Research On Data Collection And Application Methods Of Concealed Construction

The quality of building and infrastructures is one of the most significant policies in China.The construction quality not only plays an important role in the economic,social and environmental performances of a project,it also ensures the success in fitness,safety,reliability,robustness,economy and environment aspects.By contrast,the construction quality and safety defects always carry out the terrible threats against public property and health,as well as the development of the construction industry and national economy.In the construction process,it is significant for superintendents to control and manage each of the associated factors along the entire process,which enables the project to fulfill the requirements of the stake holders,to be in conformity to the national regulations,standards,specifications,the design shop drawings,and the contracts.Recently,researchers from academics and industry proposes a three-level hierarchy monitoring system for construction quality: enterprise level,government level and society level.However,due to the large number of involved stake holders in a construction project,the long life-cycle of a building,and some other factors and restrictions,constriction defects are still general around China.One of the root reasons is possibly that blind spot does exist in the control and management of construction projects-concealed projects.A construction project is generally composed of two kinds of construction processes: one is named observable construction,in terms that the entire process can be directly observed or measured,such as the site leveling,water-proofing work,etc.;the other is called concealed construction that a part or the complete process of it is immeasurable and invisible,for instance,the concrete consolidation,the connection among prefabricated components,etc.The quality of an observable project can be controlled and monitored by workers or inspectors,meanwhile that of a concealed project cannot be achieved immediately because of the immeasurable property of the concealed projects.It is therefore impossible and difficult to apply the conventional quality monitoring approaches,such as predicting the quality and safety issues ahead of time,identifying the potential quality and safety issues in a timely manner,and taking effective actions to prevent the quality and safety defects.The quality management of concealed projects thus has become the bottleneck of modern construction management.To fulfill the gap in research due to the lack of available approaches for concealed construction quality control and management,this study aims to establish and work out a theory and a system,along with series of methods,for data collection and analysis to boost the capability of controlling quality and to enhance the quality management of concealed projects.Specifically,the major propositions described herein are as follows:(1)Establish the fundamental methodology for quality control and management in concealed projects Based on the area-restricted and inevitable property of concealed projects,this study clarifies that the geographic locations and quality-risktaking behaviors are the crucial data to be collected.On one hand,the location tracks connected the workers and building components that have an identification of responsibility.On the other hand,the quality-risk-taking behaviors reveal the construction process through quantitative building activities and motions,which can make an assessment of the associated construction assignments.Combing these two valuable data enables the superintendents to control and manage the construction quality in a timely,fully,and life-cycle manner.This study then proposes a novel approach to track the behaviors through the track of construction tools.Such method is non-intrusive that lead to a series of prediction,control and management of construction quality.(2)Propose the method to collect data for construction projects using locationbased-services On the basis of the management theory for concealed projects,the study begins with tracking and recording the dynamic temporal-spatial locations and postures of the workers,materials,equipment,tools,etc.Considering the accuracy,cost and deployment of different types of real-time location systems,the authors determined to combine the received signal strength indication and weighted maximum likelihood localization to construct the RTLS for on-site applications.When the proposed RTLS is installed,it is possible to extract the real-time distribution of workers as they conducting concealed projects.Meanwhile,based on the as-built locations,as-plan workspaces and their geometry relationship,these records enable the task interdependences and responsibilities.(3)Propose the method to collect the data for construction projects through inertial measurement unit The RTLS is capable of capturing the temporal-spatial data for concealed projects,whereas the system performs not as good as expected with the respects of precision.Similarly,based on the fundamental theory of quality control and management,this study proposes another data collection system for concealed projects utilizing the inertial measurement unit and its relative navigation mechanism.To address the accumulated errors,the sources and the characteristics of errors are further analyzed and then this study proposes a cyclic solution to tackle the errors due to the periodic property of the construction assignments.(4)Validate the proposed concept and prototype by vibrating the concrete for consolidation Since the concrete vibrating process is a typical kind of concealed projects,this study decides to take it as an example to illustrate the detailed data collection and analysis.Based on the rheological theory for concrete consolidation,the authors propose and develop a data collection prototype through tracking the internal concrete vibrators to evaluate the quality of concrete products.Specifically,the quantitative indicators,including the vibrating duration,the speed when inserting or pulling the vibrator,the straightness,parallelism and perpendicularity,the depth and the region of action,are accessible by the visualization of the entire vibrating process.To conclude,due to the characteristics within the production of the concealed projects,this study proposes an effective and efficient data collection and analysis methods using LBS and IMU to gain the dynamic location and postures over the entire construction process.The results of concrete vibrating process for concrete consolidation show that the proposed management theory and developed prototype are valid.This study fulfills the theoretical gap between the normal and concealed projects,the proposed management methods and tools not only reduce the safety and quality risks but increase the systematic reliability of the building projects.