When coordinating design, construction, and commissioning services across multiple disciplines, leveraging building information modeling (BIM) and virtual design and construction (VDC) processes can ease a project’s overall development.
When performing design, construction, and commissioning services on a project, the coordination and integration aspects across multiple disciplines typically have a substantial impact on the project’s outcome. Building information modeling (BIM) is frequently used when working across many areas including mechanical, electrical, plumbing, and fire protection (MEP/FP) engineering as well as with other stakeholders, such as architects, contractors, etc. Virtual design and construction (VDC) is a project management process where multidisciplinary models of a design and construction project are used to show project teams “virtual” computer-based models and descriptions of the project. Leveraging BIM and VDC processes allows all project stakeholders to align project goals and objectives sooner by following one plan.
Beginning with the design phase, using 3-D intelligent models helps achieve many tasks on a design/ construction project beyond serving as just a visual. With the advanced design software applications that are available today, the design’s 3-D models are used to produce the contract drawings that will be issued for construction. This connection between the model and drawings allows designers to efficiently create and update the plans, elevations, and sections that are necessary to convey design intent to other project stakeholders. Other benefits include the creation of door, window, and equipment schedules and providing a connection to the project’s specifications. These 3-D intelligent models help convey design intent, but they also can be used to perform other key project management activities as the design progresses to the construction phase. For example, a 3-D intelligent model is shown in Figure 1. With 3-D intelligent models at the core, BIM and VDC processes help architects, engineers, and contractors effectively collaborate to meet a client’s expectations by delivering projects on time and on budget.
Creating the BIM execution plan
Successful project execution begins with proper planning. A standard industry tool that is widely used by the architecture, engineering, construction community to plan how to use 3-D intelligent models during the design, construction, and operations phases is a project execution plan (PxP). This plan may also be known as a BIM execution plan. The purpose of this plan is to document the planned uses across the project lifecycle to all project stakeholders. It has a specific focus on the technology aspects of using 3-D intelligent models to produce the design information, leverage the 3-D intelligent models to build the work in the field, and when part of the scope, turn over the 3-D intelligent models to the client for operations and maintenance.
The PxP is a living document that is continually updated through the life of a project. Key aspects of the execution plan include an overview, information about the project, key project contacts involved in the technical delivery, project goals, objectives specifying the intended uses of the 3-D intelligent models during each phase, and process maps for the uses defined in the plan. When diving into the technical details, it is important to define the level of development (LOD) for the 3-D intelligent models at each phase, the specific software and versions to be used, the workflows for documenting changes to the 3-D intelligent models and drawings, as well as the collaboration procedures necessary to coordinate and integrate the individual project teams.
There are many industry standard applications for VDC including:
Existing conditions modeling·
- Cost estimating (5-D)·
- Phase planning (4-D)·
- Site analysis·
- Design reviews·
- 3-D coordination·
- Site-use planning·
- Construction system design·
- Digital fabrication·
- 3-D control and planning·
- Record modeling/turnover deliverables· .
Existing conditions documentation
To facilitate integration with an existing facility on retrofit and renovation projects, 3-D laser scanning is a valuable tool for documenting and capturing existing conditions efficiently. 3-D laser scanning systems collect data at a very high speed, some capturing more than 1 million measurements per second. Today’s systems also capture additional information, including 360-deg. high dynamic range (HDR) photos, survey targets to measure and verify positional accuracy, and other relevant environmental conditions. An image of the 3-D laser scanner used at the Washington, D.C. water main process train project is shown in Figure 2.
Once the laser scans are registered and stitched together, the architect, engineer, and contractor now have access to very accurate and timely information about the existing facility to use during design and construction activities. This alleviates the uncertainty of unknown site conditions, which typically results in conflicts or errors tying into existing conditions during the design phase.
In addition to leveraging the 3-D laser scans, BIM elements may also be extracted from the 3-D laser scans collected in the field. This process is known as “Scan” in BIM and provides many benefits to the design and construction teams. 3-D laser scanners produce large files, which are not always efficient to use based on the individual’s experience with them. The process simplifies the large files into more usable 3-D intelligent models of the existing conditions to use by the design team. They are produced in the same formats that the engineers and designers use to produce the new design elements. This allows them to reference the 3-D intelligent model’s existing conditions and produce a more accurate design that integrates better with the existing facility. A combined view of a 3-D laser scan and one with a BIM overlay is shown in Figure 3.
Drawing production
Using BIM to produce contract drawings is a very efficient method, for example, with Autodesk Revit software. Many of the design authoring platforms that are used have a direct connection between the 3-D intelligent model and the 2-D drawings, which are a reflection of the model. As the 3-D intelligent models for each discipline are developed, the plans, elevations, sections, and details are extracted from the 3-D intelligent model to create the 2-D views. The 2-D views are directly connected to the 3-D model, so any updates to either model are updated in the other.
In addition, each discipline’s 3-D intelligent model is referenced to all other disciplines. For example, the HVAC designer needs to continuously maintain awareness of the configuration of the building architectural and structural components. By linking to the architectural and structural 3-D intelligent models, the HVAC designer always has the current version of those designs. This allows the MEP/FP designers to monitor the other disciplines for changes to systems and see conflicts in nearly real time as the design evolves.
Design coordination
Clash detection and management is a valuable process for coordinating spatial requirements and conflicts between disciplines. This process allows for all design disciplines to identify and resolve conflicts as the design progresses. Resolving these conflicts between the building systems earlier during the project lifecycle helps both the design and construction teams. The benefits include fewer modifications to building systems during shop-drawing development, which may affect system performance. Additionally, the construction team benefits from the resolving of construction issues during the design phase, which will result in fewer field conflicts during construction. Ultimately, the design and construction teams are more tightly integrated, and this process enhances the coordination to resolve issues that typically are not addressed until later.
When leveraging clash detection in a project, it is important to document the details in the PxP. For example, determining the clash ground rules and priorities at the discipline level before the project starts is a critical step in the process. This provides each discipline with the hierarchy before design or construction begins and allows the clashes to be tested and resolved in a logical sequence. This results in less rework because everyone understands the priorities from the beginning, the tests are conducted in a systematic way, and there are no redundant clash tests being performed. An example clash test sequence is shown below in Table 1.
4-D simulation to a 3-D intelligent model
Leveraging the connection between a 3-D intelligent model and project schedule provides many benefits when coordinating the sequence of events required to successfully build a facility. As previously mentioned, clash management aids in resolving spatial conflicts, but traditionally does not include the aspect of time. Adding the fourth dimension of time to a 3-D intelligent model allows all team members to visualize the construction sequence and assess the project schedule for needed logic corrections to successfully execute the project.
This digital rehearsal allows the construction team to review the baseline schedule and sequence of activities to make sure the schedule logic is sound. Key elements of integrating the 3-D intelligent model and project schedule include software selection, aligning the work breakdown structure (WBS) and cost estimates with 3-D intelligent model elements, and structuring the 3-D intelligent models and data in an efficient way to link them back to activities in the schedule. Other considerations include determining the update frequency for rerunning the 4-D simulation based on changes to the schedule, necessary deliverables for the task, and any review meetings that will leverage the simulation to help keep the team in alignment. It is important to capture and document the details of how 4-D simulation will be performed on a project in the PxP.
Cost estimating with BIM
Leveraging the “I” in BIM allows the construction team to use 3-D intelligent models in additional ways. The 3-D intelligent models that are used contain a variety of data that can be used for downstream uses. Leveraging the 3-D intelligent models for quantification is a cost-effective way to extract permanent material quantity takeoffs for cost estimating purposes. Construction estimators typically spend a lot of time measuring, counting, and quantifying information contained in the contract drawings to input into cost estimating software. When used properly, it allows the construction team to automate this traditionally manual, labor-intensive process.
While this process does create efficiencies, it also requires proper planning and coordination between the design and construction teams. Make sure the proper data is included in the 3-D intelligent model and is accessible to the construction team when quantification is performed. The PxP will include the details regarding this process and how it is intended to be used on the project. Key elements of this process include aligning the WBS of the cost estimate with the data required in the 3-D intelligent models and verifying software applications and versions, cost accounting codes, and necessary units of measure for quantities and intervals at which quantities will need to be extracted.
3-D coordination
As the design approaches completion, the construction team aligns with and procures trade contractors to perform the field construction. The process of performing 3-D coordination is similar to the design coordination process, but it differs slightly given the enhanced LOD that trade contractors need to perform their work. In many cases, the construction models developed by trade contractors are created in specialty software platforms. The main reason this occurs is that MEP/FP contractors use software in different ways than the designers. For example, a fire protection contractor may leverage generating automated pipe cutting and spool from the software platform. This requires integrating the software application and computer-aided manufacturing (CAM) systems to assist with prefabrication.
As these fabrication models are developed to produce shop drawings and assist with prefabrication, it is imperative that the models are coordinated to resolve clashes before work is performed in the field. Trade contractors will typically model additional elements that are not in the design models. Some examples are small-bore piping and conduit; actual cable tray sizes and fittings; HVAC equipment; ducts and fittings; and fire piping, risers, and actual fittings per the shop drawings. As the models become more detailed, clash detection and management is required to manage dimensional changes to these systems as the actual sizes, routing, and layouts are further defined.
The process of establishing clash priorities during design may differ from the priorities needed during construction. Some of the variables that go into construction prioritization include subcontract value, estimated labor hours onsite, long lead equipment procurement, and the logic built into the project schedule. These items need to be addressed as the construction team onboards new trade contractors, integrates them into the project, and make updates to the PxP during this process
Dimensional control with models
Once the fabrication models are coordinated, it is paramount that the actual construction in the field matches the coordinated models. When this does not occur, elements are not installed per the coordinated model and result in physical conflicts, which delay construction activities and increase the cost to build the project. The method for layout, verification, and documentation of installed components involves various types of field-survey technologies.
A key aspect of maintaining positional accuracy of installed components is planning. This involves identifying trade-contractor capabilities regarding the layout, maintaining an accurate survey-control network, mapping the process for taking the fabrication model data to the field for layout, and the quality assurance/ quality control process for confirmation that components are installed per plan. This will ensure that all previous efforts performed by the design and construction teams are properly executed during construction and provided back to the engineer of record for closeout documentation.
Mobility
While many of the previous topics are centered around using 3-D intelligent models during design and construction, the critical success of a project is defined by how the work is executed in the field. Using 3-D intelligent models to perform layout and access specifications, contract and shop drawings, equipment data sheets, and other necessary information while in the field is paramount. There are a variety of software platforms that allow for field mobility with tablets and smartphones.
Take, for example, BIM 360 Field software, which is a mobile-centric platform that allows field personnel to capture necessary information in the field at the point of interest via a mobile device. The software is used on a tablet that allows the user to fill out checklists, create issues, capture photo documentation, update equipment status, and fill out daily reports—with no internet connection required in the field. Upon returning to the office, the user then synchronizes the data with the project by uploading all information gathered in the field and downloading updates from other users and administrators.
This centralized approach allows a tighter integration between the design, construction, and commissioning teams, as well as streamlines access to a single version of the truth for all project documentation generated and captured during field construction. Having all of this information captured and easily accessible provides many benefits during construction, but also prepares the project team to provide all necessary documentation to the commissioning team for project start-up and closeout.
Building commissioning
When commissioning any type of facility, it is imperative that the documentation generated and captured during design and construction is available for the commissioning team. Contract specifications and drawings, shop drawings, equipment data sheets, warranty information, and even 3-D intelligent models if required by contract, need to be easily accessible for the team to perform commissioning operations. On many projects, this information resides in multiple storage locations and is difficult to find at the end of the construction phase.
This effort is a monumental task if not planned properly early in the project. Integrating the needs of the commissioning team into the PxP is an important step in this process. Working with the team to understand the plan for start-up and commissioning and knowing what deliverables they need to efficiently perform their tasks, where those items will be stored, and when they will have access to the final versions of those documents must all be addressed during preconstruction.
When coordinating design, construction, and commissioning services across multiple disciplines, leveraging BIM and VDC processes can ease a project’s overall development. It is paramount to implement the proper BIM/VDC uses that will benefit a project, provide the intended value, and meet the client’s expectations.
