Engineering Innovations in Dock Rehabilitation: Addressing Seismic Challenges & Aging Infrastructure

Abstract: Dock platforms in marine environments can face extreme conditions such as hurricane storms and seismic demands, specialized loading phases, corrosive saltwater surroundings, and high humidity. Over time, these operating conditions, coupled with potential damage due to vessel impact and aging infrastructure, necessitates repair and rehabilitation efforts. This paper discusses two unique projects involving the repair and reconstruction of dock platforms located in high seismic regions, highlighting the challenges faced and innovative solutions employed.
Vessel impact is not often a design constraint; however, it unfortunately is common and can result in varying degrees of dock damage depending on the size, speed, and direction of the vessel at the time of impact. The first project involves reconstructing a loading platform in Panama to replace one damaged beyond repair by a 300,000 Deadweight Tonnage oil tanker strike in 2020. Given the region's high seismic demands, a traditional large pile footprint with batter piles was initially assumed to be required for the replacement terminal. This repair would have required more piles, more money, and a longer schedule to complete. However, Lloyd Engineering and SGH proposed an innovative compact plumb pile layout using a steel jacketed frame and steel plumb piles. This design met the stringent seismic design requirements for the region. This alternate design allowed greater lateral displacement of the elevated deck during earthquakes compared to the original deck, which necessitated evaluation of the new piping system that also connected to the existing land trestle. Ultimately this design was appealing to the owner due to the proposed savings and schedule implications.
The second project involves designing a partial dock replacement to support a ship loader. A portion of the original dock needs to be replaced due to aging infrastructure and operational limitations. The new dock platform will house a modern tower type ship loader. To accommodate the modern ship tower loader in a seismic region, the analysis involves complexities of eccentric loading conditions resulting from different boom positions with different loading conditions. The key challenges included small pile diameter and quantity due to permitting limitations and studying the interaction between the tower loader and platform for its inertial effects during seismic events. Towards this, an in-depth nonlinear analysis was conducted, resulting in developing performance specifications for vendors to design the tower loader based on its interaction with the platform.
This paper presents comprehensive analyses of two innovative dock replacement projects that address challenges posed by aging infrastructure, seismic demands, interaction between existing and new structures, and site restrictions. This paper provides engineers with invaluable insights and practical solutions gleaned from two innovative dock replacement projects. Engineers will benefit from learning about alternative design approaches, such as the compact plumb pile layout and tower loader interaction analysis, which optimize material usage, construction timelines, and costs while enhancing project safety and resilience.

How does this project / topic contribute to the advancement of the industry and profession?: The projects showcase innovative engineering solutions tailored to the unique challenges of replacing critical aging marine infrastructure in high seismic zones. The creative compact pile layouts, studying dynamic equipment/structure interactions, and frameworks for mitigating hazards like pounding advance design practices for safer and more resilient dock facilities.

Does the project / topic implement new and innovative techniques, materials, technologies, and delivery methods?: Yes, the two projects discussed in the paper highlight several innovative techniques, such as the compact plumb pile layout with a steel jacketed frame, and the in-depth analysis of eccentric loading and inertial effects from the tower loader and platform interactions. These approaches were developed in accordance with ASCE 61-14: Seismic Design of Piers and Wharves.

What was the most challenging aspect of your project / topic and how did you handle it to ensure success?: The two projects discussed in the paper had their own challenges. The first involved replacing a damaged loading platform, using a compact plumb pile layout instead of a traditional larger pile footprint to meet seismic requirements while accommodating greater deck displacement. The second project replaced part of a dock platform with a new platform featuring a tower loader, requiring analysis of eccentric loading conditions, interaction between the loader and platform during earthquakes, and accounting of pounding effects despite permitting restrictions on pile size/quantity.

Who is the target audience for this paper?: The target audience would be marine/port engineers, structural engineers specializing in waterfront structures, marine contractors to opt for new construction methods, researchers studying seismic design of dock facilities, port authorities undertaking rehabilitation/replacement projects, and the broader maritime engineering community interested in advancing design practices for resilient marine infrastructure.