This paper presents the effect of steel finger-type expansion joints on the overall seismic response of a bridge. For this purpose, two nonlinear hysteretic models are developed for finger expansion joints. Complex interaction of longitudinal and transverse hysteretic behavior such as slip-out, collision, and failure of fingers is included in the models. The models are implemented to seismic response analysis of a three-span simply supported bridge. It is found from the analysis that the effect of expansion joints is significant in the plastic curvature of columns at their plastic hinge and the response displacement and residual displacement of decks and columns.

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Vibration control technologies, both passive and active, have recently seen significant improvements due to technological advancements in computers, sensors, and actuators. Though passive control methods provide greater advantages in terms of maintenance and reliability, active methods are expected to be adopted for important civil engineering structures since they promise more effective structural response control. In this paper we investigate an active control method using hyper vision technology, and derive recurrence relations for time integration which include controlling forces. The feasibility of the active control method is confirmed by numerical simulations and by shaking table tests.

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Ultrasonic tip echo is scattered wave which radiates all direction from the sharp tip of reflection source such as fatigue cracks. Tip echo has been utilized for sizing defects as so-called “tip echo method” and also may apply to identify fatigue cracks from other defects. In this study, radiation characteristics of the tip echo were experimentally examined. A linear phased array ultrasonic testing system was applied to send and receive ultrasonic waves in various directions. The experimental results demonstrated the relationship between incident wave directions and directivity of the tip echo. Besides, the tip echo method was applied to a fatigue crack in a welded steel plate, and damping of echoes due to fatigue crack closure was indicated.

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In this study, a system of scene evaluation and the computer-aided design of girder bridge is proposed for quick response in an agreement formation stage using XML which can also peruse the Internet using the analysis result by the sensitivity engineering technique of girder bridge. In addition, the example of a bridge and the display method of a score which agreed as a policy for supporting a scene design in the evaluation simulation and two or more design concepts accompanying category change were proposed. Moreover, in order to examine the usefulness of the built system, comparison with the example of a scene design of a real bridge was tried, and the validity of an output result was considered.

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