BIM-based Multi-objective Optimization Research On Collision Coordination Of Building Components

The increasing functional richness of buildings determines the complexity of architectural,structural and MEP system design,leading to unavoidable engineering changes,which have a huge impact on the project schedule and project cost.At present,the automatic collision detection function of Building Information Model(BIM)can help identify design conflicts among multiple disciplines in the design coordination process,but it is difficult to provide effective support for resolving collisions.The existing research adopts a holistic view based on graph theory to solve the problems related to collision adjustment by constructing a spatial relationship network of building components,and gives a collision adjustment optimization method with a single optimization objective of minimizing the number of changed components.However,the actual collision adjustment should consider not only the number of changed components,but also the cost of changed components and other factors.Therefore,the consideration of multi-objective optimization collision adjustment is more in line with the engineering reality,and is of great significance to the collision adjustment in the design phase of construction projects.In this paper,we first analyze the three types of spatial relationships among building components,such as connection,influence and collision,and design an algorithm to obtain component information in BIM model using C# language,and query the three types of relationships based on the definition of the three types of relationships and collision detection software.Combined with the four types of invalid collisions defined in previous studies,the design algorithm identifies and clears the invalid detection results in the automatic collision detection of BIM software,and generates a spatial relationship network of building components.Secondly,a multi-objective optimization model for collision adjustment of building components based on BIM is constructed.The model system considers the limitations of member movement space and priority rules,and establishes a multi-objective optimization model for building member collision adjustment with the objectives of minimizing the number of changed members and minimizing the cost of changed members.Again,the NSGA-Ⅱ algorithm with elite strategy is used to design the multi-objective optimization algorithm for collision adjustment of building components.The coding and decoding methods are designed according to the collision adjustment strategy generation characteristics,the algorithm implementation process of collision adjustment strategy generation is analyzed,and the genetic operation method suitable for the collision component adjustment rules is selected to realize the BIM-based building component collision adjustment multi-objective optimization model algorithm.Finally,an example application of collision adjustment of building components in a building project in Mentougou district of Beijing is carried out.The optimization calculation of building component collision adjustment was carried out for the first floor of the case using Visual Studio 2019 software,and the model was modified according to the generated collision adjustment strategy,which was analyzed by combining the spatial relationship network of building components and the actual collision adjustment strategy.The results show that the collision adjustment strategy generated by the BIM-based multi-objective optimization model of building component collision adjustment is feasible and practical.The BIM-based building component collision adjustment multi-objective optimization model can provide an effective collision adjustment solution,which can meet the needs of reducing the number of component iterative adjustments and reducing the cost of changing components.The main innovation of this paper is that,compared with the existing research on single-objective generation collision adjustment strategy,this paper generates a spatial relationship network of building components with a holistic view,which improves the scientificity and accuracy of collision detection results and makes collision adjustment no longer focus on a single collision.Moreover,the multi-objective optimization model of BIM-based collision adjustment of building components is established based on multi-objective optimization theory,and the obtained collision adjustment strategy can provide reference for design coordinators,so as to improve the efficiency of design coordination.