In 2014, DuroTerra leaders took on a wonderful opportunity when they launched their company while working with Austria-based Tiroler Rohre, GmbH (TRM), a manufacturer of ductile iron piles. These piles have been used in Europe for more than three decades and in the United States for more than 10 years.
"The sister company of DuroTerra, LLC, is a specialty geotechnical contractor in the Northeast U.S. and has installed more than 50 successful ductile iron pile projects," said Rimas Veitas, P.E., who along with partners Chad Graybill and Christian Littlefield (owners of Helical Drilling and who have more than 80 years of combined experience in the specialty contracting and engineering industry) comprise the DuroTerra's corporate team.
Brendan Fitzpatrick, P.E., a prior vice president at Geopier Foundation Company, joined the team in 2014 as director of engineering/marketing and manages operations of the company.
With its corporate office and distribution yard located in the Greater Boston, Mass. area, DuroTerra is a distribution company specializing in ductile iron piles, which it distributes through a client base across U.S. and Canada along with select locations throughout Latin America.
"In addition to material supply, DuroTerra also provides its customers with project feasibility assessments and preliminary design evaluations based on geotechnical site conditions and foundation plans to help evaluate the construction and technical suitability of the system," said Veitas.
 "We also provide equipment and construction support to assist installers in getting adequately set up for a ductile iron pile job and following construction guidelines to aid in the installer's construction success."
Benefits of ductile iron piles
Ductile iron piles are a modular, low-vibration driven pile system. The system utilizes a medium-sized excavator and percussion (demolition-type) hammer to install the piles, making it well suited for constrained urban sites or interior renovation work where overhead clearances are 18 feet or higher.
"The equipment needed is simple and makes installation simple," said Graybill. "While the system has been used cost-effectively on wide-open sites, the vast majority of our customer's projects include building additions, interior retrofit work or tight, urban development sites. The system is versatile and can be installed to develop capacities ranging from 25 to more than 100 tons in either end-bearing on a competent bearing layer (i.e., rock or very dense ground) or by using an oversized pile shoe and continuously pumping grout during driving to create an efficient grout-to-ground bond zone for frictional capacity."
Littlefield added, "Projects primarily include industrial and manufacturing additions and improvements, warehouse retrofits, commercial and residential buildings and additions and the occasional bridge support and municipal application. When a project uses ductile iron piles, the pile can go 150 feet without mobilizing a large crane. All that is needed is an excavator."
When asked how contractors can find out whether ductile iron piles would be the right choice for their project, Littlefield said that besides meeting directly with project teams and participating in industry events, "Our team works with geotechnical contractors, engineers and owners to evaluate applicability of ductile iron piles for their projects. Involvement and feasibility assessment occur at all stages from early design phases prior to the selection of foundation systems through bidding (including value engineering opportunities) and even into construction when specified solutions are encountering issues and teams are looking for alternatives."
Littlefield says the system is more cost-effective compared to micropiles, which can help a contractor secure the job.
Fitzpatrick, who has more than 20 years of design/build geotechnical construction experience, concurs.
"I encourage all of our existing and future customers to provide us with project information (structural foundation plans, geotechnical reports, boring logs, etc.) to evaluate and discuss whether the system is well-suited for their project. While it'd be great for all projects to make sense for ductile iron piles, we recognize that there are many different foundation solutions available to project stakeholders. We want to make sure that our solutions are providing value against other options."
As for a project that stands out, DuroTerra was recently brought in as an alternative to a micropile system on an active project where a new interior mezzanine level was being constructed for an international shipping company. The project had overhead clearance restrictions of generally about 30 feet, but as low as 24 feet in some locations.
"After encountering conditions that required the specified micropiles to go deeper than planned, the project team was looking for alternatives to avoid costly foundation overruns," said Fitzpatrick.
"The ductile iron pile system was selected on a 1:1 replacement of the 50-ton micropiles and construction immediately proceeded to keep the project schedule on track. A total of 116 piles were installed in only six days, while working around existing distribution facility operations."
He adds that the success of the ductile iron pile system for this project has led to ductile iron pile solutions on three other similar projects for the same international shipping company.
"The most notable was a large interior project installed by PDCA member GeoStructures, Inc. near the Philadelphia International Airport. The project involved another mezzanine expansion and required more than 330 piles installed to depths ranging from 70 to over 100 feet to develop capacities of 45 to 75 tons. Overhead clearances were limited to around 35 feet in many locations, but did drop to 25 feet in limited locations. The pile installations were completed in four weeks while working around active facility operations."
[Editor's note: GeoStructures, Inc. received a PDCA Project of the Year Award for the above-mentioned project; read the full story on page 75 of this edition of PileDriver.]
These projects, Fitzpatrick says, along with a number of other similar jobs, illustrate some of the advantages of the system when working on projects with tight access, overhead clearance restrictions and vibration-sensitive conditions.
PDCA membership and the future
A relatively new member of PDCA, DuroTerra recently joined the association at the suggestion of Larry Moore, P.E, past president of PDCA and COO of GeoStructures, Inc.
"We joined as a way to become more connected with the pile driving community," said Veitas. "We are looking forward to being better connected with contractors in the driven piling industry."
As for the company's plans, Veitas says that like most companies, DuroTerra is focused on growth.
"From a start-up company five years ago to having successful projects with customers in about half of the U.S. and Canada we see growth opportunities both geographically as we develop a greater customer base in the U.S. and abroad, and also by raising awareness of the DuroTerra™ brand and the benefits offered by the ductile iron pile system. Despite its long-term use in Europe and availability in the U.S., many contractors and engineers are not yet familiar with the system and the substantial benefits it provides in the right application."

With approximately 850 employees across the U.S. in four regions northern Utah, southern Utah/Las Vegas, Idaho and Wyoming Sunroc Corporation provides construction materials and services throughout Utah and the Intermountain West for both public and private sector customers.
The company was first established in 1937 as Utah Service when founder W.W. Clyde purchased a small service station in Springville, Utah. Directly adjacent to the station, he added a hardware store and lumber yard. Since that time, Sunroc Corporation has continued to grow beyond the Utah Service hardware store and service station, expanding to nearly 50 operating locations including masonry block plants, aggregate facilities, construction offices, asphalt plants and concrete facilities.
"Essentially, Sunroc Corporation is a wholly-owned subsidiary of Clyde Companies, Inc., a family-owned and operated company headquartered in Orem, Utah," said Mark Wimmer, Sunroc vice president. "Our president, Scott Okelberry, oversees the growth, operations and vision of the company and reports to the president of the Clyde Business Group at Clyde Companies, Inc. His vice presidents, Russell Leslie and myself, lead the construction and construction materials divisions of the company, respectively."
Sunroc specializes in pile driving and earth shoring operations, including precast prestressed concrete piles, H-piles, pipe piles, sheet piles, soldier piles and soil nail/shotcrete, at present.
"We recently completed work on a high-profile project for UDOT, driving piles for the SR-68/I-215 Interchange Bridge," said Eric Hendriksen, general manager of the piling and shoring division.
This a major interchange that is relied on by motorists traveling between Salt Lake and Davis counties. Plans called for 16-inch by ½-inch wall pipe piles, driven [to] lengths up to 125 feet. We were chosen by the general contractor as a subcontractor for the pile driving work because of the relationship of trust and proven results we have with them.
Work began in July on UDOT's highest priority project, Mountain View Corridor 4100 S to SR-201, a two-year project consisting of four miles of new roadway with two lanes in each direction, with biking and walking trails, 13 bridges and six pedestrian bridges.
When asked how Sunroc differs from its competitors, Hendriksen doesn't hesitate.
"Our perfect safety record, for sure. Our core group of people has been together for decades and I believe we have far more experience than competitors in our area."
Added Wimmer, "Sunroc is unique in the large variety of construction and material services provided from earthwork, excavation, shoring, piling, ready mix, sand and gravel, asphalt paving and masonry products with an excellent footprint in the Intermountain West. What else differentiates us is that we are large enough to take on large projects, but still provide personal service and detail in each of our individual locations."
Leslie agreed: "Over the last few years through acquisition, we have significantly increased our footprint and have brought on some very qualified employees that are experts in their chosen fields. We strive to do the project right the first time. If there is an issue, we work to quickly remedy the situation. We have been very successful in doing multiple projects with the same customer. This happens because of our ability to establish and maintain exceptional relationships with owners and customers."
PDCA and the future
Sunroc has been a PDCA member for many years.
"My previous employer was a member from the early days of the organization, joining in the first or second year," said Hendriksen. "I have been connected for many years and have maintained membership with each change in business structure from Desert Deep Foundations LLC to DDF Inc. and now Sunroc. Aside from the benefits we derive (education, networking and making connections with other contractors, suppliers and manufacturers, etc.), I feel it's important to support the driven pile industry as a whole, helping promote, publicize and educate others on the benefits of driven piles, while alleviating unfounded concerns sometimes associated with driven deep foundations."
As for what the next five to 10 years hold for the company, Hendriksen said, "My plan is to continue for the next five or six years, training others to pick up the ball and keep moving it forward. I have learned a lot since my first experience with driven piles in 1983, and I still have lots more to learn. Hopefully, by the time I'm ready to step away, Sunroc will be widely recognized not only for excavation and civil work, but also as the most reliable and trustworthy source for driven piles and earth shoring in the region."
Said Wimmer, "The company plans to continue to grow and provide more services both organically and through acquisition over the next one to 10 years."
Leslie agrees, "There are still areas that I feel we have the ability to grow in geographically. As long as the markets continue moving forward in a positive way, we will continue to grow."

During the summer of 2014, the Salt Lake City Department of Airports (SLCDA) broke ground on one of the most complex construction projects in Utah history. In order to keep pace with the demands of the nearly 23 million people that use its facilities each year, the SLCDA initiated a $3.6 billion redevelopment program that will transform the current Salt Lake International Airport into one of the nation's most efficient airports. The first phase of the program features a modernized three-story terminal building, two new concourses, several new parking structures and the longest bridge constructed in Utah all supported by a deep foundation system consisting of over 95 miles of driven steel piles!
Installing this massive deep foundation system by December 2018 was critical to keeping this high-profile program on schedule and setting the stage for its successful delivery. Ralph L. Wadsworth Construction Company, LLC (RLW) was the firm selected to shoulder the burden of getting the project started correctly. Working as a subcontractor to HDJV Construction, a joint venture between Holder Construction and Big-D Construction, RLW overcame a multitude of challenges related to schedule, design, safety and logistics.
Schedule
The schedule for pile driving operations was aggressive and unforgiving. From start to finish, the project required more than 5,300 separate pipe piles (16"×0.5"), and 550 H-piles (14"×102') to be delivered, driven, spliced, welded, cut and poured. (A partial aerial view of the site is in Figure 1.)
The schedule required the team to work year-round and in all types of weather conditions, driving 60 to 80 piles each day. At the peak of the work, RLW had more than 30 construction professionals working at the site, using day and night shifts as well as weekends.
Pile depths and weights
The individual pipe pile lengths ranged from 45 feet to 80 feet per piece (Figure 3), and the weight was 82.8 lb. per foot. Several piles were installed to depths that ranged between 88 to 120 feet, which required the team to splice piles together.
Logistics
This project required 26 different lengths of pile, many in excess of 80 feet. Beyond handling the sheer quantity of pile pieces, their length created challenges for transporting, storing and maneuvering them at the site. Manufactured in California and Mississippi by Skyline Steel, the piles were transported by barges and then by rail to Salt Lake City. Trucks with extra-long beds carried the more than 70-foot-long piles through city streets to the project site, transporting no more than six piles at a time. RLW carefully scheduled deliveries around traffic patterns and managed inventories to minimize the amount of storage space required on-site.
RLW's team also procured and modified specialized pieces of equipment to unload trucks and move piles around the site (as shown in Figure 4). These machines used clamping forks to hold the large piles in place while moving allowing the team to transport them efficiently and, more importantly, safely.
The massive size and scope of the entire construction program together with a single point of site access demanded extensive coordination with other contractors and trades working at the Airport. RLW met with other contractors several times each week to plan deliveries, adjust storage areas and coordinate sequencing details.
Special innovations: Techniques, equipment and materials
Several factors made this 130-acre site unique. First, the soil conditions and geology fluctuated substantially within the vast construction area. Second, the various structures each had specific engineering requirements that called for different pile sizes and lengths. Lastly, some of the work needed to be performed in small areas, either pinched between or immediately adjacent to existing structures still in operation. No two areas were exactly alike, which compelled a customized area-by-area approach to pile driving.
In order to efficiently drive pile in these varied conditions, RLW utilized its full breadth of equipment optimizing equipment strengths to specific challenges. Seven different sized ICE hammers, both hydraulic and diesel, were used according to area soil conditions and proximity to buildings. Six different sized Manitowoc cranes were used, engaging both swinging and fixed leads, to maximize production and safety.
For the work performed immediately next to the existing airport terminal, vibration and noise impacts needed to be minimized to avoid disrupting airport operations. RLW used special equipment and techniques to mitigate these pile driving affects, including predrilling, sound curtains, optimized hammer selection and automated vibration monitoring with real-time text and email notifications if vibrations reached allowable limits.
Many piles were specified to be driven to depths of 120 ft., which required splicing that had to be UT tested. In order to maintain the aggressive schedule and execute high quality splicing operations, the team drove the first (bottom) pile during the day. Night shift crews welded the second (top) pile together with the first (as shown in Figure 2). Day shift crews finished driving the extended pile the following day. By performing all the welding operations at night, RLW was able to keep the hammer continuously working through daylight hours to maintain the schedule. This efficient approach allowed the team to continue installing 60 to 80 piles each day.
Unique application of piles
Part of this project included extending an existing concrete tunnel proposed to provide underground transportation for passengers between terminals. The tunnel had a bottom elevation of 28 feet below grade, and since the water table was only five feet below grade, an earth shoring and dewatering system was required to expose the work area.
A significant challenge arose when the geotechnical engineer-of-record calculated that the required dewatering efforts would cause the tunnel to settle about seven inches the structure's allowable settlement tolerance was less than half an inch.
The owner and the design team developed several designs to support the existing tunnel and limit the settlement due to dewatering. The frontrunner was a proposed solution to use micropiles drilled through the tunnel's six-foot-thick mat footing floor. The significant drawback to this solution was that it would damage the tunnel's existing waterproofing and expose the tunnel to potential long-term water-penetration issues.
Although this work was outside RLW's original scope, its on-site management team learned of the problem and seized the opportunity to find a better way using driven piles. RLW's team proposed driving 20 piles to a depth of 120 feet on both sides of the existing tunnel. Beams would then be placed on top of the driven piles and would span overtop the tunnel. These beams would then be connected to the tunnel's lid using threaded rods and welded connections. Hydraulic jacks installed between the beam and driven pile would allow the system to adjust to compensate for any differential settlement that might develop along the length of the tunnel. The strength of RLW's driven pile method was that it was quick, simple, flexible and required no modifications to the existing footing below the water table mark.
After reviewing RLW's solution, the owner and design team scrapped the other designs and selected the driven pile option, concluding that "it offered the best value to the project" (Figure 7 depicts this solution). The implemented solution worked beautifully.
Construction problems and creative solutions
Part of the redevelopment program included a pedestrian bridge to connect the new terminal to the existing airport facilities. The original plans for this bridge used 36-inch and 48-inch caissons drilled to depths approaching 80 feet. Once installed, the plans called for a 10-foot to 13-foot concrete column to then be poured as a separate component on top of the drilled shaft.
Challenges for the general contractor arose in the constructability of such a design in the middle of an operating airport. Situated between the airport's busiest domestic terminal and the international terminal, the structure spanned over a central walkway, the staff bus stop, the long-term parking bus stop and the airport's retail delivery access point. In order to minimize disruptions to daily operations and reduce safety risks to passengers at the airport, this work had to be completed at night, with working hours restricted to an eight-hour window between 9 p.m to 5 a.m. Moreover, the actual production hours were further limited by the requirement to mobilize all equipment to the work area, perform the work, clean, demobilize the equipment to a storage area and reinstall safety devices all within the eight-hour window.
Once again, RLW saw an opportunity to improve this design concept using driven piles. Its team met with the general contractor, airport, geotechnical engineer, and structural engineer and proposed revising the design to use continuous 36"×0.5" and 48"×0.5" driven steel piles instead of caissons and columns. This structurally acceptable design allowed the foundation work and column work for the bridge to be completed as one unit, cutting the construction time by half. The new piles were driven and vibrated to depth, and were left extending 10 to 12 feet above the existing ground elevation. Beyond its schedule advantage, this approach also had other benefits to the project. First, it did not require holes to remain open for any length of time, thereby eliminating the public safety risk of the proposed design. Second, it afforded the use of dynamic testing methods, which immediately verified the pile capacities and allowed the embedment length to be reduced by 33 percent saving the project significant cost savings. RLW installed two piles per night with minimal disruption to airport customers and operations. (Construction of the pedestrian bridge is shown in Figure 8.)
Innovative project management
Typically, a new airport would be built at a separate location either across town, similar to Denver's approach with its international airport, or on a parcel adjacent to an existing airport. The new Salt Lake City International Airport is unusual because it is designed to be constructed in phases on the existing footprint. This presented numerous challenges that required a high level of coordination between the construction team and airport operations.
RLW's pre-construction support for the foundation design of the pedestrian bridge and the dewatering and earth shoring of the tunnel demonstrates a spirit of true partnership. Participating in the design process was not part of the firm's scope or contract, yet RLW's project team repeatedly demonstrated a willingness to share ideas openly and a passion for thinking creatively. This collaborative approach was consistent with the Construction Manager at Risk (CMAR) contracting method used by the airport and the general contractor, which allowed the construction team to provide input during design.
During construction, RLW's management team adopted a proactive management approach for scheduling, pricing and coordination. They coordinated with the owner's construction and QA/QC teams on quality requirements, hold points and materials testing and certification. They coordinated with the FAA to ensure that all piling and foundation operations met federal guidelines including those for crane heights and temporary lighting for night construction work. Using weekly schedule updates, the team pre-planned all operations, using night shifts and weekends to complete key activities on time.
This proactive pre-planning approach paid off during the summer months when temperatures rose to over 100 degrees during a critical time when significant field welding was required. The heat posed a major safety risk to the workers dressed in full leathers. Even cooling vests and shaded work areas were insufficient to protect the welders from heat exhaustion. Night work was discouraged at the site due to its potential for negative impact on flight operations. Exceptions required a detailed plan and routinely took over two months to approve. Fortunately, RLW's management team identified the risk of approval delays as part of an internal brainstorming session held well before the start of work. As a contingency, the team had submitted several alternate work plans to the airport for review, and worked through the approval process for each, not knowing if they would ever be needed. One of these included a directional lighting plan that allowed limited work at night. Armed with an approved work plan, RLW had the flexibility to separate the crews, leaving some to drive pile in the day and moving others to weld at night. Not only did this mitigate the safety risks from the heat, but the cooler temperatures also expedited UT weld testing and ultimately allowed the project to gain 17 days on the schedule.
Conclusion
In summary, RLW met the challenge of this difficult job through the use of cost saving value engineering methods in the design and construction of the deep foundation systems. Both client and owner appreciated RLW's quality of work and their ability to meet a demanding project schedule in a safe and productive manner.
When overall excellence is discussed concerning large deep foundation projects, partnering with the owner and stakeholders must be at the forefront. RLW's relationship with its owners and general contractors is second to none due in large part to the open communication and close collaboration maintained throughout the project. The project NCR log never carried more than five items at any one time and project completion showed less than 25 total issues logged. The success of this project is a testament to the close collaboration within the project team is an excellent example of how the simplicity, durability and flexibility of driven steel piles still reigns supreme in the deep foundation marketplace.