In the process of using digital twinning technology to realize the intelligent management of the installation of precast components, the key elements of the construction site are concentrated on the macro positioning after the completion of the lifting of components, the precise positioning of the splicing between components, and the monitoring of the connection firmness of components.

The intelligent component is a whole composed of component ontology, active RFID tags, various sensors, embedded terminals and other components.

The embedded terminal is the most important component of the components supported by the Internet of Things technology, and plays the role of uploading and receiving data.

By deploying multiple types of sensors in the intelligent construction activities, the analog signals of the physical properties of the environment and components (stress, strain, load, displacement, real-time configuration data, etc.) are collected, and then the analog signals are converted into digital signals by the signal acquisition instrument and transmitted to the upper system.

According to the construction process, each dimension model is associated and integrated to realize deep level, multi-angle and all-round simulation.

The components mainly include precast components such as laminated boards, stairs, walls, balconies and so on.

When the protruding reinforcement and the reserved hole in the front process are aligned and assembled, the shotcrete pipe will extend from the shotcrete hole at the lower part of the component to start the shotcrete operation.

▲ Implementation method of digital twin framework modeling for precast building installation construction Multi-dimensional and multi-scale digital twin virtual body modeling Digital twin virtual body modeling integrates and builds models of component installation elements in precast building construction site from the dimensions of information, time and model type.

Model type dimension modeling refers to the model built by the twin from the point of view of component mechanical properties, construction progress visualization, site related information, etc., and by the finite element model, BIM model, 3D laser scanning model, etc.

The time dimension modeling can be designed with reference to the overall logic of the construction and installation progress, including the design planning stage, the installation and construction stage, and the operation and maintenance feedback stage.

When the concrete slurry flows out from the grout outlet on the upper part of the component, the grout outlet shall be blocked in time.
.

After fine calibration of components, the embedded terminals on the components acquire relevant information and transmit it to the upper data platform to realize real-time monitoring and adjustment of the installation accuracy between different components.

▲ Information acquisition process structure: component installation monitoring method based on digital twinning technology.

The monitoring method of component connection firmness in the installation stage takes the shotcrete reinforcement process in the shear wall splicing construction process as an example.

Digital twin precast building installation management model building installation construction elements integration and framework building a multi-dimensional model of precast building installation management based on digital twin is to build a virtual management model from the perspective of information, time and modeling types based on the installation site, so as to realize the application of digital twin technology in the construction industry.

BIM model at design stage.

▲ Digital twin modeling process First of all, information dimension modeling is the key basis for realizing the intelligent construction of digital twin and precast buildings.

The calibration signal is triggered by infrared, so that the ultrasonic transmitter of the signal receiving reference point can transmit the calibration ultrasonic to the measured point.

In the same way, TOA transmission algorithm is used for ranging and positioning through timers and other devices to reduce power consumption pertinently and make infrared technology and ultrasonic technology complement each other.

The research of positioning method requires that the positioning module on the component can provide accurate site positioning, and that the positioning system has accurate and fast capture efficiency for the signals from the component.

Taking the shear wall as an example, when the foundation is built, the splicing accuracy of reserved protruding reinforcement and reserved holes between the shear walls is the core link that the installation management of precast building components driven by digital twin technology should be improved.

Lifting Socket

The embedded terminal has the functions of data acquisition and transmission, and can transmit the data collected by the sensor to the virtual model and processor in real time.

Take Localizers, a representative system in the UWB industry, as an example to carry out precise positioning measurement through the pseudo-code delay technology of UWB signals.

The composition can be summarized into four levels: “geometry physics behavior rules”.

The index component ID can be used to query the component construction process and all information required by the quality of each construction process in the cloud database.

While realizing real-time data interaction between the physical model and the virtual construction site, the physical construction site and the virtual construction model data are uploaded to the cloud to form a twin data platform and establish a digital twin-based assembly-type component installation management framework.

Physical entity model data acquisition and management methods The intelligent component derived from the Internet of Things technology provides practicality for data acquisition.

▲ The intelligent component composition structure uses the component ID, type, material, geometric size, storage location and production information stored in the label.

The sensors include mechanical sensors, displacement, strain sensors, and positioning sensors, which can sense the mechanical properties of components and the changes of position in the site in real time, and are connected with embedded terminals.

During the production of precast components, active RFID tags and embedded terminals are tightly attached to the components.

In view of the intelligent management requirements of assembly component installation, wireless communication technology with precise positioning in complex environments, represented by ultra-bandwidth technology, has become the key to realize this mechanism.

Ultra-bandwidth technology has become the first choice for accurate positioning in complex environments due to its high bandwidth occupancy, high signal transmission speed, large system capacity, low operating costs, and low power spectral density.

▲ Installation and accurate positioning schematic The combination of infrared sensing technology and ultrasonic technology can realize the positioning and calibration functions.

The grouting method is usually used to pour concrete slurry from the lower mouth.

▲ On-site positioning method based on UWB component splicing precise positioning monitoring Take the installation process of shear wall as an example, analyze how to monitor and adjust the relative position between components in the splicing process.

RFID tag is the practical application of the Internet of Things technology in the production scenario, which undertakes the task of component identification and information writing.