Building Information Modeling Boosters Are Crossing That Bridge
Virtual design and construction tools are crossing over from buildings to transportation projects. Officials admit that 3D parametric modeling in the transportation sector has trailed the buildings sector, but they say change is afoot. “In 10 years, we will be living in a BIM world,” predicts Cosima Crawford, chief engineer for the New York City Transit Authority. “It’s our new reality,” she says.That reality has transportation teams tackling the same challenges their building counterparts are seeing in their transition to building information modeling. These include BIM technology issues, process change and institutional buy-in.
A few years ago, NYCTA’s parent agency, the Metropolitan Transportation Authority, began to use VDC, in which a project is built virtually in the computer using “intelligent” 3D software packages, for megaprojects, such as the $1-billion Fulton Street Transit Center and the $4.451-billion Phase One Second Avenue Subway project. VDC approaches help develop work phasing, passenger flows and placement of columns and piles. Visualizations “give [local businesses] an understanding of the construction process early on,” says says MTA’s William Goodrich, program executive for the Second Avenue Subway project.
“Time sequence is critical for any project that expands beyond one property area,” says Rachel Arulraj, director of the Virtual Design and Construction Geotech & Tunneling Technical Excellence Center with the Second Avenue project’s owners’ consultant construction manager, Parsons Brinckerhoff, New York City. On that job, a contractor’s Primavera scheduling software links to a single, shared database, which is used to analyze sequences and component interface issues. The model only is only detailed as needed, she adds. “VDC is not [just] a fancy tool—it’s an approach.”
BIM is also starting to infiltrate cost estimating. Eventually, “we’ll need to understand and link to as-built BIMs that will ‘talk’ to the maintenance staff,” says Judith Kunoff, NYCTA’s chief architect.
It’s not just in-house staff that will need to be BIM literate. “We’re now demanding it of our consultants,” says Kunoff.
Contractors are already onboard. “The more successful contractors expect it,” says Bob Dennison, chief engineer with the New York State Dept. of Transportation. “Once, we put out a project that didn’t have it, and they were disappointed.” Dennison says about 50% of all NYSDOT projects come with a BIM option. “We Webcast our bid openings. I can see a day when you receive your plans electronically, prepare and submit them electronically, and watch the process on your computer.”
NYCTA is about to take a big step in that direction. On Oct. 1, the agency, which uses software from vendor Bentley Systems Inc., Exton, Pa., will start all new projects using Bentley’s V8i platform, released last December, to create bi-directional data flow among project collaborators. The move is expected to solve BIM’s plagues: lack of interoperability and compatibility.
Jerry Zogg, a Wisconsin DOT roadway standards engineer, says contractors like using a VDC grading tool for automated machine guidance (AMG), which prompted research with the University of Wisconsin. The pilot program to grade projects using BIM, based on 2D documents given to contractors, resulted in higher-quality construction that was faster and less costly, he says. The end result is a statewide specification that gives grading contractors an AMG option.
WisDOT plans to develop a spec for roadway base courses and, then, paving. “From a design perspective, we have to take a look at hardware requirements and information technology capabilities,” says Zogg. “The industry is champing at the bit for us to move ahead more quickly.”
Not everyone has jumped on the BIM bandwagon. Some engineers think BIM is overkill for simple bridge jobs. Restructuring entrenched systems and cultures are also issues. For California Dept. of Transportation divisions, a bridge Website for submittals is “kind of archaic,” says Doug Dunrud, Caltrans’ chief bridge design engineer. Each division has its own server. “You take a bunch of papers and move them from one location to another,” he says. “Instead of sharing information, you’re handing over a baton.”
Nevertheless, Caltrans is gaining BIM speed. As far back as 1997, the department had asked PB to create 4D models, which also include job-task sequencing over time, and simulations for projects related to the Oakland-San Francisco Bay Bridge. But a more recent project, called Doyle Drive, to replace the south access road to San Francisco’s Golden Gate Bridge is the first state project using BIM as both a design development and...
...communication tool. Brady Nadell, PB’s Doyle Drive project manager, says Caltrans requested PB and its joint venture partner, Arup, design using BIM early in design. Caltrans is engineering the new road and bridge, while PB and Arup work on two tunnels. Caltrans submits 2D plan sets to the team for creation of 3D road models, and 4D models to represent scheduling for contractors. As far as BIM goes, “Doyle Drive is a real quantum leap,” Nadell says.
Changing an overall DOT culture takes time, says Dunrud. “It’s not like the private world, where you get a bonus for finishing quickly,” he says. But public demand for agencies to deliver projects faster and cheaper may help change that.
Open BIM standards from vendors would also help, adds Arun Shirole, senior vice president of civil engineer Arora and Associates PC. Shirole and Stuart Chen, a professor at the State University of New York at Buffalo, coined the term “BrIM” for bridge information modeling. Their team is working on a federally funded project to study integrated bridge project delivery and life-cycle management. “The idea is not [to use] the most optimal software,” he says. “Our goal is to use any commercial [packages] and link them.”
While owners may seek interoperability among software brands, Bentley has acquired various bridge software products and has been working to integrate them into a complete life-cycle package. “We’ve been focused for a year and a half on this,” says Gabe Norona, a Bentley senior vice president.
The vendor says it is trying to remain open to the idea of open standards for BrIMs. “Unless we develop approaches the majority [of vendors] agree upon, we won’t turn out useful stuff,” says Jackie Cissell, a Bentley spokeswoman.
As with building BIMs, bridge designers have had compatibility issues, says Craig Finley, founder of the Tallahassee-based firm that bears his name. An example is concrete analysis software that doesn’t link with rebar programs. “If [a design-build partner is] not used to these products, it’s a problem,” he says. “You can struggle to get equal results with different models.”
Alex Harrison, senior bridge technologist with CH2M Hill, Englewood, Colo., notes different software tools from a single vendor can be incompatible. “We’re still running different programs for different things,” he notes. “As you add on more layers, it gets more complex.”
But as technology evolves, users will find that the learning curve, even when working with different software products, is not as steep, says David Fagerman, transportation technical specialist for Autodesk, San Rafael, Calif. On Doyle Drive, PB uses Bentley products for design, Autodesk’s for merging models and Oracle’s for scheduling.
Austin Commercial, which is building a $27-million checkpoint for the Phoenix Sky Harbor Airport, used BIM to help place 90-ft-long, 50-ton steel-plate girders for a terminal bridge expansion over a road and under a parking garage. “The project is vertical in nature, but with extensive foundations, [it’s] like a bridge,” says Steve Jensen, Austin’s project manager.
The complexity made it a great candidate for BIM, he adds. The challenge was developing an accurate model of existing conditions, including adjacent structures and underground utilities. “Working through these issues virtually is far better and cheaper” than solving problems in the field, he says.
Dennison hopes BIM will draw in the next generation of transportation experts. “It’s how you will attract people to this business,” he says.
