Hexu Liu

Ontology-based semantic approach for construction-oriented quantity take-off from BIM models in the light-frame building industry

Proposing ontology-based semantic framework for quantity takeoff (QTO).Establishing construction-oriented product ontology for light-frame building projects.Querying a BIM design model for construction-oriented QTO using richer vocabulary.Prototyping Autodesk Revit add-on toolwith light-frame building application case. In building information modeling (BIM), the model is a digital representation of physical and functional characteristics of a facility and contains enriched product information pertaining to the facility. This information is generally embedded into the BIM model as properties for parametric building objects, and is exchangeable among project stakeholders and BIM design programs - a key feature of BIM for enhancing communication and work efficiency. However, BIM itself is a purpose-built, product-centric information database and lacks domain semantics such that extracting construction-oriented quantity take-off information for the purpose of construction workface planning still remains a challenge. Moreover, some information crucial to construction practitioners, such as the topological relationships among building objects, remains implicit in the BIM design model. This restricts information extraction from the BIM model for downstream analyses in construction. To address identified limitations, this study proposes an ontology-based semantic approach to extracting construction-oriented quantity take-off information from a BIM design model. This approach allows users to semantically query the BIM design model using a domain vocabulary, capitalizing on building product ontology formalized from construction perspectives. As such, quantity take-off information relevant to construction practitioners can be readily extracted and visualized in 3D in order to serve application needs in the construction field. A prototype application is implemented in Autodesk Revit to demonstrate the effectiveness of the proposed new approach in the domain of light-frame building construction.

Automated production planning in panelized construction enabled by integrating discrete-event simulation and BIM

Panelization, a form of off-site construction with origins in the manufacturing industry, has emerged as a popular, more efficient approach to constructing residential projects. This approach transfers some of the construction activities traditionally carried out on site into factory production tasks, and divides construction management into factory production management and on-site assembly management. This change poses some challenges to construction practitioners with respect to project planning and management, such as how to efficiently create work flow, balance the production line, and satisfy various panel requirements to ensure smooth on-site operations. This paper thus explores an automated approach for construction planning in the production plant with the objective of improving productivity and balancing the production line, which achieves a seamless integration of building information modelling (BIM) and discrete-event simulation (DES). Specifically, a BIM-based specialpurpose simulation (SPS) template for the production line is developed in Simphony.NET in order to facilitate more efficient modelling of the production line. The new simulation template provides a BIMbased interface which permits enriched information exchange between the BIM model and the simulation model. A case study of a production line for light gauge steel panels is presented to demonstrate the methodology. The simulation results show that proper production sequencing improves production performance, and that the newly developed simulation template is a useful planning tool for the panelized construction system.

An Automatic Scheduling Approach: Building Information Modeling-Based On- site Scheduling for Panelized Construction

Panelized/modular construction is increasingly adopted within the industry as a primary construction method, with in-plant fabrication and on-site assembly as two of the main processes. Each of these two processes involves a different emphasis regarding productivity improvement: for in-plant fabrication, manufacturing process management is the main focus, while, for on-site assembly, scheduling and management of assembly operations are of particular interest. This paper proposes a generic approach by which to generate the on-site schedule automatically based on a building information model (BIM), considering the structural supporting and topological relationships among building elements, as well as knowledge of steel panel construction. The BIM model is developed in an Autodesk Revit environment, based on which precedence relationships of elements are derived automatically, and is utilized to perform the on-site schedule through the Autodesk Revit Application Programming Interface (API). The generated schedule results are exported into Microsoft Project for further analysis, such as resource leveling. A case example is provided to demonstrate and validate the methodology. This paper explores the implementation of BIM, with the scheduling of panelized construction as the focus. This research lays the foundation for further implementation of BIM using Autodesk Revit.

Online simulation modeling of prefabricated wall panel production using RFID system

The use of discrete-event simulation (DES) in the construction and manufacturing industry has been increasing significantly over the past few decades. However, DES at present is mainly utilized during the construction planning phase as a planning tool, and it still remains a challenge to apply simulation during the execution phase for the purpose of construction control without an automated real-time data acquisition system. This study exploits an approach that involves the integration of a radio frequency identification (RFID) system and DES model in order to capture the real-time production state into the simulation model, thereby enabling real-time, simulation-based performance monitoring. The proposed methodology is implemented at Landmark Building Solutions, a wood-frame panel prefabrication plant in Edmonton, Canada. A simulation model is developed in Simphony.NET and integrated with the RFID system in order to enable the online simulation and to obtain real-time simulation results for the purpose of production control.

BIM-Based Integrated Framework for Detailed Cost Estimation and Schedule Planning of Construction Projects

With the increasing popularity of Building Information Modeling (BIM), several research studies have focused on its application in the construction industry, and advancements such as developments of BIM-based tools for construction scheduling and cost estimating have been carried out. Nevertheless, these tools are each developed only for one particular aspect of construction management, such as scheduling or cost estimating. As such, most are still limited to the product element level, rather than the construction operation level. This paper thus presents a BIM-based integrated framework for detailed cost estimation and schedule planning of construction projects. In the proposed framework, a BIM product model developed in Autodesk Revit, is integrated with a construction process model retrieved from RS Means, with the objective of generating detailed cost estimation and a workface construction schedule simultaneously. In this paper, the literature pertaining to BIM, cost estimating and scheduling is surveyed; then, the proposed framework is presented, and a simple building project is used as a case study to facilitate understanding of and verify the applicability of the integrated framework. Finally, findings from the implementation of the proposed framework are summarized.

Simulation of mobile falsework utilization methods in bridge construction

Scaffolds and shoring systems are generally referred to as the falsework in bridge construction, serving as temporary structures to support bridge span construction. The falsework cost usually accounts for 50-70% of the total project concrete budget. Falsework installation and advancing methods can greatly impact the completion time and actual cost. Thus, simulation can be instrumental in planning bridge construction operations and analyzing various options by evaluating postulated “what-if” scenarios. This study uses a previously constructed bridge in Sweden as a case study to test three feasible construction sequence alternatives. One of these alternatives was implemented on the actual construction of this bridge. Modeling was performed in Simphony, which captures the unique construction sequence requirements and constraints, resulting in project durations for each alternative. Results from simulation experiments were corroborated by the construction engineer who had worked on the bridge project in terms of the advantages that each alternative method possesses.