In this study, we examined the fundamental property of the shrinkage of high strengthconcrete over 600kgf/cm^2 by experiment. And we tried to suggest a formura estimating.the shrinkage of high strength concrete. The results are as follows. (1)The ratio of the shrinkage due to drying to the shrinkage due to hydration gets higher as concrete strength increase. (2)The shrinkage of high strength concrete due to hydration is influenced by cement contents and admixture, and the one due tp drying is influenced by water cement ratio,, cement contents and volume ratio of agregate.

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Air permeability of cement mortar was discussed in consideration of effect of moisture in pores of it. .Micro-structures of mortar specimens of various moisture content were measured using mercury intrusion technique, and were compared with air permeability of them. It was made clear that air permeability of cement moratr is not affected by pore structures but also moisture in it, and decrease of moisture content induces rise of air permeability. On the basis of the results, we proposed a simple model of pore structure containing moisure in it and tried to estimate air permeability of cement mortars.

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Fracture parameters for elasto-plastic materials were investigated. Cohesive force model concept was employed to modeling the fracture process of quasi-brittle materials with fracture process zone. Tension softening diagram as the constitutive equation for the cohesive zone was estimated numerically by the poly-linear approximation analysis method with the data of load-loadpoint displacement curve. The energy consumed in 'cohesive zone (dW_f) is calculated by integrating the work done by cohesive force acting on the fictitious crack surface. Fracture. parameters for elasto-plastic materials, such as energy release rate G_p, R-curve, G_F ^<TSD>, K_<IC>^5 were estimated based on the value of dW_f. The energy consumption measured by off-set test for notched concrete beam specimen agrees with the result of numerical analysis. Fracture parameters for concretes were measured and their characteristics were discussed.

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The objective of this experimental investigation was to clarify the effect of coarse aggregate on fracture behavior of high-strength concrete in mixed-mode loading 'conditions. Energy absorption in mixed-mode fracture was evaluated by the total work of fracture calculated by analysing the load-load point displacement curve. Mixed-mode loading, conditions were set for a wide range which consists of shear/compression and shear/tension. In case of shear/tension mode, energy absorption was decreased with.increasing the factor of tensile force, and major factor effecting the cracking is the interface property of aggregate and mortar. In case of shear/compression mode, energy absorption was increased with increasing the factor of compressive force. Aggregate property was the important factor to improving the toughness of high-strength concrete specimen.

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Polymer-modified mortars using three types of polymer dispersions are prepared with various polymer-cement ratios, and the effects of ambient temperature, relative humidity and carbon dioxide exposure period oh their accelerated carbonation are examined. Regardless of the temperature and relative humidity, there is a close correlation between their carbonation depth and exposure period, which is approximated by carbonation depth - (time)^<1/2> expression. The carbonation depth decreases with increasing polymer-cement ratio irrespective of the temperature and relative humidity. Their carbonation rate coefficient can be predicted as a function of the temperature, relative humidity and polymer-cement ratio.

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Genetic algorithms, a search algorithms based on the mechanics of natural selection and natural genetics, is finding widespread application in many kinds of optimzation problems. For its application to structural reliability analysis, in this paper, a concept of intelligent living beings is proposed, in which the fitness of chromosomes can be heighten by the improvement of their engineering values from the judgement of the biological environment in the reliability problem. From some structural reliability examples using the GA search based on the proposed concept, the affection of the intelligence on the process of structural reliability analysis is discussed and it is shown that the problems in deciding the length of.chromosomes can be effectively improved.

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Overturning of furniture due to the 1993 Kushiro-oki earthquake was surveyed in office rooms at Kushiro City Hall and Kushiro Local Meteorological Observatory, and. the relations of the overturning rate with the floor response were examined for typical office furnitures. For a simple furniture standing alone, the critical peak floor response velocity. which separates overturning from non-overturning conditions is much larger than that derived from the shaking table test and computer simulation for a simple body. Based on the observations, the empirical relations for estimating the overturning rate of office furniture were proposed as a function of the peak floor response velocity.

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In the beginning of the design process of the membrane structures, it is recommended to adopt the minimal surface as the original design surface. In the numerical calculation for pursuing the objective minimal surface, we, however, can not always obtain the converged solution because of the strong nonlinearity involved in the problem. In the present paper, we propose "combined variational functional" which is composed by introducing the new functional concerned with elements' area into the original functional. Convergence characteristics of the stationary solution are discussed through some numerical examples.

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The purpose of this paper is to study dynamic buckling behaviors and dynamic characteristics of shallow arches subjected to cyclic loads, aiming to analysis the global stability for rotational shells. A great deal of effort has been made on the dynamic buckling. What seem to be lacking, however, is the problem of dynamic buckling on nonconservative system. Therefore, on this paper we investigate basic characteristics of dynamic behaviors for shallow arches subjected to cyclic loads. In the numerical research the following results were obtained. 1) Backbone curves have two types on phenomena, softening and hardening types. 2) The discontinuous point appears on the backbone curve of softening type and jump phenomena occur on this point. 3) There are three types of jump phenomena in response curves, one of which means the dynamic buckling behavior. 4) The dynamic buckling loads drastically decrease to be affected by the dynamic resonance on symmetrical and asymmetrical modes.

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We conducted the test on the assumption of lap splices that are located at the plasticity hinge area in beams under tensile loading. In order to clarify of the structural characteristic of lap splices in the range of plastisity due to rate the individual effect on that, we investigate the following contents: 1) Relationship between failure mode and spliced arrangement 2) The stiffness of spliced members 3) The structural criterion of the splices to ensure the same performance as non-spliced member 4) Resistance mechanism of splices and share of stress in the splices 5) The stress distributions in spliced main bars 6) The. ratio of bond strength in the straight parts of spliced bars to the total strength of splice The effect of the slope of moment in the members and of the compression strut from the bents of the spliced bars to compression zone of the members on the ductility of lap spliced members should be confirmed by supplementary examination.

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An experimental investigation was carried out to study the joint strength of lapping splices using spiral sheaths for precast concrete members. Two series of pullout tests were carried out. The influence of the height of sheath lug, thickness of cover concrete, lateral reinforcement ratio, lapping length, and loading history on the joint strength of the lapping joints in the first series as well as the influence of the lapping splice type, position of bar inside the sheath and the number of lapping bars on the joint strength hi the second series were investigated and discussed using the existing strength equations for lapping splices.

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The authors are devoting themselves to construction of a hysteretic constitutive model for reinforced concrete(RC) panels under reversed cyclic in-plane stresses to be used in Finite Element Analysis. They have already proposed an elasto-plastic hysteretic constitutive model of RC panels subjected to reversed cyclic, in-plane shear stress. To establish a more general constitutive model, a test series of RC panels subjected to reversed cyclic combined in-plane shear and normal stresses were conducted and a new model was constructed based on the test results. The model modifies the decrease in compressive strength for cracked concrete depending on tensile strain normal to crack direction. It also newly formulates the decrease in yield strength for embedded reinforcing steel bars based on the test results. The appropriateness of the proposed analytical model was verified by applying it not only to the authors' tests but also to other existing RC panel tests.

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Recently, more rational and economical design method has been required to the steel structural design. As one of the solutions, "Standard for Limit State Design of Steel Structures (draft)", based on the theory of reliability, was published in 1990. However, regarding design of the bracing member, this draft standard adopted basically the conventional design method, because there were not enough data to make a new design method. To obtain the applicable data to limit state design, the present study aims elaslo-plastic behavior of a steel column or beam with the bracing member. This paper represents results of its numerical analysis. Furthermore, mechanical properties of the bracing member is examined in the three kinds limit state, which are "Buckling Limit State", "Full Plastic Limit State" and "Deformation Capacity Limit State".

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As part of study on fatigue damage, in the present paper,we have made four experiments employing SM490 in order to predict fatigue life and examine miner's law. Four experiments are carried out as follow :1) the invariable reversed and pulsating repeated stress loading test, 2) the repeated stress loading test under variable strain cycling, 3) the multiple repeated two-step stress-strain loading test under K, 4) the multiple repeated two-step stress-strain loading test under 〓ε. The test specimens are composed of WES-162, No.3 .They are 10 millimeter in diameter of minimum section . We investigate applicability of cumulative fatigue damage D from the experimental results, and the proposal of D-〓N curve has made possible predicting fatigue life to these tests.

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A lot of study has been executed on the compressive strength of concrete Filled steel tube(CFT). Especially, confined effect of the in-filled concrete by the steel tube has been investigated enthusiastically, and it has been estimated numerically in case of low strength filled concrete. But in case of the CFT in which high compressive strength concrete such as 1,000 kgf/cm^2 is used, the confined effect has not yet been estimated clearly. In this study, we did the experimental researches to investigate the contribution of the confined effect to compressive strength of CFT which has circular and square hollow section tube and also 1,000kgf/cm^2 compressive strength filled concrete. The CFT is completed by using centrifugal compaction and autoclaved curing. Using the test results, the proposed equation has been derived so that ultimate compressive strength of the CFT can be estimated.

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The generation of external (window) flame due to a compartment fire depends on the behavior of the compartment fire. For clarifying the effects of ventilation opening and conditions of fuel on fires behavior in enclosure, small scale model fire tests were conducted using methanol, PMMA, and wood as the fuels. The external flames were observed for different fuel conditions and ventilation parameter AH^<1/2> whether they are generated or not. And the burning rate, temperature, and heat release rate in enclosure were measured. As the results of this study, it is found that the maximum burning rate under ventilation control regime agree with Kawagoe's results (m_<pk>=0.1AH^<1/2>(kg/s)) regardless the fuel type. And where AH^<1/2> is small, the criteria can be established using stoichiometric air/fuel ratio and ventilation parameter AH^<1/2> for judging whether external flames are generated.

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Simple predictive equations, for the room fire behavior were proposed. These were obtained by applying simple predictive method for pre-flashover compartment fire temperature proposed by Quintiere et al. to ventilation controlled fire. These equations can easily predict the temperature inside the compartment, the rate of heat loss due to ventilation and the rate of heat loss to compartment boundary. These can be used when the room fire is ventilation controlled regime. The results of the prediction using the simple equations were compared with the results of a more detailed computer model. Through this comparison, it was confirmed that these simple predictive equations are practical useful to estimate ventilation controlled compartment fire behavior, even though there is a little error caused by neglecting heat loss by radiation through the openings.

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