The existing airport maintenance bridge over Oyster Creek is a 10 ft. wide and 60 ft. long wood structure that was built in the 1950's. The bridge has been used by airport vehicles and equipment to cross over Oyster Creek to maintain the safety area and electronic aviation equipment located north of the airport's runway.

During Hurricane Harvey, flow velocities in Oyster Creek and accumulated debris under the wood bridge spans displaced the bridge horizontally more than 10 inches from its intermediate bend support in the middle of the span. An inspection and assessment of the bridge condition was conducted in February 2018, by a qualified structural firm. It was determined that the bridge was not safe to use and should be replaced.

The project’s initial scope of work was to replace the bridge with a similar bridge located at the same elevation over Oyster Creek. However, a hydraulic analysis indicated that replacing the existing bridge at the same elevation would have created an adverse impact on the water surface elevation of Oyster Creek and would not be in compliance with the City's design standards which requires any bridge to be 18 inches above the Base Flood Elevation (FEMA 100-year water surface elevation).

The ongoing Airport Master Plan recently identified future projects that would require new construction on the north side of Oyster Creek. In anticipation of those future projects, airport staff considered that this bridge, with a capacity of 10,000 lbs and only 12 ft. wide, would not be sufficient for heavier vehicles and equipment that will need to access the north bank of Oyster Creek.

Based on the hydraulic impacts to Oyster Creek and the decision to increase the bridge loading capacity, the Airport and Engineering Department recommended constructing the bridge at a minimum low chord elevation of 18 inches above the Base Flood Elevation, which increased the length of the bridge from 60 to 80 ft. Additionally, the bridge loading capacity was increased from 10,000 lbs to 54,000 lbs and the width of the bridge increased to 15 ft. wide. The proposed bridge will allow airport personnel to access the north bank during flooding events. The existing wood bridge will be completely removed and the pile bends will be cut at the soil level.

Due to the project’s close proximity to the runway approach/departure path, the airport would be required to close the runway when a large crane is used. Therefore, the contractor will have to work at night during the installation of the piers at the north and south banks. City staff are aware that the modifications to the bridge design, in conjunction with the requirement to work at night, would increase the cost of the bridge from the original estimate that established the budget of $300,000 for both design and construction.

Airport and Engineering staff preferred to bid and receive qualified bids to determine how much additional funds would be needed before requesting a budget amendment from City Council in FY20 so that we do not tie up the Airport funds if not necessary.

The bridge design plans and bid documents were completed in August 2019. The construction project was advertised on September 4 and September 11, 2019. Bids were opened on October 3, 2019. Six (6) bids were received with Leland Bradlee Construction, Inc., being the apparent low bidder.

It is recommended by staff to contract Leland Bradlee Construction, Inc. for a total contract amount of $364,392.00. The design consultant, Aguirre and Fields, Inc., has reviewed the bids, checked references, and recommends selecting Leland Bradlee Construction, Inc., as the responsible low bidder. An additional $179,974.00 is needed in order to cover construction costs, 5% contingency, associated materials testing, and construction administration. To cover all expenses associated with the Oyster Creek Maintenance Bridge Construction, a budget amendment from the Airport Fund in the amount of $179,974.00 to CIP AP1901 is recommended.

Based on preliminary results (prior to year-end accruals and adjustments), the Airport Fund has ended fiscal year 2019 with lower than budgeted expenses, resulting in an ending balance of approximately $732,000 over budget. Based on these results, funding is available from the Airport's operating fund balance to support the additional cost of the project with no negative impact to the five-year forecast. A budget amendment to the Airport operating fund provides pay-as-you-go funding to be transferred to AP1901 in FY20.

The Notice to Proceed for the project is anticipated to be issued in November 2019. The work is to be completed within 90 calendar days, placing final completion in approximately February 2020.

This project is located in a restricted area of the Sugar Land Regional Airport and will have no impact to the residents of Sugar Land. The Engineering staff will maintain continuous updates through the web page and CIP Story Map, maintaining clear lines of communication with airport staff, FAA, Gulf Coast Water Authority (GCWA), and other airport and Oyster Creek stakeholders to minimize any impact on the airport operation and Oyster Creek during the bridge construction.

The Engineering and Aviation Departments recommend that the City Council approve a construction contract with Leland Bradlee Construction, Inc., in the amount of $364,392.00 for the Oyster Creek Airport Maintenance Bridge, CIP AP1901; and authorize a budget amendment in the amount of $179,974.00 from the Airport Fund to CIP AP1901.