Urban Waterfront Placemaking – Creating Improved Public Space on an Old Municipal Pier

Abstract: This paper summarizes the challenges associated with introducing a state-of-the-art, visually compelling shade canopy structure onto a 35-year-old timber and steel open-ocean pier. The wind and wave exposure, coupled with the need to maintain the canopy’s visual elegance made for a challenging engineering and artistic assignment.
The City of Imperial Beach and the San Diego Unified Port District have made a concerted effort to enhance the experience at the Imperial Beach Pier to make it a destination for local citizens and tourists. To continue the pier improvement process, urban designers, with input from the community proposed concepts for enhancements, including:

1. Replacing timber railing with stainless steel post and cable railing, proposed to improve vistas from the pier.
2. Adding an artistic canopy shade structure, proposed as a gathering place for the public and provides shade, which is lacking on the pier.
3. Providing novel accent lighting at both railing replacement and canopy shade structure.
The feasibility of the pier improvements was then determined by a waterfront engineering consultant and entailed:
• Developing metocean data to determine lateral loads on the piling supporting the canopy.
• Structural analysis to determine the ability of the existing structure to support the increase in vertical and wind loading.
• Developing alternative canopy framing arrangements and materials.
• Preparing cost estimates.
• Developing a technical report and exhibits to present findings.
This paper will focus on the unique marine engineering requirements and approach necessary for the design and construction of a one-of-a-kind high-tech steel structure placed on an aging pier in an extreme environment. The shade structure is composed of powder-coated, galvanized steel structural members. The exposed finish elements are stainless steel architectural components that include a suspended shark figure and panels having a variety of openings to imitate bubbles in the water. Adjustable lighting was installed at the canopy and railing to highlight the shark design and provide lighting to the pier at night.
Technical challenges discussed in detail include:
- Material selection: The Imperial Beach Pier is an open-ocean pier. Materials were selected to provide a 25-year service life while exposed to saltwater spray, fog, bird droppings, dirt, and vandalism.
- Considerations for aging and brittle infrastructure: The capacity of the existing structure was analyzed for additional loading and the effects of construction operations.
- Construction over water and in an environmentally sensitive area: The shading from the structure and the effect of the lighting down on the water required careful consideration.
- Construction logistics: The pier had to stay open during construction, allowing maintained access to the existing facilities (restaurant, public restrooms, lifeguard station).
- Precision of the design: Close tolerances were required by the urban designer as a function of appearance. The design of the structural frame connections and architectural elements needed flexibility in erection to account for required construction tolerances.
- Mounting the canopy: Canopy columns needed to connect to the steel pile caps below deck. This connection was designed for load transfer, prevention of electrolysis, and adjustability.

How does this project / topic contribute to the advancement of the industry and profession?: This project, construction completed in 2023, shows there are strategic ways to incorporate new, interesting elements to aging waterfront structures that can improve the quality of experience in these spaces.

Does the project / topic implement new and innovative techniques, materials, technologies, and delivery methods?: Whereas the analysis itself was conventional, the material selection and connection details required thoughtful solutions that allowed for construction on an aging pier with limited capacity and space. The connection design needed to be adjustable to allow for construction tolerances, while maintaining the required precision to execute the architects’ requirements (i.e., keeping hanging panels level and having gaps between the panels be consistent).

What was the most challenging aspect of your project / topic and how did you handle it to ensure success?: The custom nature of the design was challenging. Understanding the existing pier condition was necessary to determine size and weight limitations. The design required effective communication/coordination between the structural, urban designer, and electrical to ensure the proposed enhancements were executed.

Who is the target audience for this paper?: Marine engineers and owners of aging piers (cities, port authorities, etc.).