A dedicated team from Hanson helped Norfolk Southern Corp.
rebuild a bridge in 27 days after it collapsed under the pressure of a flooded
river and debris.
A buildup of tree limbs and high water had been pushing on
the 103-year-old rail bridge over the Grand River near Brunswick, Missouri,
leading Norfolk Southern to cut the rails the evening of Oct. 1 to relieve
pressure and prevent further damage to its rail line. A portion of the bridge
was wiped out within minutes. Four spans and three piers — about 267 feet of
the 1,110-foot-long bridge — were swept away. (Watch a news broadcast about the
collapse from Kansas City’s KCTV here.)
Workers clean up Oct. 3, two days after part of the rail bridge over the Grand River was wiped out.
With the bridge out, up to 14 trains per day had to be
detoured, causing delays that affected the area’s economy. Grain is carried out
of Chariton County on the tracks, which run through Brunswick. The bridge
collapse occurred during harvesting season — another blow to farmers who had
been set back by severe flooding in the spring. And the longer the bridge is
closed, the risk of financial loss increases for Norfolk Southern. The railroad
faced an urgent repair.
The next morning, Norfolk Southern contacted its contractor,
Massman Construction Co., and Hanson for assistance. Hanson obtained hydraulic
and geotechnical data from the Missouri Department of Transportation on the
U.S. 24 bridge, which was a few hundred feet upstream. “This initial
information proved valuable to determine an approximate elevation and material
type for the local bedrock,” said Mat Fletcher, P.E., S.E., a senior project
manager at Hanson’s Peoria, Illinois, office who oversaw the firm’s work for
the Norfolk Southern bridge.
Meanwhile, Massman sent two barge-mounted cranes to the site
of the damaged bridge to prepare for the reconstruction. Hanson’s
subconsultant, Prairie Engineers, mapped what was underwater at the site by
conducting what is called a bathymetric survey, which gathered as much data as
possible about the location of the toppled piers and bridge debris in the
riverbed. Prairie’s crew continued to provide hydrographic surveying support throughout
the project.
Within a week of the collapse, Hanson had assessed the
aftermath, started developing a plan for the replacement section, worked with
the railroad to produce an initial layout and collected soil borings from the
site to refine the estimated geotechnical parameters that were based on the
U.S. 24 bridge.
A piece of track from the bridge collapse is removed from the water Nov. 11.
Deep scour was expected at this bridge. Scour — sediment
that is moved away from or against bridge piers by currents, changing the flow
around the piers — is a major cause of bridge failures in the U.S. Considering
scour, the likelihood of future debris buildup and the collected data, two of
the three replacement piers required drilled shafts socketed into the shale
bedrock. The third pier, near the eastern bank of the river, would be installed
with pipe piles driven deep below the riverbed. It was anticipated to take as
long as two weeks to get the 6-foot-diameter drilled shafts in place. “Ultimately,
it only took four days,” Mat said.
Saving time was crucial. Precast concrete was used to
accelerate the construction of the piers. The design team adapted the
foundation elements to be precast and used the updated field measurements to
locate the connection points for erection. The precast fabricator made the
final adjustments and delivered the precast by truck. The precast pier caps
were made using high early strength, high-performance concrete, then
steam-cured overnight, which meant these pieces could be delivered and ready to
install within 24 hours after the concrete was poured. To install the caps —
which each weigh 63 tons, equivalent to about 25,000 bricks — onto the piers,
Hanson determined that using post-tensioning rods would save time and
materials. Other bridge components were already available elsewhere, such as
steel spans from Norfolk Southern’s inventory that could be transported by
railcar.
“Once the caps were installed, Massman could proceed with
erecting the adjacent spans with new bearings, and Norfolk Southern crews could
finish installing the open deck ties and, eventually, the rail,” Mat said.
After some final adjustments, the bridge reopened to trains Oct. 28.
A Norfolk Southern train crosses the rebuilt bridge.
Everyone on the project was focused on quickly rebuilding
the bridge to get Norfolk Southern’s track back in service. Several Hanson
employees worked during the evenings and weekends, and the contractor team
pulled double shifts to keep the construction going around the clock. Hanson’s
preliminary design drawings were provided to all team members to review and
offer input.
Drew Dragoo, P.E., a Hanson railroad engineer
who works with Mat in the Peoria office, was at the site to help with
coordination and provide construction management services, and Hanson used a drone
to photograph the project’s progress. “Everyone can say that working as a team
with Norfolk Southern, Massman Construction Co. and Hayes Drilling Inc. during
the accelerated construction of the replacement bridge was a rewarding
experience to be a part of,” Drew said. “It was critical to be ‘hands on’
during the construction as the contractor worked around the clock. Communicating
to gather everyone’s expertise in a timely manner kept the construction moving
forward at an accelerated pace until the first train crossed the river.”