Top Ten Engineering Leaders Continue Upward Trend in Trenchless Design in 2016
Billings for trenchless design among North America’s leading engineering firms in 2016 suggest an increase in trenchless work over the past year. Collectively, this year’s Top 10 completed more than $876 million in trenchless design — an increase of $56.7 million over 2015, or 7 percent. Nine of the Top 10 firms from 2015 retain their position in this year’s Top 10.
READ MORE: Trenchless Technology’s Top 50 Trenchless Design Firms of 2016
This year’s top firms also reported completing more than 18,000 trenchless projects between 2010 and 2015, including the following:
CH2M, working for El Paso Water Utilities, recently completed a significant flood risk reduction project. The Magnolia stormwater project was developed to relieve flooding of I-10, which occurred during 2006 storm events in El Paso. The conveyance project consisted of about 1,800 lf of 84-in. gravity pipeline and 6,000 lf of 60-in. force main to convey up to 175 cfs of stormwater from Interstate-10 to the Rio Grande. Multiple segments of the pipeline required trenchless construction techniques; the gravity pipeline segment from Interstate-10 to the project pump station includes three tunneled crossings of TXDOT’s Interstate-10 and its frontage roads, as well multiple railroad lines on UPRR property, of up to 450 ft in length, with 96-in. pipe-rammed steel casing or tunneled liner plate.
The pressure pipeline from the pump station through commercial and residential streets to the Rio Grande includes four crossings of TXDOT roadways and irrigation canals of up to 450 ft in length utilizing 78-in. steel casing, tunnel liner plate and steel ribs and lagging. The project tunneling terminates in a 40-ft deep concrete outfall constructed in the USACE Rio Grande levee that also serves as the U.S.-Mexico international border. Subsurface conditions include loose poorly-graded sands that constituted running ground conditions for tunneling in the absence of appropriate mitigation.
Mott MacDonald LLC
The Statue of Liberty is a World Heritage Site and universal symbol of freedom and democracy. Adequate water and wastewater service is necessary to protect the cultural and historic landmarks on Liberty Island, and to serve more than 4 million visitors per year. The Jersey City Municipal Utilities Authority retained Mott MacDonald for the Liberty Island Water and Wastewater Upgrade — the design of a new system to replace the existing water and wastewater pipelines, which were installed in 1992 as a temporary replacement for leaking cast-iron mains.
Construction of the new pipelines included a combination of HDD, pipe bursting and pipe ramming. The 2,400 ft of 12-in. water main and 2,400 ft of 6-in. sewer pipe were separately installed by HDD through bedrock and 3,000 ft of 10-in. water main and 3,000 ft of 4-in. sewer pipe were installed by pipe bursting. Existing water and wastewater pipelines had to remain in service during construction.
Despite the unstable fill beneath both Liberty Island and Liberty State Park, the exceptionally strict limits on construction, and unanticipated uncharted obstacles, Mott MacDonald coordinated with clients and contractors to deliver an effective solution that allowed public access to the Statue and Liberty State Park to be maintained throughout construction.
Stantec is designing the underground aspects of the City of Atlanta’s top priority infrastructure project — the Raw Water Supply System. Current infrastructure consists of components dating back to the 1890s, with critical portions well beyond their design life. The new system moves raw water from the Chattahoochee River to a quarry and the Hemphill and Chattahoochee water treatment plants to provide water sustainability for more than 100 years.
The project consists of five miles of a 10-ft diameter tunnel in hard and abrasive Gneiss bedrock, the use of a 2.4-billion-gal quarry for raw water storage (one of the largest in the world), 10 shafts, raw water intake, pump station retrofit and three new pump stations. The tunnel varies in depth from 250 to almost 500 ft. Project challenges include mining near the river, mining under existing unlined raw water reservoirs, the Brevard Fault system, inability to shutdown treatment facilities and construction near residences. The project is being delivered via a CMAR contract, making it the longest such tunnel ever built in North America.
The Lockbourne Intermodal Sewer (LIS) project will provide sanitary sewer service to the Intermodal Facility at the Rickenbacker International Airport, as well as developing areas south of Columbus, Ohio. The downstream end of the LIS will connect to the existing Big Walnut Augmentation/Rickenbacker Interceptor tunnel. The LIS consists of approximately 3.27 miles of sanitary sewer; approximately 1.94 miles of the 78-in. diameter pipe will be constructed by microtunneling; and the remaining 60-in. diameter pipe by mostly open-cut-and-cover methods. The sewer will be constructed through a complex stratigraphy of glacial, alluvial and lacustrine deposits with numerous cobbles and boulders presence. AECOM provided complete design services for the project, which consisted of an alignment study, geotechnical investigation, preliminary and final designs, preparation of bid and contract documents, and will be providing engineering services during construction.
Hatch recently completed design and construction administration for the Region of Peel’s Etobicoke Creek Trunk Sanitary Sewer Twinning Project. The project involved construction of 600 m (approximately 2,000 ft) of 1,800 mm (72-in.) internal diameter trunk sanitary sewer beneath the busiest runway at Canada’s busiest airport, Toronto Pearson International Airport. The sanitary sewer was installed in a single drive by microtunneling. Due to the presence of critical operating facilities above the tunnel alignment including runways, taxiways and service roads, there was no opportunity for intermediate or rescue shafts. As such, the tunnel boring machine was designed with an airlock, allowing compressed air interventions through the machine should tooling changes be required or an obstruction be encountered. This is the first known application of an airlock to a microtunnel project in Canada. All construction work was completed within the secure “airside” area, requiring significant coordination with airport and federal authorities. The project was completed successfully with no negative impacts to runway traffic and operations.
Black & Veatch
The Paradise Whitney Interceptor (PWI) Sewer project consists of several components, but the overall concept is an approximately 48- to 66-in. sewer interceptor that is designed to convey raw wastewater from the southwest part of the Las Vegas Valley to the Clark County Water Reclamation Central Plant on the east side of town. The interceptor generally follows the existing topography and includes an elevation difference of approximately 600 ft over a distance of approximately 71,000 lf.
Black & Veatch designed the central portion of the PWI alignment which includes approximately 20,000 ft of open-cut pipeline and approximately 8,000 ft of trenchless crossings. Design included completion of a detailed geotechnical investigation and hydrogeological model along with preparation of a Geotechnical Data Report and Geotechnical Baseline Report.
The trenchless crossings, primarily 60-in. diameter FRPMP sanitary sewer pipe, were constructed with Earth Pressure Balance (EPB) tunneling equipment and direct jacked pipe. The crossings included an interstate, railroad tracks, a park, and locations where sensitive existing utilities and dewatering induced settlement precluded the use of the open cut construction method. Ground conditions included desert conditions, and granular deposits with varying amounts of sand, clay and silt. Varying amounts, locations and thicknesses of caliche were also found during the geotechnical investigation.
CDM Smith has been working with the Metropolitan District Commission of Connecticut (MDC) for more than 10 years to help it manage more than 1,000 miles of aging sanitary sewers to help it meet its consent order. The project involves cleaning, inspecting, reviewing/organizing the MDC’s CCTV data, and replacing and rehabilitating its sewer system. Specifically, in the past year CDM Smith has been involved with developing a 10-year plan for capital improvements and O&M programs to maximize the MDC’s capacity, prevent blockages and collapses and reduce overflows.
In 2015, Arcadis completed a first-of-its-kind, at-risk sewer rehabilitation project for Hampton Roads Sanitation District (HRSD) in Virginia Beach’s Basin 340. This design-build pilot project was conducted for HRSD to evaluate the design-build project delivery approach in its 20-year, $2 billion Wet Weather Management Plan. Arcadis risked 100 percent of the project profit in attempting to reduce I&I by 19 percent from the public half of this 50 percent public: 50 percent private sewershed. Arcadis additionally provided a 10-year warranty on performance of all rehabilitation work. Of the rehabilitation, 100 percent was conducted using innovative chemical grouting practices. Independent flow metering and modeling showed a nearly 40 percent reduction in total I&I volume during a 10-year design event.
Jacobs Engineering Group
Jacobs was part of a design-build team to design and construct a challenging 4,200-ft crossing of the St. Johns River in Jacksonville, Fla., with a 42-in. steel casing pipe installed by HDD. After the steel casing was installed, a 36-in. diameter HDPE carrier pipe was installed to convey pressurized sewer flows. The entry for the HDD crossing started in the heavily used parking lot of EverBank Field, home of the Jacksonville Jaguars. From the parking lot, it crossed under a detention pond and Gator Bowl Boulevard. It continued to thread between the piles that support the elevated Commodore Point Expressway, dipped below a deep bulkhead, and then traversed the St. Johns River. Once on the south side of the river, the alignment and finally exited near an active pump station.
While the preliminary alignment was severely constrained due to the complex surficial and sub-surface features noted above, selection of the entry location was further complicated when, during pre-design, abandoned gantry rails/piles and a box culvert was discovered in the parking lot of EverBank Field. Other constraints included ROW restrictions, concerns about drilling near a historical museum and FDOT concerns regarding drilling between and below the piles supporting the elevated expressway. To accommodate these surface and subsurface features, the HDD alignment traversed through vertical and horizontal curves and was drilled using conductor casing and the intersect method. While there were significant challenges during pre-design and design to find the best route through the obstacles, the hard work paid off during construction with clearly identified existing features, settlement monitoring of key structures and construction being completed in time for kickoff of the Jaguars football season.
Cardno is providing survey and mapping, subsurface utility engineering and utility coordination services to support the engineer of record’s design efforts for improvements of 14.5 miles of I-4 (SR 400) reconstruction from west of US 27 in Polk County to west of SR 528 (Beachline) in Orange County. Upon completion, I-4 will consist of three general use lanes and two special use lanes in the eastbound and westbound directions, alleviating the traffic congestion of this well-travelled corridor connecting the east and west coasts of Florida.
Andrew Farr is associate editor of Trenchless Technology magazine.