Levelling Calibration and Intelligent Real-Time Monitoring of the Assembly Process of a DfD-Based Prefabricated Structure Using a Motion Capture System

Abstract

AbstractConventional measuring techniques and equipment such as the level and total-station are commonly used in on-site construction to measure the position of building elements. However, a motion capture system can measure the dynamic 3D movements of markers attached to any target structure with high accuracy and high sampling rate. Considering the characteristics of prefabricated structures that is composed by lot of discrete building elements, advanced requirements for the on-site assembly monitoring is required. This paper introduces an innovative real-time monitoring technique for the DfD-based (Design for Disassembly) structure with the application of motion capture system and other hardware in an IoT-based BIM system. The design and construction method of the structure system, on-site setup of monitoring system and hardware, data acquisition and analysis method, calibration algorithm as well as the BIM system are further illustrated in the paper. The proposed method is finally applied in a real building project that is composed by thousand discrete building elements and covers a large area of 50*25 m. As demonstrator, such monitoring system is applied in the real construction of a DfD-based prefabricated steel structure in the “Water Cube” (Chinese National Aquatics Centre) in Beijing. The building process is successfully recorded and displayed on-site with the digital twin model in the BIM system. The construction states of the building elements are gathered with different kind of IoT techniques such as the RfID chips and QR-Codes. With the demand to control the flatness tolerance within 6 mm (within a 25*50 m area), a large area monitoring system was applied in the project and finally reduced the construction time within 20 days. The final tolerance is verified and further discussed2.