This paper concludes that 4D models are a useful alternative to project scheduling tools like CPM networks and bar charts. They enable more people to understand a schedule quickly and identify potential problems. By developing a 4D model for a commercial construction project, we were able to detect the incompleteness of the original schedule, find inconsistencies in the level of detail among the schedule activities, and discover an impossible schedule sequence. We were also able to anticipate potential time-space conflicts and accessibility problems. The results of the case study show that 4D models are effective in evaluating the executability of a construction schedule. The case study also highlighted the need for improvements to 4D tools. 4D tools should include bar charts, component lists, and annotation tools in their graphical user interface. Automating schedule data preparation and 4D model generation in the design stages of a project can expedite 4D model development and use. Users need to be able to generate 4D models at multiple levels of detail and generate and evaluate alternative scenarios rapidly.

Closure of "Feasibility Study of 4D CAD in Commercial Construction"

SUMMARY: Coordination of Mechanical, Electrical and Plumbing (MEP) systems is a huge challenge for many technical projects such as Healthcare projects, Bio-tech projects and projects in the area of Advanced Technology The use of Building Information Modeling (BIM) or Virtual Design and Construction (VDC) tools and processes promises to address the challenges of the MEP coordination process This case study presents the use of BIM / VDC tools and processes for the coordination of MEP systems on a $969M healthcare project in Northern California, USA We discuss the challenges project team members faced in implementing the BIM / VDC tools and processes for MEP coordination, the specific quantitative and qualitative benefits from the use of BIM / VDC tools and processes that each project team member recognized and the lessons that the project team learned by implementing BIM / VDC tools and processes for the coordination of MEP systems Some of the challenges we discuss include the creation and organization of the MEP coordination process using BIM / VDC tools, creation of the guidelines for the most efficient use of BIM / VDC tools for the process of conflict identification and resolution between the MEP subcontractors, and aligning the contractual interests of the coordination team to meet the overall project schedule Some of the benefits that the project team achieved by using the BIM / VDC tools and processes for the coordination of the MEP systems include labor savings ranging from 20 to 30 % for all the MEP subcontractors, 100% pre-fabrication for the plumbing contractor, only one recorded injury throughout the installation of MEP systems over a 250,000 square feet project area, less than 02% rework for the whole project for the mechanical subcontractor, zero conflicts in the field installation of the systems and only a handful of requests for information for the coordination of the MEP systems between contractors and the designers, and 6 months’ savings on the schedule and about $9M savings in cost for the overall project The lessons the team learned include the level and type of details team members need to include to achieve benefits from the use of BIM / VDC tools for the coordination of MEP systems

Benefits and lessons learned of implementing building virtual design and construction (VDC) technologies for coordination of mechanical, electrical, and plumbing (MEP) systems on a large healthcare project

BIM- and 4D-based integrated solution of analysis and management for conflicts and structural safety problems during construction: 1. Principles and methodologies

A proactive system for real-time safety management in construction sites

3D and 4D modeling tools have been available in the marketplace for some time. The past few years has seen a growing interest from the design and construction community to adopt these tools. As many project teams are realizing, implementing 3D and 4D modeling on an actual project is a complicated process that requires a coordinated effort. No guidelines currently exist on using these tools in a multi-disciplinary and multi-organizational environment and project teams are forced to figure this out on their own in real time as the project progresses. This paper addresses this shortcoming by providing guidelines that describe how to overcome the technical, procedural and organizational issues confronted by project teams as they undertake this new way of working. Specifically, the paper describes different approaches for assembling a project team to leverage these technologies, the modeling requirements for implementing 3D and 4D projects, the 3D and 4D modeling processes, the benefits and shortcomings of the process and technologies, the effect of these technologies on the project's outcome, and the lessons learned. This paper is intended for industry professionals interested in pursuing this type of innovative project delivery. This paper will also be of interest to researchers as it illustrates the limitations of emerging 3D and 4D technologies

3D and 4D modeling for design and construction coordination: issues and lessons learned

Automated generation of workspace requirements of mobile crane operations to support conflict detection

Identifying spatial-conflict free locations of mobile cranes that could minimize delays associated with crane relocation can result in productivity and safety improvements on construction sites. Existing approaches for identifying possible crane locations are based on two-dimensional (2D) work envelopes created by reasoning about the lift capacities of a crane during operations. Since spatial conflicts related to crane operations typically occur in three dimensions and during any period of operation, representing possible crane locations based on such 2D work envelopes can result in identifying some locations as good when in fact they might result in conflicts and missing possible locations that might be feasible. This paper presents an approach that determines possible locations of mobile cranes based on discrete-event simulation of crane operations incorporating dynamic behaviors of cranes. This approach starts with identifying a search space for possible crane locations by reasoning about a reachability radius of a crane determined by crane characteristics and the weight of the load to be carried. Later, it reduces the search space through boom-line intersection tests. For the remaining locations, it checks for potential spatial conflicts between building components and cranes moving in three dimensions and across time. Validation studies show that the developed approach can accurately identify possible locations for mobile cranes that minimize the relocation of mobile cranes and avoid potential spatial conflicts.

Simulation-Based Identification of Possible Locations for Mobile Cranes on Construction Sites

In complex construction projects, superintendents need to coordinate equipment space requirements and allocate workspaces to major pieces of equipment properly to avoid equipment related spatial conflicts. These spatial conflicts can cause delays at the start and at the completion of activities resulting in possible late completion of a project and in claims between involved parties. Currently, some commercially available 4D CAD systems enable spatial representations of the dynamic motions of equipment operations. This paper discusses the technical capabilities of a commercially available 4D CAD system to model, visualize, communicate, and coordinate spaces required by equipment. It summarizes the benefits and limitations of equipment space representations on a largescale construction project using a 4D CAD simulation system and states some recommendations for improvement.

Kevin Tantisevi

Papers

Automated generation of workspace requirements of mobile crane operations to support conflict detection

Simulation-Based Identification of Possible Locations for Mobile Cranes on Construction Sites

Assessment of the Capabilities of a Commercial 4D CAD System to Visualize Equipment Space Requirements on Construction Sites

Transformation of a 4D product and process model to generate motion of mobile cranes