Sixth Street bridge may cost 50% more than original estimate

On Jan. 25, the Milwaukee Metropolitan Sewerage District (MMSD) commission approved a revised agreement with the city of Milwaukee to rebuild the Sixth Street bridge over the Kinnickinnic River between Cleveland and Harrison avenues. MMSD now estimates the project, which is to receive $1,579,034 in federal stimulus funds, at $3,671,508.

Under the original 2009 agreement, the city would not have paid a cent, but upon revised MMSD cost estimates, MMSD is requesting that the city and Wisconsin Department of Transportation (WisDOT) contribute up to $600,824. MMSD will contribute up to $1,690,140, up from an estimated $869,000. 

The project estimate was revised upwards by $1,223,474, or roughly 50 percent of the original $2,448,034 estimated price tag.

Two issues caused the significant cost increase, according to MMSD: the realignment of MMSD’s sewer within the proposed bridge and the relocation of the city’s combined sewer from Sixth to Eighth Street.

“Initially, it was believed that the limits of the MMSD sewer realignment would be confined to the area of bridge construction. However, as the bridge elevation was finalized and all other utility conflicts were identified in final design, it was discovered that the realignment would need to extend approximately 250 feet to the north in order to match up with the existing sewer elevation,” according to MMSD project manager Patrick Elliott.

At a public meeting Oct. 22, 2009, MMSD and the city shared bridge designs inside Manitoba Banquets, 3001 S. Sixth St., a few blocks south of the bridge. Engineers showed renderings of the proposed bridge, including cross sections containing sewer and utility lines. They discussed the proposal to move utilities up into the bridge structure, not rerouting them.

But, according to Elliott, because of the elevation of upstream house laterals, the city’s combined sewer could not be raised within the proposed bridge.

“We had some of this information at the time of the public meeting, but we had not completed the final design or performed the final revised estimates. With the fast-paced design schedule driven by the federal stimulus award, much of the final design and cost information was not pulled together until the month of November, after the meeting,” according to Elliott.

The city can still afford the project, according to Craig Liberto, Milwaukee Department of Public Works structural design manager. He said funds for the work were budgeted through the city’s Capital Improvement program. The Milwaukee Common Council approved the agreement with MMSD Dec. 22, 2009.

Next, Liberto said the city, MMSD, and WisDOT will review bids submitted for the project March 23. A bid analysis will then be conducted to determine whether to award a construction contract.

Liberto said the original cost estimate included in the application for stimulus funds April 4, 2009 was based on conceptual plans using square-foot costs of similar type bridges.

MMSD is leading the effort to replace the Sixth Street bridge as part of its Kinnickinnic River Watercourse Management Plan. The new steel bridge should allow 1-percent flood flows of the Kinnickinnic River to pass beneath. The existing concrete culvert bridge contains an 11-foot-high dirt/fill layer beneath the roadbed, which impedes flood flows.