As part of its long-term strategic plan to support large-scale containerships, the Port of Long Beach initiated the Pier G Berth G232 wharf and backlands redevelopment project to serve ships capable of holding the equivalent of more than 8,000 twenty-foot-long containers.
Yet, the port's goal was to do more than just build big. Using the Green Port Policy adopted in 2005, the agency looked to create one of the industry's most sustainably constructed and operated ports -- in just 18 months. Its "green" emphasis began even as the first excavators began demolishing the existing paved backlands and embarking upon excavation and relocation of the rock dike at the Pier G berth.
The challenge was to remove all existing improvements within the 405,000-square-foot backlands area and excavate most of the utility trenches below groundwater levels in order to construct a new $54 million, 1,300-foot-long, 125-foot-wide reinforced concrete container wharf with concrete runways for port cranes. Construction of the wharf and backland improvements required very close coordination between the project team and the port's tenant to reduce disruptions to the terminal operations. Kleinfelder, a national engineering firm, provided services to the port as the geotechnical engineering consultant during both the design and construction phases of the project.
From the beginning, the goal was to reuse or recycle as much existing soil and pavement materials as possible. Design and construction also had to move forward simultaneously to meet the tight timeline. The engineering teams used offshore and onshore exploration programs to shape a constructible design for the pile foundation support system while excavators began digging up the soil and asphalt and storing it in a designated area near the new wharf construction site.
During the process, engineers noted poor subgrade soil conditions in a portion of backlands area, which could have significantly hindered the recycling effort and caused potentially significant delays in the schedule. Fortunately, the project team was able to reinforce and improve the subgrade conditions by using a geotextile and the existing drain rock and by recycling selected demolition materials as crushed miscellaneous base.
Once subgrade preparation within the backland area was complete, the contractor began driving more than 900 precast octagonal concrete piles, each of 24-inch diameter and 300-ton capacity, and started on construction of such associated backlands improvements as new utility lines, power substations and asphalt concrete pavement. The wharf design also included construction of a cutoff wall made of precast concrete panels on the land side of the wharf that sits below high-tide water levels.
Ultimately, the construction team stripped and reused almost all of the existing asphalt pavement section and base material. On-site soils were used as backfill for numerous utility trenches and as compacted subgrade to support new improvements such as pavements, crane and shore power substations and restrooms.
The Pier G redevelopment plan also included installation of continuous deflective separation, or CDS, units to protect the harbor waters and a commercial shore-to-ship power supply system that helps to mitigate environmental impacts and reduce air pollution due to traditional in-port power usage. With the implementation of this system, the onboard auxiliary diesel generator's power is replaced by shoreside electricity, eliminating diesel exhaust emissions.
With the wharf and backlands project complete, the port began construction on the rest of the Pier G megaterminal buildings and infrastructure.
The Port of Long Beach and Kleinfelder were awarded a 2009 Engineering Excellence Merit Award from the American Council of Engineering Companies-California for the Pier G terminal renovation.
