America Center is a 63-acre brownfield redevelopment project located adjacent to the San Francisco Bay. It contains 30 acres of land preserve dedicated for Burrowing Owl habitat. Phase 1 of the project included two six-story class A office buildings totaling 420,000 SF located atop a closed landfill that extends 65’ deep.
CONSTRUCTABILITY REVIEWS – Lusardi Construction was brought on board early in the design phase to provide design assist services. Constructing mid-rise buildings on a closed landfill posed significant challenges. Not only were there structural issues with building on top of 65 feet of trash, the native soil underneath the landfill was Bay Mud, adding to the challenge. Through various design options and pricing exercises, it was determined that concrete reinforced piles were the most economical solution. However, there was significant concern that conventional pile driving methods would drive trash and unknown liquids down into the native soil which would lead to environmental exposure. Various pile driving and drilling specialists were consulted and the decision was made to use a drill rig to core out for the piles prior to driving them and to seal the area between the Bay Mud and trash mound with a bentonite plug. This would insure that no contaminates could penetrate below the landfill. Further issues arose with how to keep the cored hole from caving in given the inconsistent nature of the dump material and the heavy vibrations of the pile driving rig. The design called for a 42 inch diameter steel pipe to be temporarily put in the hole to act as a sleeve so the pile could be driven and back-filled. The steel pipe was then to be removed and reused. Unfortunately, we could not locate a piece of equipment that had the capacity to remove the 42 inch diameter, 65 foot long pipe once it had been back-filled. Various ideas were discussed and the decision was made to substitute a much thinner and less expensive corrugated metal pipe to act as the sleeve and to leave it in place permanently. Not only was this a more constructible solution, it was more economical. Extensive constructability reviews were also completed for the methane collection system, liquid boot methane barrier, utility flex connections at each point they entered the building, building-to-site transitions that were going to be susceptible to differential settlement, and building management system.
ESTIMATING – While construction of the America Center project started in 2007, the original estimates were done in 2004. These original estimates were done by the same project manager that completed the project in 2009. This consistency insured that there were no omissions or oversights on the project budget. The first estimate was done from a conceptual set of plans consisting of just a few plan sheets and some record documents of the feeder utilities. As drawings progressed the project budget was updated accordingly. The project was “shelved” for about two and half years before being brought back to life in January of 2007. A revised estimate was done and the project was given the green light. Lusardi Construction continued to work with the designers and Legacy Partners through the balance of the preconstruction updating estimates and helping with details, material choices, and finish selections as the plans progressed.
BID PACKAGE DEVELOPMENT - Immediately after the building plans were submitted for 1st plan check in 2007, a dedicated “structural steel” plan set was drafted due to the long lead time for structural steel at the time. It was a great challenge to obtain bids from steel subcontractors that were accurate without having finished structural or architectural plans. Through in-house take-offs, clear bid instructions, and a complete understanding of the intent of the structural detailing, we were able to get accurate sub bids and avoid costly change orders. The structural steel was located, purchased, fabricated, and shipped to the site on time.
SCHEDULE DEVELOPMENT – With schedule always being our major focus, we began drafting the master schedule (inclusive of both preconstruction and construction phases) as soon as we started our formal preconstruction meetings. We worked with the design team to identify target dates for plan development (50% set, 70% set, 90% set, etc.) and plan submittals to the City. We worked with Legacy Partners to include owner plan review periods and the necessary approval dates. We incorporated all of the long lead time items (steel, glass system, GFRC, piles, etc.) and the corresponding shop drawing, material procurement and fabrication times. All of these items were tied into our master schedule and analyzed at our weekly meetings. Keeping the project tracking well was critical. As the preconstruction phase began winding down and start of construction neared, we prepared a detailed construction schedule utilizing our project manager, site superintendents, and Vice President of operations. Not only did we use Lusardi Construction’s extensive experience, but we also solicited input from many of the major subcontractors. The end result was a well thought out and logical construction schedule that we used as a working document throughout the project.
IDENTIFICATION OF LONG LEAD ITEMS – As noted above, the structural steel, glass system, GFRC, and piles were all long lead items and were tracked throughout the preconstruction phase. The piles were the most critical due to the need to perform an indicator pile program to determine the correct length of the piles. Because of the Bay Mud, the piles were designed as friction piles and obtained their support from the lateral forces of the Bay Mud in lieu of vertical forces of bedrock. Lusardi Construction and Legacy Partners entered into a separate contract to complete the indicator pile program in order to keep the project on track. This was done because financing for the entire project had not yet been secured.
SELF PERFORMED WORK - Lusardi Construction self-performed the bentonite and pile backfilling work. We completed all concrete work for the foundations (pile caps and grade beams), building slabs, and elevated floor and roof slabs. We self-performed all parking lot curb work as well as the parking lot methane ventilation system. Lusardi Construction self performed over $7M of the total contract work at America Center, nearly 10% of the total project.
GREEN PROJECT OF THE YEAR - America Center was awarded Green Project of the Year for 2008 by the Silicon Valley Business Journal. The project has been LEED pre-certified Gold and therefore has adhered to the strict guidelines of the U.S. Green Building Council. The project features high-efficient HVAC equipment and lighting, water-efficient plumbing fixtures and landscaping, and a solar reflective roof decreasing cooling requirements. As part of Lusardi Construction’s tasks in achieving LEED Gold, heavy emphasis was put on the use of materials high in recycled content, the use of materials harvested and manufactured locally, pollution prevention throughout construction, indoor environment air quality during construction, and construction waste management. We feel that having built one of the largest LEED Gold projects in the entire Bay Area is a substantial accomplishment for our company.
SAFETY MANAGEMENT – America Center presented unique safety challenges due to the constant presence of methane gas. In an effort to provide the safest working environment possible, Lusardi Construction facilitated a mandatory site specific training program for all subcontractors working below grade. This training program was to supplement the required OSHA 40-hour HAZWOPER training program. In addition to the site specific training program, all Supervisors with employees working below grade were required to complete OSHA 8-hour supervisor training. Regular site visits were conducted by Lusardi Construction’s full time safety officer, and outside methane testing was conducted by a local environmental firm. The end result was a safe working environment and a project without any methane related accidents.
CLOSING – The project was a phenomenal success! Legacy Partners was extremely pleased, not only with the completed project, but with the performance of Lusardi Construction throughout the job. As with all projects, challenges did arise. However, with a great deal of experience, effort, creative thinking, and cooperation, we overcame those challenges to complete the project on time and on budget while producing top quality results.