The purpose of this study is to obtain the effects of reinforcements on the thermal cracking of mass concrete wall structure. Four specimens are prepared, and they have same experimental conditions except their reinforcement size, ie. no reinforcement, D6, D13 and D25 bars. The reinforcements, as a result, effected on the widths of the cracks, but on the age of the first cracking, there were no difference among the specimens. Analytical study on the conditions was also tried using the personal computer program developed by the JCI Mass Concrete Research Committee. Analyzed results on steel stress were showed a good coincidence with the experimental results, but on vertical pattern of crack width there showed different results.

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This paper is intended to develop and study the technology to produce the ceramics of cement mortar by using cement, fritted glaze, silica fume and some special sands. The specimens were casted (2×2×8cm) with this mortar. And after curing, they were fired at 940℃ or 1000℃ for two hours to measure the properties of these specimens before and after firing. As the result, the fritted graze of low fusing point with 20% frits/cement ratios and of 5〜8% silica fume/cement ratios was found to be most suitable for these ceramics of cement mortar. And the most suitable firing temperature for the properties of these specimens after firing is found to be 1000℃. And the surface of these mortar was tested to be colored with the glaze by these firing.

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The purpose .of the study is to establish the evaluating method of the fracture of framed floors and walls under dynamic loads affected by human. In this paper, part 2, the apparatus for evaluating the fracture of framed floors and walls was newly designed and manufactured. The apparatus is composed of three parts, namely, mechanical loading system, fracture detector, and base of these, which are based on the properties of dynamic loads affected by human, investigated in part 1. Moreover, the method of detecting the fracture of framed floors and walls under dynamic loads was presented through the experiment using newly developed apparatus for evaluating the fracture.

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Recently, the concept of reliability-based design has been developed and is thought to take the place of conventional experience-based design in the near future. But a detailed procedure to implement this design concept has not well been developed. In the present paper, Genetic Algorithms is used as an effective optimization method in carrying out reliability-based optimum design. The objective is to investigate the difference between the structures based on the allowable stress design and the reliability-based design. A steel frame structure is reviewed under the seismic load and elastic limit state is considered.

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The authors have examined the reliability of Large Eddy Simulation (LES) when applied to the flow analysis for unsteady surface pressure and aerodynamic forces acting on a 2-dimensional (2D) fixed cylinder. This paper deals with the interaction between fluid and body, i.e., the flowfields around oscillating square cylinders both in cases of forced oscillation and wind-induced free oscillation. Computations are based on 3-dimensional (3D) LES using the standard Smagorinsky subgrid scale model. A very simple procedure is used to incorporate the influence of body motion on the flowfield. The accuracy of the computations using this procedure is examined by comparing them with the experimental results of Bearman et al. and Nakamura et al..

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In this paper adfreezing properties of roof-snow on roofing materials in a heavy snow region are experimentally studied. We examined the forming process of adfreezing force between the roofing materials and roof-snow taking into consideration of weather conditions. With the data, we made experiments of the adfreezing properties on various roofing materials assuming three models of adfreezing process. Then we identified the adfreezing process for each roofing materials by examining the relation between its surface condition and the adfreezing force. This research has made it possible to obtain basic information about the proper treatment of snow on roofs.

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A new seismic stiffness design method is developed for a shear-beam super structure supported by a shear-beam ground. Mean peak shear deformation of the combined shear beam subjected to a set of spectrum-compatible ground motions defined at the bedrock is evaluated by the modal combination rule due to Yang et al. A hybrid inverse eigenmode problem is formulated for the corresponding undamped model and a closed-form solution to the problem is derived. It is shown that this hybrid inverse formulation plays a central role in developing a stiffness design method of the super beam structure. Fundamental characteristics of this stiffness design and the effect of ground stiffness on the design of super beam structures are disclosed. Several design examples are presented to demonstrate the usefulness of this design method and time-history response analysis is performed to demonstrate the accuracy of this method.

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This paper describes a series of seismic fragility analyses of base-isolated structures considering non-linear superstructure behavior. The Latin hypercube sampling technique is applied to construct a series of samples that explicitly account for non-Linear behavior. Fragility curves are generated that evaluate the limit state based on maximum superstructure ductility ratio. The study shows that base-isolation systems have a significant advantage for seismic protection compared with fixed-base structures. However, careful consideration should be given to the fact that plastic deformation demands on the superstructure can increase dramatically after yielding if the super-structure is designed anticipating a reduced seismic lateral shear force.

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The soil and structure interaction effects were clearly observed in the records at the Kushiro District Meteorological Observatory. The two-dimensional interaction model, in which the soil behaved nonlinearly and the structure behaved linearly, exactly expressed the dip at a period of 0.2 second and the peaks at periods of 0.1and 0.3 second, that were observed in the weak earthquake motions. The same model expressed the periods of 0.15 and 0.5 second of the peaks, that were observed in the strong earthquake motions from the 1993 Kushiro-Oki earthquake of M 7.8. However, the calculated amplitude of the peaks was a half of the observed one.

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The purpose of this paper is to predict hysteritic absorbed energy of viscously damped single-mass system subjected to earthquake. Bilinear and Slip hysterisis are dealt with. First, based on random vibration theory, a method to get an approximate value of hysteritic absorbed energy when input motions are stationary Gaussian white noise, is studied. By considering a probability distribution of damping dissipate energy per unit time, it is recognized that predicted values become more accurate for wide range of dumping factor and yield share force coefficient, than a result of a past study. Next, based on a past technique to make artificial seismic waves, a deterministic relation between Gaussian white noise and seismic waves, is supposed. And predicted values when input motins are seismic waves, are similarly gotton.

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Finite element analysis is carried out.in order to evaluate the structural strength of the underreamed end of cast-in- place concrete piles, expressing ground and concrete as elastic-plastic bodies. New failure mechanism is found, where tensile stresses in radial and circumferential direction reduces the structural strength of the end and the failure of the end occurs before ground failure. New end shapes are proposed which prevent the mechanism and enhance the structural strength.

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To make it easy to design and construct reinforced concrete frame high-rise buildings in strong earthquake zones, non-hooped columns each laterally confined in a bellows square steel tube were devised. It is manifested by the tests of 1/3 scale columns subjected to compression, bending and shear that themechanical behavior of the columns is ductile even if the columns fail in shear under high axial load. Formulars to caluculate the flexural strength and shear strength of the columns are also suggested.

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The deformation capacity of a H-shaped steel member is reduced by the coupled local buckling. It is, however, obvious that the tension flange and the web are stable at the beginning of the local buckling of the compression flange. In this paper, the new method which the steel cover plates are welded on both sides of the web is suggested. These plates restraint the coupled local buckling and contribute the bending strength after the local buckling. So that the deformation capacity of the H-shaped steel member increases. The effectiveness of these plates is shown by experiments and analysis.

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Tubular truss beams are subject to failure by member buckling or overall buckling of compression chord members. In this case, only one part of the compressive members looses its strength capacity while others remain stable. In this paper, in order to improve the plastic deformation capacity of truss beams, the supplementary members are arranged on the neutral axis of the truss beam and near the buckled compression chord members. The structural behaviors of the proposed truss beam are investigated by experiment and numerical analysis. So, the collapse mechanism and the basic way of arranging the supplementary members are shown.

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The incremental inelastic stiffness matrix of the composite column is derived. In the column, high-strength four precast-concrete panels are fixed to the steel square tube with high strength headed studs. Strain softening type stress-strain relation of precast concrete panel is assumed from the test results of short column whose length is equal to the failure length decided by Mohr-Coulomb criterion. Hysteretic rule concerning shear force-to-slip relation of headed stud is also proposed based on the test results. Analytical results agree well with the hysteretic behavior of composite columns subjected to constant axial force and anti-symmetrical repeated moment.

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The track storey is located at the lowest part of the over-track building, and therein at least two independent open spaces are furnished, so the fire behaviour is totally different from that in the general buildings. In order to study the fire engineering design method of the over-track building, we conducted a series of full-scale fire tests of a kiosk ( a principal origin of fire on the track storey)in a steel structure simulating the track storey, and grasped the fundamental fire behavior on the track storey.

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Procedures for predicting the response of a steel-frame building subjected to traffic oscillation are investigated. The procedures can be digested as follows : 1) Simultaneous vibration measurement should be performed in (on the ground surface or the basement etc.) and out of (on the sidewalk etc.) a building site where traffic oscillation is likely to affect the habitability of the building. 2) Each time the response becomes remarkably large during the measurement, the conditions (types and speeds of the vehicles, type of die ground, distance between the measurement points etc.) which may characterize the oscillation source and the propagation path are classified. 3) System identification is performed with the largest data that are considered as pseudo-stationary. 4) Identified AR parameters and residual variances are categorized referring to the conditions classified in 2). 5) Operations of 1)〜4) are carried out at various sites in order to acquire statistically determined AR parameters and residual variances. And also phase lags of traffic oscillation within the basements are investigated as well. As a result, the enforced motion input of a building under planning can be estimated from the data measured at out of the site plus the statistical AR parameters, residual variances and phase lags. Then the response of the building may be predicted with the finite element modeling and the estimated input.

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