In order to confirm corrosion of structual frames in buildings of steel construction, investigation in existing buildings and corrosion tests of steel specimen in buildings which were under construction and after completion. Consequently, the following has been clarified. (1) Structual steel frames in buildings have been slightly corroded. (2)The corrosion on steel frames are started under construction. However, after completion of the building.they have been inhibited by air conditioning. (3)The slight corrosion on the surface of structual steel frames is no problem for building structure.

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Experiments on mechanical trowel finishing were performed with ten kinds of concretes under two trowelling conditions, in order to examine the influence of concrete properties on floor finishing. In the experiments, the configuration of concrete surface was measured before and after trowelling. Dynamic reaction on trowel and penetration resistance were also measured as rheological properties of concrete at the time of trowelling. As a result, a trial method for measuring concrete properties and for judging finishing conditions of concrete floor was proved by using dynamic reaction and configuration of concrete surface at mechanical trowel finishing.

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In this study, We made some experiments to clarify the influence of observation distance and background on the appearance for stains on external building wall. The results may be summarized as follows: (1) For the same stains of wall surface, distant view with background and close view differ remarkably from each other in discomfort of degree, and intermediate view with background and close view also differ from each other in discomfort of degree close view according to kind of finishing materials. (2) A case of seeing at close range and a case of seeing at a distance differ from each other in discomfort of degree for stains.

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Along with the recent progress in earthquake engineering, a bulk of technical information is now available pertaining to seismic resistant design, analysis, construction and retrofit of buildings and lifeline physical systems. At the same time, well developed methods are in place to evaluate the system's seismic performance not just from physical but also from functional points of view. This paper develops a new dimension of earthquake engineering research by taking loss estimation into consideration when evaluating the lifeline systems's seismic performance. The recent development of Geographical Information System facilitates such loss estimation for lifeline systems.

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Structures may be affected by changes in strength and stiffness due to aging and/or repeated loading beyond the baseline conditions assumed for design. Since these changes may impair the safety and serviceability of a structure, they should be considered as part of a design process and the process by which a structure is evaluated for continued future service. This paper describes methods using structural reliability principles to evaluate time-dependent reliability of structures subjected to an aggressive environment and/or repeated loading. These methods enable the impact on safety and serviceability of uncertainties in loading conditions, structural strength, and strength degradation to be assessed quantitatively. The effect of periodic inspection and maintenance on time-dependent reliability also is considered.

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Simple inelastic deformation response estimation of one-story building systems with eccentricity is introduced based on linear static and non-linear dynamic analyses using asymmetric-plan systems simultaneously subjected to strong earthquake ground motions in the x- and y- directions. Earthquake deformation response is evaluated considering shear and torsional strength capacity and the corresponding shear force and torsional moment acting in each direction of asymmetric-plan systems. Inelastic response analysis of one-story systems with plan asymmetry having various parameters is carried out and compared with those of corresponding one-story symmetric-plan systems.

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A full-scale five-story steel frame building was tested dynamically by means of a servohydraulic-type vibrator to evaluate experimentally the soil-structure interaction effect. The test building consists of 6 pieces of isolated concrete footings, a five-story steel frame and concrete slabs. It is 15m long in E-W direction. 3.75m wide in N-S direction, and 17.4m high as shown in Fig. 1. A servohydraulic-type vibrator instead of a centrifugal-type vibrator was used to force the building and footings to vibrate. The building was subjected to horizontally incident SH or SV waves generated from two different reinforced concrete model footings. They were 4m long, 4m wide. and 1m high, and placed at a distance of 16m south and 30m east from the building. We carried out tests over higher frequency range more than the second mode of the building. Fig. 3 shows the building response for the second mode in NS direction subjected to horizontally incident SV waves generated from S(south) footing. Table 2 shows the effect of excitation at different footings on the resonant frequency and damping ratio of the building. From the experimental results, it is found that the soil-structure interaction effects of the building evaluated by forced vibration at the first floor are in good agreement with those evaluated from response of the building subjected to horizontally incident SH or SV waves generated from the model footing.

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This paper describes vibration control characteristics of a tall building in which an active tuned mass damper (ATMD, or hybrid mass damper, HMD) system is installed. The responses under harmonic active control force were studied by analyses on the two degrees of freedom models, and the forced vibration test method was demonstrated with showing an application to a tall building. Using the identified dynamic properties of the building which was obtained as the test results, the vibration control performance was directly calculated from the observed wind response data, analyzing the forced vibration responses induced by the inertia force of the mass dampers. The analyses, which were conducted on the observed wind response data of an actual tall building, verified the response control characteristics of the HMD system and demonstrated the effectiveness of the system.

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Modal energy, which is defined as the work done by elastic modal shear forces during dynamic motion is investigated on the basis of elasto-plastic response analysis of shear-type MDOF-systems. Major findings are as follows : the modal energy is primarily governed by elastic modal properties of systems represented by natural periods and participation factors, but is scarcely affected by plastic properties such as the D_s-value or the amount of plastic damage, the shape of hysteresis curves, and the distribution of yield shear coefficients or the damage distribution ; and the modal energy can be easily predicted from the smoothed Fourier amplitude spectrum of the base acceleration using the natural periods and participation factors associated with the elastic modes.

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The earth-retaining wall-structures for excavation tends to be complicated in these years, for efficient accommodation of the facilities of a building. lf we could introduce a fast calculation technique for such a three-dimensional problem, then it would be a useful tool for precise control of a complex wall-system. This paper proposes to open the closed wall system to a group of wall members in a single plane, and to correlate mutual mechanical reaction across their adjoining edges by a set of proper boundary conditions. Then the original problem is reduced to a simultaneous two-dimensional FEM problem, enabling us acalculation, much faster than the conventional three-dimensional method. Comparison of the theory with experiments on a real wall-structures was satisfactory, proving usefulness of the present method.

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This paper describes the statistical buckling behavior of clamped spherical caps with random initial imperfections under a hydrostatic pressure load. By using the Monte Carlo simulation and the statistical analysis we will explain the fluctuations and the statistical characteristics of static experimental buckling loads. Furthermore we make clear that the probability density functions of buckling loads are in agreement with the logarithmic normal distribution function. In this nonlinear analysis it is used that the method based on both of the finite element method and the mode-superposition method. The stochastic structures of geometric imperfections in caps are estimated by the maximum entropy criteria in the information theory.

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The present paper discusses the effects of the joint rigidity on the buckling strength of single layer reticular domes on a circular plan. The domes are assumed under uniform vertical loading. The effects are clarified mainly from the following view-points ; (1)how the joint rigidity reduces the elastic buckling loads, (2)how the reduction can be interrelated to column strength curves in terms of the generalized slendemess ratio for the member most relevant to the overall buckling of domes, (3)whether the column strength curves will resemble those for beam-columns in tall buildings or those for continuum shells, or will not. The discussions conclude that (1)modification of the generalized slendemess ratio- by reflecting the joint rigidity leads an almost same column strength curve for rigidly jointed members and (2)the elasto-plastic buckling loads for domes with semi-rigid connections can be estimated by applying the modified slendemess ratio.

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An analytical method of a composite beam consisting of a chord member and a web member and being connected with mechanical connectors is presented in this paper. According to the theory presented herein, the effects of the slip between a chord member and a web member and the shear deformation of a web member on the behavior of the beam can be combined by an equivalent shear rigidity coefficient or an equivalent slip rigidity coefficient and the elastic behavior of a composite beam can be represented with four parameters.

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This paper describes the bond splitting strength of lapped splices of reinforced concrete beams. Cyclic loading test was carried out on 16 specimens in which all bars were spliced at the same section. The variables of specimens were two kinds of arrangement of transverse reinforcement, such as outer transverse reinforcement and inner supplementary ties. Measurements were the maximum crack width and ultimate cracking patterns. load-deflection curves, strain distribution of longitudinal reinforcement and transverse reinforcement, and failure mode of splices. From this investigation, it became clear thatthere was a quantitative relation between the transverse reinforcement and bond splitting strength, and data for the design of the lapped splices were obtained.

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In this paper, the accumulated fatigue damage of high rise buildings due to wind-induced vibration was evaluated . To generate distribution of wind speed occurrence which is necessary for fatigue analysis, the strongest plural wind speeds in any one year were estimated statistically from well known basic wind speed. Time changes of wind speed was simplified to algebraic expression from Monte Carlo simulation of typhoons. The JSSC recommendation for fatigue design was applied to the analysis of fatigue damage. Some accumulated long term fatigue damages of sample high rise buildings, which are designed by the present standard, were evaluated by the proposed method. As a result, the allowable stress limit was eiven to control the damage factor.

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The numerical value of plastic deformation capacity of the beam-columns are sufficient for seismic design, if the web plate of H-shaped section member keeps up the strength against the axial force after large deformation. In this paper, making use of the high yield point of high-strength steel, hybrid beam-columns that consists of mild steel flanges connected by a high-strength steel web are proposed. So, a high-strength steel web, effectively, bears the axial force, and mild steel flanges having ductility carry the plastic deformation capacity under high axial force. The plastic deformation behaviors and bending strength are examined by experiments. And estimation of the plastic deformation capacity of hybrid beam-columns are attempted.

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An incremental approach is presented for design sensitivity analysis of structural systems with discontinuous properties. In the proposed approach, the transition time, at which the governing equations change discontinuously, is considered as a function of the design variables. The incremental response analysis and design sensitivity analysis are carried out simultaneously. Newton-Raphson type incremental and iterative approach is presented for systems with geometrical nonlinearity. Efficiency of the proposed method is demonstrared in the examples of a contact problem of a truss and elasto-plastic structures subjected to cyclic loading conditions.

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This paper describes a new method to presume temperatures in concrete suffered from fire. In this paper, the temperatures in fire-damaged concrete member were presumed, aiming at admixture responsive to thermal career. Although the quantity of admixture in concrete is small, the absorbance for its ultraviolet rays can be measured in high sensitivity. Concrete test samples were heated at every 100℃ from normal temperature upto 600℃, and the absorption curves were obtained at each temperature. The relations between heated temperatures and absorbances were derived from the absorption curves measured, and showed almost linear relations. Therefore, by measuring the ultraviolet absorption spectra of admixture, it was found that heated temperatures in concrete were possible to be presumed from absorbances.

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