Balfour Beatty US is the general contractor responsible for the delivery of the Topsail Island Bridge Replacement project on NC 50/210, which is on schedule for completion 300 days ahead of contractual requirements. The high-profile bridge project involves the complete replacement of the existing steel truss swing-span bridge with a two-lane, fixed-span, high-rise bridge over the Intracoastal Waterway (ICW) and associated approaches at beach end. The new bridge is currently under construction just south of the existing bridge. When it opens to traffic in 2019, Balfour Beatty will demolish the original structure. Originally built in 1954, the existing, functionally obsolete bridge is one of two bridges that provide access to and from Topsail Island. Traffic must be stopped and the bridge mechanically turned 90-degrees to allow large vessels to travel the ICW because of the bridge's low clearance a process that can stop traffic for as much as 30 minutes. The new 3,700 foot, 29-span, high-level Topsail Island bridge has a 65-foot clearance to accommodate marine traffic below without disrupting vehicle traffic above. Since the shallow depths of the wetlands and adjacent waters of the ICW prohibit the use of barges for material deliveries to the project area, the team had to put the trestle in place in its entirety to access the 3,700-foot bridge deck. By using drivel piles, Balfour Beatty was able to complete the 4,000-foot-long trestle within the in-water work window of October 1, 2016, to March 31, 2017, to begin construction on the bridge structure. If the team did not complete the trestle prior to the start of the fish moratorium on April 1, 2017, the delivery of the entire bridge could have been delayed by a year. Balfour Beatty made creative adjustments to the schedule to drive the piles and complete the trestle while meeting in-water work limitations. To start, the team worked double shifts seven days each week to drive approximately six 30-inch steel pipe piles per shift and installed the trestle structure to gain access to the next pile locations. With limited storage on-site, the team scheduled pile deliveries for on-time delivery staggering the deliveries of piles sourced from existing projects in Wilmington, N.C., Savannah, Ga., and Milledgeville, Ga., to exactly the right the amount of piles needed each day. In addition to this complex coordinated scheduling effort, the team had to work with the Coast Guard to redesign access across the ICW to solve inadequate access issues present in the original design documents. Balfour Beatty successfully completed the redesign and drove 39,870 feet of piles within the first six months of the project. Working with the U.S. Army Corps of Engineers, the North Carolina Department of Environment and Natural Resources and the North Carolina Division of Coastal Management, Balfour Beatty was able to complete the work using environmentally sensitive methods. Throughout it all, the team has not incurred any environmental violations, lost-time or recordable safety incidents. Originally contracted for completion by 2020, Balfour Beatty is on schedule to open the Topsail Island Bridge to traffic in 2018 300 days ahead of the contractual schedule. This extraordinary feat would not be possible without the use of driven piles. All eyes are on this critical infrastructure project as the new Topsail Island Bridge winds its way across the ICW. To date, the existing bridge, providing the only southern point of access to the island, is functionally obsolete and structurally inefficient. Its low clearance and swing-span design cannot simultaneously accommodate vehicle and marine traffic as it must be mechanically-turned every hour to allow marine vessel passage. Residents and visitors are anxiously awaiting the delivery of the new bridge, which will increase traffic capacity and allow for safe marine passage without affecting vehicle traffic flow. Special innovation in construction techniques, equipment and/or materials Designing a temporary trestle to support pile driving and bridge construction is no easy task particularly when there are access and schedule restraints, and the trestle provides the only access to the bridge for construction. Upon the award of the project in August 2016, Balfour Beatty immediately recognized insufficient access at the ICW to build the trestle and the bridge. With only six months to complete all in-water work, including the 4,000-foot trestle and its 39,870-feet of driven pile, Balfour Beatty had to act fast. The team worked with the Coast Guard to redesign the access and commence pile driving efforts as quickly as possible. However, delayed right-of-way acquisition and regulatory issues delayed the team's access to the site even further. The team did not mobilize the pile driving and trestle installation effort until November of that year, which cut the already-tight, in-water work window by a third. To recover this blow to the schedule, Balfour Beatty engaged the team of 40 field employees to work two 12-hour shifts each day, seven days each week. The trestle is divided into two parts: one trestle extends to the ICW from the mainland side and another trestle extends from the island side. With the access issues resolved by the team's initial redesign and coordination with the Coast Guard, Balfour Beatty still had to maintain clearance through the waterway. To do so, the trestle does not meet in the middle. This allows marine traffic to safely move through the construction site on its way through the existing bridge. The team coordinates work on each side of the trestle each day to avoid delays associated with crossing the existing bridge to access the other side. The temporary trestle was the only point of access to construct the bridge deck, and the compact work site provided no material storage space. Looking ahead, Balfour Beatty designed the temporary trestle system to support immediate equipment traffic and subsequent use of two 275-ton cranes that would be necessary to set the 180,000-pound horizontal bridge girders in place in March of 2018. Balfour Beatty also devised a complex, staggered delivery schedule for the 90-foot piles to be driven in rapid succession. With daily deliveries of piles, the team had to move the 90-foot piles from the trucks to the trestle quickly and safely to drive them into the riverbed each day. If the team encountered delays in its daily pile driving quota, they would have no space to store additional piles on the compact work site. Construction problems and creative solutions The annual fish moratorium and site access issues contributed to the challenging execution of this pile driving and bridge construction project. The team completes daily work on the bridge from two compact site locations and is further challenged by the large volume of vehicle and marine vessel traffic that interacts with the project area on a daily basis. Ranked number two on the ENR 2017 list of Top Contractors in the Southeast, Balfour Beatty regularly delivers complex infrastructure projects in challenging locations. The team used its lessons learned from similar roadway and bridge over water projects built throughout California to develop and adhere to a strict daily schedule of tasks for the Topsail Island Bridge replacement project. By following and adjusting the schedule as necessary, Balfour Beatty has been able to stagger deliveries for all construction materials to avoid storage issues. The team also avoids incurring time delays related to driving across the existing bridge to access the other side. At the start of each shift, after the job briefing and safety discussion, Balfour Beatty ensures that the correct field forces are in place on each side of the divided trestle and equipped with the correct materials to execute the day's work without wasting time traversing the site. This coordinated approach to on-time material delivery and an emphasis on lean construction enabled Balfour Beatty to drive piles as they arrived on site and ultimately expedite the entire project schedule. The new high-level bridge will be almost 4,000-feet long and 53-feet wide. Balfour Beatty is currently completing phase one of the project to construct the 29-span bridge, roundabout intersections, MSE walls and approaches that will connect the new bridge to the existing roadways on the mainland and the island. Once complete, the team will begin phase two, which involves tying in the roadways and switching traffic onto the new bridge. During phase three, Balfour Beatty will remove the existing swing bridge, reduce the roads from three lanes to two and add a new 10-foot-wide multi-use pedestrian path. Constant attention to the short-term and long-term schedules is a key component of the team's successful delivery of these multiple project components. Cost saving measures Expediting the overall project schedule enabled the Balfour Beatty team to avoid unexpected project costs. By meeting the initial in-water work window at the start of the project, Balfour Beatty is on track to open the high-level bridge to traffic nearly one year ahead of schedule. This type of achievement is nearly unheard of in infrastructure project delivery and it stands to infuse millions of dollars back into the local economy. With increased traffic capacity and improved commuter times, the new Topsail Island Bridge will bring tourists to the beach destination more quickly each day. It will make the area a more attractive destination for vacations, events and the retail businesses needed to support the increase in consumer traffic. Innovative project management Led by Balfour Beatty's area operations manager Jay Boyd, superintendent Mike Ewell and project engineer Robert Mann, the team has worked together to coordinate multiple project components to keep the bridge project on schedule. The established team has worked together on many similar marine projects with restricted work windows such as the nearby Wilmington Bypass project in Wilmington, N.C., a previous PDCA Project of the Year Award Winner. These proven team relationships provided a strong foundation to implement similar strategies and methods to deliver a successful bridge project for the residents of Surf City and Topsail Island. Located just 30 miles northeast of Balfour Beatty's southeast region headquarters in Wilmington, N.C., the management team filled other critical staff and production positions with personnel familiar with projects with pile driving efforts of this magnitude. Coupled with the understanding and familiarity with the local subcontracting community, this team continuity has enabled Balfour Beatty to drive 37,980 feet of piles, install 4,000 feet of trestle and nearly complete the structure of the new bridge in record time. Additionally, for the complex operation to put the 180,000-pound horizontal girders in place in the spring of 2018, Balfour Beatty coordinated with the Coast Guard and law enforcement to shut down the ICW to get these girders across the channel. Teammates Mike McDermott, Mike Ewell and Robert Mann contributed to the in-house planning efforts to self-perform the lifts over a meticulously planned two-day operation. Management or mitigation of environmental considerations Balfour Beatty is committed to delivering every project with Zero Harm to people and to the environment. Throughout the delivery of the Topsail Island Bridge Replacement project, the team has maintained that commitment and instilled a strong Zero Harm culture on-site. The team is familiar with the intent of fish moratoria and the adverse effects that large infrastructure construction projects can have on the environment when contractors do not exercise extreme care throughout project planning and delivery. From the moment of project award, Balfour Beatty worked closely with the U.S. Army Corps of Engineers and the North Carolina Division of Coastal Management to learn about the environmental considerations specific to the stretch of the ICW running through the Surf City, N.C., area. They met all of the permit requirements for the six-month window that prohibits bottom-disturbing construction activities in the shallow water of the site's stretch along the ICW, and they have not incurred any environmental citations throughout the project's lifetime. Balfour Beatty has full-time environmental inspectors assigned to the project and the team coordinates monthly environmental inspections from the U.S. Army Corps of Engineers, North Carolina Division of Coastal Management and North Carolina Department of Environment and Natural Resources. These monthly inspections are instrumental in successfully minimizing delays and ensuring all environmental conditions in the permits are strictly followed. Team safety discussions at the start of each work shift include updates on environmental conditions and considerations for construction activities that could disrupt local wildlife or pollute the water in any way. As part of the project environmental mitigation plan, the team also carefully monitors operations to ensure that materials and trash have not fallen into the water. Together, with this focus on Zero Harm and a consistent attention to detail, Balfour Beatty has met the permit requirements and maintained environmentally sensitive construction practices for the environmental health of the project area.
The PDCA Project of the Year Awards recognize excellence in driven pile construction projects completed by PDCA members throughout the year. Start thinking now about your entry into next year's Project of the Year Awards. What you can do now: Choose an innovative or interesting project that your company is currently working on that may be worthy of a Project of the Year Award. Any PDCA member is eligible to submit an entry, whether you're a contractor, associate or engineering affiliate member! Take photos and videos of the project site. Using a professional photographer, a drone, your own camera or even your smartphone, snap photos and record some videos throughout the foundation construction process. If using your phone to record videos, remember to take the video in landscape orientation (turn your phone on its side). Write notes during the construction process highlighting any value engineering; challenges related to timing, logistics, the environment or others; unique or innovative techniques; and more. If it seems interesting, write it down! If you start working on your entry for next year, once the call for entries opens, you'll already be ahead! For any questions, contact PDCA: 904-4771-4771 email@example.com www.piledrivers.org
Founded in 1920 as Corson & Gruman Co., the family-owned asphalt contractor in Washington, D.C., paved and operated asphalt plants in Maryland, Virginia, and Washington, D.C., for its first 50 years. In the 1950s, Arthur Cox, son-in-law of William Gruman, took over operating Corson & Gruman. Arthur Cox, Sr. purchased the company eventually, becoming the new owner. It was during the early 1970s when Corman Construction, Inc. was formed as a new company with an emphasis on utility construction. "Then, in the 1980s, heavy civil road and bridge capabilities were added to our scope of services, along with an opportunity to enter into the pile driving foundation market to support the civil operations," said Corman president Chase Cox. "Soon after, we branched out and formed two new divisions: bridge and utility. The company also moved from Washington, D.C., to Maryland in 1980 where we opened up a new corporate headquarter office in Annapolis Junction." In the 1990s, Arthur Cox, Sr. handed ownership over to his sons, Arthur and Bill, who assumed leadership. Arthur's son, Chase, joined the company in 2003 and, in 2016, became president of Corman Construction and Corman Marine Construction. Two vice president/general managers support Cox, each overseeing an operational group. These two groups are divided geographically: mid-Atlantic, which is between the Maryland, Washington, D.C., and Northern Virginia markets and includes the marine operations group; and Southern, which is between the North Carolina, Richmond, Tidewater and Central Virginia markets. The 2000s and today "In 2003, Corman purchased the assets of the Martin G. Imbach Company, a private marine construction firm who, since 1921, served in the Baltimore Harbor for clients, such as US Army Corps of Engineers, Maryland Port Administration, Exxon, U.S. Coast Guard, Dupont and Bethlehem Steel," said Cox. "This was our entry into the marine pile driving business." Today, the company, which has been a PDCA member for many years, has 400 employees in four facilities corporate headquarters in Annapolis, Md., which houses the main equipment facility and support functions, including finance, IT, human resources, contracts and offices for the mid-Atlantic and marine groups. The southern group operates out of Colonial Heights, Va., with an equipment and yard facility and an office in Chesapeake, Va. The company's marine group has offices, equipment and port facilities in Baltimore, Md., on Curtis Bay. Specializing in bridge, highway, marine, dredging, utility (water and sewer), underground and support of excavation construction, with an emphasis on self-performing pile foundation construction, Cox says the marine group also specializes in marine pile driving and dredging. "We service up and down the mid-Atlantic region, including Delaware, Maryland, Washington, D.C., Virginia and North Carolina. Our primary geography is Maryland, Virginia and Washington, D.C.," said Cox. The deep foundation industry has seen tremendous changes over the past century. In the last 20 years alone, Cox says upfront and foremost, safety has become a key value for the industry and PDCA. "The difference isn't only in how we manage a worksite to keep everyone safe, but also enhanced pile testing techniques to avoid the pitfalls of failing piles," he said. "The quality of the materials has improved greatly from better steel to the use of pre-stressed concrete piles. And, environmental sensitivity considerations play a larger, significant role in how we design and construct the work as a means to protect the environment." Cox says safety is Corman's most important core value and implementing safe work practices and ensuring employee and general public well-being is their highest priority. "Our Corporate Safety and Health Program includes policies/procedures that govern safe work practices to prevent injury, occupational illness and property damage, outlines the safety and health responsibilities of all involved, implements plans for safety and health education, training and monitoring to promote identifying and eliminating hazards and/or unsafe acts and identifies and addresses environmental concerns." Corman has an 11-core safety training class requirement for managers, engineers, superintendents and foremen catered to the transportation construction industry, including CPR, first aid, fall protection, excavation, rigging/signaling, manlift scissor/articulating, scaffolding, confined space, OSHA 30-hour, crane safety and guidelines for OSHA Inspection. While the advancements in the industry are impressive, attracting and retaining dedicated and talented employees in all trades at all levels remains a big challenge. "Even with increasing wages, there are not many up and coming individuals interested in pursuing a career in the foundation or construction industry. There is a stigma with many thinking the profession suffers from a lack of sophistication. With constant, major advances in technology, this is clearly not the case. As a group, we are not funneling this vision towards today and tomorrow's high school and college students. Changes need to be made as our industry presents opportunities and promise for tomorrow's leaders." Notable projects Corman has been involved in hundreds if not thousands of projects over its vast history. While all of them are notable for different reasons, Cox mentions two recent projects, the first one being the Main Pumping Station Diversions, Division I in Washington, D.C., which was completed this summer. This DC Water | Clean Rivers design-build project provides control and consolidation of flow coming from combined sewer overflow structures and is immediately north of the Main and O Street Pumping Station. It is comprised of a 100-foot long below-grade surge tank, two sewage diversion structures, flow channels, vent and odor control facilities and internal flow elements inside an existing 100-foot deep tunnel shaft. "We designed most of the excavation support, including 48-inch diameter secant piles and a combination king pile/sheet pile system with three levels of internal bracing," said Cox. "There was also a 72-inch diameter FRP sewer pipe excavated under an active arch sewer inside a liner plate tunnel." Two reinforced concrete diversion structures were constructed atop active 100-year-old arch sewers (16 feet and 12 feet wide). Excavations for these structures were 25 to 30 feet deep. "The diversion chambers take rising stormwater overflows over a series of weirs and into cast-in place concrete channels leading into a 100-foot deep shaft and tunnel for treatment at the DC Water Blue Plains Wastewater Treatment Plant. Existing utilities, including water and electric services, were relocated and protected during construction." The project is on a congested urban site in downtown Washington, D.C. There were strict dewatering standards, which required water to be quantified and tested for pH and turbidity prior to discharge. Designs for temporary excavation support were subject to restrictive load and ground movement criteria and geotechnical instrumentation devices were installed throughout the project limits to continually monitor ground movement throughout the project duration. Another project that Corman is especially proud of is the Reconstruction of Berths 1-6 Phase 2, Berth 4, at Dundalk Marine Terminal in Baltimore, which was completed in October 2016. This Maryland Port Administration project is at the Port of Baltimore, considered one the nation's busiest ports. After 80 years of being subjected to the harsh marine environment, Berth 4 (a general cargo receiver where goods are unloaded and stored onsite until transport) was failing and needed to be replaced. Railroad access to the wharf was no longer available due to weakening conditions, and the docking area needed to be deepened to accommodate the deeper draft ships transporting general cargo and paper pulp products. "The new Berth 4 was constructed near an active storage facility," said Cox. "To keep it in service throughout construction and secure it from ground movements, a new 700-LF king pile retaining wall was driven in front of it. It was installed using 106 HZ10-80M beams placed seven feet apart and interconnected with 105 AZ14 x 770 sheet pile pairs. Ten-inch PVC pipe sleeves were built into the king pile concrete cap to house the 145 soil anchor tendons augered 125 feet deep and grouted into place prior to tensioning to secure the wall. After securing the king pile wall, the old Berth 4 was safely demolished." The new wharf is 70 by 700 feet long and consists of 306 24-inch, pre-stressed concrete piles. Piles were driven in bents of six piles each to support 51 concrete pile caps and 350 precast deck slabs were set on top of caps and locked in place with a 10-inch concrete topping slab. The wharf fascia wall was constructed with cast-in-place concrete and incorporates 12 200-ton ship mooring foundations, new water and electric service and a fender system to protect it from ship traffic. The new wharf includes two new rail spurs and is topped with over 40,000 sq. ft. of 120mm interlocking concrete paving blocks. Before constructing the berth, there were test pile procedures using seven 24-inch concrete piles, which were handled and driven with a 275-ton Terex crane on a barge. Corman dynamically tested seven piles to verify load capacity followed by a Statnamic test to determine the axial compressive load. An explosive charge was detonated in the Statnamic apparatus equal to 880-kips. They then measured the pile displacement and analyzed the deflection versus static load curve to determine failure load. "Pile caps were originally cast-in-place," said Cox. "We proposed precast and worked through the design with the precast supplier and Maryland Port Administration engineers. The concrete pier caps were prefabricated offsite and then transported by barge and installed by Corman's 4100 Ringer Crane. By prefabricating the caps, we drastically reduced the amount of concrete placed in tidal areas and minimized the amount of concrete needing to be barged to placement sites." What's next? As for the what the future holds for Corman, Cox says that in the next two to five years, the company will increase its attention and strength on marine and water/sewer projects, expanding in the types of work within its markets and geographical reach. "We will also continue to focus as a 'Best in Class' general contractor in our core mid-Atlantic territory as we have for nearly a century."
GeoStructures Inc., based in Purcellville, Va., designs and builds foundation support and soil reinforcement for large commercial, industrial and residential structures throughout the eastern U.S. They joined PDCA earlier this year and couldn't be happier with the decision to become a member. "We felt this was an important step to advancing the capabilities of our group in the U.S. since we had recently become part of the Terratest Group, which has a great history in deep foundations around the world," said Michael Cowell, PE, president and CEO at GeoStructures. Cowell who previously was vice president of the Reinforced Earth Company and general manager of the Tensar Corporation formed GeoStructures in 1995 because he found that every time an innovative solution or product was developed, a contractor was needed who was willing to build it, or it wouldn't happen. "I wanted to develop a design-build company that would challenge conventional solutions and provide customers with innovative solutions to their foundation and grade separation challenges. The test against which success was measured was that every solution needed to provide customers with value in terms of cost savings over conventional methods, a shorter schedule and a seamless project delivery by a team focused on customer service through the design/build delivery. It was believed that anyone can bid specs and plans, but real value occurs by improving the plan and providing a design that is easier to build, lowers cost, improves the schedule and is accomplished with great customer service." History and today GeoStructures began as a design and marketing firm selling tieback and cantilever pile solutions to contractors in 1995. In 1997, the company obtained the Geopier® license for the mid-Atlantic area and formed a construction arm GeoConstructors to design and build Geopier ground improvement systems. The growth of ground improvement in the region led to numerous contracts on projects in North Carolina through New York, including support of embankments for the 11th Street Bridge project in D.C., the I-495 HOT Lanes, Capital One Building in Tyson's Corner, Pittsburgh Penguin Arena, Tappan Zee Bridge Abutment and office buildings, data centers and warehouses along the I-95 corridor. As the company grew, the company expanded into piling options to compliment the ground improvement. In 2010, GeoStructures worked with the Fluor-Lane JV on the I-495 HOT Lanes project designing and building all the sound walls, MSE walls and several soldier pile and tieback walls. Overall, this was a $45 million contract. "It was in January of this year that the Geo Group was sold to the Terratest Group, which will enable Geo to expand its footprint in the U.S. and provide more design-build capabilities in piling, support of excavation, diaphragm walls and tunneling," said Cowell. GeoStructures and its affiliated construction companies (including GeoConstructors) have approximately 90 employees serving customers in New York, New Jersey, Delaware, Pennsylvania, Maryland, Virginia and North Carolina. GeoStructures specializes in providing design-build construction services for foundation support (precast concrete piles, pipe piles, H piles, full displacement columns, ductile iron piles (DIPs) and diaphragm walls), ground improvement (aggregate piers, rigid onclusions and rapid impact compaction) and structures (microtunneling, diaphragm walls, SOE, sound walls, retaining walls, MSE walls, post and panel walls, concrete arches and bridges). "These technologies are used to solve problems such as settlement control of buildings, tank and MSE wall foundations, liquefaction mitigation, support of load transfer platforms for walls and embankment, economical grade separation options and repair and replacement of utility tunnels," said Cowell. He adds that over the past 20 years, a great deal of the design-bid-build work with drilled shafts and piles has switched to design-build with ground improvement. "Recently, in the last three years, we have been promoting design-build for pile foundations and combinations of piles and ground improvement. This seems to be taking hold and allowing more innovation with piles." Notable projects While GeoStructures has a number of impressive projects under its proverbial toolbelt, two notable projects include the Adele in Washington, D.C., and Virginia Tech (Brodie Hall) in Blacksburg, Va. The Adele is a redevelopment project that involved the construction of a new eight-story, mixed-use project located just three blocks north of the White House. The main challenge consisted of installing a cost-effective, low-vibration deep foundation on an extremely tight urban site. "The geotechnical engineer considered numerous deep foundation options, including caissons extending to bedrock, auger cast piles and ductile iron piles," said Cowell. "Ductile iron piles were selected because of the ability to work on the congested site, the modular and self-contained nature of the operation and the low-vibration levels during installation, which allowed us to work immediately adjacent to the property lines." The piles were designed for a working capacity of 40 tons (compression). The DIP design consisted of a 4.6-inch diameter pile with a 0.3-inch wall thickness, which could develop a working capacity of 40 tons by driving through the terrace and residual deposits and terminated in partially weathered rock. In several locations, the piles were required to support 40-ton compression loads as well as five-ton tension loads. A modified installation approach was used on the tension piles using an oversized 8.6-inch conical grouting shoe, which allowed grout to be pumped through the pile and outside the pile to create a friction bond with the soil and weathered rock. The piles were driven to termination by achieving set in the weathered rock and resisted the tensile loads with a center bar inserted into the center of the friction pile. "A compression load test was also performed at the site," Cowell said. "Deflection of the compression pile was less than a quarter-inch at the 80-kip design load. Following pre-production testing, a total of 145 piles were installed to terminate in rock at depths on the order of 25 to 30 feet below the working grade." In Blacksburg, Va., the Virginia Tech Brodie Hall project included the construction of a new five-story dormitory with 234 dorm rooms with study and lounge space on each level. Project challenges included the following: Heavily loaded mat foundations next to smaller footings Excess settlement potential from adjacent footing stresses Deep weak soil profile Variable depth to a competent soil/rock layer Tight settlement tolerances less than three-quarter-inch total "A combination of systems proved to be the best method and consisted of Geopier rigid inclusions, Geopier Rammed Aggregate Pier® elements and Ductile Iron Piles," said Cowell. "The DIPs provided an economical solution for areas where pier depths were 55 to 75 feet deep, which was beyond the depth capabilities for Geopier elements. The DIPs were able to transfer loads down to the weathered rock layer, thus eliminating adjacent footing stresses and controlling settlement to below less than three-quarter-inch." What's next? As for the near future, Cowell says over the next few years the plan is to move the needle on promoting design-build performance specifications for deep foundations. "Currently, most deep foundation designs are prescriptive, with 'one size fits all' designs. Specialty contractors are only asked to provide a price for what is specified. By providing design-build specifications, we believe that owners and general contractors can benefit greatly from the many innovative solutions that specialty contractors can provide with pile foundations."
The story of the piling industry goes back 6,000 years back to those Neolithic forward-thinkers who pounded thick wood branches into the ground to elevate their homes against flooding and predators. Over time, these rudimentary methods were replaced with piles made of treated wood, reinforced concrete and steel hammered deep into the earth by powerful machinery and sophisticated engineering design specifications. This long history of innovation in the piling industry continues with fast-growing developments in the design and creation of composite materials. With 45 years of experience in high-strength pultruded fiberglass-reinforced polymer (FRP) products, Creative Pultrusions, Inc. (CPI) brings a sophisticated level of innovation to the face of piling materials and design. Founded in 1973 in Alum Bank, Pa., the company operates 16 pultrusion machines on its 17-acre site, delivering a variety of standard FRP products, as well as custom manufactured profiles and systems for markets including defense, transportation, oil and gas and civil infrastructure. "Creative" isn't just a pretty word in the name of this company. It stands for innovation in design, manufacturing and new applications in many industries, including marine infrastructure. Proving the product first "We developed our composite sheet piling about 20 years ago," said Dustin Troutman, director of marketing and product development at CPI. "Our SuperLoc® sheet pile system is a patented pultruded sheet pile retaining wall arrangement developed for waterfront bulkhead applications." Troutman recalls how his team spent a lot of time and money early on developing the FRP sheet piling products line, working extensively with universities to understand how the products would perform in terms of mechanics of materials. "We have our own test 'bed' at our plant involving a real-life simulation. We install the sheet pile wall outside; then the University of West Virginia comes in with strain gauges and we test the sheets in full sections in order to validate their capacities. This operation is performed to validate our finite element analysis (FEA) and mechanics of materials moment capacity predictions of our sheet pile sections." The composite sheet piles have been evaluated based on creep rupture, compression strength and stiffness and shear capacity to name a few. The characteristic design strengths have been developed based on the requirements of ASTM D7290, a world recognized standard for pultruded profiles used for civil structures. The standard is intended to ensure that all manufactures publish their design data, so the engineering community can utilize the data for load and resistance factor design (LRFD) or allowable stress design commonly used today when engineers design bulkheads with legacy materials of construction. "We developed not only the sheet piles, but also the wales and caps a complete system," said Troutman. SuperWale® eliminates the need for concrete, timber or steel wale sections. Since they won't rot, decay, rust or spall, these FRP wales can be installed above or below the waterline or in the transition zone. Sheet pile corner connectors, caps, wale splice plates and washers are also available. The fender pile solution Always looking for creative solutions to changing needs and ongoing issues, CPI next tackled fendering (bridge protection systems). FRP structural pipe piles have high strength, but less stiffness than steel, allowing for greater deflection of energy. Troutman said, "We turned a perceived threat into the development of a system that absorbs a lot of energy." In 2010, SUPERPILE® was made available a composite fender pile system that makes use of the material's superior performance in harsh marine locations with no corrosion or harmful substances leached into the environment. The system is low maintenance, extremely long-lasting and installed with traditional pile-driving equipment. Troutman said, "Our piles are much lighter than concrete or steel 80 percent lighter than steel making them easier to use, not to mention the higher degree of safety involved in terms of handling." SUPERPILES® can be driven twice as fast as solid wood, concrete or thermoplastic piles, can be field drilled and cut and have very low electrical conductivity. This excellent dielectric strength is an important safety factor when driving piles near underground electric lines. Realizing they were ideal for docks and bearing piles, three years ago CPI developed the SUPERPILE® Legacy Dock Pile 10 inches in diameter with 3/8-inch thick walls. According to Troutman, the average Floridian wood pile lasts five to 20 years, depending on the environment, but these composite piles last over 50 years. The Legacy Dock Pile is more expensive than wood, developed for owners who want to install a dock and forget about the future replacements of the piles. Moving up and out into the world In 2008, recognizing these advancements in CPI's products and innovative applications, Hill & Smith Holding PLC, an international group involved in design, manufacturing and supply of infrastructure products and galvanizing services, took Creative Pultrusions under its wing as a subsidiary company. "They saw a future in composites for infrastructure applications," said Troutman. "Since then they've been very supportive of what we're doing." In turn, under its composite growth initiatives, CPI acquired three companies in the last two years: ET Techtonics (prefabricated pedestrian bridges), Tower Tech (cooling towers) and Kenway Composites in March 2017. Kenway has been in the business of supplying composite products to heavy industry since 1947. Bringing them in as a subsidiary of CPI and expanding custom manufacturing and field services work was the next step towards the growing future of composites worldwide. "It's a really good fit for us," said Troutman. "We wanted to add other manufacturing methods, such as vacuum infusion and filament winding, to our repertoire. They were already manufacturing and marketing HarborPile™, a composite pipe pile that can be made up to 78 inches in diameter with wall thicknesses ranging from a half-inch to two inches, and HarborCamel™, used as a log camel to dissipate vessel hull mooring loads across multiple dock fender piles." With Kenway's product lines already in place, this allowed CPI to expand their product offerings in terms of fendering systems and bearing piles without making a major retooling investment. Replacing old with new In 2012, Hurricane Sandy caused extensive damage to Liberty Island, home to the Statue of Liberty. The surrounding docks sustained the worst of it and the pier used to bring heavy equipment onto the island was completely rebuilt using Creative Pultrusions SUPERPILE® pipe piles to replace the destroyed timber piles. Corrosion-resistant and designed to withstand extreme weather, 198 FRP fender and bearing piles, 49 feet long, 12 inches in diameter, with walls half an inch thick were equipped with steel-pointed driving heads to protect the pipes from filling with dirt so they could later be filled with concrete. The next year, CPI Supplied 230 SUPERPILE® fender piles ranging in length from 60 to 66 feet for a total rebuild of a U.S. Navy refueling pier near San Diego. Each pile carried a 20-inch HDPE sleeve designed to help mitigate abrasion from marine camels. They were installed using the APE 150 vibratory hammer with steel driving head. "We've done quite a bit for the U.S. Navy," said Troutman. "That's because they want something that will stand the test of time. Although most of our business has been domestic, there have been some applications in Australia and the Caribbean." The future is now Word is getting out about the many advantages of using FRP composite products in the pile driving industry, and that means the CPI team spends a lot of time teaching engineers how to use these unique products in their design. "We have experts on staff who test the structural integrity of our products all the time, supporting the development of design codes and specifications for the materials," said Troutman. "We are now ISO 9001:2015 approved for manufacturing and design." "Eventually we are going to get into the foundation side of the Bearing Pile market wherever it makes business sense dealing with corrosion issues associated with our aging infrastructure." Troutman talks about 200-plus great employees dedicated to the group's products, not only in terms of manufacturing, but also in development and sales. A strong safety department pays particular attention to all the moving parts in the factory, while the company works with the community, helping out wherever they can, such as the recent donation of piles for a local baseball field lighting project. As a member of PDCA for six years, CPI takes part in the larger community of the industry, participating in trade show events and networking with a variety of member companies involved in the marine industry. Composites hold an important place in the future of pile driving, both in replacing old corroding and damaged infrastructure and in new projects. With its commitment to product design and manufacturing, and belief in innovative applications, Creative Pultrusions Inc. is taking its place in the pages of pile driving history.
For over 50 years, Japan's Giken Group of Companies (Giken Ltd.) has been making revolutionary advances in piling technology. Their aim has been to use their innovations to create dynamic, positive change that enhances efficiency and delivers social benefits. Following the devastation of the Second World War, Japan had a lot of rebuilding to do. In fact, Japan's major cities were massive construction projects, with people living side by side with heavy equipment, clouds of dust and constant noise. This was the world in which Akio Kitamura, founder of The Giken Group of Companies, started his career as a builder and innovator. Kitamura got his start in construction as an assistant equipment operator with the Kochi Construction Centre back in the 1960s. He learned much and was able to take this forward with the founding of his first enterprise, The Kochi Giken Engineering Consulting Company, a firm he launched in 1967. The company was busy, and Kitamura soon learned that citizens of the city were unhappy about the constant noise of vibration hammers that were pounding foundations into the ground as the country rapidly rebuilt. Following an incident where an angry resident, whose restaurant business was hampered by the construction noise, assaulted one his workers, Kitamura vowed to find a solution. Solutions to the noise problem proved challenging. To make progress, Kitamura enlisted the help of Yasuo Kakiuchi, a construction professional with an engineering background. Together, the pair was able to create the world's first silent, vibration free piling machine in 1973, with the Giken Silent Piler making its local market debut two years later. In 1975, the Silent Piler was introduced to the world at the International Environmental Prevention Exhibition in Osaka. And, while the patent gave sole use of the Silent Piler to Kochi Giken Engineering Consulting Company, a fact that could have presented a strong business hand for the firm, Kitamura saw the benefit the device could have for society, so he agreed to allow the sale of the Silent Piler widely in Japan. By the 1980s, the Giken Silent Piler was in use globally, with Sweden taking the first European order in 1983. The Silent Piler is a "reaction-based" hydraulic pile-jacking, non-vibratory machine that operates with a minimal noise impact to install steel sheet and tubular piles. This technology can be applied in both soft and hard ground conditions and for the installation of U and Z profile sheet piles in both singles and pairs. Unlike traditional impact hammer and vibratory systems, Giken's equipment utilizes forceful hydraulics to push the piles down into the ground in a manner that greatly reduces noise pollution. These systems are also compact, which means piling contractors can more easily access challenging sites. With the Giken Silent Piler making positive advances in construction, the company began opening international offices to consolidate support for sales. The London, U.K., office opened in 1990, followed by another European location launched in the Netherlands the next year. Driving Giken farther still has been the company's "Construction Revolution" concept, based on five core principles: environmental protection, aesthetics, safety, the economy and speed. Since 1993, Giken has advocated and promoted this "Revolution" to create a new standard that surpasses the conventions of the current construction industry. According to the company, "The 'Construction Revolution' breaks the shackles of convention and leads to a great paradigm-shift of the global construction industry." A good case-in-point has been the development of EcoPark and EcoCycle, two examples from the 1990s of revolutionary design approaches to a city planning challenge. EcoPark is an earthquake-proof underground car parking facility that uses a robotized system to place vehicles in a silo-like below grade garage. EcoCycle offers a similar set up, but for bicycles. Behind this is Kitamura's philosophy that a culture of a city should be above ground for the people to enjoy, while the functionality of a city should be below ground and out of view. Both EcoPark and EcoCycle allow for greater harmony within the urban environment and conform to Giken's core principles. Both projects also demonstrated Giken's abilities to create complex underground structures that met the challenges of Japan's unique geology. Working to further develop its press-in technology, Giken joined forces with Cambridge University in 1993. This initiative has led to the launch of the International Press-in Association (2007), a group tasked with research and development of the technique that has gained wide-global acceptance. Internationally, Giken Ltd. has been able to grow its global market though an expanding network of sales offices. Already mentioned are the European branches that opened in 1990 and 1991. By 1996, Singapore had come on board and the U.S. joined the team in 1999, with an office in Orlando, Fla. It was during this period in the 1990s that Giken announced it had sold its 2,000th Silent Piler machine. It also announced a major addition to the product line-up with the Crush Piler (1997), a press-in piler that featured a simultaneous auger to tackle hard subsurface jobs hampered with boulders and rock layers. A major test of Giken's engineering came during Japan's earthquake of 2011. Using its press-in method, Giken had created a number of implant structures designed to withstand strong ocean forces following an earthquake. While other devices such as concrete buttresses were washed away in the post-earthquake tsunami, the Giken implants worked as designed. Today, Giken has built and delivered in excess of 3,500 Silent and Crush Pilers. This success has generated real value for stakeholders of the company that is now listed on the Tokyo Stock Exchange. Revolutionary thinking Giken reports that its growth has been steady and measured. The mission to challenge traditional methods has been consistent all along the road from 1967 to 1975 to 2018. An example of this thinking can be seen in how Giken looks at permanent structures. The traditional approach is to see functionality as never changing. Giken said, "In this decade, when the progress of technology development and cultural development is significant, we need to change our way of thinking regarding the 'permanent structure' that makes its purpose, location and functionality unchangeable. This endorses the need for society to demand a new approach to construction. "In order for us to sustain our society, we need to adjust ourselves according to changes of time and development of culture. It will require us to flexibly manage the life cycle of functional [structures] such as changes in function of infrastructures, restoration of natural environment and re-cycle of construction material. "The issue of how to demolish and re-use or recycle structures at the end of their life should be 'engineered' into every structure. This is the key to sustainable development and total design, incorporating flexible functional changes and end-of-life recycling processes." Behind this thinking is a desire to discover solutions. Certainly, the provision of solutions to engineering challenges is what drives Giken forward. For example, in New York City, Hurricane Sandy hammered the 114-year old subway in 2012. Repairs have been fraught with challenges. To get on the right side of these challenges, the New York Transport Authority approved the use of Giken's Hard Ground Press-in Method to get around problems such as rock and buried metal, and limit damage to existing below grade infrastructure. The reports have been so positive on Giken's Press-in pilers in New York's subway repair that expectations are that these devices will make themselves better known across the U.S. The path from a Kochi work site and an angry sushi chef that resulted in the development of the first Silent Piler has been a long one. However, the socially positive philosophies of Kitamura and the engineering prowess that sought those first solutions is one that promises to maintain the drive to innovate and push The Giken Group of Companies to even greater heights. Expect much from this company in its next 50 years. t This article first appeared in Piling Canada and is reprinted here with permission.
Shannon & Wilson, Inc., a geotechnical engineering and environmental consulting firm based in Seattle, Wash., is known for innovation and technical expertise. It's a tradition that began with the two men who started the company in 1954, Bill Shannon and Stanley Wilson. "I think it really goes back to both of our founders, but in particular Stan Wilson, who was quite an innovator and had multiple patents," said Dr. Kathryn Petek, a geotechnical engineer with Shannon & Wilson. She notes that the slope inclinometer, which continues to be a key source of geotechnical data in construction today, was actually derived from a prototype built by Wilson in 1952. "We have a really strong culture of technical excellence. We have a very deep and wide bench of specialists and experts, who span all aspects of geotechnical and environmental engineering," said Petek. Shannon & Wilson established themselves as a leader in driven piles back in the early 1980s with the West Seattle Freeway Bridge replacement project. For this project, the company's engineers developed and executed an extensive static and dynamic load test program on instrumented 36-inch diameter open steel pipe piles and 24-inch octagonal, prestressed concrete piles. The results of the load test program led to reductions in production pile lengths and an improved understanding of pile drivability that ultimately resulted significant cost savings for the project. Over the years, the company has utilized driven piles for many public-sector infrastructure and private development projects. It's an impressive list that includes such structures as the CenturyLink Field Stadium and Exhibition Hall sports complex and the Safeco Field ballpark in Seattle, as well as numerous major bridge, railroad and port projects throughout the U.S. and Canada. For CenturyLink Field Stadium and Exhibition Hall in Seattle, Shannon & Wilson provided geotechnical engineering and environmental consulting services for the pre-design, design and construction phases of the large sports complex that's home to the Seattle Seahawks of the NFL. More than 1,000 18- and 24-inch closed-end steel pipe piles were required for the project, which was completed in 2002. In another driven pile application, Shannon & Wilson provided geotechnical and hydrogeologic services for design and construction of a four-acre pontoon casting facility in Aberdeen, Wash. Completed in 2011, the site was used to build 33 concrete pontoons needed for the new SR 520 Floating Bridge on Lake Washington. The project included more than 900 18- and 24-inch diameter open-end steel pipe piles. The piles were driven and cut-off 30 feet below grade with a specially designed down-hole tool that expedited subsequent site excavation. Over the last 60-plus years, Shannon & Wilson has witnessed the size of its projects increase. While maintaining roles in small and mid-size projects, Shannon & Wilson has taken on numerous mega-projects, including schedule driven design-build projects with high price tags. "The projects have become much more complex with [a] higher dollar value," said Shannon & Wilson president Gerard Buechel. "We're now involved in one and two billion-dollar projects." Buechel maintains one of the keys to the company's success has been the quality of Shannon & Wilson's staff, which numbers around 300 people. "We like to hire very smart people, and typically once they join our firm they stick around for a long time. For example, I've been here 38 years and there's probably 10 percent of the firm here that's been here more than 30 years; so there's a lot of tenure and expertise," Buechel said. "I think, in general, we're scientists at heart, and we like to take on the tough, challenging jobs. We've been successful enough to win those kinds of projects, and this keeps people engaged and retained." Buechel notes that while Shannon & Wilson does much of its work in the Pacific Northwest, the company's market area extends well beyond that. In addition to its head office in Seattle, Shannon & Wilson has 11 other branch offices in Washington, Alaska, Oregon, California, Utah, Colorado, Wisconsin, Missouri and Florida. "Our motto is 'Have Job, Will Travel', so we are licensed in all 50 states and we've done work in all 50 states," Buechel said. Shannon & Wilson has a seven-member board of directors that's chaired by Greg Fischer, and it is employee-owned, with over 80 percent of the firm's staff members holding ownership. "Being able to own part of the company certainly transforms the way we approach our work," said Petek. "I believe it results in a higher level of commitment in the projects we do." Expert in large diameter open-end steel piles Petek points out that Shannon & Wilson has become a leader in deep foundation projects that use large diameter open-end steel pipe piles. A notable example is the Port Mann Bridge replacement project near Vancouver, B.C., Canada. The new bridge is the second longest cable-stayed bridge in North America and, at the time of its completion, its 200-foot width made it the widest bridge in the world. Shannon & Wilson utilized six-foot-diameter open-end steel pipe piles on the project, which was completed in 2015 with a new 10 lane, 1.4-mile-long bridge spanning the Fraser River. The north and south bridge pylons, along with 10 additional approach piers, were supported by piles driven into very dense, glacially overridden deposits with lengths greater than 230 feet. "The project included an extensive deep foundation load test program, that included an instrumented static load test on a six-foot-diameter pile to over 12,000 kips," Petek said, adding that this static load test remains the largest ever performed with a conventional load testing frame in North America. "The static load test, combined with extensive dynamic load testing, enabled the use of higher resistance factors in design. The successful testing reduced the required number of piles by approximately 30 percent and ultimately led to significant cost savings for the project." Shannon & Wilson supported early applications of large diameter open-end steel pipe piles in the Pacific Northwest, including the WSDOT SR 529 Ebey Slough Bridge replacement project in Marysville, Wash., completed in 2012. For the Ebey Slough Bridge, four-foot and six-foot diameter piles were driven to depths greater than 220 feet. At that time, the piles were the longest and largest diameter piles driven for a project in Washington State. Shannon & Wilson has continued to utilize large diameter open-end piles ranging from 36 to more than 96 inches in diameter for numerous other projects, including the Alaskan Way Holgate to King Street Viaduct in Seattle, the Coast Meridian Overcrossing in Vancouver, B.C. and the Tanana River Bridge in Salcha, Ala. Shannon & Wilson's innovation in driven piles has led to its role as Co-Principal Investigator on a current Federal Highway Admiration (FHWA) research project on the bearing resistance of large diameter open-end piles. "This research builds upon Shannon & Wilson's experience with design and load testing of large diameter piles and aims to address some of the uncertainty associated with their design. The project team has used collected static load test data to evaluate static design methods," Petek said. "Based on the research, the project team has developed new resistance factors specific for large diameter open-end piles and is finalizing design recommendations to be synthesized in upcoming FHWA guidance and ultimately the AASHTO code." Shannon & Wilson is a relatively new member of PDCA. Petek says her company values the relationships it's already forged since joining the association in 2013. "We see PDCA as an increasingly important organization for developing connections across our industry and promoting advancements in driven piles," she said.
Prior to the inception of combined wall systems, sheet piles were commonly used for earth retention and support of excavation projects. During this time, the largest domestic sheet pile section had a section modulus of about 60 in³/ft. If design stresses exceeded that, engineers had to get creative by adding steel cover plating to the top and bottom flanges of the sheet pile. The additional steel would boost the section properties. This cover plating fabrication was a solution for the time when heavy civil/marine applications like deep excavations and port berthing structures needed something more than sheet pile could offer. It was effective, but not the most efficient solution. The plating material and fabrication were costly with poor engineering economics. Today, there are at least two hot rolled sheet pile series with wider, lighter and stronger sections that approach moduli of 100 in³/ft. Today, cover plated applications are rare and usually a last resort when efficient heavier sections are not available. The right combination Higher modulus wall solutions were explored early on by pile manufacturers. Dating back to the early 1900s, mill engineers envisioned multiple concepts, but as with most innovations, barriers to market such as manufacturing costs, application demand and expected return on investment dead-ended most patents before they received serious market consideration. The real breakthrough in high modulus wall design came when pile producers combined steel sheet pile sections with large beam shapes, (King Pile Combi-Wall) resulting in system properties and weight efficiencies like no other prior concept. The marriage of two conventional hot rolled sections made the combi-wall concept more attractive with minimal financial risk to develop. Unlike wide flange (WF) beams, H-King pile beams are designed to be geo-structurally supported by soil, so the buckling and slenderness ratios that govern unsupported column design can be stretched, allowing for wider and lighter dimensions compared to wide flange shapes. Although there are two domestic mills that make hot rolled sheets, none produce an H-King pile. Suppliers can offer an alternate with domestic sheets and WF beams, but there are engineering and material cost limitations. There is only one North American beam producer that makes the heavier, deeper WF sections. Even still, the flange widths are narrow and the connector weld locations create second moment properties. The result is poor unit weights with lower properties. Lastly, the weld-on connectors are not domestically produced. For these reasons, 100 percent domestic beam systems are not as viable. Combi-wall breakdown Traditional high modulus combined walls are made up of three components: 1) king pile the primary load member, either beam or pipe; 2) sheet piles the intermediate spanning elements that reduce panel weight, but contribute little structurally; 3) interlocking bars the weld-on connectors that structurally join the two piles. The system width is measured in panels from the centerline of one king pile, across the sheet piles to the centerline of the other. Like sheet pile, combi-wall properties are specified in the same units: section modulus (in³/ft), moment of inertia (in⁴/ft) and bending moment (kip-ft/ft). When a designer or contractor is considering pipe or beam combi-wall options, wider, lighter and stronger are the key measurable variables, but there are other commercial, structural and installation factors that impact overall cost and feasibility. Pipe Z and H-King Z: pros and cons The shape of the primary load member (beam or pipe) has pros and cons. Pipe can get wide and deep, so the inertial properties are good, but the cross-sectional area is spread throughout the diameter, so the section modulus is not proportionate and often lower than what the analysis requires. More steel is needed, so the wall thickness must increase. Striking a balance between the pipe diameter (30-inch to 84-inch) and wall thickness (0.375-inch to one inch) to meet both property requirements can be an iterative process. The pipe Z panel widths (7.5-feet to 12-feet) require fewer panels to install compared to H-King single and double beam configurations (5.75-feet to 8.33-feet), but the pipe unit weight is typically much higher and site restrictions often limit the section depth. A larger OD pipe will have more concrete and rebar for the splash apron, cap and moment connection. They may also have backfilling requirements inside the pile. Pipe is readily available with ample domestic and foreign production. Hot rolled Z sheets also have foreign and domestic options and the weld on pile connectors are well sourced. If the material is available, 12-week lead times are possible. H-King beams are specifically designed for high modulus wall loading to maximize structural properties and weight efficiency. They achieve very high modulus numbers with single and double pile layouts with 33-inch to 48-inch beams. Since no domestic mills produce a true H-King high modulus system, lead times typically range from 16 to 20 weeks. All these factors should be considered when evaluating the most economical solution. Piling market Since 2016, the market has one H-King combi-wall producer. ArcelorMittal (Luxembourg) has been the gold standard in high modulus walls for decades. Their current HZM system was an evolution from the original HZ predecessor. Beam modifications and mill upgrades in the mid-2000s, combined with 700mm and 770mm AZ sheet piles resulted in better strength to weight efficiencies, further distancing their competitive advantage. Salzgitter Mannesmann's Peiner system (Germany) was a formidable competitor until the line was discontinued in 2016. Since then, HZM has been the sole sourced king beam combi-wall system in the world. When the German Hoesch sheet pile mill closed in 2016, a large void was left in the North American piling market. As the exclusive partner of Hoesch, JD Fields & Company, Inc. (JDF) grew their Larssen "Z" line to 100,000 annual tons in the U.S., Canada, Mexico and the Caribbean. With only two domestic mills producing a limited range of light to heavy sections, news of Anshan Zizhu coming on line with a new mill had North American distributors scrambling to China in hopes of replacing the lost tonnage. After careful consideration, Zizhu recognized the market success Hoesch experienced with JD Fields, and selected them as their exclusive North American piling partner. The mill leaned on JDF's experienced sales and engineering leadership for domestic market and technical input with the new "ZZ" (Double Z Series). Agreeing to maintain the grade 60 standard JDF had established in North America, the "ZZ" launch was a successful collaboration resulting in the smoothest product release of a full range of light to super heavy "Z" sections with outstanding quality. High modulus math: JDF + ZZ = HZZ King beam and pipe combi-wall systems all share a common thread in their build and functionality: welded interlock connectors. These components add 2045 plf to each beam depending on the configuration and require costly fabrication. Now imagine the time and money to be saved if all of that could be estimated. That is exactly what JDF and Anshan Zizhu set out to do when they developed the new HZZ system. On the coat tails of a successful sheet pile launch, both partners were intrigued with the possibility of developing a high modulus wall solution to compliment the Double Z series. Not interested in just another "me too" king beam system, JDF challenged the mill to produce a beam that did not require a welded interlock connection. Anshan's technical team was progressive in embracing this out-of-the-box concept. After multiple design iterations, a breakthrough came in the shape of a unique hot rolled flange with a drop down nose and Larssen interlocks on the edges of the section. The HZZ Direct Connect Flange Technology™ was born. The nose shape serves three structural purposes: 1) It pushes the web-flange connection away from the x-y plane, addressing any concerns of having the weld on the shear axis; 2) Gives the beam strength to resist transverse stresses in the same manner as hot rolled beams or the flange-web transitions in a hot rolled sheet pile; and 3) Provides an excellent surface area for automated full penetration welds. Features and benefits From a commercial perspective, removing two, four or six connectors reduces up to 40 lb/ft per beam, eliminates fabrication and decreases lead-time. Regarding drivability, high modulus wall beam lengths can reach 100 feet with driving depths of 50 feet or more. H-King beam systems have good driving characteristics, but if there is a weak link, it's the connector. In comparison, the HZZ beam-sheet interlock connection is an integral part of the system, not a component add-on. The single beam configuration does not command a bottom interlock connection; further material savings are realized by using hot rolled plate. In a double pile scenario, the direct connect flanges are needed on top and bottom to interlock the beams, but the system allows for variable flange thicknesses. By selecting the heavier, thicker HZF 35T for corrosion durability on the top waterside and applying the lighter HZF 25 on the less corrosive soil side, the system offers custom weight efficiencies without compromising design integrity. These product innovations set HZZ's engineered beam technology apart from any other. Paradigm shift Combined walls are marketed and specified through product look up tables in catalogs. Take the HZM system for example, it is comprised of 11 beam sizes varying in weight and height, with two, four or six connectors, and four typical stock sheet pile sections. These components are offered in a variety of single and double beam configurations resulting in over 100 different wall solutions. The HZZ Direct Connect system is not limited to a finite number of beams or connectors. The hot rolled flange design and fabrication process allows for unlimited combinations of section height, web thickness and flanges for single and double beam layouts. This is the first and only high modulus combined wall system that can design and build a custom wall solution based on specific application requirements. This is a reversal in the catalog specification that will challenge the conventional marketing process. JD Fields immediately recognized that the HZZ system customization feature would be restricted within the pages of a printed manual. They had to envision a marketing medium that would showcase the dynamic versatility. The solution will be revealed in interactive design software in Q1 2019. The online platform is currently under construction, but JDF is already quoting and taking orders. The HZZ Wall Builder™ tool is going to be the most comprehensive technical graphic interface and marketing platform with cradle to grave input modules and comparison tools. From geostructural analysis, durability and cost engineering, to custom generated CAD files and data tables, this platform will revolutionize high modulus wall applications. Owners, engineers and contractors working in the marine piling and deep foundation industry have a lot to be excited about. Look for this game-changing platform in Q1 2019. Fields' technical team currently offers no cost engineering seminars and lunch and learns on the HZZ system and its Wall Builder design software.
Treated timber has been a mainstay in aquatic construction projects for many years and remains so today. It has been used successfully in a variety of structures such as docks, retaining walls, bridges, boardwalks and building foundations. The strength, ease of installation, low cost and natural appearance make timber a practical choice for many applications. The durability of timber is a key consideration in its selection for aquatic settings such as oceans, rivers and wetlands, which can be harsh environments. To ensure durability and a long service life, timber is pressure treated with preservatives that inhibit biological attack. The preservatives in most common use today are waterborne preservatives, chromated copper arsenate (CCA), ammonical copper zinc arsenate (ACZA), alkaline copper quat (ACQ) and copper azole (CA-B & C). These preservatives do an excellent job of extending the service life of timber so it can provide decades of use. Preservatives consist of chemical components that discourage or prohibit biological attack. These chemicals, like the chemicals in any number of consumer products, are beneficial when properly used in appropriate quantities. The preservatives used to treat timber are subject to approval by the Environmental Protection Agency. They have been rigorously studied and approved for their intended use. When treated timber is immersed in water, preservatives can leach out in small amounts. Most preservative loss occurs within the first few days of immersion. Rates of preservative loss decline quickly and are often undetectable after a week or two. Preservative components that have leached from treated wood can accumulate in sediments surrounding a structure and these accumulations are typically minimal and do not pose any environmental risk, as evidenced by the long history and large number of timber structures constructed along waterways surrounded by abundant plant and animal life. The use of treated timber in or over water will not create a significant risk unless a large quantity of material is installed in an area with little to no water movement or at a site that had been previously contaminated from other sources. Every structure placed in an aquatic environment has an environmental impact. This includes both the structure and the construction process. Minimizing environmental impact is an important part of project planning. Despite the negligible environmental impact posed by treated timber, it further benefits everyone to minimize any potential release of preservatives into the environment. There are several simple, basic steps that can ensure that the use of treated timber is as efficient as possible. The first step is to select the proper preservative for the species of wood being utilized. The American Wood Protection Association (AWPA) has developed standards for the appropriate use of wood preservatives for many wood species to meet a variety of service conditions. Through a system of Use Categories, the AWPA specifies the amount of preservative needed to accomplish a given task based on exposure conditions. The primary Use Categories that apply to treated timber in aquatic applications are UC3B, UC4A C and UC5A C. UC3B addresses above ground timber used in proximity to fresh water, UC4A C address timber and piles used in fresh water applications while UC5A C address timber and piles used in marine conditions. Like all products that rely on chemical components, the objective is to use no more preservative than is necessary to accomplish the specified task. Using the minimum amount of preservative needed leaves no surplus to be absorbed by the surrounding environment. In general, higher rates of preservative retention in treated timber increase the potential for the leaching of chemicals into the environment. Using a higher preservative retention than prescribed by AWPA standards "just to be sure" increases the environmental impact without providing additional protection. Other means of introducing excess preservative into the environment are utilizing timber that has been pressure treated more than once or using treated timber with visible surface deposits of preservative. Both should be avoided in aquatic areas. The second step is to allow sufficient time for fixation of the preservative. Fixation is the chemical process that binds the preservative to the wood thereby increasing its resistance to leaching. Most fixation occurs relatively quickly after pressure treatment, but the rate of fixation soon slows. Incremental increases in the amount of fixation take progressively longer periods of time. The amount of time required for the fixation process to be completed can last from days to weeks, depending on the temperature. Warm weather enhances the fixation process while cold conditions slow it down. The more time that can be allowed for the fixation process to bind preservative to the wood, the better the wood will be protected and the less preservative will be available for leaching. A third step to minimize environmental impact is to minimize the amount of field fabrication required for construction. To the fullest extent possible, the timber should be prefabricated prior to treatment. Prefabrication not only allows the pressure treatment process to provide the best protection possible, it speeds installation on the site and eliminates or minimizes the amount of debris and retreatment that results from field fabrication. Field fabrication, when required, should be accomplished in upland areas away from water when practical. Sawing, drilling and fitting in the field results in treated timber debris in the form of sawdust and scraps. When this debris is allowed to fall into water the amount of preservative leached is often at a much higher rate than the primary structure due to the relatively larger amount of surface area. Whether field fabrication occurs on land or over water this debris should always be collected for proper disposal. Field fabrication also damages the protective preservative envelope created by the initial pressure treatment. To protect the wood, all cuts and holes must be retreated with the AWPA recommended copper naphthenate preservative containing a minimum of two percent copper. Care should be taken to prevent the liquid field preservative from entering water and all excess solution should be removed or allowed to dry before the material is placed into service. If field retreatment is required, take all appropriate steps to prevent the liquid preservative from entering the environment. For a more comprehensive review of this topic see "Treated Wood in Aquatic Environments." Copies can be downloaded from the Timber Piling Council website, www.timberpilingcouncil.com. t The Timber Piling Council serves as a resource for the proper design and use of treated timber piles.
The origins of confinement reinforcement requirements specifically, circular spiral for square, octagonal or circular concrete piles have long been somewhat of a mystery. The outcome has been a myriad of prescriptive rules, which vary widely depending on the code, standard or specification applicable to a project. The graph below shows the historical variability of some of these prescriptive requirements for 24-inch-octagonal prestressed concrete piles. Inexplicably, the requirements also vary significantly depending on whether the piles are cast-in-place or precast concrete and driven. These provisions affect the size, spacing and depth below the pile head where varying quantities of spiral reinforcement are required. Clearly, these provisions significantly affect the cost of piles. This article reviews the status of recent research and its applicability to concrete piles. Background The primary purposes of spiral reinforcement are to provide confinement to the pile concrete core so that it behaves in a ductile manner under combinations of axial and lateral loads, to provide support to restrain bucking of non-prestressed longitudinal reinforcement and to provide adequate shear strength. The lateral loads imposed by earthquakes are of great concern. Therefore, the spiral reinforcement requirements naturally escalate as the Seismic Design Category (SDC) increases. Spiral reinforcement in high SDCs, sized in accordance with current requirements, can become very heavy, and, in some cases, may be unconstructable, particularly for smaller pile sizes. For driven piles, the spiral also confines the concrete at the head and tip to mitigate bursting during driving. Mild steel driving rings have also been used for this purpose. In 1993, the Precast/Prestressed Concrete Institute (PCI) published its "Recommended Practice for Design, Manufacture, and Installation of Prestressed Concrete Piling" (RP).1 This document provided equations for determining spiral volumetric ratios in moderate and high seismic regions, based primarily on research performed in New Zealand by Joen and Park.2 However, the equation in the PCI RP for high seismic regions provided roughly half of the spiral volumetric ratio recommended by the New Zealand research shown in the graph below. This PCI equation was proposed in the apparent belief that half of the target ductility sought by the New Zealand researchers would be sufficient for high seismic regions in the United States, although the reason for this conclusion is not clear. The PCI RP equation was adopted in the 2000 edition of the International Building Code (IBC). However, IBC 2000 maintained the upper limits on volumetric ratio from previous editions.3 Chapter 20 of the PCI Bridge Design Manual4 recommends the full volumetric ratio of spiral resulting from the New Zealand research, although this recommendation has not been adopted into American Association of State Highway and Transportation Officials' AASHTO LRFD Bridge Design Specifications.5 Iowa State University research In light of the uncertainty surrounding prescriptive requirements for spiral reinforcement, PCI funded a research project in 2006 at Iowa State University to develop a rational means of determining spiral volumetric ratios in prestressed concrete piles. The results of this research were detailed in a final report,6 and a summary was published in the PCI Journal.7 A single equation is proposed to quantify spiral volumetric ratios depending on target curvature ductility. A value of target curvature ductility is suggested for high seismic regions based on a review of literature published on pile testing and a "back-end" analysis of piles subjected to actual earthquakes. Lower values of target curvature ductility are also suggested for low and moderate seismic regions. Values of target curvature ductility other than those suggested, such as those derived from a performance-based analysis, can also be used. The research establishes axial load limits for different sizes and shapes of prestressed concrete piles. The purpose of these limits is to ensure that, under combined axial load and moment, the pile cracks before the concrete cover spalls. When the opposite is true, the decrease in moment capacity due to concrete cover spalling is significant, and the pile does not behave as intended. The 2018 edition of the IBC adopted these recommendations in place of the previous PCI RP provisions, while maintaining the same upper limits on volumetric ratio provided in previous editions.8 The American Concrete Institute (ACI) Committee 318 intends to adopt requirements for deep foundations in the 2019 edition of Building Code Requirements for Structural Concrete (ACI 318-19). Historically, ACI 318 has not included provisions for piles, unless portions of the pile are not adequately laterally restrained by stiff soil and for SDCs D, E and F. Even then, with the exception of provisions related to seismic detailing, no specific provisions existed for piles, which were essentially to be designed under the same rules as columns. Provisions in the AASHTO LRFD specifications for confinement reinforcement in piles are similar to the ACI 318 provisions for columns. ACI Committee 318 is currently balloting provisions for piles similar to those in the 2018 IBC. AASHTO Subcommittee T-10 on Concrete Design should also consider revisions to the AASHTO LRFD specifications to incorporate the most recent research on concrete pile confinement reinforcement. Precast, prestressed concrete piles versus cast-in-place piles As mentioned, spiral reinforcement requirements vary significantly depending on the type of concrete pile selected. Most of these differences are inexplicable given that different types of concrete piles should be expected to perform similarly under the same conditions. Also, differences that should be considered between the pile types, such as susceptibility to downdrag, cross-sectional tolerances and tolerances for placement of reinforcement, are generally not considered in prescriptive design provisions for buildings. Such differences should result in higher resistance factors for precast concrete piles than for cast-in-place piles, as is the case for bridge construction. Mays provides an excellent discussion of these aspects of concrete pile design and detailing.9 Because time is of the essence for the 2019 release of ACI 318, it is not possible for these differences to be remedied for ACI 318-19. As a member of ACI Committee 318, the author has requested that these discrepancies be taken up as new business in the next code cycle. t A version of this article was originally published in the Fall 2018 issue of ASPIRE® (www.aspiremagazine.com). ASPIRE's editors have given permission to reprint the article in whole or in part. References 1. Precast/Prestressed Concrete Institute (PCI) Committee on Prestressed Concrete Piling. 1993. "Recommended Practice for Design, Manufacture, and Installation of Prestressed Concrete Piling." PCI Journal 38(2): 14-41. 2. Joen, P.H., and R. Park. 1990. "Flexural Strength and Ductility Analysis of Spirally Reinforced Prestressed Concrete Piles." PCI Journal 35(4): 64-83. 3. International Code Council (ICC). 2000. International Building Code. Falls Church, VA: ICC. 4. PCI Committee on Bridges. 2004. PCI Bridge Design Manual. Chicago, IL: PCI. 5. American Association of State Highway and Transportation Officials (AASHTO). 2017. AASHTO LRFD Bridge Design Specifications. 8th ed. Washington, DC: AASHTO. 6. Fanous, A., S. Sritharan, M. Suleiman, J. Huang, and K. Arulmoli. 2010. Minimum Spiral Reinforcement Requirements and Lateral Displacement Limits for Prestressed Concrete Piles in High Seismic Regions. Final report to PCI; ISU- ERI-Ames Report ERI-10321. Ames, IA: Department of Civil, Construction, and Environmental Engineering, Iowa State University. 7. Sritharan, S., A.M. Cox, J. Huang, M. Suleiman, and K. Arulmoli. 2016. "Minimum Confinement Reinforcement for Prestressed Concrete Piles and a Rational Seismic Design Framework." PCI Journal 61(1): 51-70. 8. ICC. 2017. 2018 International Building Code. Washington, DC: ICC. 9. Mays, T.W. 2016. "Rethinking Seismic Ductility." STRUCTURE 23(3): 10-13.
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