To meet the need for increased delivery of oil from Canada and North Dakota, a pipeline client planned an expansion of a terminal in the midwestern U.S. For the project, Barr designed the pipe rack, which supports more than two dozen 36-inch-diameter pipes over a distance of 1,300 feet—the equivalent of 6 miles of pipe. The rack had to accommodate up to 7 inches of thermal expansion, fit in a congested area, allow traffic to pass under it, and provide maintenance access to below-ground piping. Coordination between Barr’s geotechnical, structural, and mechanical teams was critical to verify that the ground could support the heavily loaded rack.
Minnesota Power wanted to evaluate potential modifications for a paper machine at its Rapids Energy Center. The proposed tie-in would direct steam in a singular path that would allow use of desuperheaters to reduce steam temperature and provide better operating control.
After performing an initial evaluation, we suggested a review of the 50-pound steam line to determine actual pipe routing, existing turbine loading, defective support locations, and sagging piping locations. We performed 3D scanning to create a model and develop a baseline of the existing system. By conducting a pipe stress analysis, we compared existing forces and moment loads to the original allowable design loads and identified problem areas. Issues existed with pipe supports, horizontal pipe sag, and exceedances in allowable turbine force and moment loads.
Barr recommended two options for analyzing the piping system before modifying tie-ins and pipe and routing supports. We then analyzed three load-case conditions, calculated the loads, and compared them to the original design loads. We also presented two support options with pipe-routing and turbine-nozzle load variations.
In the project’s second phase, Barr conducted pipe stress analysis for both support options. We then designed the new piping system, verified piping changes, and sized new supports. Minnesota Power proceeded with tie-in modifications to the paper machine, following piping and support-hanger modifications recommended by Barr.
To reconnect Pine Creek in southeastern Minnesota with its floodplain and improve fish habitat, MNTU hired Barr to help restore a one-mile reach of the creek. The stream reach is located within a Minnesota Department of Natural Resources fishing-access easement, so close coordination was needed. Barr also worked with the MNTU Hiawatha Chapter, Natural Resource Conservation Service (NRCS), and landowners to identify project objectives and scope that would improve stream habitat and still allow use of adjacent agricultural and pasture lands.
A geomorphic assessment and site topographic survey were conducted. These data and hydrologic and hydraulic modeling were used to define new channel geometry and floodplain dimensions. Because the actively eroding, existing stream reach was deeply entrenched in legacy sediment, a new section was constructed to establish a more-expected radius of curvature and planform. Approximately 60,000 cubic yards of soil were regraded and/or removed to create an accessible floodplain. In-stream habitat elements, including bioengineered fabric-wrapped bank lifts, boulder-constructed rock riffles, wood and rock vanes, rock clusters, and root wads, were installed. These features provided in-stream cover as well as interim stabilization of the newly graded streambanks and floodplain. Barr coordinated with landowners and the NRCS to facilitate fencing to help manage grazing along the riparian corridor.
When significant flooding happened four years after completion, the restoration held up well. All of the designed habitat features remained in place, and the created floodplain helped dissipate flood energy so effectively that only minor bank erosion occurred in a few isolated areas.
A municipal hydroelectric facility and its turbine required replacement after reaching the end of their useful service life. The City of Redwood Falls hired Barr to design a new powerhouse and turbine support structure and coordinate the electrical and structural work with the suppliers of the new turbine and generator. The existing hydro turbine was replaced with a 500 kW turbine. Because the facility was rated for 500 kW, Barr coordinated with FERC and the city to keep the upgrade within facility limits, so that no relicensing would be required.
Barr designed a new reinforced-concrete and masonry superstructure powerhouse in line with the existing concrete penstock. HVAC and electrical components of the building were included in the design. To tie the new structure into existing facilities, Barr first performed an inspection and survey of the site, penstock, and adjacent utility building as well as a geotechnical investigation. Site improvements included design of topographic features, surface water drainage, and a reinforced-concrete retaining wall. Barr prepared the civil, structural, electrical, HVAC, and piping plans and specifications in accordance with FERC requirements and coordinated the evaluation, design, and construction with both FERC and the Minnesota Department of Natural Resources. We also provided construction observation.
When a confidential power client proposed expanding its existing landfill-gas-to-energy facility by adding two 1.6-megawatt engines, Barr was hired to develop an application to obtain an air construction permit for the installation of two engines. The application included a calculation of emissions from the landfill-gas-fired engines; review and compliance demonstration for state and federal standards, including the U.S. EPA’s MACT standards for engines (Subpart ZZZZ); and NSPS (Subpart JJJJ).
Barr modeled air emissions to demonstrate compliance with the state toxic-air-pollutants rule. We also completed an evaluation to show the project would meet presumptive BACT requirements under state law. The state regulatory agency issued the permit for construction of the two new engines in 2013.
Barr’s Grand Rapids office assisted a major pharmaceutical manufacturer with the decommissioning and demolition of a 27-acre manufacturing facility located in Michigan. Our initial activities involved completing a pre-demolition hazards characterization assessment of the facility. Based on the assessment, we assisted in the development of a bid specification for the demolition contract. Once bid, Barr’s staff provided on-site oversight during demolition to confirm the proper management and disposal of all materials and to address environmental conditions encountered during the work. Our staff served as the owner’s representative for all waste characterization and management decision-making, including the preparation of waste profiles for the various waste streams generated during demolition.
Our team also prepared a comprehensive asbestos survey and provided oversight of environmentally sensitive aspects of the demolition process. This included concrete impacted from historic spills of polychlorinated biphenyl (PCBs) and RCRA-listed hazardous wastes, PCB-containing coatings on process equipment and building components, asbestos-containing caulks and coatings, accumulated stormwater, and concrete flooring and foundations in areas of impacted soil and shallow groundwater.
As a result, there were no unanticipated costs or delays due to environmental issues encountered during demolition. The project team also successfully petitioned the Michigan Department of Environmental Quality for approval to use crushed concrete from the demolition as on-site backfill, resulting in significant cost savings. After demolition, we prepared a comprehensive demolition report, which is maintained by the client as a permanent record of the former manufacturing facility.
Capitol Region Watershed District’s new headquarters is located in Saint Paul’s Midway neighborhood, an area where existing residential, commercial, and industrial uses intersect. Previously the site of MacQueen Equipment, the property had environmental contamination from decades of past commercial and industrial uses. To assist with redevelopment of this brownfield site, CRWD hired Barr to investigate the site and develop designs for environmental cleanup and stormwater management. Barr’s objectives were to mitigate soil gas contamination, manage petroleum-impacted soils encountered during construction, and facilitate infiltration of stormwater in an area of residual contamination.
To address vapor intrusion risk, Barr designed a sub-slab mitigation system that bridged new building construction and an adjacent existing building undergoing renovation. Areas of petroleum-impacted soils related to historical underground storage tanks were either capped on site or removed and transported to a landfill. To help with the CRWD’s goal of reusing and infiltrating as much stormwater as possible, Barr conducted an award-winning and MPCA-approved evaluation involving groundwater modeling and monitoring to demonstrate the infiltrated stormwater did not exacerbate residual petroleum impacts in the groundwater.
To take advantage of better technology and boost capabilities, one of the largest clean energy developers in the United States sought to replace existing turbines with new models. Barr assisted this client by performing a structural assessment for the repowering of a 150-megawatt wind farm.
Barr first conducted a desktop evaluation to determine if the proposed foundations could support the new loads. Additionally, since industry design practices for anchoring turbine towers to their foundations had changes since their original design, we also developed a calculation procedure based on an analogous design formula and our knowledge of historical foundation performance. Based on these evaluations, our determination was that the new specifications could be met.
To validate our initial determination, we selected a subset of foundations at the site for further inspection and testing. Field investigation involved structural health monitoring (SHM) to determine each foundation’s performance while its turbine was operating. We also performed visual inspections and coring inside the foundations to check for cracking or hidden issues.
We determined the foundations at this site could support the new turbines without costly modifications. Our team also developed a foundation risk-management program that consisted of performing SHM on select foundations over specific intervals. These findings and recommendations allowed the client to move ahead with repowering while continuing to produce power for 40,000 households.
Barr provided engineering services for a large pipeline company’s reversal project. Our work included preliminary engineering, capital cost estimate, laser scanning and modeling, detailed design engineering, soil borings and geotechnical engineering, purchasing assistance, and environmental permitting assistance.
The project included modifications to 11 pump stations and one new pump station. Most stations included two 1,500 HP mainline units; ultrasonic flowmeters; electrical service buildings and substations; PLC and controls; and civil work and fencing.
At some of the sites, we provided engineering services for 120,000 BBL storage and 3,000 BBL surge tanks, including foundations and dikes; tank manifolds; station booster pumps; and trap modifications.
Barr’s work for these projects typically began by laser scanning the site and developing a CADWorx model of the piping. We designed new station layouts, fitting the new pumps and piping in, while maintaining existing operations. We also provided mechanical, electrical, structural, civil, and geotechnical engineering services.
In August 2007, the City of Rushford experienced a flood that overtopped its levees and flooded many of the homes and businesses in the city. The peak flow was over two times the design flow and was the result of the largest 24-hour rainfall recorded in Minnesota history.
Barr worked with the City of Rushford and the U.S. Army Corps of Engineers (USACE) to design corrective measures for the levee and flood conveyance system to protect against flooding from the Root River and Rush Creek. These corrective measures allowed the levee to be compliant with current Federal Emergency Management Agency (FEMA) and USACE standards. The corrective measures also reinforced channel armoring and addressed deficiencies noted during inspections. The primary corrective measures included over 3,600 lineal feet of seepage collector and approximately 450 relief wells to capture seepage below the levee.
The flood protection system was extended by constructing a new, 800-foot-long levee. Barr evaluated the freeboard protection based on anticipated future sedimentation and recommended areas where the levee should be raised. The corrective measures also required Barr to design roadway changes and utility relocation.
Levee system repairs were completed in 2012. During construction, Barr worked with the city to obtain bids, administer the construction contract, and document construction. After construction, Barr provided the certification documentation to FEMA to demonstrate that the levee meets applicable flood protection standards for the city’s residents and business owners.