This paper reviews the development of pseudo strain-hardening cement based short fiber composites employing the Performance Driven Design Approach. The micromechanics theory behind the design concept is reviewed, and the unique mechanical properties of the resulting composite are summarized. The translation of material properties to structural properties is demonstrated with the structural response of the Ohno shear beam.

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The objective of this paper is to construct a method of evaluating the dynamic collapse of a cantilever column under the axial compression and the lateral disturbing force simultaneously. First, a parametric study is carried out to investigate the dynamic collapse behavior of the column idealized by the flexural multi-degree spring-mass system, under the axial compression and the harmonic disturbing force. Secondly, through the results, a method of evaluating the dynamic collapse of the column is proposed by developing the method for this type of SDOF systems. Finally, the dynamic collapse of a uniform column and a stepped one is evaluated by the proposed method.

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A generalized two-surface model is proposed which can be used in multidimensional stress state even within the yield plateau. The description of the cyclic behavior observed in the uniaxial cyclic experiments is also included in the present model. Moreover, the proposed model has been implemented by the finite element method numerically. A good agreement between the experimental results and prediction by the proposed model has been obtained.

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Coupled flutter of non-analogous vertical and torsional modes, which may typically occur in mono-cable suspension or single plane cable-stayed bridges, for example, and multimode flutter including higher modes are studied both analytically and experimentally. In such cases, the lateral locations of rotational center of girder vary along the span, so that a two-dimensional or spring mounted model test loses its validity. The proposed multi-mode flutter analysis using the flutter derivatives is expected to be useful to predict the coupled non-analogous and/or multi-mode flutter along with the three-dimensional model tests.

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Presented are inpedance matrices for rigid square foundation on layered media and some numerical aspects for generating these impedance matrices. The analysis method employed is analytically solving wave equations in cylindrical coordinates, and then coordinate transformation, variational principle and reciprocal theorem are used to generate the impedance matrix for structural foundation. Since the interaction stresses between foundation and surrounding soil are assumed to be piecewise constant, the element size for the piecewise constant stress distribution is investigated. In order to demonstrate the reasonability of the assumed element size, some typical distributions of interaction stresses are presented. An example of a rigid square foundation rigidly attached to a two-layer medium and subjected to torsional, vertical, rocking and horizontal excitations is used to show the influence of layered stratum to the impedances.

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The purpose of this study is to propose a simple and accurate numerical method to analyze the dynamic response of structure-water-ground interaction systems in the time domain.
For this purpose, a frequency independent semi-infinite element is newly proposed to model the part of the water system away from the structure. This method is not only suitable for describing the behavior of unbounded water systems, but also for significantly decreasing the number of finite elements. Examples given in this study indicate that the method has excellent computational accuracy and feasibility for analyzing the effects of hydrodynamic pressure on the response of structure-ground interaction systems.

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Genetic algorithm (GA) includes genetally three genetic operators, reproduction (selection), crossover and mutation. The lack of dependence on function gradients makes it more suitable to such problems, like as discrete optimization design problems and optimization design problems with nonconvexities or disjointness in design space. The method is tried to apply to the discrete structural optimization in this paper. The outline of a simple GA is described first. In order to improve the realiability and efficiency, a modified method, or in another word, a new genetic operator ‘growth’ is proposed. The concept and application in specific optimization design problems is explained. It is also compared with simple GA. Numerical examples presented here show that the GA with growth operator is superior to simple GA.

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Eighty cases were considered for the trial design of simple pedestrian bridges in which resonance are easily caused by human walking. Natural frequencies of each designed pedestrian bridge were analyzed, and also the response amplitude were calculated when a person walk on the bridges with the same pace as natural frequency. Vibration serviceability of the pedestrian bridges at resonance was discussed. From the results, it became clear that the pedestrian bridge of which dead load is more than 2.0tf/m has enough serviceability even at resonance. Moreover, simplified formula which can calculate accurately the maximum response amplitude was developed for bridge design.

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Steel plate and concrete composite slabs described herein are the so-called Robinson's slabs as open sandwich plate elements, that are made of thin steel plate with headed studs and in situ concrete. It can be found their applications to bridge decks and some members of marine structures such as undersea tunnels. The purpose of this paper is to discuss their failure modes and loading capacities. First, patch loading tests of 12 square slabs with some different stud arrangements have been carried out. Second, we have developed 3D rigid body spring model considering material nonlinearity to simulate their behavior up to failure. The validity of the model has been verified in comparison with the experimental results

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Basic characteristics of bridge buffeting in yawed wind, i. e. a wind that is not normal to the bridge longitudinal axis, were studied. Cantilever beams with rectangular cross-section were used as the model which can be thought as a simple version of a cable-stayed bridge under construction. Experimental models with flat plate cross-section showed comparatively large vertical responses in a yawed wind from the free end direction. This tendency was enhanced for the wider models. The conventional buffeting analysis was modified so that the response of the cantilever models under yawed wind can be predicted. Two effective wind velocities were considered separately. One is the velocity components normal to the side and the other is the component normal to the free end of the model. The analytical results for the flat plate cross-section models generally explained the findings regarding the effect of the wind yaw angle.

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To evaluate spring constant between the underground transmission line and ground, we carried out the tests in which static and dynamic loads were directly applied to the reduced model burned in embankment. It is found that the deformation of the ground induced by the movement of the model concentrates near the model and that sliding deformation becomes predominant when the movement of the model increases. A method is proposed to evaluate the characteristics of spring constant. The accuracy of the method is comfirmed by comparing the numerical results with the testing results.

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Using the concept of neural network we have developed an algorithm to control seismic responses of structures. To take into account the uncertainty of dynamic characteristics of structural system the back-propagation learning process is applied to identify the structure parameters such as mass damping and stiffness matrices. A new closed-open-loop optimal control scheme that has been derived by minimizing the sum of the quadratic time-dependent performance index and the seismic energy input to the structural system is implemented into the learning process of a layered network. This algorithm is simple and reliable for on-line control operations and effective for a structural system. Numerical examples are worked out to demonstrate the control efficiency of the proposed algorithm.

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Three-dimensional time domain boundary element method with the fundamental solution of the infinite-space is applied to the analysis of the near-field of a dislocation source. Although, the discretization of the free surface is necessary, the fundamental solution is rather simple, then the coefficient matrices can be calculated readily. Through the application of the method to the 1989 Loma Prieta earthquake, the feasibility of the method is discussed based on the comparison of the numerical results and the observred records, and the CPU-time and memory requirement in the analysis.

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This paper deals with the detection of small fatigue cracks by the nondestructive tests in unpainted weathering steel welded joints after 10-year of atmospheric exposure. The nondestructive tests were carried out to find small cracks before and after the rust removal. The detectable limits of fatigue crack depth with or without the rust were 1.2mm by the magnetic particle test and 0.9mm by the eddy current test. The ultrasonic test was not applicable, when the test was carried out over the patina of about 0.1mm.

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