In this study, we assumed that the cement paste and mortar are continuums and proposed a rheological constants estimation equation that can be applied to both cement paste and mortar. After that, the effectiveness of the proposed equations was verified using MPS analysis, and the effectiveness was confirmed in cement paste and low-fluidity mortar. However, for high-fluidity mortar, the actual measurement results could not be reproduced well by MPS analysis. In the case of high-fluidity mortar, the actual measurement results could be reproduced well in the MPS analysis considering thixotropy.

In this study, The bond performance of reinforced concrete having a thermal history was evaluated using neutron diffraction. And The restoration of bond stress by re-cured for 3 days was estimated by the same method. As a result, Local restoration of bond stress was observed in specimen with a re-cured after being heated at 600°C. However, In the case of re-cured for 3 days after being heated at 600°C, Restoration of the average bond stress did not occurred. Also, When the conventional method of evaluating bond performance was applied with heated concrete, Some differences were observed between measured value.

This study proposed a method to estimate the compressive strength of early-age concrete before demolding using a pin penetration device. Small holes were prepared on molds to apply for this method. A strong correlation was obtained between pin penetration depth and compressive strength despite the materials and mix proportions difference. This method was applicable between 5 and 15 MPa compressive strength, which is the demolding criterion. Within the experimental results, the penetration depths of 12.5, 9.5, and 8.5 mm (Flat), and 13.0, 10.0, and 9.0 mm (Sharp) were sufficient to demolding criteria of 5, 10, and 15 MPa, respectively.

The effects of the demolding time and formwork material on the color of the colored mortar were investigated. As a result of the experiment, the influence of the demolding time on the color of the color mortar was small. In addition, when rubber and metal (stainless) were used as the material of the formwork, in some cases, the color unevenness of the mortar could be suppressed more than when the coated plywood board was used.

For the purpose of fixing CO₂ to concrete, a method for manufacturing concrete using carbonated cement slurry was examined. In the process of injecting CO₂ into the cement slurry, more than 90% of the injected CO₂ is fixed as fine calcium carbonate particles. Concrete using carbonated cement slurry did not cause a decrease in fluidity due to two-stage mixing method and showed the same level of strength development and durability as blanks. The amount of CO₂ in concrete exceeded 20 kg per ton of cement. In addition, it was possible to manufacture concrete with CO₂ fixed in the actual plant.

Equivalent linearization is an available method widely used to conveniently predict the nonlinear responses of buildings. The present study proposes a seismic response prediction method based on equivalent linearization of stud-type viscoelastic dampers with amplitude dependencies for that there is not a lot of research discussing on estimation method for such dampers. Through the present analyses, the authors found that the proposed prediction method leads the structural design process to be more effective one saving costs by comparison with former trial-and-error approach with time history numerical analysis.

To evaluate Q–Δ resonance, which is a torsional resonance phenomenon caused by geometric non-linearity, we proposed a simplified model for an n-story non-eccentric building model with a shear-type structure. We designed and fabricated a four-story small-scale specimen assuming a non-eccentric steel structure with a height of 324 m, and conducted shaking table tests. As a result, the occurrence of Q–Δ resonance was confirmed as predicted by the simplified model. In addition, the simplified model reproduced the resonance amplitude in a finite element model of the specimen with the out-of-plane rotation of slabs constrained and its validity was confirmed.

A tuned viscous mass damper (TVMD) that tunes only the shear component of a flexural shear-type model was examined, and the range of application of a design method for shear-bending model with TVMD was investigated. It was found that the design for the equivalent shear model is applicable when the bending deformation ratio of the structure is small. On the other hand, when the bending deformation ratio is large, the TVMD can be designed by considering the overall bending deformation, and it is shown that the damping performance can be assured by updating only the support stiffness of the TVMD.

This paper presents a FEM model that can simulate the in-plane behavior of Cross laminated timber (CLT). In the analytical model, the wood was modeled by orthotropic elasticity and the adhesion surface was modeled by Cohesive Zone Model. In order to verify the accuracy of the analytical model, several previous experiments were simulated. Generally, the good agreement between the analyses and all experimental results was shown, and the in-plane behavior of CLT could be simulated.

For the application of diagnostic imaging by utilizing deep learning in seismic damage inspection, a novel methodology to assess damaged finishing on a timber house was proposed and validated through a shaking table test. As a result, the optical conditions were revealed, and a simple way to check them was proposed. Furthermore, the estimation methodology of experienced deformation was validated based on diagnostic imaging results. The results close to actual measurements were obtained based on the quantitative damage assessment. From the above, it is confirmed that the diagnostic imaging methodology has the potential to introduce seismic damage inspection.

This paper proposes a method of flexural analysis for structural performance evaluation of the RC secondary flat walls without wall vertical rebar anchorage. An idealized deformation model for the walls restrained axial elongation was also proposed and applied to the flexural analysis. Consequently, the results from the flexural analysis had good agreements with the experimental results, which identified the failure mode in flexure of the tested specimens. Furthermore, a simple theoretical equation was proposed to quantitatively estimate the maximum compressive axial force applied on the flat walls based on the above idealized model.

The social demands on the building performance are not only to secure human lives but also to keep the original functions during and after hazards. Engineers have been developing resilient building structural systems and design methods that explicitly quantify damage levels of members, that is, limit states of members. In this study, numerical analysis using a multi-spring model is conducted to predict the damage level of a real scale five-story reinforced concrete building tested in BRI in 2014 so that the obtained information may be used to evaluate the cost of repair after earthquakes.

This paper describes the effects of anchorage reinforcement for the structural performance of RC L-shaped beam-column joints using mechanical anchors at the ends of column longitudinal rebar. The requirements of the anchorage reinforcement are summarized referring to the previous study. Static loading tests of two specimens with and without the requirements of the anchorage reinforcement were conducted to verify its effectiveness; however, anchorage failure occurred at the ends of exterior column longitudinal rebar. Therefore, the requirements were modified based on the experimental damage, which was verified the effectiveness to completely prevent the occurrence of anchorage failure.

Strength and deflection for beams in cruciform unbonded precast prestressed concrete frames are evaluated using a skeleton curve consisted of four characteristic points (flexural cracking point, tendon’s elastic limit point, ultimate flexural point, safety limit point), based on theoretical approach. The flexural cracking point is evaluated by elasticity theory, and other points are estimated by a macro-model, which well produces the seismic behavior of the target structure. Skeleton curves composed of four characteristic points correspond well to the load-deformation relationship of previous experimental results. Calculated strength and deflection, as well as the tendon strain, show good agreement with the experiments.

When hot-dip galvanizing a square hollow section column, it is necessary to provide holes in the diaphragms. These holes affect the local rigidity and local strength of the beam to column connections. It requires local strength evaluation formulae to properly design the hole diameter and the plate thickness of the diaphragms. In this paper, the behavior of the connections and the failure mode is examined by loading tests. The shortage of test parameters is supplemented by performing finite element numerical analysis. Evaluation formulas for local yield strength and local ultimate strength are proposed based on limit analysis.

In this research, static loading test of Engineering Wood Encased Concrete-Steel (EWECS) columns with different steel depth has been conducted. From the results, it was confirmed that deterioration in capacity during large deformation, and the concrete failed in shear. Flexural strength could be estimated by the generalized superposed strength theory and shear strength could be estimated by the simplified equation given in the Standard for Structural Calculation for Steel Reinforced Concrete Structures. In addition, an evaluation equation for stiffness reduction factor at yield point in the skeleton curve and ultimate deformation have been proposed based on test results.