The paper addresses results of an international effort in further developing a novel friction damper device for a reduction of induced vibrations in structures. A description of the device, results of small-scale experiments, and results of full-scale shaking table tests are presented. The result of the investigations shows that the effectiveness of the device is determined not only by the friction material but also by the location as well as the way of its installation. The devices have a stable energy dissipating behaviour. They are flexible in their application, since they only need limited space. The device can be installed easily and readjusted after installation. The damping capacity of the device can be increased by simply adding friction layers. The friction damper device proves to be an efficient and economical device for a reduction of dynamic response of structures.

Structural health monitoring of RC structures under seismic loads has recently attracted attention in the earthquake engineering research community. In this paper, a piezoceramic-based device called "smart aggregate" was used for the health monitoring of RC frame structures under earthquake excitations. Four RC moment frames instrumented with smart aggregates were tested using a shake table. The distributed piezoceramic-based smart aggregates embedded in the RC structures were used to monitor the health condition of the structures during the tests. The sensitiveness and effectiveness of the proposed piezoceramic-based approach were investigated and evaluated by analyzing the measured responses. The displacement ductility demand of the structural members was calculated and compared with the damage index determined from the health monitoring technology using the smart aggregate. The comparison has shown that the damage index is compatible with the calculated ductility demand.

Structural health monitoring of concrete structures under seismic loads has always attracted much attention in earthquake engineering community. In this paper, a piezoceramic-based device, called "smart aggregate", is proposed for the structural health monitoring of concrete structures under earthquake loading. A concrete column instrumented with smart aggregates was used as a testing object. A shake table is used to simulate the earthquake ground motion for the testing object. During the shake table tests, the distributed piezoceramic-based smart aggregates embedded in the concrete column are used to perform the structural health monitoring. For the health monitoring purpose, one smart aggregate is used as an actuator to generate propagating waves, and the other smart aggregates are used as sensors to detect the waves. By analyzing the wave response, the existence of crack can be detected and the severity can be estimated. A damage index matrix is developed to evaluate the damage status of the structure. The experimental results demonstrate the sensitiveness and the effectiveness of the proposed piezoceramic-based approach in the structural health monitoring of the concrete structure under earthquake loading.

This paper presents the seismic performance of raised floor system by shake table excitations. The tested raised floor system was assembled by 7x7 panels with pedestal-stringer frame structure, supporting a simulated equipment with varies weight and geometry shape, the size of the panel is 60x60 cm, the height of the pedestal is 45 cm. This raised floor system was the typical system that frequently used in Taiwan semi-conductor FAB. The input motions for the shake table tests were the waffle-slab floor acceleration responses of a typical semi-conductor FAB by input simulated ground motions. The dynamic characteristics include the acceleration amplification and dependence of input motions by raised floor system was studied and discussed. This study also employee the finite element package to carry out numerical simulation on seismic responses of raised floor systems and compared with the experimental data, and show that the proposed simulation model was very excellent.

In recent years, researchers have focused their study on many possible approaches to enhancing the seismic performance of structures. One promising solution which is receiving attention today is the application of Shape Memory Alloys (SMA). In this study, high seismic performance shear walls have been proposed to have SMA bars acting as a kind of structural bracing system at both sides of the shear walls to increase the ductility and the energy dissipation capacity of the low-rise shear walls. This paper presents the results of the reversed cyclic tests on low-rise shear walls with SMA bars. The height, width, and thickness of the designed shear walls were 1.0 m, 2.0 m and 0.12 m, respectively. SMA bars were provided in the directions of 25 degrees to the horizontal (from the top corner to the bottom corner of the wall). The steel ratio in both perpendicular directions of the shear walls was 0.24%. The main parameter used in the study is the type of SMA bars, namely Superelastic and Martensite SMA bars. The force-displacement hysteretic loops of the low-rise shear walls under reversed cyclic loading are presented. Test results show that the maximum shear strengths of the tested walls are affected by SMA bars. It was found that the shear wall with Martensite SMA bars has greater residual displacement. In contrast, the shear wall with Superelastic SMA bars has less residual displacement. At the ultimate state, one of the four Superelastic SMA bars buckled, resulting in less energy dissipation capacity than the expected value. How to prevent the buckling of SMA bars needs to be investigated in the near future.

The dynamic response of seismic isolated continuous girder bridges subjected to either near-fault or far-field ground motions is compared to the non-isolated ones. Near-fault earthquake ground motion data are collected from the 1999 Taiwan Chi-Chi earthquake. The earthquake data recorded at the same sites from other events serve as far-field ground motions. Typical three-span continuous concrete box girder bridges designed under Taiwan seismic design specifications of highway bridges are adopted for this study. These bridges are assumed straight, founded on rigid rock and only the longitudinal response is considered. Parametric studies for the dynamic responses of isolated bridges by input near-fault ground motions are developed. The PGV/PGA value of near-fault earthquake records is identified as the key parameter governing the bridge response.

The main objective of this research project is to residual deformation and collapse mechanism of structural system and to assess the seismic demand of this system. In this study three major works are developed: a. Develop a physical-based inelastic hysteretic model which contains stiffness and strength degradation, pinching and residual deformation, b. Based on the proposed model the seismic demands of structural system are examined. Emphasis is concentrated on the study of MDOF system, c. Conduct the shaking table test of collapse. Examine the collapse behavior and develop the hysteretic model which included the collapse mechanism. Through this study three research papers were generated and they are listed as follows: 1. Loh, C.H., L.P. Hong,C.L. Wu, W.I. Liao and Y.S. Yang “Evaluation of Maximum Drift Demand for Seismic Performance Assessment of RC Buildings,” Paper for the Int. Conf. of 5 Anniversary of 921 Ch-Chi Earthquake, Sept. 2004 2. Loh, C.H. and S.T. Chung, “Prediction of Equivalent Linearization Method Considering SSI Effect on Seismic Demand of Structures,” Paper submit for publication in J. of Earthquake Engineering, 2004. 3. C-L Wu, C.H Loh, Y.S. Yag, and C.H. Lin, “Consideration of Collapse and Residual Deformation in Reliability-Based Performance Evaluation of Buildings,” Proceedings of 13WCEE, Vancouver, Canada, August 2004. PART 1: Evaluation of Maximum Drift Demand for Seismic Performance Assessment of RC Buildings

This paper presents results from an international research project devoted to evaluating the seismic performance of a three‐storey steel frame structure equipped with a friction‐damping device (FDD) recently developed at the Technical University of Denmark. Experimental results indicate that the FDD performed very well in reducing the lateral storey drifts of the test frame. Numerical simulation of the seismic response of the primary and friction‐damped frame was also conducted. This paper also compares the predictions of the displacement demand from the test results with those obtained by the capacity spectrum method. Copyright © 2003 John Wiley & Sons, Ltd.

This paper describes procedures of bridge fragility analysis for the highway bridges on the south-north freeway in Taiwan, and studies the evaluation of parameters used in bridge damage assessment. The fragility curves are used to represent the probabilities that structural damage, under various levels of seismic excitation, exceed specified damage states. Since it is neither necessary nor practical to evaluate individual bridges, bridge classification and mapping scheme plays an important role. Calculation of site-specific seismic demand and damage functions (i.e., capacity curves and fragility curves) are the key features in bridge damage assessment and earthquake loss estimation.

This paper presents the methods developed to enhance the transportation lifelines module in HAZ-Taiwan for highway bridges. The objective of this paper is to define the bridge classification and provide the fragility functions of the North-South Freeway in Taiwan that by utilize the available investigation data. The organization of this paper is as follows. First, the available bridge classes of the North-South freeway in Taiwan are reviewed and a new classification based on the available data to be implemented in Haz-Taiwan is proposed. Second, the description of failure mechanisms and criteria in different damage states adopted in this research are summarized. Third, the theoretical methodology of the fragility analysis for the new bridge classes and examples for freeway bridges are presented. Parameters for describing the fragility functions for each class are also generated and shown in the paper.

This paper describes the development of seismic design provisions of highway bridges will be revised in Taiwan reflecting the destructive damage in the 1999 Chi-Chi earthquake. After the Chi-Chi earthquake, the revised seismic design force and other related requirements in the seismic design code for highway bridges are developed in Taiwan. In addition to the conventional force based design, a capacity checking level is considered for the near-fault sites by limiting the ultimate capacity to exceed the maximum possible seismic demand. The development of seismic design force and the capacity check method are described.

This paper summarizes the results of a study that is to evaluate the structural response attributes of near-fault ground motion. Ground motion recordings from the Chi-Chi earthquake are used as inputs to the structural system. An improved nonlinear hysteretic model, based on the experimental study, was used to calculate the response of the single degree-of-freedom inelastic system. Comparison of the results of analysis with traditional elastic-perfect plastic mode calculations was made. Discussions on the inelastic design spectrum, particularly the code-specified base shear coefficients, using the improved nonlinear hysteretic model incorporated with the near-fault input ground motion are made. Copyright (C) 2002 John Wiley Sons, Ltd.

The first objective of this paper is to compare the dynamic behavior of reinforced concrete building structure subjected to near-fault and far-field ground motions. A twelve-story and a five-story reinforced concrete building with moment resisting frame designed according to the Taiwan building code was selected in this study. The Chi-Chi earthquake was selected as a first set in this study to perform the near-fault earthquake characteristics, which displays a pulse like velocity waveform and permanent displacement. On the other hand, another earthquake record selected at the same sites was selected to illustrate the far-field earthquake characteristics for comparison. Through the nonlinear time history analyses the values of story displacement, inter-story drift and base shear were analyzed to study the structural damage, and the results show that the near fault earthquake presents much more damage than those far field earthquake. The second objective of this paper is to compare the predictions of ductility demand by the nonlinear time history analyses with those obtained by pushover analysis procedure.