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Taipei, Taiwan

Sritharan S.,Iowa State University | Aaleti S.,University of Alabama | Henry R.S.,University of Auckland | Liu K.-Y.,NCREE | Tsai K.-C.,National Taiwan University
Earthquake Engineering and Structural Dynamics

An innovative seismic resisting system consisting of a Precast Wall with End Columns (or PreWEC) has been developed, and its performance has been verified using large-scale cyclic testing. The wall and end columns in the PreWEC system are anchored individually to a foundation using unbonded post-tensioning. A newly designed, low-cost mild steel connector is used to connect the wall and end columns horizontally along the vertical joint. The connectors are easily replaceable and provide additional hysteretic energy dissipation to the system. The PreWEC system can be economically designed to have a lateral load carrying capacity similar to that of a comparable reinforced concrete wall, while minimizing damage and providing self-centering capability. In addition to confirming these benefits, the large-scale test demonstrated that the PreWEC system: (i) would provide superior seismic performance compared to other currently available structural wall systems especially for the precast industry; and (ii) meets all the mandatory acceptance criteria established by the American Concrete Institute (ACI) for special unbonded post-tensioned precast structural walls and building frame special reinforced concrete shear wall systems, as defined in the American Concrete Society of Civil Engineers (ASCE) 7-05. © 2015 John Wiley & Sons, Ltd. Source

Wang R.-Z.,NCREE | Wang C.-Y.,National Central University | Lin B.-C.,Chung Yuan Christian University | Huang C.-H.,National Taipei University of Technology
Tumu Gongcheng Xuebao/China Civil Engineering Journal

The main object of this research is to apply the Vector Form Intrinsic Finite Element (VFIFE, V-5) method to calculate the nonlinear dynamic response of bridge under the vehicle. The vehicle model using frame element is used to compute the motion of the vehicle. The VFIFE method also can be used to simulate the deformation of the rail and the bridge. In addition, it can't require any iteration or any parameters during computation for solving the problems. In this paper, the VFIFE method provided an effective numerical method for the vehicle-track-bridge interaction behaviors and a train derailment. Two numerical example is to demonstrate the capability and accuracy of the VFIFE method. Source

Hsu T.-Y.,NCREE | Shiao S.-Y.,NCREE | Liao W.-I.,NTUT | Loh C.-H.,NTU
7th European Workshop on Structural Health Monitoring, EWSHM 2014 - 2nd European Conference of the Prognostics and Health Management (PHM) Society

Many vibration-based structural damage detection techniques which perform damage diagnosis of a structure based on structural dynamic characteristic parameters have been proposed in the last two decades. One of the promising approaches proposed recently is the local flexibility method. The local flexibility method, which is founded on virtual forces that cause nonzero stresses in a local part of the structure, can estimate damage locations and local stiffness variations of beam structures. It does not require a finite element model of the beam structure. The structural modal parameters identified from the ambient vibration signals both before and after damage are the key information for the local flexibility method. The number of modes necessary for the local flexibility method is usually quite small, especially for a simply supported beam where only the first mode could be sufficient. However, for a hyperstatic beam, the number of modes required for estimation of the damage could be much higher. This makes the feasibility of the local flexibility method much lower because in practice only the first few modes could be identified with high quality using ambient vibration signals. Therefore, in this study, non-local virtual forces which cause concentrated stresses in a local part and nonzero stresses in the other parts of a structure are employed. The theoretical basis of the proposed method which uses non-local virtual forces is derived. The proposed method is validated with a continuous steel beam experiment. The results illustrate that the non-local virtual forces can determine the local variations of stiffness more accurately with less identified modes. Therefore, the feasibility of the proposed method is higher because limited number of high quality modes can be identified in real world application. Copyright © Inria (2014). Source

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