A digital mockup created with BIM software compared with the actual construction of the modeled building element.
This BIM model shows a 230,000-square-foot commercial building that utilized several construction methods, including steel structure, cast-in-place concrete, precast concrete and tilt-up.
Accountability is a frequently touted term in the design and construction industry. Owners and developers want to eliminate finger-pointing between members of the design and construction teams and have confidence that everyone can work together to ensure a successful completion of their project.
New technologies are constantly emerging to make this challenge easier. One technology that is assisting design and construction professionals with the coordination and collaboration process is Building Information Modeling (BIM) — the creation and use of coordinated, internally consistent, computable information about a building project in design and construction. BIM allows elements of a building to be evaluated before the structure is ever constructed, which can increase project efficiency, decrease overall cost, improve the project delivery schedule and generate the best product possible. All of these benefits are critically important to owners and allow the entire design and construction team to be accountable.
What is BIM?
Although BIM is different for everyone, in its simplest form, BIM is the creation and use of computable information from design to construction.
"BIM is not an 'on-off' switch," said Neil Rosado, BIM Specialist at Saunders Construction of Centennial, Colo. "While the ultimate use of BIM is a digital file of as-built conditions for the owner, many are using BIM at a smaller scale to detect collisions or just model the project. The key to success with BIM is understanding that it is an information rich digital representation of a project."
For nearly two decades, many in the industry having been using Computer-Aided Design (CAD) for projects. BIM is the next evolution of CAD. BIM provides constant and immediate information on the project design, schedule and cost that is reliable, integrated and fully coordinated with the entire project team. Among the many advantages of BIM are increased speed of delivery of key project deliverables, better coordination efforts among all parties involved, and decreased cost due to reduction of errors.
The two key concepts of BIM are: 1) keeping all aspects of building design in digital form makes it easier to update and share information, and 2) creating real-time design data can save significant amounts of time and money and increase project productivity and quality. BIM also provides a digital picture of the building process to assist with the exchange and interoperability (the ability for complex systems to work together) of information in a digital format and data can be viewed as a 3D model or traditional 2D construction documents, depending on the user's needs.
BIM has grown in use in recent months as architects continue to drive team members to employ it on projects. Although many think of the tool as a benefit for architects and engineers, contractors are also realizing the benefits of the system. "Our team has used BIM for estimating, during coordination meetings and for constructability analysis," said Rosado. "When BIM is used successfully, there are less change orders, because design changes can be made before groundbreaking."
While there is an upfront cost to add the software to a firm's toolkit and train employees, the investment could pay tremendous dividends. "For projects where use of BIM is appropriate, I estimate that for every hour I spend in front of the computer modeling the project, our firm can save six hours in the field on potential issues," said Rosado. "This is a substantial benefit to owners in terms of schedule and cost."
Drawbacks of BIM
Just like with every new technology, there are pitfalls that needed to be avoided when working with BIM. "The main concern is the old adage 'garbage in, garbage out,'" said Rosado. "The model is only as good as the information that you input into the system."
Beyond the costs of training and software purchase, companies must also make an investment to purchase a computer that can run a BIM model. Training costs are relatively low, because the system is intuitive. Another concern is model management. It is critical that all team members continue to make changes in the model and not just sketch them on paper.
According to Rosado, the first step when working with BIM is to determine what you want to get out of BIM. "The best way to learn about BIM is by speaking with others in your local community to determine what they are doing with BIM," said Rosado. "Determine how many are using BIM in your area and do extensive research to determine which tool is best for your firm."
It is also important to have buy-in from all levels of your firm. At Saunders Construction, they established a cross-sectional team that included estimators, project managers, project engineers, superintendents and executives to determine how to make BIM useful for all levels of the firm.
"For Saunders, our initial low-hanging fruit on BIM was collision checks, because it was beneficial to pre-construction services and in the field," said Rosado. "We began by using mechanical/electrical/plumbing, structural and architectural models to do cross checks. This greatly assisted our preconstruction and estimating team, because they were able to perform their jobs faster and more efficiently."
As with any new technology, it is not best to use BIM for the first time on a marquis project. Rosado advises that firms even model a completed project to get a feel for the software and not worry about schedule constraints. Further, Rosado recommends that BIM is not used for the first time on a remodel or reuse project. "If the original building was not modeled, it could be a very time intensive task to input all of the information into the software."
Tilt-up and BIM
Site-cast tilt-up construction is particularly well-suited for BIM. "With tilt-up, each panel has so many parts and you could view each panel as its own project," said Rosado. By using BIM, tilt-up professionals can generate lift drawings to maximize efficiencies.
One example of a BIM success story on a project is the Evie Garrett Dennis Campus, formerly known as the Green Valley Ranch E-12 Shared Campus in Denver, Colo. Denver Public Schools selected tilt-up as the construction method of choice for the 185,743-square-foot facility because of the schedule advantages the method affords. Tilt-up was four to six weeks faster than conventional steel construction.
When Saunders Construction — the general contractor for the project — secured the job, the project was already being modeled using both Revit Architecture and Revit Structure. This allowed panel shops to hit the ground running. "The design of the panels and the exterior skin really became the catalyst for the completion of the building design, as many things had to be reconciled through the panel shop drawings, including locations of embeds for structural steel members, mechanical and electrical blockouts and penetrations, window/door opening locations, etc." said Rosado. "The tilt-up shop drawing process really set the pace for the balance of the design."
Using BIM brought several advantages to the project. First, it allowed the team to view an architecturally and logistically complex project in 360 degrees and provided an integrated approach to the design for the project team. "Visualization and modeling enabled the process of accurately locating dimensionally and in elevation thousands of structural connections (embeds) within the panels," said Rosado. Second, BIM provided a rapid understanding of the architecture and structure by viewing the building in 3D and allowed Saunders Construction to correct errors before they were realized in the field, saving time and money. The architectural and structural models will be used to coordinate mechanical/electrical/plumbing design and initiate clash detection prior to installation in the field.
Rosado explains that the key to success when working with BIM is creating a good quality model that will save dividends on the backend. "Trying to work with a poor model or haphazardly creating your own is a path to disaster," said Rosado. "The productive gains, the associates time saving and eventual dollar saving is only as good as the model."
In addition, models need constant maintenance because they are a living document. Making sure you are working with the most accurate set of information can be a time consuming task. "Just as we measure twice and cut once, we should have trust in the model, but we should never have faith in the model," said Rosado.
Looking toward the future
In many markets across the country, BIM is already becoming the platform of choice, so it is important to begin understanding the software or your firm could get left behind. As more companies pursue ways to "go green," some are envisioning paperless jobsites and BIM is a tool that could make this a reality. "In the coming years, we will see the position of 'model manager,'" said Rosado. "As more firms incorporate BIM into their toolkit, it will be critically important to have an individual coordinating all the data to make BIM work at its optimal level."