The delay in adding more arch segments to the Interstate 74 bridge is caused by challenges with the pulley system that will help make the arches on either side of the Mississippi River meet in the middle. The system is complicated, DOT officials said, and the contractor, Lunda Construction, has been trying for several weeks to properly position the cables that are needed to keep the arches aligned.
The crown jewels of the new Interstate 74 bridge — its high-rising arches — are so complicated to build, transportation officials say, progress is slowed again.
Little headway was made in July on the arches that will rise above the westbound span of the new bridge, which originally was to be finished in just a couple of months. The anticipated completion of the westbound (Iowa-bound) span already has been pushed into the middle of next year, following a particularly harsh winter and multiple spring record floods in the work zone.
But the lead agency for the project, the Iowa Department of Transportation, was expecting progress on the arches to move more rapidly when Mississippi River floodwaters receded. While the river has been below major flood stage since mid-June, the arches remain at just 10 erected segments out of a total of 30 that will go into each span.
"The contractor has experienced some challenges with installing the stays and pulley system," said Danielle Alvarez, I-74 project manager for the Iowa DOT. "It’s a difficult process and requires extreme precision, because the stays will be used to adjust the angle of the arch segments to ensure the correct fit.
"The true arch design is unique and challenging, and we are working closely with the contractor to identify and resolve issues as quickly as possible."
More specifically, the delays are being caused by difficulty in getting cables from their concrete housings that are built into a pier near the shoreline to thread through the blue/green towers that stand between the arches and the shore. The cables must then be placed onto the arch segments themselves, because they will be used to help direct the positioning of each added arch piece.
"It’s taking time, because the stays must be meticulously placed and threaded through the mechanism at the top of the tower," Alvarez elaborated last week in an email. "This process is critical, and everything must be positioned accurately before any new segments can be added to the arch.
"As we mentioned, if the alignment of the arch is off this early in the process, it would create fit-up issues down the road. Accuracy is key at this stage."
The cables running from the housings (also called anchorages) to the tower are back stays, and the ones running from the towers to the arches are called fore stays. The towers are more than 200 feet high, so the process of precisely looping cables through them with cranes is tricky work.
-
{{title}}
{{start_at_rate}}{{format_dollars}} {{start_price}} {{format_cents}}{{term}}{{promotional_format_dollars}}{{promotional_price}}{{promotional_format_cents}} {{term}} - {{html}}
Thanks for being a subscriber.
Sorry, your subscription does not include this content.
Please call 800-660-2472 to upgrade your subscription.
You have free articles remaining.
Once the cables are placed, though, the progress on adding more arch segments will happen more quickly, Alvarez said.
"The contractor is also planning ahead for when the arch is near completion," she said. "They are coordinating with the U.S. Coast Guard to obtain approval for briefly closing the navigation channel when the last few segments of the arch are ready to be set.
"The arch meets in the middle of the navigation channel, and the contractor will need to station a barge and their equipment in the channel in order to set the last few segments. The channel can only be closed for brief periods of time and requires prior approval from the USCG."
At this point, it does not appear it will be necessary to request a channel closure in August, because the arches will not be ready, she said.
By using the pulley system for guiding the arches toward their meeting point in the center, the contractor avoids the need for long-term obstructions in the navigation channel. Barge traffic already took a major hit this spring when long-term flooding closed the river to navigation.
"We had hoped that the arch erection would proceed smoothly after flooding receded, but the challenges with the stays and controlling proper arch alignment have slowed our progress," Alvarez wrote. "Progress on other parts of the bridge continue, including constructing the deck over the piers south of the arch as well as pre-assembling the arch flooring system (the section that will run the length of the arch and support the concrete deck)."
Much of the arch work is being done by members of Ironworkers Local 111, which is based in Rock Island. Earlier this summer, 53 ironworkers from 111 were working on the bridge, union leaders said, and another 30 were expected to be called into action by July.
While many ironworkers continue to work on the bridge decking for both spans, very little activity has been underway near the arches.
040319-qct-qca-arch-001
Work continues around the anchors for the arches on the new Interstate 74 bridge Tuesday. The predicted higher flood levels on the Mississippi River may impact progress on the main feature of the "basket-handle design," which will rise 164 feet above both spans of the new I-74 bridge. The first pieces of arch were in place this week on three out of the four anchors.
040319-qct-qca-arch-002
Work continues around the anchors for the arches on the new Interstate 74 bridge Tuesday. Milling and painting of the westbound arch is complete with plans to install the first segments in the coming weeks. The predicted higher flood levels on the Mississippi River may impact progress on the main feature of the "basket-handle design" which will rise 164 feet above both spans of the new I-74 bridge.
040319-qct-qca-arch-003
Iron workers tie rebar for the eastbound arch piers for the new I 74 Interstate Bridge Tuesday, April 2, 2019.
040319-qct-qca-arch-004
Work continues around the anchors for the arches on the new Interstate 74 bridge Tuesday, April 2, 2019. Milling and painting of the westbound arch is complete with plans to install the first segments in the coming weeks. The predicted higher flood levels on the Mississippi River may impact progress on the main feature of the "basket-handle design" which will rise 164 feet above both spans of the new I74 bridge.
040319-qct-qca-arch-005
The green towers at left were raised to help accommodate the construction of the arches on the new Interstate 74 bridge. Three out of four of the first pieces of arch are in place on their anchors, but floodwater could slow progress.
040319-qct-qca-arch-006
Plans are to begin installation of the first segments of the westbound arch in the coming weeks, however, the predicted higher flood levels on the Mississippi River may impact progress on the main feature of the "basket-handle design" which will rise 164 feet above both spans of the new I74 bridge.
040319-qct-qca-arch-007
Work continues around the anchors for the arches on the new Interstate 74 bridge Tuesday, April 2, 2019. Milling and painting of the westbound arch is complete with plans to install the first segments in the coming weeks. The predicted higher flood levels on the Mississippi River may impact progress on the main feature of the "basket-handle design" which will rise 164 feet above both spans of the new I74 bridge.
040319-qct-qca-arch-008
Work continues around the anchors for the arches on the new Interstate 74 bridge Tuesday, April 2, 2019. Milling and painting of the westbound arch is complete with plans to install the first segments in the coming weeks. The predicted higher flood levels on the Mississippi River may impact progress on the main feature of the "basket-handle design" which will rise 164 feet above both spans of the new I74 bridge.
040319-qct-qca-arch-009
Workers have completed milling and painting of the westbound arch piers on the Illinois side of the river. The plan is to install the first segments in the coming weeks, however, the predicted higher flood levels on the Mississippi River may impact progress on the main feature of the "basket-handle design" which will rise 164 feet above both spans of the new I74 bridge.
040319-qct-qca-arch-010
Workers have completed milling and painting of the westbound arch piers on the Illinois side of the river. The plan is to install the first segments in the coming weeks, however, the predicted higher flood levels on the Mississippi River may impact progress on the main feature of the "basket-handle design" which will rise 164 feet above both spans of the new I74 bridge.
040319-qct-qca-arch-011
Workers have completed milling and painting of the westbound arch piers on the Illinois side of the river. The plan is to install the first segments in the coming weeks, however, the predicted higher flood levels on the Mississippi River may impact progress on the main feature of the "basket-handle design" which will rise 164 feet above both spans of the new I74 bridge.
020119-qct-big-story-bridge-001
Iron workers with Rock Island-based Local 111 have spent more than a year helping to build the new Interstate 74 bridge between Bettendorf and Moline.
020119-qct-big-story-bridge-002
Millions of tons of rebar, or reinforced bar, is going into the new Interstate 74 bridge. About 150 iron workers from Rock Island-based Local 111 will spend several years manipulating the rebar into precise configurations to give the span its strength.
020119-qct-big-story-bridge-003
An iron worker twists rebar, dubbed "rod busting," on a section of new bridge deck for the new Interstate 74 bridge between Bettendorf and Moline. Some iron workers do not like laying rebar for decking, because they must spend hours bent over.
020119-qct-big-story-bridge-004
Night-time work on the new Interstate 74 bridge is more frequent in warmer weather, and iron workers say the snow and ice make their work most dangerous. While few fear falling, slippery iron makes them more cautious.
020119-qct-big-story-bridge-005
On many days, cement trucks are constantly coming and going from the Moline shoreline and onto the Mississippi River. More than 100,000 cubic yards of cement is being used on the new Interstate 74 bridge, and the trucks are ferried by barge to the spots where they are needed.
020119-qct-big-story-bridge-006
Many of the jobs being done by iron workers from Rock Island-based Local 111 are performed high above the Mississippi River. They are responsible for the proper placement of tons of rebar, which is the green rods seen in this photo and throughout the project area.
020119-qct-big-story-bridge-007
Iron workers build the "molds" into which concrete is poured for piers and other essential parts of the new Interstate 74 bridge. About 150 members of Iron Workers Local 111, Rock Island, ultimately will work on the new bridge.
020119-qct-big-story-bridge-008
More than a dozen cranes sometimes crowd the work zone on the Mississippi River, where the new Interstate 74 bridge is being built. The workers are ferried to the site by barge tows and boats.
020119-qct-big-story-bridge-009
Two 200-foot towers were shipped to the construction site of the new Interstate 74 bridge to support the erection of the arches. They arrived in 100-foot sections, were put together by iron workers, who then were lifted to the top to disconnect the towers from the cranes that raised them.
020119-qct-big-story-bridge-010
The piers that are visible at right will support the westbound span of the new Interstate 74 bridge. To their left, caissons are visible, and piers for the eastbound span will be built upon those.
020119-qct-big-story-bridge-011
This photo was taken by Davenport iron worker Josh Rangel, looking down through one of the two 200-foot towers he helped put together. The towers will give support to the arches as they are built on either side of the river, meeting in the middle.
020119-qct-big-story-bridge-012
This odd-looking structure contains the base for the basket-handle design arches that will rise nearly 200 feet above the Mississippi River on the new Interstate 74 bridge.
020119-qct-big-story-bridge-013
Built by iron workers from Rock Island-based Local 111, this is one of eight bearings, four for each span, that will serve as anchors for the arches on the new Interstate 74 bridge. They will sit inside the top of the arch piers.
020119-qct-big-story-bridge-014
On the barge platform at right, two of the eight bearings that will anchor the arches for the new Interstate 74 bridge await completion. Iron workers must tie the bearings in rebar before they are set into the arch piers.
020119-qct-big-story-bridge-015
About 60 local iron workers are assigned to the new Interstate 74 bridge. That number will more than double in the spring. The workers are ferried to areas of the work site by boats and, sometimes, barge tows.
020119-qct-big-story-bridge-016
An iron worker from Rock Island-based Local 111 took this sunrise photo of the work zone for the new Interstate 74 bridge. Some workers said they take pictures of their progress every day.
020119-qct-big-story-bridge-017
Iron workers spend a considerable amount of their time on the new Interstate 74 bridge climbing and manipulating rebar into precise configurations. They build mold-like frames into which concrete is poured for piers, footings, bridge decking and other structural components.
020119-qct-big-story-bridge-018
Local iron workers spend time high above the Mississippi River, but they also spend time inside of it. Coffer dams were built to hold back water while caissons and other supports are built, drilling deep into the bedrock for strength.
020119-qct-big-story-bridge-019
020119-qct-big-story-bridge-020
Two 200-foot-tall towers are placed on either side of the piers from which the arches will rise for the new Interstate 74 bridge. Once erected, iron workers from Local 111, Rock Island, were raised onto the top of the towers to disconnect them from the cranes.
020119-qct-big-story-bridge-021
An iron worker with Local 111 is shown. In this photo, he is disconnecting a crane from one of the 200-foot-tall towers that were erected to help with the upcoming construction of the arches for the new Interstate 74 bridge.
020119-qct-big-story-bridge-022
020119-qct-big-story-bridge-023
020119-qct-big-story-bridge-024
020119-qct-big-story-bridge-025
020119-qct-big-story-bridge-026
021019-qct-qca-bridge-001
Gerald Rangel, left, and his son, Josh Rangel, stand in front of the Interstate 74 bridge at Leach Park in Bettendorf. Josh is an iron worker with Local #111 and currently is working on the new Interstate 74 bridge, and Gerald was an apprentice with Local #111 when he worked on the existing bridge in 1971.
021019-qct-qca-bridge-002
Gerald Rangel, left, shares memories of working on the Interstate 74 bridge with his son, Josh, at Leach Park in Bettendorf, Sunday, Feb. 3, 2019. Josh is an iron worker with Local #111 currently on the new Interstate 74 bridge project, and Gerald was an apprentice with Local #111 when he worked on the existing bridge in 1971.
021019-qct-qca-bridge-003
Gerald, left, and Josh Rangel stand in front of the Interstate 74 bridge at Leach Park in Bettendorf, Sunday, Feb. 3, 2019. Josh is an iron worker with Local #111 currently on the new Interstate 74 bridge project, his father, Gerald, was an apprentice with Local #111 when he worked on the existing bridge in 1971.
021019-qct-qca-bridge-004
Gerald, left, and Josh Rangel stand in front of the Interstate 74 bridge at Leach Park in Bettendorf, Sunday, Feb. 3, 2019. Josh is an iron worker with Local #111 currently on the new Interstate 74 bridge project, and his father, Gerald, was an apprentice with Local #111 when he worked on the existing bridge in 1971.
062619-qct-74-bridge-001
Looking across the Mississippi River at the new construction leading to the new I-74 bridge, Wednesday, June 26, 2019, from the Bettendorf side of the Mississippi River.
062619-qct-74-bridge-002
Construction on the new I-74 road westbound looking toward the Lincoln Road bridge, Wednesday, June 26, 2019, on the Bettendorf side of the Mississippi River.
062619-qct-74-bridge-003
Passengers on the Celebration Belle get a close-up view of the construction of the new I-74 bridge, Wednesday, June 26, 2019, on the Mississippi River.
062619-qct-74-bridge-004
Scenes of construction on the new I-74 bridge, Wednesday, June 26, 2019, on the Bettendorf and Moline side of the Mississippi River.
062619-qct-74-bridge-005
Scenes of construction on the new I-74 bridge, Wednesday, June 26, 2019, on the Bettendorf side of the Mississippi River.
062619-qct-74-bridge-006
Scenes of construction on the new I-74 bridge, Wednesday, June 26, 2019, on the Bettendorf and Moline side of the Mississippi River.
062619-qct-74-bridge-007
A construction worker secures the base of a street light on a portion of the new I-74 bridge, Wednesday, June 26, 2019, on the Bettendorf side of the Mississippi River.
062619-qct-74-bridge-008
Workers are shown June 26 scaling the arch segments on the new I-74 bridge to access and connect the sections. Last week, a winch that was being used to pull the critically needed cable to the top of the tower suddenly gave out.
062619-qct-74-bridge-009
Scenes of construction on the new I-74 bridge, Wednesday, June 26, 2019, on the Bettendorf side of the Mississippi River.
062619-qct-74-bridge-010
Scenes of construction on the new I-74 bridge, Wednesday, June 26, 2019, on the Bettendorf side of the Mississippi River.
062619-qct-74-bridge-011
Passengers on the Channel Cat get a close-up view of construction on the new I-74 bridge, Wednesday, June 26, 2019, from the Mississippi River.
062619-qct-74-bridge-012
Construction workers take delivery of pieces needed to build the arches for the new Interstate 74 bridge. Parts and pieces are raised to the workers by crane, and ironworkers must enter the arches to connect each piece.
062619-qct-74-bridge-013
Scenes of construction on the new I-74 bridge, Wednesday, June 26, 2019, on the Bettendorf side of the Mississippi River.
062619-qct-74-bridge-014
The construction zone for the new Interstate 74 bridge is a maze of cranes, towers and cables. Workers have been trying in recent days to connect an important set of cables to the towers in the photo, which will hold the arch pieces in place.
062619-qct-74-bridge-015
Looking across the Mississippi River at the new construction leading away from the new I-74 bridge, Wednesday, June 26, 2019, from the Moline side of the Mississippi River.
062619-qct-74-bridge-016
Scenes of construction on the new I-74 bridge, Wednesday, June 26, 2019, from the Moline side of the Mississippi River.
062619-qct-74-bridge-017
Scenes of construction on the new I-74 bridge, Wednesday, June 26, 2019, on the Moline side of the Mississippi River.
062619-qct-74-bridge-018
Scenes of construction on the new I-74 bridge, Wednesday, June 26, 2019, on the Moline side of the Mississippi River.
062619-qct-74-bridge-019
Scenes of construction on the new I-74 bridge, Wednesday, June 26, 2019, on the Moline side of the Mississippi River.
062619-qct-74-bridge-020
Scenes of construction on the new I-74 bridge, Wednesday, June 26, 2019, on the Moline side of the Mississippi River.
