By SETH CONDELL, P.E., LEED AP, ENV SP, M.ASCE, and THOMAS SPOTH, P.E., M.ASCE
The new Goethals Bridge between New York and New Jersey incorporates into its towers a completely new style of cable-stay anchor box that resembles a saddle—but has the advantages of a cable end anchor. Other innovations include smart-bridge technology, resilience to superstorms and earthquakes, uncommon funding mechanisms, and 3-D printed models to facilitate understanding.
The story of the Goethals Bridge is a story of firsts. The original bridge and the Outerbridge Crossing were the first facilities constructed by the Port Authority of New York and New Jersey, opening on the same day in 1928. The replacement Goethals Bridge crossing, which opened in May 2018, is the Authority's first infrastructure project delivered via public—private partnership (P3). The new bridge also features several unique structural systems, including the first use of an innovative stay-cable anchor box design at the tops of the towers that meets stringent redundancy and resiliency requirements never before applied to a major highway bridge.
The Goethals Bridge spans the Arthur Kill between Staten Island, New York, and Elizabeth, New Jersey. As traffic increased on the original Goethals Bridge, a steel truss cantilever bridge designed by John Alexander Low Waddell, the crossing was eventually deemed to be functionally obsolete. Drivers had been enduring a white-knuckle experience, navigating steep grades on the bridge's four narrow lanes with no shoulders and no median while dealing with heavy truck traffic generated by the bridge's proximity to the Howland Hook Marine Terminal and the New Jersey Turnpike. Solutions to these conditions had been explored for years to ensure the sustained economic vitality of the region.
To move forward with the $1.5-billion project, the Authority chose for the first time in its history to use the P3 delivery method. After an open competition that resulted in a short list of three candidates, the Authority selected the NYNJ Link team, which comprises Macquarie Infrastructure and Real Assets, Kiewit-Weeks-Massman AJV, and Parsons Corp., to design, build, finance, and maintain the replacement crossing. Macquarie is an international infrastructure investment firm headquartered in Sydney, Australia, and Parsons is an international engineering and design firm based in Pasadena, California. Kiewit-Weeks-Massman is a joint venture of Kiewit Infrastructure Co., of Woodcliff Lake, New Jersey; Weeks Marine Inc., of Cranford, New Jersey; and Massman Construction Co., a heavy civil and marine contractor headquartered in Overland Park, Kansas. Systra/International Bridge Technologies (IBT), of San Diego, was chosen as the developer's bridge-check engineer, a task contractually required. The Authority provided design and construction oversight, with HNTB, of Kansas City, Missouri, serving as the owner's engineer. The project was funded through a combination of loans guaranteed by the Transportation Infrastructure Finance and Innovation Act (TIFIA) and private equity invested by the developer, which will be recovered through availability payments—fixed monthly payments based on the facility's availability for use—over the course of a 35-year concession.
The new Goethals Bridge comprises two cable-stayed bridges, each with a 900 ft main span and measuring roughly 7,300 ft in length from abutment to abutment. Each includes prestressed, concrete-girder, high-level approaches. The twin structures are mirror images, except for a 10 ft wide shared-use path on the north side of the westbound bridge. The path extends outside the cables and offers a scenic view of the New York City skyline.
The Authority sought a distinctive state-of-the-art structure, which NYNJ Link delivered while meeting rigorous structural performance requirements, incorporating a unique yet functional tower configuration, and giving full attention to visual impact—including programmable lighting. Project-wide, NYNJ Link ensured a consistent aesthetic narrative. The bridge's main towers and stay-cable array are visible for miles, so the arrangement of the towers and stay cables was subject to intense review. To provide open views for the traveling public, the team elected to avoid placing any bridge elements over the roadway.
Each of the four 272 ft tall towers has a pair of outward-leaning legs that are in line with the outward lean of each stay-cable plane. This 5-degree-outward-leaning arrangement of 36 stay cables for each of the four cable planes minimizes the extent to which ice may fall from the stay cables to the roadway in the winter months; this increases the crossing's operational reliability and safety. The 144 stay cables vary in diameter, reaching up to 10 in., with the longest 400 ft in length.
Additionally, unique cable anchors in the tower tops allowed the team to minimize the height of the towers, economize on the tower leg cross section, and, in combination with a unique below-deck redundancy truss, yield unprecedented redundancy and resiliency.
Members of NYNJ Link's team had recently successfully delivered a similar cable-stayed bridge project near Montreal, the Autoroute 25 Bridge (now called the Olivier-Charbonneau Bridge). This experience essentially eliminated the team-building learning curve and facilitated open and direct communication regarding any issues and challenges. Using experienced union craftspeople who had worked for the contractor in the past also made the communication of expectations simpler and more pointed. The contractor was able to place crews with proven skill sets on critical tasks, which improved the levels of safety and quality required for this type of construction. Additional partners were brought on to increase the contractor's capacity as required and for specialty work when appropriate. These partners included some of the top specialists in their fields, such as Rowan Williams Davies & Irwin, of Guelph, Ontario, Canada, for aerodynamic analyses; Dan Brown and Associates, of Sequatchie, Tennessee, for deep foundations; Haley & Aldrich, of Burlington, Massachusetts, for subsurface investigation and geotechnology; Illumination Arts LLC, of Bloomfield, New Jersey, for aesthetic lighting; and KTA-Tator Inc., of Pittsburgh, and Tourney Consulting Group LLC, of Kalamazoo, Michigan, for service life and material durability consultation.
Parsons served as NYNJ Link's lead engineer, producing a design that significantly modified the illustrative design that was included in the request for proposals. To successfully deliver the Goethals Bridge replacement, the team had to consider solutions for several design challenges, including the potential for seismic-induced lateral spreading of soils and vessel collision; the team also had to ensure extreme-event aeroelastic stability and optimal wind performance of the westbound bridge, which would include a 9 ft tall pedestrian fence that might become iced over during winter months.
The dual-span structure carries westbound and eastbound traffic independently with built-in structural and operational redundancy and is designed to accommodate a future mass transit corridor, which can be created by stitching together the dual structures using steel framing without additional in-water work or foundations. Very little new structure would need to be financed and built for a future transit corridor, making it easier to put off until the need has developed.
This configuration also resulted in benefits during construction. A nearby warehouse was being demolished, which delayed the start of construction of the eastbound bridge tower. But the team was able to recover the time by shifting resources seamlessly to building the westbound tower foundation first. The dual-span configuration also benefited the Authority and the developer by allowing service to begin on the eastbound structure while the westbound structure was being completed.
A project of the size and complexity of the Goethals Bridge replacement involves numerous design decisions and considerations. To improve safety, for example, the roadway was provided with 42 in. tall, crash-tested, test-level-5 traffic barriers; saw-cut, grooved riding surfaces; and a pedestrian fence. The structure was also subject to a full threat evaluation study, which included both marine- and land-based standoffs and the strategic use of hardening features.
Sidebar: Collaboration is Key
An additional factor that required significant planning was the potential for vessel collision. Initially, the team anticipated using pier protection cells, as had been used in the original bridge. However, after an extensive review of vessel data combined with finite element modeling of vessel groundings, it was determined that the potential for impact from a fully loaded vessel was quite small. This is in part because of the underwater topography, the shoreline features, and the shipping channel alignment, which takes a turn at the bridge site. The study concluded that a heavily loaded vessel would ground out before impacting the New York-side tower; the New Jersey-side tower is set back within an old docking slip that is protected by a stand-off fender. Lightly loaded vessels did not present a controlling case. Obviating the need for in-water pier protection cells vastly improved the character of the navigation channel.
Upstream of the Goethals Bridge, the Bayonne Bridge, also owned by the Authority, was also being retrofitted to raise the roadway to account for post-Panamax ships. (Read "Rising Above,"
, November 2018, pages 54-63.) These ships will be routed under the Bayonne Bridge and will turn north, not south toward the Goethals Bridge, so there was no need to increase vertical clearance or consider this class of vessels for the Goethals Bridge replacement project.
Because the replacement bridge is classified as a critical bridge, the team designed it for a functional evaluation earthquake with a mean return period of 1,000 years, as well as a higher-level safety evaluation earthquake, which has a mean return period of 2,500 years. For the initial design—and to address relatively large spectral accelerations—Parsons performed a response spectrum analysis using a 3-D structural model of the entire eastbound and westbound structures. The global seismic analysis model for the main span used explicit modeling of the foundations, including the pile caps and individual piles. Soil springs were used to represent the soils' interactions in the model. This captured the deep foundation deformations and their effects on the structure. For the final design, a state-of-the-art, time-history, nonlinear analysis was used; this entailed a full-bridge 3-D computer model in software produced by ADINA R&D Inc., of Watertown, Massachusetts.
The seismic studies also considered design loads that could result from liquefaction on the New York side and the resulting lateral spreading of a unique geological formation in that area.
Most loads that had to be accounted for were defined by guidelines produced by the American Association of State Highway and Transportation Officials (AASHTO), with the exceptions of project-specific security requirements, site-specific wind climatology, and overloaded truck considerations. For the main span bridge, load cases were all accounted for and served to develop the overall structural system of a cable-supported, steel, edge-girder superstructure that includes full continuity at each tower, each anchor pier, and each flanking span. The developed system essentially consisted of a highly redundant end-to-end frame that was then proved for service and seismic loads via rigorous computer modeling and analysis.
In this way the structural system for the cable-stayed bridge was developed absent mechanical devices such as superstructure dampers, bearings, wind shoes, or lockup devices. The approach spans were similarly constructed as very long 3-D frames with a minimal number of bearings by using concrete hinges for the vast majority of pier locations. This offers cost savings as well as long-term maintenance advantages because there are few bearings to replace and limited expansion joints to leak. It also improves seismic performance by providing an integrated structural system of framed elements and integral pier columns, each with individual drilled shaft foundations that are socketed into rock.
The team performed extensive wind-tunnel testing for the main spans to determine wind loads and the aeroelastic performance of the two bridges side by side, as well as of the dual span with the mass transit addition in place. The team also tested models of the bridge with the pedestrian fence, with and without an ice covering, to be sure it would perform well in either case.
The stay-cableanchorages within the tower tops represent a new form in the industry. These all-welded steel anchorages were specifically designed for this structure to minimize the cross section of the concrete towers, reduce material usage, accommodate restrictions on the tower heights, and increase the towers' redundancy and resiliency in the event of the loss of a stay. Partially because of the constraint on the maximum height of the towers, which was because of its proximity to New Jersey's Newark Liberty International Airport, the design team was faced with the need to deviate from customary anchor box designs and innovate a new solution. NYNJ Link studied many different configurations for the anchors, but none fit within the constraints, as all anchor boxes designed to that point were intended to fit within the confines of the interior chase of the tower.
Because the team wanted the anchor boxes to extend beyond the limits of the tower's interior chase, and to get the cable-to-cable vertical spacing as tight as possible in consideration of the shortness of the towers, the team developed a completely new style of anchor box that has a form resembling a saddle but includes advantages of a cable end anchor in that it will not slip, as could be the case with a saddle in an unbalanced condition or if a stay is lost. (See the figures in the center of the opposite page.) These boxes would be independent, eliminating a progressive-collapse scenario, and would be directly fixed with shear studs to the tower concrete and fully embedded while allowing easy inspection access from the tower's interior.
Steel fabricators initially declined to bid on the team's new anchor box design, claiming that it would be impossible to fabricate. In response, the team printed 3-D models of the anchor box design, including element-by-element subassemblies, to illustrate step-by-step how the box would be fabricated, assembled in a trial, assembled in the field, welded, tested, shipped, and erected. Upon seeing the models, the steel fabricators better understood Parson's design, and in the end, Tampa Tank Inc./Florida Structural Steel, of Gibsonton, Florida, was able to produce the innovative anchor boxes in a value-added manner. The comparatively lower cost and high value for the money spent of this configuration, as well as its redundancy and robustness, were overriding factors in the contractor's decision to embrace this innovation.
The eastbound bridge was ultimately constructed ahead of the westbound bridge so that traffic could be moved to one side while work was completed on the other. The team was able to demolish the site's existing infrastructure to clear a way for the eastbound bridge first, which would not have been feasible for the westbound bridge. The team first demolished the eastbound approaches in New Jersey, then moved traffic onto a configuration of two lanes in each direction on the existing westbound approach to clear access for the eastbound bridge over the New Jersey Turnpike. This put the construction of the spans over the New Jersey Turnpike on the critical path, highlighting the team's vital coordination with the Turnpike Authority. (See "Collaboration is Key," page 67.)
On the basis of on some original geotechnical information, the Authority's geotechnical data, and the team's own supplemental investigations, NYNJ Link chose to use drilled shaft foundations exclusively on this project. These rock-socketed shafts varied in diameter from 4.5 to 9 ft, each drilled in a steel casing that had been driven to rock and then left in place to serve as armor and corrosion protection. The depth of the rock sockets varied relative to the geotechnical conditions and pile diameter, with the larger-diameter shafts having 17 ft deep rock sockets.
Competent rock is typically 45 ft below the surface of the ground and water, and NYNJ Link determined that, compared to pile-supported footing, drilled shaft foundations would better manage the possibility of encountering contaminated materials at this site. They also better accommodated the potential liquefaction issues on the New York side; created a straight, clean look with a uniform reinforcing steel cage from rock to pier cap; and required a minimal footprint for construction.
The drilled shaft method also allowed for tremie construction, obviating the need to dewater the shaft areas and risk a cave-in below the level of the steel casings. The main tower foundations were constructed in the dry by way of conventional cofferdams and a seal slab, each supported on six drilled shafts with rock sockets.
The bridge's near jointless concrete-girder approach spans, at lengths of 2,564 ft in New Jersey and 2,789 ft in New York, join with the steel flanking spans of the cable-stayed spans at one of the few locations at which traditional modular expansion joints are used. Leading up to the bridge approaches, the original highway alignment was repaved to aid the connection to the new approaches. In New York, between the bridge and a toll plaza, the roadway was widened to accommodate extra lanes, which drove the need to replace a bridgethe Travis Spur Rail Bridge. This replacement used an accelerated bridge construction technique called roll-in construction and was undertaken in a single weekend. (See "All in a Weekend's Work," page 72.)
The approaches have an integral concrete wearing surface, and the cable-stayed spans feature an impervious polyester polymer concrete overlay consisting of a custom blend of aggregate and polyester binder to meet the 100-year service-life requirement for the bridge. The approach surface course was chosen for efficiency, cost, and simplicity of maintenance—it can be easily milled and resurfaced when needed. On the cable-stayed spans, the overlays are atop precast-concrete panels that are made composite with the steel superstructure and include stainless-steel reinforcement bars.
To ensure that the Goethals Bridge operates as efficiently as possible well into the future, NYNJ Link incorporated several elements of smart-bridge technology, including a roadway weather information system, a traffic-detection system, a structural-health-monitoring system, closed-circuit television (CCTV), a research-grade weigh-in-motion system, control systems, adaptive signalization control technology, and a full supervisory control and data acquisition (SCADA) system. All this technology allows for enhanced asset management and security and improved operations.
As a long-service-life facility, the construction of which was awarded on the basis of lowest net present value, the team was inherently conscious of the value of each dollar spent and the need to minimize long-term maintenance. To achieve the long service life, NYNJ Link developed an extensive corrosion protection plan, in which each component was assigned a specific exposure category and its own corrosion prevention strategy, ensuring that the structure itself wouldn't require significant rehabilitation for 100 to 150 years. Attention was focused on the concrete mix design to minimize chloride intrusion; for this reason, a low-permeability mix, which exhibits very low ion-diffusion rates, was chosen. Additionally, corrosion inhibitors and sealants were selected for use at strategic locations at customized levels; this addressed the varying environmental conditions present at locations across this long bridge. NYNJ Link also made extensive use of off-site fabrication and concrete precasting to save on labor costs, which are particularly high in the New York City metropolitan area.
Sidebar: All In a Weekend's Work
In addition to the cable-stayed bridge and the rail spur bridge, the project encompassed connections to existing transportation facilities at both ends of the bridge, including the toll plaza; access to Authority building facilities; roadway widening and reconstruction; smart-road technology; six maintenance travelers; a maintenance and control facility for the developer; and a sectionalized fire standpipe. The smart-road technology includes structural health monitors, research-grade weigh-in-motion stations, lane-control signalization, variable message signs, and a complete SCADA system.
The new Goethals Bridge is also fully integrated with the regional transportation network, its operations linked to the Authority's Staten Island bridge-control center near the bridge's toll plaza and the developer's maintenance and control facility. The maintenance and control facility's design is fully resilient in the event of future storm surges, such as the one that accompanied Hurricane Sandy in 2012. To achieve this level of resiliency, the floor slab is elevated to raise critical operations above the floodplain, which was increased as a result of Sandy. The developer chose to locate the maintenance facility along the project alignment to minimize response time and reduce lane closures in the event of traffic accidents. Additionally, the toll plaza has been converted to all-electronic tolling with new signage.
The team also provided considerable public relations support for the project's historic resources mitigation plan, including developing a 30-minute PBS-style special and preparing a fourth-grade lesson plan, a history book, and curations of documents in the Library of Congress.
The new Goethals Bridge is now operational, and the original bridge has been taken down and its steel sent for recycling. The response of the Authority, other stakeholders, and the public has been tremendously positive, both regarding the aesthetics and the user experience. The days of white-knuckle crossings on the old Goethals Bridge are in the past, and safe, efficient trips across the Arthur Kill—with inspiring views of New York City; Jersey City, New Jersey; and downtown Newark—stretch well into the future on the innovative new Goethals Bridge.
Seth Condell, P.E., LEED AP, ENV SP, M.ASCE, is the New York and New Jersey regional bridge practice lead for Parsons, working out of the firm's New York City office. Thomas Spoth, P.E., M.ASCE, is Parsons's national bridge practice lead and serves on Parsons's board of fellows.
Owner Port Authority of New York and New Jersey
Developer NYNJ Link, comprising the lead contractor and the lead engineer
Lead contractor Kiewit-Weeks-Massman AJV, a joint venture of Kiewit Infrastructure Co. (KIC), Weeks Marine Inc., and Massman Construction Co. KIC, a subsidiary of the international construction firm Kiewit, is based in Woodcliff Lake, New Jersey; Weeks is based in Cranford, New Jersey; Massman is based in Overland Park, Kansas
Lead engineer Parsons Corp., Pasadena, California
Aerodynamicist Rowan Williams Davies & Irwin, Guelph, Ontario, Canada
Durability and service life KTATator Inc., Pittsburgh, and Tourney Consulting Group LLC, Kalamazoo, Michigan
Deep foundations Dan Brown and Associates, Sequatchie, Tennessee
Subsurface investigation and geotechnology Haley & Aldrich, Burlington, Massachusetts
Steel fabricator (girders) Canam Steel Corp., Point of Rocks, Maryland
Steel fabricator (anchor boxes) Tampa Tank Inc./Florida Structural Steel, Gibsonton, Florida
Precast girders Northeast Prestressed Products, Cressona, Pennsylvania
Precast deck panels Unistress Corp., Pittsfield, Massachusetts
Lighting Illumination Arts LLC, of Bloomfield, New Jersey
© ASCE, Civil Engineering, June, 2019