The Experts below are selected from a list of 159 Experts worldwide ranked by ideXlab platform

Fu-kuo Chang - One of the best experts on this subject based on the ideXlab platform.

  • Health monitoring of bonded composite repair in Bridge Rehabilitation
    Smart Materials and Structures, 2008
    Co-Authors: Zhanjun Wu, Xinlin P. Qing, Kumar Ghosh, Vistasp Karbhar, Fu-kuo Chang
    Abstract:

    Structural Rehabilitation with carbon fiber reinforced composite materials has proven to be an excellent way to enhance/repair steel reinforced concrete structures and prolong their service lives. However, disbonds between composite repair patches and host structures continue to be a great concern of this technology. In this paper, a built-in piezoelectric sensor network based structural health monitoring system is introduced for monitoring the disbonds between composite repair patches and the host structures. This diagnostic system combines the sensor network, diagnostic hardware and data analysis software allowing for real-time monitoring of the integrity of the bonded repair. The effectiveness of detecting disbonds using the system has been demonstrated on a full scale Bridge model in a laboratory setting. The Bridge model was loaded incrementally to failure, and disbond monitoring was carried out during the loading intervals. Test results showed that the system could detect the disbonds before they have a noticeable effect on the global stiffness of the Bridge model. 2008 IOP Publishing Ltd.

  • structural health monitoring of composite repair patches in Bridge Rehabilitation
    Smart Structures and Materials 2006: Sensors and Smart Structures Technologies for Civil Mechanical and Aerospace Systems, 2006
    Co-Authors: Kumar Ghosh, Xinlin Qing, Vistasp M Karbhari, Fu-kuo Chang
    Abstract:

    In recent years, there are many issues involving safety on old Bridges, aircrafts and other structures, which threaten the lives of the people using those structures, as well as the structures themselves. To prevent future failure, various measures are being taken. Structure Rehabilitations with carbon fiber reinforced composite patches have been adopted and demonstrated to be an excellent way to enhance/repair the structures and prolong the service life. However, there are still many problems residing in this kind of technology that remain unsolved, for example, the failure of the interface between composite repair patches and their host structures. This is a critical issue that must be addressed in order to show the viability of composite patches. In order to study debond occurring between composite repair patches and their host structures, a structure health monitoring scheme was demonstrated on a concrete Bridge model in the laboratory. The system is based on active sensing with diagnostic lamb waves, in which piezoelectric transducers are used as both sensors and actuators. In the test, six SMART Layers, each having eight piezoelectirc transducers, were integrated with two composite repair strips on the deck slab of the concrete Bridge model. For the three diagnostic layers with each composite repair patch, two layers were bonded on the top surface of the patch, and the other is embedded at the interface between the composite repair patch and the deck slab of the concrete Bridge model. The loading procedure of the test included three phases. First, the Bridge model was preloaded to initiate cracks on the deck slabs and the repair patches were then implemented. Second, the load was raised to reach the shear capacity of the girders of the Bridge model and then the repair patches were implemented on those girders. Lastly, the structure was loaded to damage the deck slabs. During the test, the initiation and development of debond between composite repair patches and deck slabs were clearly revealed by the active sensing system. It was demonstrated that the active sensing system employed is prompt, robust and a precise technique to monitor the debond process of the composite repair patches for structural Rehabilitation. Besides the study of the mechanism of debond between repair patch and host structures, an on line health monitoring system can give the user an indication of the structural health status and alert technicians when it approaches the failure capacity.

Sabah Alkass - One of the best experts on this subject based on the ideXlab platform.

  • decision support method for multi criteria selection of Bridge Rehabilitation strategy
    Construction Management and Economics, 2008
    Co-Authors: Saleh Abu Dabous, Sabah Alkass
    Abstract:

    Bridge management is the decision‐making process for selecting and prioritizing the actions necessary to maintain a Bridge within acceptable limits of safety and serviceability. The current decision‐making approach for Bridge management is based on optimizing the life cycle cost of the structure. This is a single criterion decision‐making process which does not include the indirect impact of the maintenance, repair and replacement actions. Sound Bridge management decisions should be made through balanced consideration of multiple and conflicting criteria. This requirement motivated the development of a multi‐criteria decision support method for Bridge deck management. The method is based on a modified analytic hierarchy process (AHP) to evaluate and rank alternative Bridge Rehabilitation strategies. The modified AHP provides an effective analytical tool to deal with complex decision making and has the following features: (1) multi‐criteria decision‐making process; (2) accounts for the uncertainty associat...

Kumar Ghosh - One of the best experts on this subject based on the ideXlab platform.

  • Health monitoring of bonded composite repair in Bridge Rehabilitation
    Smart Materials and Structures, 2008
    Co-Authors: Zhanjun Wu, Xinlin P. Qing, Kumar Ghosh, Vistasp Karbhar, Fu-kuo Chang
    Abstract:

    Structural Rehabilitation with carbon fiber reinforced composite materials has proven to be an excellent way to enhance/repair steel reinforced concrete structures and prolong their service lives. However, disbonds between composite repair patches and host structures continue to be a great concern of this technology. In this paper, a built-in piezoelectric sensor network based structural health monitoring system is introduced for monitoring the disbonds between composite repair patches and the host structures. This diagnostic system combines the sensor network, diagnostic hardware and data analysis software allowing for real-time monitoring of the integrity of the bonded repair. The effectiveness of detecting disbonds using the system has been demonstrated on a full scale Bridge model in a laboratory setting. The Bridge model was loaded incrementally to failure, and disbond monitoring was carried out during the loading intervals. Test results showed that the system could detect the disbonds before they have a noticeable effect on the global stiffness of the Bridge model. 2008 IOP Publishing Ltd.

  • structural health monitoring of composite repair patches in Bridge Rehabilitation
    Smart Structures and Materials 2006: Sensors and Smart Structures Technologies for Civil Mechanical and Aerospace Systems, 2006
    Co-Authors: Kumar Ghosh, Xinlin Qing, Vistasp M Karbhari, Fu-kuo Chang
    Abstract:

    In recent years, there are many issues involving safety on old Bridges, aircrafts and other structures, which threaten the lives of the people using those structures, as well as the structures themselves. To prevent future failure, various measures are being taken. Structure Rehabilitations with carbon fiber reinforced composite patches have been adopted and demonstrated to be an excellent way to enhance/repair the structures and prolong the service life. However, there are still many problems residing in this kind of technology that remain unsolved, for example, the failure of the interface between composite repair patches and their host structures. This is a critical issue that must be addressed in order to show the viability of composite patches. In order to study debond occurring between composite repair patches and their host structures, a structure health monitoring scheme was demonstrated on a concrete Bridge model in the laboratory. The system is based on active sensing with diagnostic lamb waves, in which piezoelectric transducers are used as both sensors and actuators. In the test, six SMART Layers, each having eight piezoelectirc transducers, were integrated with two composite repair strips on the deck slab of the concrete Bridge model. For the three diagnostic layers with each composite repair patch, two layers were bonded on the top surface of the patch, and the other is embedded at the interface between the composite repair patch and the deck slab of the concrete Bridge model. The loading procedure of the test included three phases. First, the Bridge model was preloaded to initiate cracks on the deck slabs and the repair patches were then implemented. Second, the load was raised to reach the shear capacity of the girders of the Bridge model and then the repair patches were implemented on those girders. Lastly, the structure was loaded to damage the deck slabs. During the test, the initiation and development of debond between composite repair patches and deck slabs were clearly revealed by the active sensing system. It was demonstrated that the active sensing system employed is prompt, robust and a precise technique to monitor the debond process of the composite repair patches for structural Rehabilitation. Besides the study of the mechanism of debond between repair patch and host structures, an on line health monitoring system can give the user an indication of the structural health status and alert technicians when it approaches the failure capacity.

Zhanjun Wu - One of the best experts on this subject based on the ideXlab platform.

  • Health monitoring of bonded composite repair in Bridge Rehabilitation
    Smart Materials and Structures, 2008
    Co-Authors: Zhanjun Wu, Xinlin P. Qing, Kumar Ghosh, Vistasp Karbhar, Fu-kuo Chang
    Abstract:

    Structural Rehabilitation with carbon fiber reinforced composite materials has proven to be an excellent way to enhance/repair steel reinforced concrete structures and prolong their service lives. However, disbonds between composite repair patches and host structures continue to be a great concern of this technology. In this paper, a built-in piezoelectric sensor network based structural health monitoring system is introduced for monitoring the disbonds between composite repair patches and the host structures. This diagnostic system combines the sensor network, diagnostic hardware and data analysis software allowing for real-time monitoring of the integrity of the bonded repair. The effectiveness of detecting disbonds using the system has been demonstrated on a full scale Bridge model in a laboratory setting. The Bridge model was loaded incrementally to failure, and disbond monitoring was carried out during the loading intervals. Test results showed that the system could detect the disbonds before they have a noticeable effect on the global stiffness of the Bridge model. 2008 IOP Publishing Ltd.

Saleh Abu Dabous - One of the best experts on this subject based on the ideXlab platform.

  • decision support method for multi criteria selection of Bridge Rehabilitation strategy
    Construction Management and Economics, 2008
    Co-Authors: Saleh Abu Dabous, Sabah Alkass
    Abstract:

    Bridge management is the decision‐making process for selecting and prioritizing the actions necessary to maintain a Bridge within acceptable limits of safety and serviceability. The current decision‐making approach for Bridge management is based on optimizing the life cycle cost of the structure. This is a single criterion decision‐making process which does not include the indirect impact of the maintenance, repair and replacement actions. Sound Bridge management decisions should be made through balanced consideration of multiple and conflicting criteria. This requirement motivated the development of a multi‐criteria decision support method for Bridge deck management. The method is based on a modified analytic hierarchy process (AHP) to evaluate and rank alternative Bridge Rehabilitation strategies. The modified AHP provides an effective analytical tool to deal with complex decision making and has the following features: (1) multi‐criteria decision‐making process; (2) accounts for the uncertainty associat...