One branch of structural health monitoring (SHM) utilizes dynamic response measurements to assess the structural integrity of civil infrastructures. In particular,modal frequency is a widely adopted indicator for stru...One branch of structural health monitoring (SHM) utilizes dynamic response measurements to assess the structural integrity of civil infrastructures. In particular,modal frequency is a widely adopted indicator for structural damage since its square is proportional to structural stiffness. However,it has been demonstrated in various SHM projects that this indicator is substantially affected by fluctuating environmental conditions. In order to provide reliable and consistent information on the health status of the monitored structures,it is necessary to develop a method to filter this interference. This study attempts to model and quantify the environmental influence on the modal frequencies of reinforced concrete buildings. Daily structural response measurements of a twenty-two story reinforced concrete building were collected and analyzed over a one-year period. The Bayesian spectral density approach was utilized to identify the modal frequencies of this building and it was clearly seen that the temperature and humidity fluctuation induced notable variations. A mathematical model was developed to quantify the environmental effects and model complexity was taken into consideration. Based on a Timoshenko beam model,the full model class was constructed and other reduced-order model class candidates were obtained. Then,the Bayesian modal class selection approach was employed to select the one with the most suitable complexity. The proposed model successfully characterizes the environmental influence on the modal frequencies. Furthermore,the estimated uncertainty of the model parameters allows for assessment of the reliability of the prediction. This study not only improves the understanding about the monitored structure,but also establishes a systematic approach for reliable health assessment of reinforced concrete buildings.展开更多
During the use of constructions, they will be degraded. Due to the negative impact on structures such as increase in vertical load, horizontal windy load needs to evaluate the current state of the constructions before...During the use of constructions, they will be degraded. Due to the negative impact on structures such as increase in vertical load, horizontal windy load needs to evaluate the current state of the constructions before renovating, especially the current state of the main structural system whether necessary to carry out repair and reinforcement or not. In addition, the inspection of the current status constructions before renovating is also the legal basis for the granting of construction permits to renovate and repair degraded works. Reinforced concrete buildings in the coastal areas in Vietnam, in particular, are working in the marine environment leading to damage the reinforced concrete construction. It should be significantly noted. Although there have been legal documents related to the inspection of constructions issued in Vietnam, the detailed contents and procedures of institution for each type of construction have not been mentioned yet. Therefore, the topic research paper of “research on technical solutions to renovate constructions with reinforced concrete structures in Vietnam” is to improve the quality and efficiency of construction. This investigation in Vietnam is very essential. This study uses the method of surveying the current state of the construction works in use, using the experimental sampling method to analyze and evaluate the damage of the work, then propose typical solutions to repair construction. The purpose of this study is to provide a process to check the damage of the works, and to propose solutions to repair them. This work is very important and has practical significance, helping managers to maintain works better.展开更多
基金Research Committee,University of Macao,China Under Grant No.RG077/07-08S/09R/YKV/FST
文摘One branch of structural health monitoring (SHM) utilizes dynamic response measurements to assess the structural integrity of civil infrastructures. In particular,modal frequency is a widely adopted indicator for structural damage since its square is proportional to structural stiffness. However,it has been demonstrated in various SHM projects that this indicator is substantially affected by fluctuating environmental conditions. In order to provide reliable and consistent information on the health status of the monitored structures,it is necessary to develop a method to filter this interference. This study attempts to model and quantify the environmental influence on the modal frequencies of reinforced concrete buildings. Daily structural response measurements of a twenty-two story reinforced concrete building were collected and analyzed over a one-year period. The Bayesian spectral density approach was utilized to identify the modal frequencies of this building and it was clearly seen that the temperature and humidity fluctuation induced notable variations. A mathematical model was developed to quantify the environmental effects and model complexity was taken into consideration. Based on a Timoshenko beam model,the full model class was constructed and other reduced-order model class candidates were obtained. Then,the Bayesian modal class selection approach was employed to select the one with the most suitable complexity. The proposed model successfully characterizes the environmental influence on the modal frequencies. Furthermore,the estimated uncertainty of the model parameters allows for assessment of the reliability of the prediction. This study not only improves the understanding about the monitored structure,but also establishes a systematic approach for reliable health assessment of reinforced concrete buildings.
文摘During the use of constructions, they will be degraded. Due to the negative impact on structures such as increase in vertical load, horizontal windy load needs to evaluate the current state of the constructions before renovating, especially the current state of the main structural system whether necessary to carry out repair and reinforcement or not. In addition, the inspection of the current status constructions before renovating is also the legal basis for the granting of construction permits to renovate and repair degraded works. Reinforced concrete buildings in the coastal areas in Vietnam, in particular, are working in the marine environment leading to damage the reinforced concrete construction. It should be significantly noted. Although there have been legal documents related to the inspection of constructions issued in Vietnam, the detailed contents and procedures of institution for each type of construction have not been mentioned yet. Therefore, the topic research paper of “research on technical solutions to renovate constructions with reinforced concrete structures in Vietnam” is to improve the quality and efficiency of construction. This investigation in Vietnam is very essential. This study uses the method of surveying the current state of the construction works in use, using the experimental sampling method to analyze and evaluate the damage of the work, then propose typical solutions to repair construction. The purpose of this study is to provide a process to check the damage of the works, and to propose solutions to repair them. This work is very important and has practical significance, helping managers to maintain works better.
