This summer, the Sonoma-Marin Area Rail Transit District (SMART) will begin construction of a clean-diesel passenger railroad through Sonoma and Marin counties in Northern California. Once complete, the 70-mile project will include 14 stations, a comprehensive operations and maintenance facility, and approximately 56 miles of multi-use pedestrian and bike pathway. Most of the funding for the $690 million project will come from Measure Q, which passed a one-quarter percent sales tax increase in 2008.
For help producing the initial 20-percent conceptual design package for the railway, SMART turned to several engineering firms, including AECOM for project management, PGH Wong Engineering for track design, and Winzler & Kelly for hydrology and hydraulics analysis. Cinquini & Passarino Land Surveying was responsible for surveying the entire rail corridor. The team used an intelligent, model–based design process and digital workflow to produce the conceptual design package.
Following completion of the conceptual design package, SMART’s board of directors faced some tough decisions. “The recent economic downturn reduced projected revenues,” says Gregg Jennings, P.E., senior rail engineer for SMART. The projected shortfall forced SMART to revise its original plans and build the project in stages. This approach will help SMART adapt to the anticipated shortfall and deliver the railway’s first fully operational segment for public use by fall 2014.
A fast-paced, challenging project
To take advantage of favorable market pricing, SMART requested delivery of a 30-percent design-build package for the project’s initial operating segment (IOS) on a compressed, three-month delivery schedule. When complete, the 37-mile IOS will connect San Rafael and Santa Rosa, the area’s two largest cities. “My role was to oversee the project consultants as they put together the plans and specifications for the design-build package that we will use to select the design-build contractor who will complete the design for and, ultimately, perform all construction on the IOS,” Jennings said.
A relatively young organization, SMART initially lacked a clear set of baseline design standards, specifications, and workflows. “One of our biggest challenges was trying to establish these types of things, while simultaneously putting out a design-build package on a compressed schedule,” Jennings said. The standards, specifications, and workflows would help ensure coordination among the approximately 60 geographically dispersed engineers working on the project.
The sheer scope of the project presented another significant challenge. “Any time you’re dealing with a long, linear project, you need a system that can manage a very large geographic area and multiple coordinate systems, file formats, and data structures,” said Kourosh Langari, a civil engineering consultant on the SMART design team.
To complete the bid package, the team used a model-based design process and a variety of products, including AutoCAD and AutoCAD Civil 3D software for track design and corridor modeling, and Autodesk Buzzsaw software as a service for management of models, data, and documentation. Civil 3D is the civil engineering design solution from Autodesk for building information modeling (BIM) — a model-based process that helps building and infrastructure professionals plan, design, and build projects faster, more economically, and with less environmental impact.
One of SMART’s first tasks was assigning project responsibilities to members of the design team — all of whom had used Civil 3D software before, though never on a railway project. That factor, together with the compressed schedule, led Jennings to assign all track design to PGH Wong. “I wanted them to focus strictly on engineering,” Jennings said. SMART assigned all plan production to Winzler & Kelly. “We believed that running production in parallel with design would speed up the design process and give us more flexibility. Model-based collaboration tools were definitely a key factor in making this approach viable.”
After assembling the team and assigning roles, SMART and the consultants turned to development of the baseline standards, specifications, and workflows. “We started looking at the configuration and establishing templates that would be utilized by engineers using AutoCAD and, eventually, Civil 3D,” Langari said. For help creating the templates, the firms relied partially on existing metadata created by large state agencies such as the California Department of Transportation. SMART staff was responsible for certifying these templates and ensuring that no unnecessary or unwanted changes were made. The certified templates resided on Buzzsaw, where SMART and the design team could access the most current copies at any time.
Once the team had established the templates, PGH Wong and Winzler & Kelley updated and reorganized the existing conceptual design data, bringing all alignments, switch points, culverts, signals, and more into agreement with the newly created templates.
Next, Cinquini & Passarino used Civil 3D to set up a digital terrain model (DTM). “On a project this large, you have to have a good base map,” Langari said. The team created the base map from a number of sources, including airborne LIDAR, conventional survey data, and as-builts from local cities and counties. “In some cases, we had to do additional potholing to identify underground utilities. Essentially, our DTM became a mass product of all these various sources of survey data,” Langari said. Cinquini & Passarino provided a repository for the various survey data and verified the data against the Civil 3D templates and styles on Buzzsaw.
Upon completion of the DTM, PGH Wong began work on the rail corridor design. Based on information learned during the conceptual design phase, the design team decided to break the corridor into a series of 18 adjoining, two-mile tiles, which served as background and vertical reference design data. Phelps and Langari then set up a file management system on Buzzsaw to enable multiple engineers to populate the individual segments with design data simultaneously.
In addition to housing the SMART templates and standards on Buzzsaw, the team also used it to store all base map files, individual objects, and production sheets. “Nothing lived on individual machines or servers,” said Colby Phelps, senior civil designer at Winzler & Kelly. “That was a very strict rule.”
Throughout the project, Buzzsaw served as the team’s primary collaboration tool. Buzzsaw enabled the team to set access permissions, history policies, and automatic notifications. These types of capabilities helped the team collaborate more efficiently, while minimizing unwanted design changes and errors. “The technology served as an engineering document management system that enabled everyone on the team to design to a single standard,” Langari said.
The team also used the data shortcut functionality in Civil 3D to help keep drawings in synch and inform the engineers whenever an object was updated. “We were operating in a very dynamic environment with many changes to the design requirements as the project evolved,” Langari said. ”With help from Civil 3D and Buzzsaw, our model was always up-to-date.”
“With 60 engineers and a compressed schedule, file sharing could have been a big challenge on this project,” said Phelps. With help from model-based tools, Langari and Phelps broke out pieces of the track corridor into a wide variety of adjacent base files, including alignments, right-of-way, station platforms, signal equipment, retaining walls, and bridge structures. This approach made it easier for multiple people to work on the corridor at once — a necessity on such a fast-track project.
Smooth transition to a better final product
In the end, Winzler & Kelly used the completed digital design model for plan production. “By splitting track design and plan production between PGH Wong and Winzler & Kelly, we enabled engineers to concentrate on their own areas,” Langari said. “As a result, the final product came out much more consistent, cohesive, and homogeneous than it would have with multiple firms working on the drafting.”
On traditional projects, design-build contractors often must reverse-engineer the models they receive — a waste of valuable time and resources. The team anticipates that the design-build contractor will be able to use the model and the established file structure housed on Buzzsaw to reconstitute the design environment in its shop in a matter of hours or days instead of weeks. “The beautiful thing about our approach on the SMART project is that the design-build contracting firm will have everything it needs to begin designing almost immediately,” Phelps said.
At project’s end, the team delivered the 30-percent design-build package on time and under budget. The bid process is currently underway. “We provided a digital design model and a digital document package to SMART by the required deadline,” Phelps said.
“The engineering on the design-build package is so tight that the contractor won’t really have to do any reverse engineering,” said Langari. “They’ll be able to hit the ground running and progress toward 60- and 90-percent design packages.”
“The consultants came in well under the projected budget,” said Jennings. “Model-based design played an important role in helping us control the information that we presented to the team and to provide as much guidance as possible up front.” This approach took a little more time initially, but yielded impressive results. “We realized at least 50 percent efficiency in both time and cost later in the project.”
“We created a system that helped us work faster and virtually eliminated the need for workarounds,” said Jennings. “By really being strict about it, we made it very easy for these guys to do their jobs and to find out real-time answers to any questions they might have.”
“The biggest benefits of this model-based approach were collaboration, scalability, and the dynamic environment,” Langari said. “It helped us collaborate more effectively among team members, scale the solution up or down as needed, and more easily modify design features on the fly. Overall, it was a very positive experience for the team members.”
On future projects, SMART and the consultants look forward to expanding their use of model-based tools into a more holistic BIM for infrastructure process that not only includes design and documentation, but also uses information from the model to gain greater insight into project performance through visualization and virtual construction. “With the good work we performed on the IOS, we’re well prepared — and very committed — to get even more out of the model on future projects,” Jennings concluded.
Karen M. Weiss, P.E., is AEC Industry marketing manager – Transportation & Land for Autodesk Inc. Gregg Jennings, P.E., is senior rail engineer with Sonoma-Marin Area Rail Transit.