The Texas Dept. of Transportation and the Flatiron/Dragados joint venture resolved the last outstanding design issues on the nearly $1-billion US 181 Harbor Bridge project in Corpus Christi, Texas early this month.
The concerns were about the proposed design of the jointed pier segments, which will allow the main span to expand and shrink depending on outdoor temperatures, and was among the issues that stalled the project last July. Temperatures in the summer average around 94°F.
"TxDOT and the developer of the New Harbor Bridge, Flatiron/Dragados, have reached concurrence on the technical resolution of the safety concerns related to the design of the cable-stayed bridge," the agency announced on its website. "TxDOT and (Flatiron/Dragados) will continue to coordinate through construction as the design solutions are incorporated into the project."
Last summer, after an independent inspection by France's International Bridge Technologies found several issues with the bridge, TxDOT halted construction on the cable-stayed portion.
The first issue was inadequate capacity of the piles, according to the TxDOT website. Work is underway to add additional drilled shafts to foundations at the north and south pylons.
Another problem involving the north and south pylons was deficiencies in footing caps. Crews are adding supplemental shafts to increase capacity.
The third issue was defects in the delta frames and adjacent precast concrete units. The capacity of the impacted connection will be increased by roughening the concrete surface and adding rebar.
The fourth issue was uplift at an intermediate pier. That will be addressed by updating the design of the last segments at either end of the cable-stayed bridge to add rebar and modify the external bearings on the transition pier cap.
Finally, the report found excessive torsion and other stresses related to crane placement during construction. This concern is being addressed by a revised erection plan that will incorporate counterweights to account for possible high winds as the main span nears completion.
TxDOT last summer issued a notice of default to the Flatiron/Dragados team. In October, TxDOT and the contractor reached an agreement on addressing the concerns.
The 1,661-ft-long bridge is expected to be completed in mid-2025, more than five years behind schedule. Construction began in August 2016, but a series of delays pushed the 2020 completion date back, including a design firm change in 2019 and last summer’s construction halt over the design concerns.
TxDOT informed local governments that overruns are “likely,” but did not give a new cost estimate.
When completed, the New Harbor Bridge will measure 138-ft vertical clearance, and the longest cable-stayed bridge in the nation. It is replacing the current 70-plus-year-old Harbor Bridge that crosses the city’s shipping canal. State officials say demolition of the old bridge is scheduled once the new bridge is complete and will take about a year.
