Papers by Author: Ming Chih Huang

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Authors: Tzu Kang Lin, Ming Chih Huang, Jer Fu Wang
Abstract: A bridge health monitoring system based on neural network technology is proposed in this paper. Two major ground excitations recorded in Taiwan were used to establish the NARX-based system. Analytical results from different methods including transfer function, ARX-based model, and the proposed neural network-based system were used to evaluate the efficiency in health monitoring. The result shows that the proposed system can be used successfully with superior advantages after major earthquakes for bridge health monitoring.
Authors: Chern Hwa Chen, Yuh Yi Lin, Cheng Hsin Chang, Shun Chin Yang, Yung Chang Cheng, Ming Chih Huang
Abstract: To determine its actual dynamic responses under the wind loads, modal identification from the field tests was carried out for the Kao Ping Hsi cable-stayed bridge in southern Taiwan. The rational finite element model has been established for the bridge. With the refined finite element model, a nonlinear analysis in time domain is employed to determine the buffeting response of the bridge. Through validation of the results against those obtained by the frequency domain approach, it is confirmed that the time domain approach adopted herein is applicable for the buffeting analysis of cable-stayed bridges.
Authors: Ming Chih Huang, Yen Po Wang, Chien Liang Lee
Abstract: In this study, damage localization of frame structures from seismic acceleration responses is explored using the DLV technique and ARX model for system identification. The concept of the DLV method is to identify the members with zero stress under some specific loading patterns derived by interrogating the changes in flexibility matrix of the structure before and after the damage state. Success of the DLV method for damage localization lies on the ability to identify the flexibility matrix. The ARX model, a discrete-time non-parametric auto-regressive system identification technique is adopted to identify the modal parameters (natural frequencies, transfer functions and mode shapes) from which the flexibility matrices of the intact and damaged structures are constructed. To explore the effectiveness of the DLV method, a five-storey steel model frame with diagonal bracings was considered for seismic shaking table tests. The damage conditions of the structure were simulated by partially removing some of the diagonals. With the flexibility matrices of both the intact and damaged structures synthesized on a truncated modal basis, the damage locations have been successfully identified by the DLV method for either single or multiple damage conditions, regardless of the damage locations. This study confirms the potential of the DLV method in the detection of local damages from global seismic response data for frame structures.
Authors: Ming Chih Huang, Yen Po Wang, Tzu Kang Lin, Jer Fu Wang
Abstract: In this paper, a pseudo-single-degree-of-freedom system identification procedure is developed to investigate the dynamic characteristics of energy-dissipated buildings equipped with symmetric ductile braces (SDBs). The primary structure is assumed to be linear on account of substantial reduction of seismic forces due to the installation of SDBs for which a bilinear hysteretic model is considered. The hysteretic model is in turn characterized by a backbone curve by which the multi-valued restoring force is transformed into a single-valued function. With the introduction of backbone curves, the system identification analysis of inelastic structures is significantly simplified. The proposed algorithm extracts individually the physical parameters of each primary structure and each energy-dissipation device that are considered useful information in the structural health monitoring. A numerical example is conducted to demonstrate the feasibility of using the proposed technique for physical parameter identification of partially inelastic energy-dissipated buildings.
Authors: Tzu Kang Lin, Yen Po Wang, Ming Chih Huang, Chen An Tsai
Abstract: Bridges are prone to suffer from multiple hazards such as earthquake, wind, or floods for the special structural characteristic. To guarantee the stability of bridge structure, how to precisely evaluate the scour depth of bridge foundation has become an important issue recently as most of the unexpected damage or collapse of bridges are caused by hydraulic issue. In this paper, a vibration-based bridge health monitoring system considering the response of superstructure only is proposed to rapidly evaluate the embedded depth of bridge column. To clarify the complex fluid-solid coupling phenomenon, the effect of embedded depth and water level was first verified through a series of static experiment. A finite element model with confinement simulated by soil spring was then established to illustrate the relationship between the fundamental frequency and the embedded depth. With the proposed algorithm, the health condition of the bridge can be inferred by processing the ambient vibration response of the superstructure. To implement the proposed algorithm, a SHM prototype system monitoring the environmental factors such as temperature, water level, and inclination was developed to support on-line processing. The performance of the proposed system was verified by a series of dynamic bridge scour experiment conducted in laboratory flume and compared with the reading from water-proof camera. The result has shown that by using the proposed vibration-based bridge health monitoring system, the embedded depth of bridge column during complex scour process can be reliably reflected.
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