Many types of accelerated tests for carbonation have been undertaken in order to investigate the carbonation process of concrete. In this study, we chose the following as the factors which would have an influence on the results of accelerated carbonation tests for concrete : the dimensions of the specimen, the pre-curing conditions and the accelerated conditions. The test results are summarized as follows. (1) The relation between time and carbonation depth varied with the test conditions. Carbonation depth was proportional to the power of time (b) which was a little less than 0.5 on average, but the value can be considered to be 0.5 for practical circumstances. (2) The carbonation rate reduces with the increase of the dimensions of specimen. (3) The carbonation rate of seal-cured concrete is a little higher than that of concrete cured in water. (4) The carbonation rate of concrete cured for 7 days is nearly equal to that of concrete cured for 28 days, but that cured for 3 days becomes about 20 % higher than that cured for 28 days. (5) The carbonation rate of concrete increases with the increase of 'the period of drying before the accelerated carbonation tests. (6) The carbonation rate increases with the increase of temperature. (7) It is supposed that there is a pessimum condition of carbonation rate near 40 % humidity. (8) The carbonation rate was proportional to the power of density of carbon dioxide which was a little less than 0.5 on average, but the value can be considered to be 0.5 for practical circumstances.

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Prediction of strong ground motion at a site near a fault is an important subject for the earthquake resistant design of a structure such as a reactor building. In this paper, we apply the semi-empirical synthesis method by IRIKURA (1983, 1986) to the estimation of site specific ground motion using accelerograms observed at Kumatori in Osaka prefecture. Target earthquakes used here are a comparatively distant earthquake (Δ = 95 km, M = 5.6) caused by the YAMASAKI fault and a near earthquake (Δ =27 km, M = 5.6). Then we discuss some problems to apply this synthesis method to the estimation of strong ground motions. The results obtained are as follows. 1) The accelerograms from the distant earthquake (M = 5.6) are synthesized using the aftershock records (M = 4.3) for 1983 YAMASAKI fault earthquake whose source parameters have been obtained by other authors from the hypocentral distribution of the aftershocks. The resultant synthetic motions show a good agreement with the observed ones. 2) The synthesis for a near earthquake (M = 5.6, we call this target earthquake) are made using a small earthquake which occured in the neighborhood of the target earthquake. Here, we apply two methods for giving the parameters for synthesis. One method is to use the parameters of YAMASAKI fault earthquake which has the same magnitude as the target earthquake, and the other is to use the parameters obtained from several existing empirical formulas. The resultant synthetic motion with the former parameters shows a good agreement with the observed one, but that with the latter parameters does not show so good agreement. These results suggest that the scaling relation between moment and magnitude may vary regionally. Therefore, we should adopt the empirical formulas for synthesis parameters in the region where we predict the strong ground motions because the existing empirical formulas predict the average of regional variation. 3) We estimate the source parameters from the source spectra of several earthquakes which have been observed in this site. Consequently we find that the small earthquakes (M <4) as Green's functions should be carefully used because the stress drops are not constant. 4) We propose that we should designate not only the magnitudes but also seismic moments of the target earthquake and the small earthquake to apply this synthesis method to the prediction of strong ground motions. Additionally, it is desirable to examine the scaling law of the earthquake sequences ocurring near the site based on the earthquake observation in advance.

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This is the last paper on the Pseudo-Dynamic tests of the full-scale reinforced concrete seven story structure. The contents of this paper include overall discussions on the earthquake resistance capacity of the tested structure and correlation studies between the tests of the full-scale structure and associated small-scale models. Major findings from the studies are as follows ; 1) Three-dimensional effect has a significant effect on the responses of a structure to earthquake loading such as lateral load carrying capacity and plastic hinge formation, 2) There is a possibility of relaxing present requirements in Japanese building code for lateral seismic load of a ductile frame-wall structure, and 3) As to a structure with flexural failure mode, a small-scale model, even one-tenth scale model, can simulate overall behavior of the full-scale structure while local behavior such as crack formation and fracture of reinforcement can not be simulated by such a very small-scale model.

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The results of basic experimental studies for opening and closing behavior of a crack in RC members are reported. The preceding paper reported the influence of the concrete cover, crack spacing, a diameter and properties of reinforcement and the shape of ribs of a reinforcement on the opening and closing behavior of a crack. In this paper, the factors in the specimens are concrete strength, the number and the spacing of longitudinal reinforcement and a lateral reinforcement ratio. The objectives in this research are to clarify the opening and closing behavior of a crack empirically and modify the crack model that was proposed in the preceding paper. An axial force was applied to the prism type specimens in order to represent the constant moment region which appears between tensile cracks. Eighteen prism type specimens and four beem type specimens were tested. The following facts were clarified. 1) The difference in the shape of the hysteresis loop by these factors in this paper was not observed. 2) The relation between the axial force and crack width that was obtained from the experiments including the preceding paper was modeled in numerical formulae. The proposed model considers a complex element of the reinforced concrete including a crack and bond action. This model represent the influence of the reduction of the bond action and the local contact effect of a crack. 3) The opening and closing behavior of a crack in the RC beem under reverced cyclic loading was represented very well by the proposed model. Therefore, this model was confirmed as the suitable analytical model for the complex elements of the cracking area of RC members.

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In design practice, the demand to provide web openings in prestressed concrete beams is increasing. However, so far an efficient design method has not been proposed. In order to design openings in beams safely, it is required first to know the elastic stress states, strengths and deformations at the openings, and then to establish reinforcing details around the openings. The target is to establish a design method, which provides guidelines so that the beams with openings to be designed, do not fail at the openings and have a performance equivalent to the beams without openings. It is common that the sectional design of prestressed concrete members are carried out on the basis of both allowable stress and ultimate strength design methods. In the present paper, the authors propose the sectional design method for prestressed concrete members with web opening at the center of the span, and describe it by applying it to practical design examples. The objective of the present design method is to find out the fiber stresses of prestressed concrete beams simply but accurately. First, axial stresses induced by prestressing forces, and flexural stresses induced by prestressing and external forces are separately calculated by the finite element method. In the next phase, the ratios of these stresses to the axial and flexural stresses calculated by the elementary beam theory, which considers the effect of axial forces, are evaluated. Finally, the fiber stress of prestressed concrete beams with openings is ev- aluated by multiplying these ratios to the design formula based upon the beam theory. For the convenience of design practice, a diagram to obtain the fiber stress is illustrated. The variational parameters stated in the above analysis are the shapes of openings (rectangular or circular), the ratio of depth of openings to depth of beam, and the ratio of width to depth of openings, etc.

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The response variability and reliability of linear beams due to spatial variation ot mechanical property is investigated. Assuming that beam bending flexibility constitutes one-dimensional, normal, stochastic field, the covariance functions associated with deflection and deflection angle can be evaluated by means of the procedure analogous to the random vibration theory. The present paper clearly shows that the response can be expressed in terms of the convolution integration involving the original stochastic field and the resulting response, in general, exhibits non-homogeneity and non-normality under the condition mentioned above. For those resulting stochastic fields, the probability that the beam deflection stays in a specified threshold is estimated by using the classical first excursion theory which is capable of dealing with the non-homogeneity (non-stationarity) of the deflection field. Two kinds of beam structures are analyzed as numerical examples ; a cantilever and a both-end fixed beam. The response statistics and the reliability associated with the beam deflection are evaluated along with the cor- responding Monte Carlo simulation. As the results, the proposed analytical procedure gives us very close results to those from the simulation. Through this fundamental study, the following conclusion is obtained ; 1. the problem of stochastic beams is analogous to that of the random vibration of deterministic systems subjected to random input, 2. the classical first excursion theory can exactly be applied to estimate the reliability of beam response.

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The Waseda bore-hole seismometer array, Tokyo, occasionally records periodic repetition of seismic pulses in coda part of seismic waves. Each pulse looks like a Ricker wavelet of several to ten second duration and of repetition intervals for about 10-20 and 50-60 sec. Total duration of the ground motion of this type reaches 5 minites. Obervation at other stations seems to suggest that such coda pulses of our interest could be observed in a considerably wide area in and around Tokyo Metropolis. Seismological analyses of the records and numerical tests of wave propagation prove that a possible mechanism of the present pulse events is generation of local surface waves and multiple horizontal reflection of them between underground boundaries. The main reflector may be located at the outer rim of the thick sedimentary basin. Further conclusion must be made after precise location of the reflectors, using dense array newtwork data and information of local underground structures. From the engineering point of view, repetition of seismic pulses as above may affect seismic vibration of artificial structures. Large artificial structures of long period and low damping factor might undergo additional vibration by the pulses, if the characteristic periods fit the interval of the pulses.

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The properties of the first-mode vibration system of structures under ambient excitations and the influences of wind forces on it are investigated through both observed data and a model simulation. Transfer functions and coherence functions, which calculated statistically between two vibrations, are used for evaluating the vibration systems. Among these, coherence functions give effective information on the degree of correlation, which indicate system nonlinearities derived from the mixing of several linear input-output relations. As a result, it is clarified that the system consists of two major ingredients : one is the response excited by microtremors of ground, the other is the component caused by wind excitations, and the ratio of these two ingredients varies with the wind force. A model with this properties are made in the form of eq. (8), in which the pa- rameter Cw is indicating the degree of wind influences. The evaluation of some parameter-estimating methods applied to transfer functions of ambient vibration is also performed on the basis of the properties of the vibration system above mentioned. The estimated parameters, especially damping factors, are affected to a great extent by wind excitations.

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Although a considerable amount of studies have been carried out for many years related to response of building of long and huge configuration in plan, none of those studies gives theoretical explanation clearly on actual dynamic behaviors. In this paper, authors describe methdology of modelling of this type of building using an actual structure and present theoretical explanation on actual response behaviors they acquired through earthquake obsevation for past years. The modelling for computer simulation was based upon the following conditions : 1) Beams and columns are treated considering bending and shearing deformation. 2) Slabs and shear walls are replaced by macro type of finite elements formed into frameworks. 3) Soil is treated as half space and the values of static soil springs is corrected for layered soil condition. 4) Dynamic soil-strcture interaction effect is approximately taken into consideration using additional mass. 5) Influence between adjacent foundations and from adjacent buildings are assumed to be negligible. First total structure is subdivided into 10 structural blocks and stiffness matrices of them are to be calculated. As for the blocks representing tube structures enclosing staircases inside, the stiffness matrices can be obtained by 3-D frame analysis based upon assumption of rigid slab. On the other hand, as for the blocks representing main frameworks of the building, flexibility of slab is taken into consideration when analysed in order to obtain the stiffness matrices. Next objective restoring matrix concerning whole structure can be composed by means of connecting stiffness matrices of subdivided structural blocks by those of slabs. Here as for the soil springs sustainig superstructure, they are obtained by Tajimi's method modified by authors for extended application. In this method static soil springs are calculated, using fundamental functions related to displacement distribution in half space imposed a unit force on its surface. And the results are corrected approximately for layered soil condition based upon assumption that stress distribution in layerd strata is the same as one in half space. According to an earthquake observation being conducted by authors in Hatoyama Campus of Tokyo Denki University since 1983, ground motins can be thought to be spatially variant although some of them can be approximately regard as uniform ground shaking. Based upon the above observation and analitical results they have already published (Ref. 8 and 16), two types of exciting ground motions were adopted for the computer simulation. Namely in case of Eastern Offsore Ibaragi Pref. Earthquake of Feb. 12, 1986, traveling wave was assumed in time domain where the maximum acceleration of the motion appeared. Subsequently random phase variation of high frequency components due to difference between observation sites and unpredictable factors was assumed in the rest time domain. On the other hand in case of Kanto-Chubu Border Earthquake of Feb. 14, 1984 and Kujukuri Cost Boso Pen. of Dec. 17, 1987, uniform ground excitation was assumed. As a whole, theoretical results obtained through simulation were in good accordance with actual response behaviors. Difference between calculated behavior and actual one is about 8 % at the top of the structure and 22 % at the base on the average when observed amplitudes give maximum acclerations. According to comparison of simulation with observation, complicated base motion in transversal direction was able to be explained as response of foundation including sway under uniform excitation. Significant characterestics such as higher mode excitation with remarkable slab deformation caused by time delay which exists propagating ground motion and its rapid amplitude degradation due to a sort of kinematic interaction effect of spatially variant ground motion were also explaned.

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The design seismic force is determined in proportion to the sum of dead and live loads in usual earthquake resistant design procedure. In case the floor loads are not fixed on the floor, this design practice must be changed. Sliding of floor loads will occur during earthquake excitations, that causes change of frame responses. Moreover, in some cases the floor loads collide against the loads nearby and the movement of loads is restrained by stoppers provided on the floor. These behaviors will also influence on the frame response. In this paper, first, rigorous solutions are derived from the basic equation of motion for a frame model with a block weight unfixed on the floor of the frame. Secondly, for analyses of rather complex frames with sliding blocks, a numerical method is proposed. These analyses are carried out by computer. The preciseness of computed results is proved by the experimental results which have been obtained by shaking table tests on a simple one-story frame model and a three-story frame model with a sliding block on each floor. Finally, response behavior of frames with sliding floor loads during earthquake is compared with the results of the computer analyses.

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In the large displacement analysis of thin shells, a flat triangular finite element has been used for a long time. Such a triangular element is very efficient to analyze a shell with an arbitrary shape numerically. Contraversely, it is impossible to evaluate the effect of the curvature in a shell exactly by the usual flat element. On the other hand, the general shell element which is based on the shell theory, is exact for the reason that it is estimated the curvature, but has been involving important numerical problems, so-called the membrane locking behavior and so on. In this paper, we describe the new large displacement analytical method of shell structures using the triangular finite element proposed by Carpenter et. al. This simple three-node low-order triangular element is baed on Marugerre's shallow shell theory, and is considered having away from the membrane locking behavior. The characteristics of this new numerical analytical method is the formulation technique in applying to the incremental theory. Namely, the local deformed shape of the analysis model is recognized as effect of curvature of the each element like the initial geometrical imperfection, but the global deformed shape of the analytical model is done by updated Lagrangian formulation. At last, we show some numerical examples to examine the validity and efficiency of the present numerical analytical method.

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To study on load-settlement mechanism and on behavior of inside soil of Framed Foundation, vertical loading tests of model Framed Foundation (internal diameter of frame D = 150mm) were performed on three different loading types (separate type, combined type and frame loading type) and four different depth ratios (L/D = 1 to 4) respectively. In this paper the result of model tests and of investigation on behavior of inside soil are reported. The conclusions are summarized as follows. (1) The bearing capacity increases according as L/D increases in all loading types. There is no significant difference between separate type and combined type at the same L/D. But the bearing capacity of frame loading type decreases after inside soil slips. (2) On separate type and combined type, frictional resistance of outside of frame and point resistance of frame is very small, and point resistance of inside soil is dominant. (3) Inside soil of separate type is compressed from both the top and the bottom under the condition that soil is fixed to frame at the central depth. Inside soil of combined type is thrust up from the bottom under the condition that soil is fixed to frame at the top. Compressibility of inside soil of frame loading type is equal to that of combined type at L/D when inside soil is blockaded. (4) The behavior of inside soil of Framed Foundation can be explicable by model analysis using authors' theory.

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