Tampa's Elevated Connector Tests the Team
Prior to the start of construction, the joint venture suggested to FDOT that the agency initiate a design change and switch to a foundation of driven piles. While the conditions would have challenged crews under that scenario as well, PCLAW says it still thinks a switch would have made construction easier and less costly. However, making such a change would have likely delayed the start of construction, which also would have impacted the contractor's financing.
Generally, because lending costs accrue whenever any work starts, financing is a factor for the contractor when it considers a change to the work plan.
"It gets counterintuitive, but things we thought we could speed up a lot of times, we couldn't because it was cost prohibitive," Fullington says.
The contractor faces liquidated damages of $24,175 for each day it is late. But FDOT has stretched the original completion from March 2013 to the fall of 2013 to accommodate the complications.
The project received more than $91 million in stimulus money for construction in 2010. Availability payments to repay the contractor's financier begin in 2013 and extend through 2018.
The Tampa office of Parsons Brinckerhoff (PB) is designing the northern portion of the connector, near I-4. Atkins' Tampa office has the south section and Figg Engineering, Tallahassee, is designing the segmental bridge structures for Atkins in the south section.
With three engineers of record on the job, coordination of common design details is another complication, says Bob Szatynski, PB's lead engineer.
"The list of details that you want to match is just endless," Szatynski says. Identical details include foundations, rebar sizes and railings.
PCLAW will erect 2,765 segments—ranging from 65 tons to about 109 tons each—via a mix of span-by-span and balanced-cantilever methods.
Crews are erecting about 74% of the segments using the balanced-cantilever method. Crews first place units on a pier. They then progress outward from the pier in both directions.
The joint venture is mostly using a crane for traditional bottom-up placement, but also a pair of segment lifters for some top-down balanced-cantilever erection.
PCLAW brought the segment lifters primarily for use where placement of a crane is problematic—for example near active rail lines. But crews are using the lifters elsewhere on the project to justify their expense. Lifters sit atop the emerging structure, one on each side of a pier. They then each raise a segment into place, progressing outward in both directions.