The purpose of this study is to measure the rheological constants of high-fluidity concrete that requires compaction, and to verify its effectiveness by the reproducibility of slump flow behavior by MPS analysis. Mortar and concrete were regarded as Bingham fluids, and the rheological constants were measured by Sphere pull-up test on concrete matrix mortar. MPS analysis was applied Regularized Bingham model to the flow constitutive equation.
As the analysis result, the actual slump flow spread curve was reproduced within the range of the upper and lower limit 95% prediction interval of the measurement error of the rheological constants obtained.
Currently, domestic and international Judo standards specify some test methods on shock absorption of Judo floor and tatami. However, so far, the relation and validity of the indicators measured by the methods are not examined enough. Following the results on the safety in Ukemi, which were discussed in the previous paper, this paper aimed to examine the validity and applicability of the current test methods and indicators from the perspective of safety and playability in Tachi-waza and Ne-waza, as well as the safety in Ukemi.
In this paper, ship tracks during the huge tsunami in the 2011 Great East Japan Earthquake are extensively investigated based on Automatic Identification System data and others and ships smaller than 500 GT were identified more likely to be carried inland, resulting in potential impact load sources to buildings. Case studies are further made to compute required capacity of buildings against the combination of tsunami wave and impact loads due to tsunami-driven ships. It is then found buildings designed against tsunami wave and seismic loads will not sustain critical damages against ship impact when ship is smaller than 500 GT.
Shaking table tests and three-dimensional finite element analyses were conducted to investigate seismic response and nonlinear characteristics of pile-soil springs of a structure supported by a pile group in granular soil deposit on a sloping bedrock. The experiment and its simulation were for a nine-pile group in the square arrangement, and showed that constraint condition at the pile tip influenced bending moment response of piles during large input motion. The influence of the sloping bedrock on pile-soil springs, evaluated by an experiment and an analysis, depended on the pile location, direction of pile displacement, and depth.
In this paper, we study a simple method for evaluating the static interaction between a pile group and a footing group on an elastic half space. As this simple method, we formulated closed form approximations. We evaluated the approximations by comparing them with the analytical solutions.
As a result of the study, we concluded that our approximations are sufficiently accurate for use in practical engineering (error ratio is less than 12 % in our evaluation), provided that the width of the pile group is large enough for pile length in the pile group.
The biomimetics has been applied in many fields while its application in structural engineering has not been fully promoted. The applicability of bi-valve shells to spatial structures have been investigated, however, the usefulness of bi-valve shell is not revealed. This is because the mechanical and geometric properties of bi-valve shells are not understood due to its complex shape. In this study, a novel method for measuring mechanical and geometric properties of real shaped bi-valve shell by using X-ray CT images is proposed. Thickness and curvature, and stress evaluation on dead load analyzed using the model created by CT images.
In Japan, it is assumed that there will be many new constructions of stadiums with roofs and expansions and renovations of stadium roofs in the future. The authors focused on a roof structure consisting of radially arranged cables. This structure has been adopted extensively both for new and renovated roofs on the stadiums outside of Japan, but there are no actual buildings which have been reported in Japan. In this paper, with a view to adopt this structure in Japan, the authors consider the structural characteristics under wind load.
Yield displacement is an important parameter that is directly used in computing damping factor of buildings in the Capacity Spectrum Method. In this paper, an evaluation method of a yield displacement of a building is firstly developed so that it can quantitatively consider hysteresis energy absorption characteristics of structural components. The proposed method is, secondly, examined based on a shaking table test of an 80% scale 5-story RC frame specimen to find the hysteresis damping factor of the specimen estimated following the proposed method can have a good agreement with those obtained based on Sa – Sd hysteresis test results.
This study reports the experimental verification of the reinforcing effect of the open web type SRC beam-column joints strengthened by additional members on one side. In strengthened specimens, RC members were added to one side of the existing SRC beam-column joints and beams, and the additional members and existing beam-column joints were prestressed in the horizontal direction with PC rods to reinforce them. From the test results, strengthened specimens were able to suppress cracks and shear deformation at the beam-column joints. The maximum story shear force can be evaluated by the equations shown in various standards.
It is important in the spectral inversion analysis to take into account the local inhomogeneity of the attenuation structure. In this paper, we present a two-step spectral inversion method based on a Bayesian model to estimate source parameters, local attenuation structure, and site effects from observation records. It is expected that the introduction of a Bayesian model allows us to estimate appropriate solutions even for a small number of observation records and to evaluate local attenuation structure. The applicability of the proposed method is discussed through an experiment using actual observation records and numerical estimates.
In this study, high-temperature compression tests were conducted on a dowelled connection in structural glulam timbers to investigate the effect of temperature and moisture on the embedding strength and the embedding stiffness. The embedding strength and stiffness of the specimens heated below 200°C decreased significantly up to 1 hour from the beginning of heating and then the strength recovered at 4 hours with the change in moisture content. The relationship between the internal temperature and the reduction factor of the embedding strength on the parallel to the grain approximately agreed with that of the compressive strength by Eurocode 5.
The formula proposed in the above paper for calculating the plastic strength of panel zones having a circular hollow section is inadequate. Another calculation formula is proposed here in accordance with the theory of plasticity.
We are grateful for Prof. Kuwamura’s discussion to our paper. In this answer, we give our opinions on each of the three issues raised in the discussion.