Testing high strength concrete (HSC) is a critical issue on which no consensus has yet been reached. Among the factors which affect the measured compressive strength, the method of preparation of specimen ends plays the most significant role. The effects of capping materials and the effects of specimen end conditions before capping on the measured compressive strength as well as on the failure mode are investigated experimentally. Additionally finite element analyses are conducted to make clear the optimum end preparation concerning mechanical properties of capping materials and capping thickness. Consequently, cement paste capping with 3mm thickness allows to be applied to HSC and machine grinding is the best method of end preparation of HSC.

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We carried out experimental research to clarify the effects of different construction method on snow-sliding properties of sheet-metal roofe. In this experiment, the construction methods of roofing adopted were flat plate, standing-seam roofing, corrugated roofing, flat-seam roofing, diagonal roofing and stepped roofing. Experimental results clarified that the snow-sliding velocity of sheet-metal roofing is greatly influenced by the type of construction method. The sliding velocity of the flat-seam roofing or stepped roofing tends to be greater than that of standing-seam roofing or corrugated roofing. Furthermore, in roofs utilizing the same construction method, the snow-sliding velocity is affected by joint details. It was also confirmed that the interval and form of joints, e.g., flat lock seam and steps joint, influence the snow-sliding direction.

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Rods of glass and stainless steel were piled up in several layers like a thatched roof. They were exposed in artificial rainfall and the quantity of drainage water was measured at slopes of 10°-45°. The drainage efficiency of them improved according to increase of number of layers, diameter of rods and the slope of them. The two types of rainwater flow such as the stream running around the surface of rods and the one running in the gaps between them were observed, and it was found that the latter is superior to the former in drainage efficiency. Finally, we described the reasonable compositions of rods for a rod thatched roof.

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Applicabilities on the empirical prediction of earthquake ground motion intensities are studied by comparing with observed strong motion records at near-field from large events. The response spectra are predicted as products of the predicted response spectra at seismic-bedrock and the ground amplification factors calculated by using the frequency-dependent Q^<-1> model. Peak accelerations and velocities are predicted from spectrum intensities of the response spectra. Further the attenuation characteristics of the predicted peak ground accelerations and velocities for short fault distances and large magnitudes are estimated by assuming ground structure models from the seismic-bedrock to the surface.

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In order to grasp the dynamic characteristics of structure considering soil structure interaction, the eigenproperty of structure having identical stiffenss and mass distribution is evaluated. As evaluation methods, two approaches are introduced. The first is based on explicitly representing the determinant of dynamic stiffness matrix by the polynomial expression using the property of the cofactor expansion of tridiagonal matrix having common elements. The another method is based on explicit representation of transfer function using the transfer matrix method which is powerful for periodic structures. The dependency of the eigenfrequencies and damping ratios on the analysis model, story and size of structure and stiffness of soil are studied. First, the effect of soil-structure interaction on the eigenfrequencies for undamped models are studied. Secondly, the effect of damping on the eigenproperty is studied through the complex eigenvalues and transfer functions and it is clarified that the soil-structure interaction gives a large influences on the dynamic property of structures, which points out the limitage of conventional real eigenanalysis and the importance of proper selection of damping model.

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Using seismic records observed in 4 borehole arrays, characteristics of vertical seismic motions in sedimentary layers are investigated. The results are as follows. 1) P-waves having intensive effect to vertical component are propagating within sedimentary layers even after the S-wave onset time (S-wave part). 2) Frequency dependent Q-values for P-waves (Qp) in Tertiary sediment layers obtained from the optimal analyses to spectral ratios have the tendency to be identical with Q-values for S-waves (Qs) with the same wavelength. 3) Observed vertical motions in upper ground can be simulated by the multiple reflection theory of P-waves based on the optimized velocities and Q-values.

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This paper presents a two-dimensional dynamic response of a structure with an embedded rigid footing to an alluvial valley. The soil-structure system under a topographic site condition is subjected to a nonvertically propagating seismic SH wave. Since we assumed a semi-cylindrical alluvial valley model as well as an alluvial valley model whose soil interface is arbitrarily shaped, we used two different methods, i.e., a Fourier series expansion method and an indirect boundary integral equation method, so-called "Source method" to obtain two physical quantities requisite for evaluating the dynamic response of the soil-structure system, i.e., the impedance function and the "driving force" of the rigid footing. The results obtained for the two dimensional antiplane soil-structure interaction system show that the more closely the structure is located to the edge of the alluvial valley, the more pronounced the effect of the incident angle of SH waves on the displacement amplitude of the structure becomes.

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This paper presents a three-dimensional dynamic response of a structure with a rigid footing to a two-dimensional alluvial valley which is subjected to non-vertically propagating seismic SH waves. The superstructure modelled herein consists of a top mass supported by four columns on a rigid flat circular footing placed upon the surface of the arbitrarily shaped alluvial valley. Since it may be expected that the variation of the surface displacement amplitudes of the alluvial valley changes rapidly according to the increase in frequency of the incident SH waves, it is necessary to consider not only the translational vibration but also the torsional one of of the three-dimensional soil-structure interaction system even though the superstructure may be idealized to have no eccentric mass and rigidity disributions. The boundary conditions on the surface ground are treated as a mixed boundary value problem, which is reduced to a set of Fredholm integral equations. It is shown for the three-dimensional soil-structure interaction system that the torsional response of the structure has predominant effect on the relative response of the structure, and that the more closely the structure is located to the edge of the alluvial valley, the more pronounced the effect of incident angle of SH waves on the displacement amplitude of the structure becomes.

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Free vibrations of a simply supported thick elastic plate subjected to in-plane stresses are studied. Taking into account the effects of rotatory inertia and shear deformations with thickness changes, natural frequencies and vibration modes of thick plates are obtained. A set of fundamental equations of a two-dimensional higher-order plate theory is derived through Hamilton's principle. Several sets of truncated approximate theories are applied to solve the eigenvalue problems of a thick plate. It is noticed that the present higher-order theories can predict the natural frequencies of an extremely thick plate more accurately compared to other refined theories.

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Strong motion records of the Hyogo-ken Nanbu earthquake of 1995 observed by the borehole array at the Port Island in Kobe are analyzed to see the effects of soil nonlinearity. The horizontal peak accelerations and the predominant period on the surface are smaller and longer than those in the borehole. We try to simulate the observed accelerograms by using 1-D linear, equivalent linear, and effective stress analyses with the reasonable soil constants derived from the boring survey. The analyses show that a) linear analysis yields much higher accelerations than the observed, b) equivalent linear analysis yields good agreement up to the depth GL-16m but fails to reproduce the surface records, and c) the nonlinear analysis considering excess pore water pressure can reproduce the observed records both on the surface and in the boreholes. The pore pressure ratios of the reclaimed and holocene sand layers reach to almost 100% within 10 seconds from the start of strong shaking. Thanks to this strong liquefaction the peak ground acceleration and velocity at the reclaimed land would be reduced considerably which should be related to the damage distribution in Kobe.

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In this paper, we propose new analytical models for the hysteresis restoring force characteristics of a rubber bearing, and could determine the nonlinear vibration properties of a rubber bearing (damping coefficient and spring constant) using the models. The analytical models are two restoring force models of power function type, which are softening and hardening type. The models were determined using the skeleton curve and the area of the hysteresis loop, which were obtained by experimental results of dynamic hysteresis characteristics tests of rubber bearings. The nonlinear damping coefficient and spring constant depending on amplitude of horizontal displacement, frequency and surface pressure were calculated by the method based on an equivalent linear system applied to the model. As a result of analyzing the vibration properties of practical rubber bearing for a bridge using this method, the utility of this method was verified. We could also describe the possibility of analyzing dynamic vibration response reflected in the nonlinear vibration properties.

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In the present practice a prestressing force distribution is calculated by assuming a friction coefficient to be constant. Tests were carried out to evaluate this assumption and the following results were obtained; 1) The friction coefficient increaees as the prestressing force increases. 2) The friction coefficient decreases in proportion to a distance from an active end. A calculation formula for the prestressing force distribution was proposed in this study taking into account a variation of friction coefficient along the tendon length by a correction factor. By applying this formula for the elongation calculation of a PCCV, it was confirmed that the proposed formula simulated the measured elongations more accurately than the present practice did.

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For static and dynamic systems, shape control structure can be defined as shape of structure is controlled by actuators, etc., in order to satisfy the prescribed shape condition. The paper presents an arrangement theory of actuator. In the first part of the paper, the load-displacement relation with the constraint condition of displacement is theoretically analyzed by using the Bott・Duffin inverse and the generalized inverse to derive the actuator forces. In the second part, necessary and sufficient condition for the existence of actuator arrangement is formmulated. In the third part, the arrangement theory of actuator is formulated by the coefficient matrix of the reaction-axial relation. In the final part, a numerical example is shown in order to examine the validity of the present method.

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The present paper deals with the dynamic buckling behavior and the earthquake resistance of double layer pin-jointed latticed domes subjected to vertical accelerations by considering an additional mass to the original dead weight. Elasto-plastic, static or dynamic analysis, accounting for both geometric and material nonlinearities, has been performed by using Taft and El-centre UD motions. Based on the results from both the static and the dynamic analysis, the earthquake resistant capacity is evaluated in terms of the safety factor for the combined load of the dead and the additional weight as well as in terms of the linear response spectra.

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The uniform truss model is now getting wider acceptance in Japan for calculating shear strengths of reinforced concrete members. The model, however, has two theoretical weak points : (1) compressive stress of concrete is assumed to distribute uniformly even in critical sections of member, and (2) longitudinal reinforcement is assumed to be strong enoueh beyond its yield strength, both of which contradict flexural analysis. This paper presents truss models which yield realistic stress distribution harmonious with flexural analysis. The models vary slightly in accordance with the amount of axial load, but they give almost same shear strength as the prevailing uniform truss model.

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An elasto-plastic-point-hinge approach incorporating non-linear strain-hardening effects was devised to calculate post-buckling load vs. deformation curves of centrally loaded struts covering a wide range from extremely short to long columns. Post-buckling curves based on this method of analysis showed a good agreement with those observed in tests irrespectively of their slenderness ratios. Further, a series of analyses were performed on cold finished circular tubular struts by using statistically processed formulas for mechanical properties of stub-columns. From this, relations between the post-buckling deformation capacity, diameter to thickness ratio and slenderness ratio were made clear.

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The ultimate energy absorption capacity of steel rods is investigated experimentally. To get a general aspect of energy absorption capacity, a wide variety of parameters is involved in the test as followings. ・materials (mild steel, high strength steel, stainless steel) ・detailed shape of the rod at the fixed end (sharp change, smooth change) ・sectional area (constant, changing) ・loading amplitude (fixed, incremental, random) ・loading direction (uni-axial, bi-axial) Hysteretic curves can be decomposed into the skeleton part and the Bauschinger part. The energy absorption capacity attained by the skeleton part can be well predicted by an analytical method and that attained by the Bauschinger part can be estimated by an empirical relationship obtained by several tests under a constant amplitude. As a result, the influence of the detailed shape of the rod on the ultimate energy absorption capacity is emphasized.

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The formulation for solution of equation of motion is shown using the wavelet transform, assuming periodicity of equation system. Then, the results of the derivative of I. Daubechies and Y. Meyer's scaling functions and the connection coefficients which are necessary for solving of equation are shown, and the characteristics of these functions are discussed. Moreover, examples of the numerical calculation concerning with the initial value and boundary value problems are shown and compared with existing method, and it is clear that wavelet based method shows high accuracy.

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