×

AEC

Army Corps Drawn to BIM Design

22 Oct, 2008 By: JoAnne Castagna

---

Corps of Engineers' use of BIM results in considerable time savings for its design team and impressive cost savings for its customers.

After the bombing campaign ceased in Kosovo in 1999, the U.S. Army Corps of Engineers was called upon to design and build two camps for its customer, the United States Army, which was there performing an operation for NATO. Camp Bondsteel was designed and built from scratch; Camp Monteith was designed and constructed on the site of a Serbian base that had been largely destroyed.

David Rackmales, a structural engineer with the Corps of Engineers' New York District found himself working in a tent in the dead of winter in Kosovo designing the camps with a team of project managers and engineers. "We were working very closely in an intense, energized environment," Rackmales said.

Rackmales had that same feeling recently while taking part in a building information modeling (BIM) workshop at the New York District facilitated by Bentley Systems, the Corps of Engineers' primary vendor for BIM software.

It happened that the New York District design team had been assigned a project involving three buildings for the U.S. Military Academy at West Point, New York. These buildings had to be designed at the same time the workshop was taking place, so the team took advantage of the opportunity to design the structures during the BIM workshop, which also served as a way to test the BIM program. As the workshop progressed, the benefits of using this software as a team, including the savings in money and time, became more apparent.

BIM is a collaborative approach to design that involves integrating the various disciplines to build a structure in a computer virtual environment. The process allows the design team to work effectively, particularly when identifying potential problems before they arise during construction. "We came together as a team," said Rackmales, who served as the BIM manager.

In the Corps environment, BIM teams work side-by-side, with a focus on a single design project. The designs are completed at a rapid, intense pace and generally much more quickly than if the designers worked individually at their respective workstations, which can be in different geographical areas in the country.

Each team member is equipped with a state-of-the-art desktop computer, which is networked with all the others, and which contains BIM 3D modeling software with discipline-specific files for various design disciplines and a master file. The buildings they design are projected onto a large screen, enabling the team to virtually walk through during the design process.

"There's an old adage for designers that says, 'Build it on paper first,' " Rackmales said, which basically means the designer should work everything out on paper before excavating and buying construction materials. "Now that we are in the 21st century, we are building things virtually in a 3D environment; that is, we're building it in electrons first."

The team includes structural engineers, architects, mechanical engineers, and electrical engineers who were eager to learn the new software and BIM design processes. The team has more than 20 years of experience using two-dimensional (2D) CAD for creating construction plans. They also have considerable experience with engineering analysis software, but the BIM software, and the experience of working together, were completely new to them. The major benefit of using BIM is the cost savings to the Corps and customers.

"The real serious money and scheduling savings with BIM comes during construction. When we build something virtually beforehand with BIM, we've already resolved 99.999% of any construction issues," Rackmales said. "This seriously reduces the number of requests for information from the field offices during construction. Information requests can result in construction modifications, emergency redesigns, and work slowdowns, which can cost us and our customer considerable money."

Benefits of BIM
A BIM model is a living design. Unlike a typical CAD model made up of lines and points, in a BIM model, the lines, points, and other objects all contain design information that can be used and modified over the lifetime of the building, from initial concept design through construction and ultimately facility operations and maintenance.

For example, a drawing of a steel beam in a CAD design may just be a collection of lines and points, but in a BIM model, in addition to those lines and points, this beam will have information linked to it such as the beam's cross-sectional dimensions, weight per unit length, and other engineering properties. This beam may also have information on its material make-up, pricing information, and possibly its manufacturer.

In the case of an entire building, the BIM model stores this and more information for every single element of the project, all of which can be extracted to generate plans, elevations, sections, schedules, material quantities, and cost estimates.

Seeing in 3D. Not only do BIM models have information behind them, but they also allow for more detail than is possible in 2D drawings. One of the buildings the New York District BIM team designed included a staircase leading to a door. They viewed the staircase in both 2D and 3D. In 2D, the staircase appears to lead to a door, but in 3D, it was discovered that it really led right into a wall. The team's architect and structural engineer were able to readily resolve this conflict that otherwise may not have been discovered until late into project construction.

Team effort. As BIM manager Rackmales said, "We're working as a team, sharing our discipline-specific BIM files through a master file, building virtually together. We can see each other's work and spot problems and correct them right away. Any designer can point out that something either doesn't look right or needs some clarification from a different design discipline. We'll then investigate the issue as a team."

While designing one of the West Point buildings, the team's mechanical engineer realized that the ceiling height was higher than it had to be and quickly coordinated with one of the team's architects to address the issue. "The customer would have been heating more room area than necessary and paying for it," Rackmales said.

The team also made adjustments to the building heights. During the workshop, the team realized that the conceptual design plans, created prior the BIM workshop, conflicted with building height requirements, almost leading each team member to design his part of the building at different heights! Had this not been corrected, it would have resulted in wasted time, money, and untold confusion, not to mention the implications of addressing such a problem during construction.

The team also optimized the size of garage doors for the buildings. They realized that different sized doors were shown in the conceptual design plans for all of the buildings and agreed to use one size for all. "BIM made our job easier because we were able to design one best-fitting garage door frame instead of several different ones, which would have added cost and confusion to those performing the construction. It's easier for the contractor to purchase the same material and just repeat the same frame rather than worry about constructing several different frames.

"The more building elements we reduce from unique to repetitive, the more we reduce any potential confusion during construction, and right away we've eliminated a possible request for information -- or worse, a claim."

After working as a BIM team for three weeks, the designers and engineers completed the same amount of design work that would normally take about three months or longer. After the workshop, the team created the design plans in less than a week, a task that typically takes a month and requires extensive collaboration with team members from various locations.

The Corps of Engineers' headquarters is implementing BIM Corps-wide. Several Corps districts have used BIM successfully on their civil works and military projects.

The Corps also maintains an ever-increasing repository of collected BIM designs, providing Corps districts the tools to efficiently adapt any project to meet its customer's demands.

Rackmales found his district's BIM workshop experience to be very rewarding and his team just as tight as the one in Kosovo, remarking, "It was the ultimate team-building experience. Our team came out of the workshop as a well-oiled BIM machine!"