Compressive strength of masonry assemblages with hollow and bond beam high strength masonry units, which was indispensable for actualizing more than medium rise reinforced masonry buildings, was experimentally examined from the viewpoints of approximating the strength, that is to say the characterized strength for masonry structural design, and predicting the fracture patterns in case of concrete and clay masonry units.

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This paper is intended to study the new method to develop high bending strength of cement paste or mortar. Up to date, the hydraulic cement product is said to have low bending strength not withstanding its high compressive strength. This paper clarified the new method to gain high bending strength of cement mortar which was mixed with silica-fume and was cured in 60℃ moisture. In this paper, these curing methods are studied in detail and the composition of the hydraulic cement product is studied in order to make clear of the reason of their high bending strength.

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The purpose of this study is to obtain the thermal expansion of air dried high-strength concrete, from 20℃ to 100℃ and then from 100℃ to 30℃, under constant compressive stress including tri-axial loading in which maximum compressive stress is below the one third of strength. The conclusion is the following; In the heating and cooling process, the thermal expansion of high-strength concrete under multi-axial constant stress is smaller than that of free expansion. The strain of this concrete can be obtained as the sum of elastic deformation, free thermal expansion and creep strain. The creep strain of concrete at any temperature can be obtained by using "Time Temperature Equivalence Principle."

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The product of parameters in the Gumbel distribution, which is frequently applied to annual largest wind speeds, is employed to analyze the wind climate of the Japanese Isles. Three annual largest values caused by typhoons, winter to spring storms and their mixed events are investigated at 40 weather stations. The products obtained from winter to spring storm winds correspond to the values over well behaved wind climate countries such as the British Isles. The trend of typhoon activity is depicted on a probability paper by the probability distributions of typhoon winds and winter to spring storms. The combined use of probability distributions evaluated for typhoon winds and non-typhoon winds is recommended to set up design wind speeds in Japan.

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In order to understand the physical mechanism about the aeroelastic instability of bluff cylinders, the two-dimensional simulations have been mainly used for computational approach because the flow structure around the oscillating cylinder is expected to become two-dimensionalized due to the effects of the body motions. However, through the comparison with the experimental data, there is a little quantitative difference in the predicted values. We discuss the necessity of the three-dimensional simulation for the unsteady problems on oscillating rectangular cylinders in uniform flow. As the length of the cylinder and the grid space in the spanwise direction are varied, we investigate the relation between the unsteady three-dimensional flow structures around the oscillating cylinder and the predicted aerodynamic forces acting on the cylinder.

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A numerical method for the analysis of the free vibration behavior of thick skewed plates having arbitrary boundary conditions by using the Rayleigh-Ritz approach is presented in this paper, together with some numerical results. The method is based on the three-dimensional elasticity theory and skew coordinate system by considering rotating inertia and shear deformation. Numerical results are compared with the available ones in the literature. The comparison shows the method presented in this paper to be useful for analyzing the free vibration of thin and thick skewed plates having arbitrary boundary conditions. The effects of skew angles and aspect ratio of plates on the free vibratory characteristics of the thick skewed plates are also investigated.

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One of aims for conducting shaker tests of a rigid bock is to obtain the experimental impedance functions for several modes, and to compare the theoretical functions which are reliable for the application to a design analysis of actual foundations. In this paper, three different kind of inverse methods for seeking the experimental impedance functions with coupled swaying and rocking modes of a rigid foundation are proposed. The methods apply to a case of the forced vibration test of a four-pile group with a reinforced concrete block at the cap, and then the resulting functions are compared with the theoretical ones obtained by the thin layer formulation which has given the well simulated results of the test. It is concluded that the inverse methods proposed are useful to evaluate the experimental impedance functions with coupled swaying and rocking modes on the basis of shaker tests of a rigid block.

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The dynamic characteristics of embedded foundation on pile group are examined analytically. Three dimensional formulation based on the volume method is employed to investigate the dynamic behavior of soil-piles-structure system with taking into account of embedment effect of foundation. The analysis method is verified using the results of the forced vibration test and the earthquake observation of 2×2 pile group foundation. Earthquake response of the structure on embedded foundation supporting by pile group is analyzed, in order to investigate the embedment effect on the inertial and kinematic interaction on pile stress.

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Confining mechanisms of rectangular transverse reinforcement in confined concrete were investigated by tests consisted of concrete columns under uniaxial compressive loads, which had various arrangements of confining transverse reinforcement, such as only square hoops, square hoops with supplementary cross ties, square hoops combined with octagonal sub-hoops and square sub-hoops etc.. Confining mechanisms of the transverse reinforcement were revealed through discussions on bending moments and axial forces acting at particular sections of the transverse reinforcements.

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During an earthquake, strength of reinforced concrete (RC) members increases greater under dynamic loading than under static loading by the effect of strain rate. The increases of flexural strength and shear strength differ from each other. This may cause a different failure mode from the one, planned in the structural design. In this paper, the relationship between the increase of strength and the change of failure mode of RC members is investigated. Analytical investigations reported that the strain rate of RC members may be around 10^4〜10^5μ/sec during an earthquake. Under this strain rate, while the increase ratio of the flexural strength is about 1.15〜1.3, the one of the shear strength is about 1.15〜1.25. When axial force is beyond the balanced axial force, the increase ratio of flexural strength is greater than the one of shear strength. To achieve the flexure failure mode irrespective of axial force level, the design shear strength must be 15% greater than the flexural strength.

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This paper deals with the compressive strength and the deformation characteristics of reinforced concrete columns composed of concrete of different strength. The authors carried out the centrally loaded compression test varing the member composition, the ratio of tie hoop reinforcement, the compressive strength of concrete and the ratio of cross-sectional area of the shell to the core respectively. Also, the failure process and the relationship between the load and the deformation are studied. From these studies, the stress-strain relation formula of concrete and reinforcing bar are introduced, and the ultimate compressive strength formula of the composite columns which are in good agreement with the experimental value are proposed.

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The objective of this paper is to propose an analytical method to predict the strength of reinforced concrete beams in shear. Kupfer proposed a truss model where the compatibility of strains and the equilibrium of stresses of the cracked concrete and shear reinforcement were used taking into account the effect of aggregate interlocking. Based on Kufer's model, an analytical method with incremental form was newly developed to classify the shear failure modes in this study. The effective compressive strength of concrete which was to be applied to high strength concrete was also proposed. The shear strength theoretically predicted by the proposed method was compared with available experimental data and the better results than other methods was obtained.

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The relationship between local bond splitting behavior and average ones in reinforced concrete members has not been clear, yet. As the first step to make clear this problem, local bond behavior in case of no lateral reinforcement is discussed based on the study by Tepfers. In this study, bond stress, τ_b, is provided as the function of internal crack depth, rt, and angle between the principal bond stress and the axis of the reinforcement, α. The bond splitting test is carried out using new-designed specimens. Test results show that the value of α is assumed to be 34 degrees, and r_i has a proportional relationship with slippage of reinforcement, s. Using these results, a new relationship between τ_b and s is proposed.

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A new design of a tube to gusset plate K-joints for tubular structures is proposed in order to permit rationalization of joints. The eccentric joint where the intersection of the gravity axes of branch pipes are shifted to the gusset plate side can increase the degree of freedom of design. In the previous report, the strength equation for an eccentric joint was found and its effectiveness was demonstrated. In the current study ,the elastic and plastic behavior of a main pipe at an eccentric joint was found by the FEM. The analysis result corresponded to the experiment result. The new method surely is effective, because the uniformity of stress distribution in cross section of a main pipe is better at the negative eccentric joint than at a noneccentric joint.

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In this paper, the energy absorption capacity of a single-degree-of-freedom system with an arbitrary load-deformation relationship is defined as the maximum input energy for which the system starts to show plastic deformations lower than a perfect elasto-plastic system. Based on the damage distribution law proposed by authors, a formula is derived to evaluate the energy absorption capacity of a system with tri-linear load-deformation relationship, consisting of elastic, hardening, and degrading parts. In this formula, the energy absorption capacity is expressed as a function of the three parameters, namely the hardening rigidity after yielding, plastic deformation to maximum strength and decay rigidity after maximum strength. This formula is found to represent well dynamic responses of structures with various hysteretic behaviors.

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Dynamic behavior of beam-to-column connections is investigated experimentally. The test parameters are details of the joints, loading rates and the temperatures. As the results of this experimental test, the conclusions are summarized as follows. 1)The loading rates have little influence upon the fracture modes and energy absorption capacity of the specimens. 2)The yield strength and the maximum strength can be investigated using the Strain rate- temperature parameter(R). 3)The temperature has very large influence upon the energy absorption and fracture modes. In case of low temperature, the energy absorption value becomes less and the fracture mode becomes brittle.

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The results of slip tests and relaxation tests on high strength bolted joints treated with zinc-rich paint are described herein. The main purpose of these tests would be to estimate the influences of thickness of zinc-rich paint on slip coefficients and to estimate the reduction of bolt tension. The thickness of zinc-rich paint and the surface conditions of specimen plate are mainly considered as tests factors. Ultimately, 38 types of specimens are prepared for slip tests and 9 types specimens are prepared for relaxation tests. And the additional tests with improved zinc-rich paint are described lastly. The main conclusions are as follows, (l)the thicker the coating of zinc-rich paint,the slip coefficients have a tendency to be higher. (2)For keeping the higher slip coefficients than 0.45, the minimal coating thickness must be kept on slip surfaces and this minimal thickness are estimated to be 20 fi in these tests. (3)After six month from initial clamping,the reduction of bolt tension with baking finished bolts is higher than that with ordinary high strength bolts. (4)The improved zinc-rich paint has an effect on increasing the slip coefficients. (5)There is no difference of the reduction of bolt tension between the ordinary zinc-rich paint and improved zinc-rich paint. The reduction of bolt tension mainly depends on the thickness of zinc-rich paint.

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Behavior of steel structure buildings which were damaged on the beams near by the beam-to-column connections during Hyogo-ken Nambu Earthquake are estimated analytically. The analysis is executed using frame models considered dynamic soil-structure interaction. The input ground motion is estimated from the record observed at the JMA Kobe station and the local topography near the buildings. The conclusions are as follows. 1)The energy input of the earthquake is extreme large. The maximum input energy VE is approximately 440 cm/sec, where VE indicates the equivalent velocity of the total energy input. 2)The maximum interstory drift is approximately 1/50. 3)The strain energy concentrates to a few stories which were damaged during the earthquake. 4)The cumulative inelastic deformation ratios of the damaged beams are relatively large than that of no-damaged beams.

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