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Rehabilitation of the Hugh L. Carey and Queens Midtown Tunnels in New York City

Hugh L Carey Brooklyn Battery Tunnel

The Triborough Bridge and Tunnel Authority (TBTA) is conducting a comprehensive rehabilitation and systems update of the Hugh L. Carey Tunnel (HLCT) and Queens Midtown Tunnel (QMT) in New York. Opened in 1950, the HLCT is 9,117 ft (2,779 m) long and includes two parallel tunnels with 4 lanes. Opened in 1940, the QMT is 6,414 ft (1,955 m) long and includes two parallel tunnels with 4 lanes. These tunnels are key parts of the transportation infrastructure and allow commuters and visitors to travel into Manhattan.

Beginning in January 2019, the Triborough Bridge and Tunnel Authority (TBTA) awarded five design-build contracts for the comprehensive rehabilitation of the Hugh L. Carey Tunnel (HLCT) and Queens Midtown Tunnel (QMT). The following five projects were concurrently conducted:

  • Ventilation system rehabilitation and new fixed fire system prototype installation at the HLCT
  • Service building rehabilitation at the HLCT
  • New fire alarm and smoke detection systems at the HLCT and QMT Facility Buildings
  • New fire alarm and smoke detection systems at the QMT
  • Rehabilitation of the tunnel controls and communication systems at the QMT

A quality oversight team oversaw the design-build contracts. For the design phase, the team coordinated and communicated with TBTA and the contractors on design issues and other critical items. During the construction phase, the team managed daily coordination and communication with the TBTA and contractors, documented control efforts and verified that all permits and licenses were obtained and current.

Figure 1: Location Map of Hugh L. Carey and Queens Midtown Tunnels

Figure 1: Location Map of Hugh L. Carey and Queens Midtown Tunnels

Background on the Hugh L. Carey and Queens Midtown Tunnels And Need For Rehabilitation

Hugh L. Carey Tunnel

Opened in 1950, the HLCT (previously named the Brooklyn-Battery Tunnel until 2012) is 9,117 ft (2,779 m) long and includes two parallel tunnels with 4 lanes (refer to Figure 1 for location of tunnel). It is the longest continuous underwater vehicular tunnel in North America, passing underneath the East River at the southern tip of Manhattan. Approximately 54,000 vehicles travel each day between Manhattan and Brooklyn via the HLCT. There are four ventilation buildings – two in Manhattan, one in Brooklyn and one on Governor’s Island that incorporate 53 Blower and Exhaust fans. The facilities to support operations are referred to as the Brooklyn Service Building, Manhattan Blower Building, Manhattan Underground Exhaust Building, Brooklyn Ventilation Building and Governors Island Ventilation Building.

Queens Midtown Tunnel

Opened in 1940, the QMT is 6,414 ft (1,955 m) long and includes two parallel tunnels with 4 lanes beneath the East River (refer to Figure 1 for location of tunnel). There are two ventilation buildings with a combined 23 Blower and Exhaust fans, one ventilation building on each side of the East River in Manhattan and Queens. The Queens Service Building also supports the daily operation of the tunnel. About 75,000 vehicles per day use the QMT to travel between Long Island City in Queens and Manhattan. This is a major entry point into Manhattan when travelling from La Guardia Airport. User fees for either tunnel vary between $6 to $10 USD per trip using an open-road cashless tolling system.

Hurricane Sandy made landfall on the New York City metropolitan area on Oct. 29, 2012, with a storm surge elevation of 13.88 ft (4.23 m). The storm caused historic damage to the city’s infrastructure and resulted in closures of nearly all road tunnels into the city in addition to closures of major bridge crossings, airports, and rail networks. Both the HLCT and QMT were significantly impacted by Hurricane Sandy. The HLCT was flooded with over 80 million gallons (302.8 million L) of seawater and was only able to reopen on Nov. 13 at limited capacity. The QMT was also closed due to flooding and reopened at limited capacity on Nov. 6. Later in 2012, both tunnels fully reopened.

After the events of Hurricane Sandy and on-going needs due to age, the infrastructure of both tunnels was identified for upgrades. This included the replacement of older technology for operating the control rooms and communication systems, replacement of the original ventilation fans, upgrading electrical systems, and installation of advanced fire alarm and smoke detection systems.

The TBTA selected to use the design-build method to perform the upgrades to the tunnels. Figure 2 illustrates the organizational structure for the portfolio of projects, the design-build teams and the Quality Oversight team that performed the work.

Figure 2: Organizational Structure for Project

Figure 2: Organizational Structure for Project including TBTA, Design Build Teams and Quality Oversight Team

Design-Build Contracts

A. Hugh L. Carey Tunnel (HLCT)

i. Ventilation System Rehabilitation and Fixed Fires Suppression System Prototype.

The contract for rehabilitation of the HLCT ventilation system included replacement of 104 low, medium, and high-speed motors powering 53 fans throughout the tunnel (refer to Figures 3 and 4). The supply and exhaust fans for the HLCT are distributed throughout the four vent buildings in Brooklyn, Governors Island, and Manhattan. The vent fans are a critical component to the life safety system for the tunnel.

Figure 3. Photo of two of the existing fan motors

Figure 3. Photo of two of the existing fan motors to be replaced at the HLCT

The HLCT vent fans circulate air during normal tunnel operations through a transverse ventilation system with separate supply and exhaust air ducts. The 53 fans control five zones for supply and exhaust in both the east and west tubes. Tunnel operators have a variety of options for ventilating smoke and supplying fresh air in the event of a fire. The reliability of the fan motors and their ability to rapidly reach their high-speed operating state under the tunnel’s fire protocols are critical to the safe operation of the HLCT. One of the key logistical challenges for the project was ensuring that each zone always had multiple motors available. This required diligent coordination of the sequence of motor replacements between the design-build team, HLCT Facility, and quality oversight team. The sequence of motor replacements was a key factor for the critical path of the project.

Figure 4. Photo of two of the new fan motors and electronic controls for HLCT

Figure 4. Photo of two of the new fan motors and electronic controls for HLCT

The project also included the design and construction of a prototype water mist fire suppression system in a portion of the tunnel (see Figures 5 and 6). While water mist fire suppression systems are in common use in rail and highway tunnels throughout Europe and Japan, this is the first system of its kind installed in North America. Implementation of this new system required collaboration between designers with knowledge of local codes, vendors, and skilled tradespeople distributed between New York, Alabama, and Cologne, Germany.

The water mist system was validated through conventional design calculations and CFD (computational fluid dynamics) analysis of the HLCT. The vendor also provided data from full-scale fire tests performed at a tunnel testing facility in Asturias, Spain demonstrating the system’s efficacy in controlling and suppressing fires in an equivalent environment to the HLCT. Additionally, the design-build team performed tests on a mock-up in the HLCT to confirm the system’s performance while the fire ventilation protocols were active. These measures demonstrated that the water mist system could be safely and effectively implemented in a critical link in New York City’s transportation infrastructure.

The existing fire suppression standpipe system relied on FDNY (Fire Department of New York) response, which could be impacted by traffic disruptions associated with a fire in the tunnel. A major advantage of the water mist system are the small droplet sizes, greatly reducing the transfer of radiant heat. This protects the traveling public and provides additional protection to the tunnel infrastructure from fire damage.

All work associated with the ventilation rehabilitation and water mist system prototype construction was performed without impacting normal traffic patterns in the tunnel or operations in the ventilation and service buildings. All work for the water mist system was performed during night shifts when the HLCT reduces traffic to a single tube. This allowed workers to safely occupy the exhaust ducts while reduced ventilation protocols were in place.

Figure 5. Water mist system prototype

Figure 5. Water mist system prototype installation in the HLCT exhaust air duct with water, electrical and data system components

ii. Service Building Electrical Rehabilitation

The contract for electrical rehabilitation at the HLCT service building focused on resiliency upgrades and included the relocation and replacement of essential distribution equipment and main feeders from an existing basement electrical room to a new electrical room located on the first floor. The HLCT service building is located in an area of the Borough of Brooklyn that was significantly affected by flood waters from Hurricane Sandy. This project significantly reduced the risk of damage to critical equipment for the operation of the tunnel from future flooding.

The electrical upgrades associated with this contract were performed early in the schedule to minimize impacts to the work associated with the other contracts. All work was performed without any closures to the tunnel or impacts to normal operations in the service and ventilation buildings.

iii. New Fire Alarm and Smoke Detection Systems

The contract to install the fire alarm and smoke detection systems throughout the HLCT provided an integrated, code-compliant fire alarm system covering all the facility buildings supporting the operation of the tunnel. The contract integrated legacy systems in other portions of the tunnel with the new equipment installed under this contract. At the end of the project the entire facility could be monitored on a centralized workstation in the main control room. The addressable system improves the accuracy of alarms while simplifying the maintenance and troubleshooting of individual components.

The design and installation of the new fire alarm system was performed concurrently with the installation of a backup control room in the Brooklyn Vent Building. This allowed for seamless integration of the new fire alarm system into the new backup control room.

Smoke and heat detection equipment was installed to provide coverage in the immediate area of all fan motors. While this provides an additional level of safety, the design and installation of heat detectors above all fan motors had to be closely coordinated with HLCT maintenance personnel, and with the design-build team for the ventilation rehabilitation contract.

This contract was combined with the contract to install a new fire alarm and smoke detection system at the QMT Facility Buildings. This streamlined the oversight process, allowed for faster design reviews, and improved efficiencies for the owner, design-builder, and quality oversight team.

Figure 7. HLCT Primary Control Room prior to upgrade

Figure 7. HLCT Primary Control Room prior to upgrade

B. Queens Midtown Tunnel (QMT)

The safe and efficient operation of the QMT relies on several key mechanical and electrical systems and devices working continuously in the various ventilation buildings. The nerve center controlling these electrical and electromechanical systems is the Control Room located in the respective service building of each tunnel. The QMT Control Room and some of its equipment are original to the tunnel and were put into service in the 1940s. Over the years, the QMT Control Room has been retrofitted with a patchwork of improvised systems within the available space, making the Control Room inefficient. The HCT Control Room was renovated and modernized under another project in 2008, see Figure 7. This design-build contract brought both tunnels into compliance with NFPA 502 standard, constructing back-up control rooms as well as modernized the QMT Control Room (refer to Figures 8 and 9).

Key elements of the base contract work included:

  • Construct a Back-up Control Room and a Back-up Technical Room at both QMT and HLCT
  • Modernize the Primary Control Room at the QMT
  • Build a Temporary Control Room at the QMT which is to be used during the reconstruction of the
  • Primary Control Room
  • Upgrade the tunnel control systems to be fully redundant, as needed

Based on the scope of work, the Quality Oversight team was tasked to review and provide oversight of all the Design-Build submittal components, ensuring they were within the contractual obligations and NFPA (National Fire Protection Association)/NYC Building codes.

COVID-19 had impacts on the project’s steel fabrication plant in Pennsylvania due to government mandated shutdowns. With uncertainty of what the steel delays would be, the Design-Build team focused on other components of the project to mitigate the schedule delays. Due to the collaborative efforts of the Design-Build team and the Quality Oversight team, health and safety plans were modified with respect to COVID-19 precautions and mitigation measures. Segregated work plans were developed to maximize physical distancing while minimizing the overall project impact. In doing so, the project achieved a Substantial Completion on Dec. 31, 2020, approximately 7 months ahead of original schedule (732 days of 940) and within budget.

Role of Design-Build Quality Oversight Team

Design-build is a relatively new contracting mechanism in New York State with phased roll-out to select State and New York City agencies occurring over the last 10 years. Design-build contracts offer many benefits to owner agencies including faster design and construction schedules, as well as reducing costs through a more efficient design process tailored to a contractor’s specific strengths. However, the benefits of design-build contacts come with owners giving up more control over the design and construction processes compared to traditional design-bid-build contracts. Owners still need to make sure their interests are represented in the process resulting in a final product that is both code-compliant and meets their project requirements.

The design-build contractors for contracts for this project (identified as QM-81, HC-30/QM-91, HC-07, and HC-64) were required to hire independent construction inspection professional engineering firms and materials testing laboratories to provide for daily quality inspections and code-required special inspections such as steel reinforcement inspection, concrete materials testing and bolting inspections. However, since these firms were hired by the design-build contractors there are always concerns over conflicts of interest. To help alleviate these concerns, oversight of the design build contractors’ quality team field activities and independent reporting of daily contractor activities was required.

The Design-Build Quality Oversight Team (DBQOT) served as the TBTA’s representative in dealing directly with the design-build teams executing contracts QM-81, HC-30/QM-91, HC-07, and HC-64. Services to the TBTA were provided during both design and construction phases. The team had to remain flexible and respond to the faster pace of the design-build process to address TBTA concerns in a timely manner with the contractors to avoid delaying work.

For the design phase, the DBQOT’s provided continuous oversight of the design process to ensure that the designs met project requirements. Typical activities included reviewing design-builder design submittals, tracking comment/responses, reviewing shop drawings, auditing the design-builder’s QA/QC processes, and providing technical support to the TBTA as required to address design issues.

For the construction phase, the DBQOT conducted field oversight inspections of contractor activities and submitted daily oversight reports to the TBTA with a summary of the contractor’s daily activities. In addition, the DBQOT supported the construction oversight by maintaining project logs (submittal, correspondence, non-conformance, etc.), evaluating change order requests, and reviewed document submittals (including schedule updates, as-built drawings, payment requisitions, maintenance and protection of traffic, quality plans, safety plans, and other submittals as required) to support the TBTA during the construction process. The DBQOT also submitted weekly and monthly reports of design and construction activities to the TBTA.

To provide effective oversight of the contractors’ field activities and maintain cost effectiveness for the TBTA, oversight inspectors were strategically assigned to the various geographic areas that had contract work. These areas were Brooklyn (service building and ventilation building), lower Manhattan (Governors Island, Manhattan Blower Building, Manhattan Underground Exhaust Building), Queens (service building, ventilation building) and the Manhattan Ventilation Building for the QMT. The inspectors oversaw work under all contracts working in each geography. The inspectors would rotate among each work area to document the contractor activity at each location, the size of the work crews by trade, equipment present, and any issues that arose during the shift. The inspectors submitted daily inspection reports to the DBQOT Resident Engineer for review and approval (see Figure 10).

Each day, the inspectors and other project staff received a daily e-mail containing a summary of daily work activities by contract and location as well as a schedule of expected work locations for the next day.
The daily scheduling and summary e-mail served two important functions on the project. First, it provided easily searchable records of work activities and provided scheduling information to the inspectors and other project staff. In addition, the e-mail helped integrate the field staff into a team providing quality oversight to several different TBTA contracts rather than individual inspectors only focused on their own work locations. Each inspector was aware of who was working at each location as well as what was going on at those locations. Therefore, when inspectors needed to cover for each other due to time off, they had an idea of what was going on and what to generally expect. Project management staff and the client were also aware of what was occurring daily without having to read each daily inspector report.

The COVID-19 pandemic added further complications to the project. Since infrastructure construction was classified as essential work by New York State during the COVID-19 pandemic, the contractors continued design and construction activities throughout the pandemic. The DBQOT had to develop protocols to continue to fully represent the TBTA while keeping office and field staff safe. The DBQOT also assisted the TBTA with daily monitoring of the contractors’ COVID safety protocols. Due to everyone’s efforts there were only a handful of COVID cases identified across all the contracts and work proceeded smoothly as possible during the pandemic.

Innovations and Lessons Learned

During the course of the project, there were several technical innovations and project management lessons learned. The project had many internal and external stakeholders. This was particularly challenging when the design and construction work needed to continue during the COVID-19 pandemic. Increased attention to stakeholder navigation was critical and required additional insights due to the COVID environment.
For all contractors to TBTA, it was important to understand and communicate a clear definition of project success. This included milestones to be achieved in terms of project quality, budget and safety.

As cited earlier, the design-build delivery model is a relatively recent development for many New York City agencies. However, design-build projects have rapidly gained traction with many agencies in recent years. The design-build model resulted in significant reductions in schedule duration for these projects. This in turn lead to cost savings and reduced impact from construction operations on tunnel operators and the traveling public.

Combining the projects into a program allows for numerous efficiencies for the owner, design-build teams, and quality oversight team. Design and construction were proactively coordinated between the five design-build contracts throughout the project. This reduced the potential for conflicts and rework that could have occurred were the projects performed separately and sequentially.

The quality oversight team was able to oversee a larger portfolio of work under the program management model than would be possible under conventional delivery methods. The breadth of the scope of work for the five projects the quality oversight team managed facilitated a high degree of familiarity with both facilities, the key stakeholders involved, and TBTA protocols that further aided the success of each project.

Steven R. Kramer, PE, FASCE, COWI North America, Jessica Perez, MTA Bridges and Tunnels – Triborough Bridge and Tunnel Authority, Sean Singh, CHA Consulting, Brian P. Cresenzi, PE, Gannett Fleming Engineers and Architects, and Matthew Yamasaki, PE, McLaren Engineering Group.

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