area, but in high strength area it was 3 to 4％. Strength reduction ratio can be predicted by smaller of Talbot’s cement-space ratio method and Sakuramoto’s paste-air method. The strength reduction ratio was not change much from the age of 7 to 91 days.

For a gable roof low-rise building, 2,000 10-minute samples of the peak pressure coefficients were measured and the probability distributions were evaluated using extreme value distribution. Using information on the probability distribution and coefficient of variation (cov), adjusting coefficients were evaluated and compared with the results on flat roof low-rise buildings. Lastly, probability distributions of wind loads on components and cladding were evaluated and it was found that Frechet distribution fits well in most cases, and cov of wind load can be evaluated reasonably well when covs of design wind speed and peak pressure coefficient were less than 10%.

This paper presents a form-finding method for shells resisting external loads through tension-compression mixed membrane stresses. The vertical equilibrium equation of the shell is expressed as a hyperbolic partial differential equation, which is discretized by the finite difference method to obtain a linear system of equations. Existence and uniqueness of the solution can be determined using the coefficient matrix of the equilibrium equations. By introducing regularization and smoothing terms, smooth shapes can be obtained even if the solutions are not unique. The validity of the proposed method is confirmed by comparison with the initial-boundary value problem for wave equations.

This study attempted to clarify the sliding behavior that occurs at the diagonal joints of wooden truss beams. Specimens were created in which the diagonal members, bottom chord members, and beams were joined in different ways, and diagonal member axial load tests were conducted to verify the relationship between load and displacement. Factors that affect deformation were extracted as spring elements, and the initial stiffness was calculated taking into account the generated frictional force, and the calculated values were compared with the test values.

This study was conducted to clarify the carbon footprint of wood and wood-based materials for the realization of decarbonized society by investigating the energy consumption of structural members up to delivery to construction sites. As a result of arranging the manufacturing process into several stages, it was found that the drying process consumes the largest amount of energy. It is clear that there is a large difference in energy consumption due to the difference in volume during drying, when lumber and lamina are compared. In addition, it was confirmed that the introduction of woody biomass has a significant effect.

Bending stiffness, yield moment, and bending capacity of steel bar-timber composite beam under an environment of wood’s moisture content decreasing were revealed by the drying and loading test, and methods for estimating those have been proposed in this paper. Internal stresses between rebar and glulam timber in the beam, derived from wood drying, did not affect the bending stiffness and capacity, but did only the yield moment similarly to that for temperature rising and wood moisture content decreasing, reported in the previous paper. Also, effects of the internal stress on the allowable moment of the beam in design were revealed.

This paper discusses an evaluation method of yield strength at the angle brace connection based on stress distribution. The monotonic tensile tests were conducted to clarify factors affecting the yield strength. As a result, yield strengths on brace connections were found to depend on connection length, the out-plane eccentricity and in-plane eccentricity. In addition, numerical analyses were carried out to investigate the effects of various parameters on the stress distribution in the yield strength of the connection. Finally, an evaluation model for the yield strength on angle brace connection based on stress distribution was proposed.

This paper describes a methodology to evaluate the elastic lateral-torsional buckling strength of the H-shaped beam whose top flange is restrained on its side-sway along the member axis. The methodology is based on energy method applying unique sine series as a new displacement function which is able to describe the buckling modes under various conditions. With this displacement function, a high-precision closed-form strength equation for any loading condition and boundary condition can be obtained. To clarify the accuracy of the proposed equation, finite element buckling analyses are conducted.

In order to establish the Multi-Spring model that can simulate horizontal shear-flexural monotonic loading tests on built-up box beam-columns, this study investigated the following.

1. First, experiments in the previous literature were organized to obtain regression equations for the local buckling behavior (i.e., strength, plastic deformation, and stiffness after local buckling), which are useful for the Multi-Spring model.

2. Next, the Multi-Spring model that can simulate horizontal shear-flexural monotonic loading tests using the regression equations is proposed. The simulation analysis by the proposed model agreed well with the experiments.

The construction of building foundations requires substantial time and effort, particularly in fabricating reinforced concrete footings and foundation beams. To address these challenges, this paper proposes a novel structural system that utilizes steel structures for the foundation beams and reinforces pile heads with double steel pipes. Loading tests were conducted to assess the influence of various factors. The applicability of existing evaluation equations is examined to highlight the need for a new prediction formula. As a result, this paper proposes an evaluation equation for the ultimate bearing capacity and a constitutive law to predict the behavior under compression forces.

The structural behavior of timber joints governs the behavior of the timber structure. Therefore, the formulation of timber joints is very important for the estimation of restoring force of the structure. The authors estimated the discusser’s research due to “a geometrical approach” for the formulation of the embedment of joints.

However, the discusser disagree with the author’s estimation for the discusser’s research as “a geometrical approach” because the two approaches : geometrical approach and mechanical approach are not defined and ambiguous. If the authors use these approaches, they should define the meaning of the approaches clearly and estimate the past researches adequately.

We are grateful for Prof. Tanahashi’s discussion to our paper. In this answer, we will give our opinions on questions about the definitions of the terms: “a geometrical approach” and “a mechanical approach”, and the validity and the significance of the definitions.