The creep behavior of high-strength concrete was experimented under variable load in early age. And the deformation behavior after unloaded and the strength after creep experiment were also experimented. The superposition law in creep behavior was investigated based on those experiments. The following results were clarified : 1) It could be said that specific creep and creep coefficient mostly follow superposition law. 2) Compressive and tensile strength after creep experiment were almost equal to those under non-loaded condition.

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Based on the experimental results of strength developments of high strength mass concrete using low-heat type cement, rational corrections of proportioning strength are investigated. Differences in strength between concrete in structures and standard cured specimen increased in proportion to specified design strength. In case of using rich-Belite Portland cement applying to high strength concrete, the age for proportioning strength of concrete cannot be extended to 91 days. And corrections of proportioning strength in term of the effect of high temperature curing in an early age are proposed in regard to rich-Belite portland cement and substituting fly-ash for 40% of normal portland cement.

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In this paper, carbonations and compressive properties of non-burnt casting ceramics are reported. These properties were investigated by measuring the change of the weight of the casting ceramics and observing the cut section of the casting with Phenolphthalein Ethanol after carbonate curing. The results are as follows ; 1) The pore volume of the casting ceramics is reduced as the carbonation proceeds, and then the compressive strength of the casting is increased. 2) The heterogeneous distribution of the carbonation on the cross section of the casting ceramics is observed. 3) The carbonation becomes slow when the amount of the water is increased and the pressure on the casting ceramics is increased during the casting process.

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The Kobe Earthquake of January 17,1995 caused an enormous amount of damage and prompted a major revision on the design, material and construction (included in manufacturing and processing). In steel structures, many damages which lead to fatal disasters occurred at the welded joints. Accordingly welding quality of welded joints directly governs capacity of steel structure. Japanese Architectural Standard Specification JASS 6 Steel Work was revised in 1996 and interpass temperature, heat input are added to main items of welding quality control. This paper describes the best control method of interpass temperature and heat input to get satisfactory welding quality based on an experiment on interpass temperature and heat input.

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We simulated strong ground motions during the 1993 Hokkaido-Nansei-Oki, Japan, earthquake (MJMA 7.8) based on its variable-slip rupture model and on two types of characterized asperity models to verify the characterizing procedure of source models for the strong motion prediction in future earthquakes. The asperity models were characterized by the total seismic moment, the short-period level of the source spectra, and the ratios of the area, the slip amount, and the effective stress on the asperity to those on the entire fault. The stochastic Green's function method was applied to the wide area including the epicentral region, and the following results were obtained : 1) The asperity model whose asperity was arranged at the shallow position according to the final slip distribution of the variable-slip rupture model produced a little larger ground motions than the variable-slip rupture model did. 2) On the other hand, the asperity model whose asperity was arranged at the deep position according to the short-period level distribution of the variable-slip rupture model produced the same ground motions as the variable-slip rupture model did.

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This paper proposes a damage identification algorithm for structural health monitoring (SHM) systems. The proposed algorithm consists of the multiple-input multiple-output (MIMO) modal analysis and the physical parameter identification. A story stiffness as a damage index of the structure is identified using complex modal parameters obtained by the MOESP subspace identification method. This algorithm was tuned to seismic isolated buildings considering their dynamics. The effectiveness of the proposed algorithm was verified through the numerical analysis. The algorithm was applied to a 4-story seismic isolated building model The proposed algorithm enhances the accuracy and reliability of the SHM systems.

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The friction characteristics of full-scale elastic sliding bearings were investigated from the results of dynamic tests performed under sinusoidal and seismic response loading. The dependence of friction coefficient on velocity, pressure and load repetition was clarified by sinusoidal loading tests. Based on the multiple regression analysis of test data, an expression for evaluating friction coefficients of elastic sliding bearings is suggested. From this, the time history of friction force that was observed in the seismic response loading tests was estimated. The simulated relationships between sliding displacement and shear force showed good agreement with the test results.

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The graphs of earth-pressure-distribution obtained by seismic observations in recent years are different from the one of the theoretical solution proposed by Mononobe and Okabe. This paper examines the results obtained from the analytical solution that the authors have formulated with compering to experiments performed by Kazama The increment of dynamic-earth-pressure subject to harmonic excitation generally shows the maximum value at the surface of the ground, then decreases with lager distance from the surface and changes its signs below some depth. Therefore the curves for absolute values of pressure-increments show zero or small value around that depth. The graphs of those calculated for the case of rotational excitation of underground walls qualitatively correspond to the experimental results during sinusoidal excitation.

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Authors have developed the slip damper as the energy dissipation device for structural seismic control. This device consists in multiple sliding plates combination so as to obtain large frictional force with small pressure between each surface. Moreover, sintered bronze alloy distributed carbon particle and stainless steel are used for frictional coupling to achieve the stable frictional motion. In this report, mechanical properties of this device were verified through quasi-static tests and dynamic tests. Furthermore, wear and corrosion properties about this device were investigated for confirming its reliability in experimental approaches.

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We propose a numerical technique for the seismic response analysis of isolated buildings on sliding bearings. The novelties of the technique is two capabilities : first, to calculate exactly the responses in the stick phase from the equations of motion with the identical degrees of freedom to those of the sliding phase, and second, to determine the phase transition time from the sliding phase to the stick phase without iterative schemes and calculate the responses in the transition. We verify the proposed technique by comparing with the numerical results of another method and by reproducing the shaking table experiment of a sliding structure.

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This paper for the first time proposes a simplified rule to estimate effectiveness of a nonlinear viscous damper that is attached in series to an elastic element such as the brace element and/or connection device. The accuracy of the rule is demonstrated by comparing with numerical experiments. Equivalent linearization that uses newly defined storage stiffness and loss stiffness is proposed. Dynamic properties and basic responses of the passive control system having the nonlinear damper are explained by using the rule.

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In order to grasp the dynamic characteristics of steel framed low-rise housing, several vibration tests are carried out for different construction stages of several housings. The dynamic properties are evaluated as natural frequencies and damping ratios by using several identification methods based on observation records obtained from free-vibration and sweep excitation tests and seismic observation. First, the differences of results among excitation conditions are examined. Next, by comparing the results for different construction stage, the effect of non-structural members and amplitude dependency is studied. When the amplitude is increases, the natural frequencies decrease and damping ratios increase. These eigenproperties shows strong amplitude dependency when the non-structural members exist. From these results, it is shown that the non-structural members act an important role for the dynamic properties.

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A revised enumeration algorithm for elastic plastic structural optimum design with discrete design variables is proposed. Number of the frame analyses is reduced by the continuous plastic optimum solution (lower bound) and the approximate discrete solution (upper bound) and the active linear constraints of continuous plastic optimum problem. This approach is able to give the global optimum point. This method is applied to a 5-story, 3-bay plane frame subjected to member stress constraints and story drift constraints and collapse load constraints of frame structure to check the calculation efficiency.

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The author has studied the time domain evaluation of soil impedance and has proposed a transform method. In a previous paper, structures deeply embedded in layered soil were investigated based on the embedded SR model. However, actual soil often has inhomogeous conditions that can not be expressed by theoretical impedance like that used in the paper. For estimating such soil conditions, discrete soil analysis models like FEM are employed. In this paper, a modified transform method was proposed to improve the convergence characteristics, first. Then, full-matrix soil impedance of structures embedded in inhomogeous soil was calculated by axi-symmetric FEM models. The full-matrix impulse response was evaluated by the modified method, and earthquake response analyses were carried out. The efficacy of the proposed method was confirmed through these studies.

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For the development of nodular cast-in-place concrete pile, the vertical loading tests of model nodular piles were carried out in loose wet sand ground. The tests were carried out for the piles with four kinds of distances between nodes and three kinds of taper angles of nodal base. The load-settlement relations and the ultimate bearing capacities were examined. The results of the tests indicate that the nodular pile with large distance between nodes can develop the bearing resistance at the nodal base, while that with small distance induces shear along cylinder with the same diameter of node. These characteristics of bearing mechanism are same as those in dense dry sand ground.

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Aspects of damage at deeper underground part of precast concrete piles, subjected to lateral flow at liquefied reclaimed land during the 1995 Hyogoken-Nambu earthquak, referred to as the K-shaped failure in this paper, are investigated. Attempt is made to utilize the distributed load method, proposed earlier by the first author, to estimate the cause of this type of failure. Results of the analysis show that the stress in pile at the slip surface exceeds the ultimate strength and, it is effective and important to consider relatively specific loading condition, consisting of the concentrated load at the slip surface in combination with the distributed load due to active earth pressure, to portray the observed behavior.

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The unstiffened tubular joint has been the most common method for the connection between CHS members at the node of truss structures. Recently, a new space truss connection detail is devised for better productibity, simple quality control and hence its structural reliability. The axial force from brace member is transferred through an arc plate to the chord member. The arc plate, attached on surface of the chord, is deemed to act with chord as one body. This paper reports a basic strength study for the connection, through parametric T-Joint test.

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Three-dimensional one-third model tests were conducted to demonstrate the transmission of vertical distributed load for light-frame single-story buildings. Three models without openings and seven models with openings were employed to verify the effects of configuration of walls and openings. The test results indicate, i) Almost 25% of vertical load is carried by plywood-sheathing of a wall and the rest is carried by studs of a wall, ii) The vertical distributed load carried by the interior walls installed in parallel to joists is from 1.8 to 3.7 times larger than the load assumed in the structural calculation regardless of the aspects of walls, iii) The vertical distributed load carried by the exterior walls installed in perpendicular to joists and adjacent to the wall parallel to joists does not agree with that assumed in the structural calculation.

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To clear the response characteristics of Japanese traditional wooden buildings, shaking table tests and static lateral loading tests using a full-scale model of traditional wooden frame were carried out. From experiments, it is found that traditional wooden frame has high performance of deformability and dumping. The hysteretic characteristics of the whole frame obtained from shaking table tests correlate closely with those of static tests. The whole restoring force increases in proportion to increase of vertical load acting on the column capitals in the model with the minimum figuration of tie-beam. The effect of the frames with without tie-beams on the restoring force were also examined. Then, the restoring force characteristics due to column rocking and the moment resistance of tie-beam play important roles in structural mechanism of traditional wood buildings.

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Stressed-skin semi-monocock structures are often used for the light structures such as aircraft airframe components. In these structures, the stresses are carried not only by the framing members but also by the surface membrane. There has recently been increasing use of moment resisting glulam timber joints in building structures. However, these joints require relatively large cross-sections because the moment resistance is carried by only the linear elements. This is not only uneconomical but also unattractive. Bending experiments on panel joints were carried out. This paper has proposed moment resisting timber joints using stressed-skin effect. It has also presented equations for estimating the rotational rigidity and the maximum strength of the joints, and demonstrated their prediction capability with sufficient accuracy. It has been shown that a frame with a smaller cross-section than that of only rib members is achievable with this joint.

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This paper deals with the analysis of the elasto-plastic behavior of composite beams consisting of timber and steel members. According to the experimental results, the elasto-plastic behavior of those beams are almost the same as those predicted by the analytical method presented herein. When the H-shaped steel is placed on the compression side, the stiffness of the composite beam is almost the same as that of the opposite section, but the load carrying capacity of the beam is small because of the fracture of the timber. The ultimate strength of the beams are smaller than the predicted one because of the compressive strength inclined to the grain of the timber.

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The report describes about the effects of slope on holizontal characteristics of a roof by panels construction. The static-lodiing test on the five full scale roofs and two types analysis,simple method and complex method,were carried out. We proved mechanial aspect about relations between slope and maximum bealing force, deformation,equivalent viscous damping factor, stiffness, shear stress intensity, vertical reaction force.

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The report describes about the effects of slope on vibrational characteristics of a roof by wooden panels construction. The full scale roofs were flat size of a 10.92m-long by 3.64m-wide and four types slopes of flat, 18-degree, 27-degree, and 45-degree. The forcing shaking test by an exciter, and free vibration test by an impulse hammer were carried out on these roofs. The dynamic shaking test showed that mode shapes were similar regardless of rise and fall of roof's slope and that natural frequencies became smaller along with roof's slope rising. Within lower degree, the observed values agreed with the frequencies based on the shearing vibration theory, but within higher mode degree, these were lower. The frequencies from eigenvalue analysis based on the shearing vibration type were a little lower than the observed values. The mode shapes were similar to sine-curves of vibration mode of the simple beam. In time history response analysis, response displacements were bigger along with roof's sloped rising, because of fall of horizontal stiffness. The effect of slope's degree was susceptible to weight.

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The boundary frame restricts the vertical deformation caused by the rotation of HPFRCC response control element. Therefore, the restraint axial force works for the response control element, and hysteresis characteristic of the response control element is greatly different from the case in which the axial force does not work. This paper proposes the prediction method that simply estimates load-deformation relationship of HPFRCC response control element. Axial displacement, horizontal displacement, restraint axial force and shear force are calculated in any compression edge strain. Therefore, it is possible that shear force-horizontal displacement relationship and axial force-horizontal displacement relationship are quantified in making compression edge strain to be a parameter. And, effectiveness of the proposed estimation method was confirmed through the comparison between results of the static lateral loading test and analytical value.

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With the aim of examining the shear fracture mechanism in construction joints of concrete structures, shear tests on the specimens of construction joint having different degrees of roughness were conducted. The loading was performed very slowly to monitor the process of crack initiation and propagation using a digital microscope. Shear failure in construction joints of concrete was found in all specimen. The process of crack initiation and propagation of shear fracture were clearly observed by using a digital microscope. Thus the experiments gave a better understanding of the fracture processes in construction joints of concrete on the meso-level and the macro-level using a micromechanics approach.

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The purpose of this paper is to clarify the stochastic properties of energy absorption capacity for steel moment resisting frames considering the uncertainty of member ductility. Six types of moment resisting steel frames with different number of story are used as basic analytical models. The member restoring force-deformation characteristics employed in the analytical models are elastic-plastic bi-linear models with a deformation limit. For six analytical models, load-deformation relations under static horizontal loads are calculated using Monte Carlo simulation and elastic-plastic pushover analysis with considering a stress redistribution after member brittle failures. Energy absorbing capacity of frames is defined for three different limit states, yield limit, initial fracture limit and failure limit. Based on the analytical results, this paper proposes practical and simple formulae which can estimate the lower percentile value of absorbed energy of steel frames.

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In order to design H-section column-to-H-section beam connection with split-T stubs, out-of-plane deformation of flange plate of H-section column should be considered, which causes semi-rigidity of the connection, especially in the connection detail without transverse stiffener. Estimation of yield and ultimate strengths of the connection is derived from plastic analysis by assuming yield and ultimate mechanisms concerning out-of-plane deformation of the flange plate of H-section column and stretch of high-strength bolts. The assumed mechanisms and analytical estimation of strength of the connection are verified by comparing with the results of experimental studies by tensile tests of the connection.

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Column base of the steel building structure is an most important part which transmits the resultant force applied to the upper structure to the foundation. Nevertheless, the difference of accuracy in constructional works between the steel structures fabricated in factories and the foundations made of the reinforced concrete executed on the construction site arises a critical problem in the structural performance of column bases. In this study, an improved type of column base which can absorb constructional errors between the upper structure and the foundation is proposed. A series of experiments is made on the improved column bases to clarify the structural performance especially under the seismic loading condition. From the experimental result, the effectiveness of improved type column base is verified.

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This paper clarifies the flexural buckling load of H-shaped compression members with lateral support at the center of their length axis and the required rigidity of the lateral supports. In this study, the braces used as lateral supports are eccentrically jointed to the compression members in their sections. The buckling load of the members with eccentric support is calculated by the energy method and the elastic eigen-value analysis. In the modeling, the braces are replaced by lateral and rotational springs. This paper evaluates the rigidity demand equivalent to immovable lateral supports and also confirms its effect using inelastic large deformation analysis.

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In this study, to improve the plastic deformation capacity, flat bars are attached on the neutral axis of the beam with slender web plate. Plastic deformation capacity of this beam is considered. The calculation method of flat bar cross-section area is shown for the target of plastic deformation capacity of beams. Flat bar length regards to the ratio of shear strength to bending strength of a beam. It is possible to make web local buckling concentricity at the beam end by the flat bar at the beam end, and it leads to improvement in plastic deformation capacity.

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The mechanical properties of high strength concrete at high temperature have been studied experimentally. The compressive tests were carried out with specified design strength of 60, 80 and 100 N/mm^2. For high strength concrete under heating conditions below 400℃, the initial slope is steeper, and the limit of linear response shows a higher percentage of the compressive strength. Also, the compressive strength decreases at 100℃ during heating, increases up to at 200℃ and gradually decreases with further increase of temperature. The formulation for stress-strain curves of high strength concrete were proposed in consideration of high temperature. Also, the formulations for compressive strength, strain at maximum compressive strength and elastic modulus were proposed in the same way.

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