Bad Pour Halts Forth Bridge Work
FIRTH OF FORTH, SCOTLAND--A marine traffic jam that slowed barge delivery of concrete is being blamed for a botched pour that burst pipes and halted work on the £1.4 billion Forth Road Bridge replacement project.
About 30 cubic meters of concrete (just over 1,000 cubic feet) were being pumped from sea level to an upper deck of the new Queensferry Crossing bridge deck on June 5 when the material stiffened up and ruptured several pipes, officials said.
Meanwhile, the concrete that had already set from the batch proved far too brittle and had to be removed, reports said.
Several reports quoted sources as saying that workers had complained about the mixture before the accident.
"Workers had reportedly warned bosses that the cement was too stiff and would wreck the pipes but were told to press on," Herald Scotland reported.
The gaffe on what was supposed to have been a "routine" pour "risked lives," added the daily Scottish Construction Now!
An unidentified source told the Daily Record that it was "a miracle" no one had been injured or killed when the pipes burst.
Workers had to dig out the set concrete by hand, damaging steel reinforcing rods in the process. Those rods must now be replaced, reports said.
|Photos: Transport Scotland|
The crossing project was awarded in 2011 to a consortium of four companies from four countries. Construction is expected to be completed in 2016.
The incident has delayed the project schedule by about two weeks, but officials had announced in January that the project was then ahead of its scheduled 2016 opening.
A new timetable on the project was not immediately available.
Transport Scotland sought to downplay the incident.
“Some difficulties were encountered on the first concrete pour on the north tower deck last Friday, causing the pour to be stopped," the agency said in a statement.
A spokesman blamed the problem on "marine traffic" around the port of Rosyth that delayed barges transporting the concrete, causing it to thicken prematurely. About six trucks full of concrete were affected, reports said.
“The small quantity of concrete placed has already been removed, cleaning work is under way, and we expect to be in a position to pour the concrete in this area next week."
The Queensferry Crossing's South Towers were well underway in April. Many more photos and videos of the entire project are available here.
The project's £1.4 billion ($2.1 billion) price tag is not affected, Transport Scotland said.
The Queensferry Crossing is part of the 13.7-mile Forth Replacement Crossing project, which includes upgrades to highways north and south of the bridge.
The 1.7-mile (2.7km) Queensferry Crossing will be the world's longest three-tower, cable-stayed bridge and, by far, the largest to feature cables that cross mid-span.
The design "provides extra strength and stiffness, allowing the towers and the deck to be more slender and elegant," according to Transport Scotland.
The Forth Road Bridge project followed the discovery of corrosion on the bridge's main cable in 2004. The bridge opened in 1964 and is one of Scotland's most critical economic arteries, carrying about 60,000 vehicles daily.
Significant corrosion was found in 2004 on the main cable of the iconic Forth Road Bridge (above). Numerous options for replacement were examined, and the current course was chosen in 2007. To the far right is Scotland's iconic Forth Bridge, which opened in 1890.
In 2006-07, Transport Scotland completed a Forth Replacement Crossing Study, which examined a wide range of bridge and tunnel options for the crossing. The new cable-stayed bridge got the green light in December 2007.
In one of the biggest procurement exercises in Scotland's history, the project was awarded in April 2011 to a consortium called the Forth Crossing Bridge Constructors.
The consortium companies are Hochtief, from Germany; American Bridge, from Pittsburgh, PA, in the United States; Dragados, from Spain; and Morrison Construction, in Scotland.
Extensive photos of videos and photos of the Queensferry Crossing project, including live webcam streaming from a variety of vantage points, are available here.
Note: This post was updated at 3:35 p.m. July 1, 2015, to correct a measurement reference.