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Trimble Quantm Optimizes High-quality Alignments for Challenging Wind Farm Road

Optimized, highly-viable 3D alignments, performs more in-depth route optimization, and generates accurate cost analysis in days compared to months with Trimble Quantm Desktop

Mortenson Construction is a well-known and extremely respected general contractor in North America that has a vibrant history dating back to 1954. With offices nationwide and a global presence, the company has expertise in commercial building, green/sustainable construction, and virtual design and construction (VDC). The organization serves nearly every industry, providing innovative and superior construction services for civil and electrical construction, education, healthcare, manufacturing, sports, renewable energy facilities, and much more.

Today, Mortenson Construction is recognized as one of North America's principal full-service wind power contractors and also as the leader in renewable energy construction. In early 2012, Sera Maloney, Professional Engineer and Senior Integrated Construction Manager for Mortenson's Renewable Energy Groups, was tasked with compiling a proposal for a wind farm project in the Canadian Rockies. The project involved installing approximately 100 wind turbines and the associated infrastructure.

In a nutshell, the team was challenged to create a design plan and road network that would string five mountain ridges together, with the chosen routes giving the best access to each ridge for installing the turbines. Maloney anticipated 80 to 90 kilometers of road building for this project with varying widths and grades. Suitable grades needed to be maintained whenever possible due to the complex turbine machinery and required construction equipment. The rugged and mountainous terrain presented unique design constraints and considerations.

To tackle this colossal effort, the team considered applying conventional alignment planning techniques. Mortenson team leaders were determined to deliver a highly attractive and competitive proposal, including innovative plans and alignment options - all without adding significant time, cost and burden to the process.

“In the proposal stage we were given basic vertical alignment options," said Maloney. "With thousands of acres in the mountains, it's not like you can walk the entire project and effectively grasp where turbines and alignments should be. We wanted to differentiate ourselves from the competition and intelligently look at alternatives that would uncover cost savings for our customer.”

Previously, in order to create viable alignments for road networks, the team had to review contour maps of an area and create models along any chosen route. They would then run profiles and fit an acceptable grade line to those profiles. For any given alignment chosen, designers had to run cross sections along that alignment to see what affect a side slope would have on the route location. They then had to rerun the horizontal and vertical alignments to reflect those changes. Jessica Dugger, Professional Engineer and Senior Integrated Construction Coordinator on the team, emphasizes that this iterative process is repeated frequently, as different inputs are added. In essence, any changes to the grade or slope had to be filtered through the alignment plan. A hyper-steep grade, for example, can require that a crane must be broken down to move to the next location. Proposed switchbacks and grades also impact how wind turbine delivery vehicles can get to that area. This can influence what equipment can be used and where dump and borrow locations are selected. This will also impact time and costs across all aspects of the project.

Looking to create a highly competitive solution, Mortenson Construction selected the Trimble Quantm Alignment Planning System. The Quantm system automates the complex calculations required to investigate a range of alternative alignments and aides the analysis and decision-making process. The team selected Trimble Quantm technology because it helps designers and engineers to more efficiently analyze routes, generating optimal 3D alignments for road projects. Useful at all phases of the construction lifecycle - from proposal, to design, to construction - the software simultaneously considers a range of factors and parameters involved in development of alignment options. The system considers topography, engineering criteria, geology, costing inputs and environmentally sensitive areas as part of the planning process, rapidly generating feasible alternatives.

The Mortenson Construction team participated in an interactive demonstration with Trimble trainers to learn the system and provide some ROI analysis. The team was impressed with the usability of the Trimble Quantm system and the clear potential in terms of reduced planning times and more competitive solutions for their customers.

Using the Trimble Quantm System, the Mortenson VDC team was able to quickly start generating new alignments using previous studies that determined where the turbines should be placed in order to maximize power production. Roads then have to be constructed to facilitate turbine placement in accordance with those studies. In just a day and a half using the Trimble Quantm System, the VDC team used their existing wind farm project dataset and project parameters to generate approximately 300 potential alignments for the 80 to 90 kilometers of proposed roadwork. Dugger and the team created nearly 30 scenarios looking at a range of different considerations including road-width, grades and various start and finish point locations. While they may only use a handful of these alignments in their final proposal, the team can be confident that the selected alternatives are the result of a very thorough analysis enabled by the application of the Trimble Quantm System.

Dugger was responsible for much of the CAD design work on the project and believes one of the biggest benefits of the Trimble system is that it gave her the ability to consider a far greater number of viable options than she could have otherwise. This also meant she was maximizing her efforts by considering in detail only the more viable alternatives produced by the system. Minor geometric edits were made to the preferred options while simultaneously evaluating the quantity and cost impacts "on-the-fly" through the real-time analysis. The preferred Quantm-generated alignment(s) were then exported to CAD where Dugger used the most feasible and cost-effective alignments to progress to detailed design.

"Instead of spending considerable time on the repetitive parts of generating alignment options, I can focus on true design work on the alignments we're most happy with, that are most innovative, and have the potential to reduce liabilities and deliver cost savings to the project," Dugger said.

Another significant benefit of Trimble Quantm System is its inherent ability to stimulate improved and effective collaboration. Using the Trimble Quantm System the team was able to quickly examine multiple 'what if' scenarios in determining effective options for many complex situations. The VDC team was able to evaluate and compare numerous three dimensional alignment options. By analyzing and refining the vertical profile and earthworks of alignment options, the team identified which options presented the largest potential to minimize construction cost based on barriers to construction, such as steep grades and multiple switchbacks.

The Mortenson VDC team performed multiple grade investigations and generated a route where one original proposed segment of road was 7 kilometers in length. Then, the project team adjusted the parameters and selected different start and finish points on the ridge, and the Quantm system was able to very quickly create a set of possible options for each of these scenarios. In one case, one of the alternatives reduced the overall length from 7 kilometers to 4 kilometers. This resulted in a tremendous construction cost saving. The route included fewer switchbacks for improved safety and resulted in reduced wear and tear on machinery. The rapid analysis and results generated by the Trimble Quantm System enabled the team to engage, interact, provide feedback, and quickly run new analyses where needed.

“One of our VDC team goals is to maximize collaboration to come up with the best solution,” said Maloney. “We never want anybody to say, 'Okay, I'm going to go back to my desk and come back in a week with answers.' We want to do it now, together. With Quantm while we're collaborating we can edit alignments and come up with alternatives that include updated quantity and cost information in real-time - that's amazing and value- added for our customer.”

Maloney believes the Quantm solution will continue to deliver a substantial return on investment as it continues to be integrated into the Mortenson proposal, planning and design processes. Dugger believes the software will help them provide a far superior customer experience by providing better alignment options in less time. Being able to simultaneously consider the topography, geometric criteria, geology and environmental factors as well and quantities and construction cost, the Mortenson VDC team can analyze alignments to minimize earthworks and structure lengths. This leads directly to cost savings for their customers.

“Quantm is a perfect application for what we do,” said Dugger. “We see it as giving us a competitive advantage because we have the flexibility and ability to identify more viable routes and we can provide far greater detail about each alignment in terms of quantities and cost estimates of each and every option being considered that goes way beyond cost-per-mile estimating.”

Not only does the Quantm system substantially reduce alignment planning time, it delivers optimized routes that meet all constraints. Looking ahead, the Mortenson VDC team is excited to utilize Trimble Quantm for more projects throughout the Renewable Energy Groups including the Wind Group, Civil Group, and the High Voltage Transmission Group. The Quantm system provides value- added benefits to customers for all these project types.