IFC-Based 4D Construction Management Information Model of Prefabricated Buildings and Its Application in Graph Database

Effective data interoperability and schedule analysis play a significant role in improving the management of prefabricated buildings. However, there is a lack of efficient strategies and comprehensive approaches for data interoperability and data-based automated schedule analysis. This paper intends to promote prefabricated buildings’ management by solving these two problems via developing an IFC-based framework consisting of three parts. Firstly, this framework proposed a mechanism to establish an IFC-based 4D construction management information model of prefabricated buildings. Furthermore, a non-relational database—graph database—is introduced to twin this model into a task-centered network to realize the interoperation of construction information among different participants. Finally, graph database-based strategies to update data, automatically analyze construction schedules and visualize the 4D construction management information model are described. The proposed framework is validated in a prefabricated engineering case. In this case, an IFC-based and graph database-based 4D construction management information model is established through IFC standard’s extension. The graph database-based analysis of the model automatically recognizes the engineering case’s critical path information, delay analysis information, and schedule network analysis information. It is illustrated that this framework can successfully establish a unified IFC-based information model of prefabricated buildings’ construction management to prompt effective data interoperability. In addition, the application of this IFC-based information model in graph database can automatically analyze the construction schedules to prevent possible delays in advance. In short, the significance of this paper is to innovatively propose an IFC-based and graph data-based information model to solve the difficulties of ineffective data interoperation and unautomated schedule analysis in prefabricated buildings’ construction management. This study can be the digital foundation of further IFC-based digital twin.

A new algorithm for finding the K shortest paths in a time-schedule network with constraints on arcs

Time-schedule network with constraints on arcs (TSNCA) means network with a list of pre-defined departure times for each arc. Compared to past research on finding the K shortest paths in TSNCA, the algorithm in this paper is suitable for networks having parallel arcs with the same direction between two nodes. A node label algorithm for finding the K shortest paths between two nodes is proposed. Temporal-arcs are put into the labels of nodes and arranged by ascending order. The number of temporal-arcs is limited to K in every label of node to improve the effectiveness of the algorithm. The complexity of this algorithm is [Formula: see text], where [Formula: see text] is the maximum number of departure times from a node, [Formula: see text] is the number of arcs in network, and [Formula: see text] is the number of nodes in network. Experiments are carried out on major part of real urban mass transit network in Beijing, China. The result proves that the algorithm is effective and practical.

A Case Study on the Optimization of Runway Reconstruction Project Scheduling Based on the Supervision Management Data

In view of the time interleaving of the relevant processes in runway reconstruction project and the simplification of the relevant processes in current schedule optimization models, runway reconstruction project scheduling is treated the same way as the ordinary construction project, which can’t meet the requirement of the efficient use of limited daily construction time. Statistics of the daily supervision management data in an actual runway reconstruction project are analyzed according to each process respectively. The law of data distribution can help to judge the reliability of the planed schedule and some process with actual physical meaning can be divided into several processes having no physical meanings as the process time interleaving taken into consideration. Then a new equivalent schedule network diagram with independent processes is built to replace the old one and the Critical Path Method (CPM) technique can be used to solve this mathematic problem and develop a schedule. The schedule plan from the modified schedule network diagram can prove the validity of the modified optimization model compared with the one from the ordinary schedule plan method.