It is well recognized that the frost deterioration of concrete is affected by its pore structure, but there is little information available with respect to the effective range size of the pore structure in the concrete body. In this paper an experimental program was conducted in order to study the frost resistance of both paste and concrete in order to clarify the range sizes of pore structure which are effective to frost deterioration. Statistics was used to analyze the experimental data. As a result the range of pore structure and its effective level on the frost deterioration were defined and given in this paper.

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A field reinforced concrete structure with and without an acrylic rubber-based surface coating was built in Okinawa for this research project, and it has been exposed to severe marine environment for ten years. The test on this structure gives the following results : (1)In unprotected concrete, the penetration of chloride ions into concrete is very rapid, and the corrosion of reinforcing bars occurs in early stage. (2)The acrylic rubber-based surface coating acts as a complete barrier to the transport of chloride ions, water and oxygen, and prevents the corrosion of the bars in chloride-contaminated concrete.

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Applications of permanent formwork using highly strengthened precast concrete instead of the conventional plywood form have been attempted recently for the automation and simplification of RC construction. In this study, large RC beam specimens were manufactured using permanent forms made from high strength glass fiber reinforced cement (GRC), which were to form part of the beams' concrete cover. Its main objective is to compare the flexural behavior of these specimens to a RC beam specimen of the same size constructed using the conventional plywood form. Experimental results show that the cracking, yielding, and ultimate loads of the RC beam specimens using GRC permanent forms are similar to the conventional RC beam.

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The purpose of this paper is to evaluate the stain relatively by cigarette smoke of finishing materials from a viewpoint of visually. We carried out the exposure test in smoking room, and described the actual state of stain by cigarette smoke of several finishing materials. As results of exposure test, the stain was increased gradually, and about 100 days after, it was stabilized, after that a degree of the stain which was measured by COLOR DIFFERENTIAL had not changed. Furthermore, we obtained the actual state of stain by cigarette smoke from another exposure test which had used 42 kinds of finishing materials.

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In this study, in order to obtain mechanical properties of hardened carbon fiber reinforced concrete (CFRC), compression, bending, fracture toughness and flexural fatigue testings were conducted. From the results, following items were investigated and discussed: 1) fundamental mechanical properties such as Young's modulus and compressive and flexural strengths, 2) tension-softening curves and J-integral values estimated by means of an inverse analytical approach using the cohesive force model, 3) evaluation of size effects on flexural strength based on a highly-stressed volume concept, and 4) flexural fatigue endurance and residual flexural strength after fatigue testing.

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This paper presents an evaluation method of the slipresistance at sliding of outdoor sports surface. We carried out sensory test using sports surfaces and players to make the evaluation scale of slipresistance. And we showed that slipresistance measured by several slip meters didn't correspond to the evaluation scale. Then we developed new pull-slip-meter to measure the slipresistance and displacement between shoes and surface that could correspond to the evaluation scale. We presented the relationship of slipresistance and evaluation scale as an evaluating index. These results were presented as an evaluation method of the slipresistance at sliding of outdoor sports surfaces.

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In this report, the temperature of basement structure containing heat storage tank was analyzed for the condition of a cold district(Sapporo) and was compared with that of a mild district(Tokyo). In a cold district, the annual average temperature of water of heat storage tank is higher than soil temperature. Therefore the rising of temperature of soil sorrounding the building during a long period of time is expected. Unsteady static heat conduction analysis was carried out for 50 years. In the analysis the parameters were heat insulating board thickness(D=O, 50mm) and thermal diffusivity of soil(a=0.0007, 0.0013, 0.0023m^2/h). As a result of the analysis, in a cold district the difference of temperature between outer wall and footing beam is larger than that of a mild district. Therefore the thermal stress of outer wall in a cold district is greater than that of a mild district. In a cold district the temperture of basement structure rises a little during a period of 50 years, but in a mild district it remains almost constant.

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In the present paper, the Substructure On-Line test(SOT) was conducted to simulate dynamic behaviors of reinforced concrete(RC) structures obtained by the shaking table test. The implicit integration scheme developed by the authors was introduced into the SOT system as a numerical integration-control algorithm. First, issues for conducting the SOT successfully were rigorously reviewed. Then, on the basis of the said issues, the results by the shaking table test were evaluated to establish a lumped-mass model with suitable damping mechanism for the SOT. The results by the SOT were compared with those by the shaking table test. It was confirmed that the SOT can simulate dynamic behaviors of structures reasonably well and the implicit integration scheme is also effective even under severe conditions.

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Vibration control theory, computer simulation and experimental verification on a hybrid mass-damper system with semi-circular curved linear-motor device for absorbing vibration are described. The control theory using output regulation with internal stability is applied in designing the system. The computer simulations of the system subjected to artificial earthquake ground motions generated in accordance with hard, quasi-resonant and soft soil conditions are presented. Shaking table tests of a steel structured model of the system for verifying realizability of the simulations are reported.

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A method is proposed to decompose two dimensional stress field into several simple stress modes which satisfy equilibrium condition. The contributing ratios of these modes are calculated using the principle of conservation of energy. As an example, uniaxial central compression in two dimensional elastic plate is analyzed when the loading width is varied. The stress field is decomposed into two modes: direct compression mode and arch compression mode.

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In this paper, two analysis models for the coupled torsional-bending responses of thin-walled beam with discontinuously variable cross-sections are presented. These models are based on a thin-walled beam theory which takes into account shear deformation by the 2D or 3D shear warping function. A C1 continuous finite element with boundary contraction technique is used for the discretization. The compatibility condition of warping, which is automatically satisfied in the 3D shear warping model, is satisfied approximately in the 2D shear warping model by use of warping error minimization technique. By an example of box girder with open section, the accuracy and efficiency of present models are shown.

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Three types of building models were tested by repeated and reversal horizontal loading to investigate the collapse mechanism of the models. Type 1: fixed on rigid base. Type 2: supported by piles in a very weak soil model which consisted of Kaolin clay with cement. Type 3: supported by piles in a weak soil model which consisted of Kaolin clay with cement. For Type 1, all beam and column edges yielded up to the plastic strength of 3.5 tf as the testing result. For Type 2, the pile heads and edges of footing beams yielded at the plastic strength of 1.7 tf. For Type3, pile heads, edges of footing beams and edges of members yielded at the plastic strength of 3.1 tf. Nonlinear frame analysis for the models with and without soil springs were carried out to compare with the test results. Experimental results were simulated very well by this analysis for Type 1. For Type 2 and 3, results of analysis showed good agreement with experimental results for the load-deflection relationship but there is a little difference for the collapse mechanism of super structure.

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In this report, simplified methods of analysis of nail jointed shear wall structures are proposed. 1) The proposed theory is applied to the investigations of shear walls with openings. The properties of stress, strength and stiffness are well explained. 2)The proposed theory is also applied to structural analysis of frame structures consist of shear walls. The stiffness and the ratio of inflection points of equivalent columns are determined from the theory of shear panel considering the shear deformation. 3)The equivalent brace models for shear panels are proposed for simplified linear and non-linear analysis. The validity of these methods are confirmed by analysis of finite element methods and full-scale experiments. And the proposed methods are useful for practical design.

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The structural behaviors of continuously spanned composite beams in steel frames are investigated. Three of 1/3-scale models of one-story three-span steel frames with/without reinforced concrete (RC) slab were tested under lateral cyclic loading. The inner RC slab in a positive moment was subjected to larger compressive strain than the exterior RC slab, and also the larger number of shear connectors (headed studs) in composite beams resulted in a slight increase of compressive strain at the inner RC slab in a positive moment and even in a negative moment. The authors pointed out that the composite beams, even if assumed to fail in axial compression at RC slab, may fail in shear at studs because of the fact that the apparent shear strength of studs decreases with the number of studs increasing. Furthermore, the authors proposed the strain amplitude evaluation for the bottom flange of composite beams under cyclic loading.

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The present paper investigates the safety and effectiveness of chemical treatments of the frictional surface of high strength bolt frictional joints, followed by storage for three years. The primary results are as follows: 1. Relaxation is somewhat large immediately after chemical treatment. After treatment, the storage shows no significant influence on relaxation. 2. Chemical treatment shows little affect on deformation properties. 3. The coefficient of slip for the chemical treatment is lager than the specification value of 0.45 established by JASS 6, confirming its safety. 4. The effects of this chemical treatment and conventional treatment, as well as their relative relaxation, were small over the storage period. 5. The surface of the frictional surface that was chemically treated showed sudden rust immediately after treatment, but little change over the period of storage.

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Tensile loading tests have been carried out to determine the local behavior of a connection between high-strength concrete-filled square tubular steel column and steel beam, reinforced with an external vertical stiffener. The vertical stiffener is installed on the inside depth of steel beam to avoid interference with finishing material and reinforcement in slabs. Test results show that the maximum strength of the connection depend on the fracture of web near the corner of the steel tube, and that the web's strength vary with height of the stiffener. The load-displacement relationships can be approximated by an analysis that assumes a tri-linear-type model for the steel tube and the stiffener.

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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 developed a simple method to predict the temperature of a steel structure in a fire of a kiosk (a principal origin of fire on the track storey) , based on a series of full-scale fire tests of a kiosk ( previously reported ) in a steel structure simulating the track storey.

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