Smart Structure System for Damage Diagnosis of Long Span Roof Trusses

Project: Research

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Long span roof trusses, for their structural efficiency, are very popular in Hong Kong (e.g., the 90mby 90m roof span of Hong Kong Coliseum) and worldwide (e.g., the 73m cantilever steel truss of theShanghai Stadium). Collapse of this kind of structures is cataclysmic owing to the large area ofcoverage (e.g., the roof collapse of Terminal 2E at Charles de Gaulle Airport, France, on 23 May2004; and the collapse of roof truss of the Sport Hall at City University of Hong Kong, Hong KongSAR, on 20 May 2016). Many collapse reports of roof trusses revealed that symptoms (e.g., crackingsounds and falling of concrete dust) were observed hours or even days before the collapse. Thesymptoms suggested that the structure may have damage accumulated on structural members and/orit may be overloaded with large deformation. The main purpose of the proposed project is to developa practical and cost-effective smart structure system for early detection of potential structural damageand abnormal deformation of long span roof trusses by proper sensing and intelligent diagnosis basedon structural responses, such as accelerations, strains, modal parameters, under operationalconditions. The proposed project put emphasis on the development of a damage diagnosismethodology for extracting information from various measurands and quantifying the damage statusof the target structure. A Bayesian probabilistic approach is adopted as it fundamentally processesthe statistical information from data for making inference and decision making. Major thrusts will bein the following areas. First, sensitive measurands shall be identified together with the correspondingoptimal sensor configurations (including number of sensors and the measured locations anddirections) to enhance the effectiveness of the proposed methodology. Second, the most“appropriate” model class of the target structure shall be selected conditional on the set of measureddata to ensure informative damage detection results. Third, long-term monitoring database ofmeasured data shall be developed for distinguishing damage-induced changes in measurands fromtheir variation due to environmental effects (e.g., temperature and ambient excitation intensity). It isbelieved that the proposed methodology can provide valuable information about the structuraldamages and abnormal deformation of long span roof trusses, so as to allow for early remediatemeasures and warning alarm for occupants to escape from the affected area. It is envisaged that thebasic methodology can also be applicable to other structural types with similar frequency ranges.?


Project number9042509
Grant typeGRF
Effective start/end date1/01/1831/12/21