DONE AND DUSTED BEFORE DAWN.

R.W. TOMLINSONOTTAWA, CANADA

SEP. 7APRIL 17 BRIDGE UNDER CONSTRUCTION NEXT TO OLD ONE TRAFFIC AS USUAL

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SEP. 7 NIGHT TRANSPORT TO DESTINATIONSEP. 6 PREPARING FOR TRANSPORT

A Z

REPLACING A BRIDGE IN OTTAWA WITH TIME TO SPARE

It’s not every day you’re tasked

with the heaviest lift installation of

a multi-span freeway overpass in

North America, but Ottawa’s Lees

Avenue rapid bridge replacement

was like no other. Weighing 2,254

tons and measuring 87.5 meters

long, the flyover is the city’s main

traffic artery, which was

expanding to accommodate its

new Light Rail System. Project

delays would mean traffic

congestion and heavy fines for

our customer, R.W. Tomlinson.

The bridge’s curved geometry and

the graded roads on which it was

transported provided a unique

challenge, to which Mammoet

successfully rose.

The Rapid Bridge Replacement

technique (RBR) switches a

complete new bridge into place

once the old one is removed. It is

favored over demolition and then

building a new bridge because it

minimizes downtime, decreases

disruption of traffic and reduces

project time significantly, in this case

more than five months. It sounds

simple, but in practice RBR requires

skill, precision and expertise.

In the case of Lees Avenue it was

like picking up a boomerang; a

reference to the curved nature of

the bridge, which made it difficult to

align the SPMTs for jacking in the

usual way. Any twist during transport

could jeopardize the integrity of the

structure.

Not only this, but there was a three

meter drop from one side of the

bridge to the other – an incline that

needed to be reduced to guarantee

safe transport of the new bridge.

In total, three months of planning

culminated in a detailed overnight

procedure for the project. To level

out the three meter elevation,

around 400 dump trucks delivered

12,000 tons of gravel in and out

in five hours.

Once everything was set, 64 axle

lines of SPMT were placed beneath

the old bridge, while falsework

towers were raised to pick the

structure from its bearings. The

trailers then transported the bridge

to its lay down position, repeating

in reverse with the new bridge.

Mammoet’s approach reduced the

usual timeline of several months

down to just two weeks; safely, and

without a single hitch. By the time

the new bridge was set down at

sunrise, partner Tomlinson was

already moving on to the project’s

next phase. The first cars rolled over

the new Lees Avenue overpass

exactly as planned and Ottawa’s

brand new Light Rail carriages some

short weeks later.

RESOURCES

CRANES 1 hydraulic crane

TRANSPORT 96 axle lines of SPMT

SPECIAL EQUIPMENT 1 forklift

CREW 12 Mammoet professionals