
12 February, 2008
Awash Bridge two weeks ago stretched by 20mm when a transformer four times heavier than its carrying capacity crossed it. The 213tns transformer with the capability to generate 540MW of electricity was intended for the Gilgel Gibe II Hydro Power Project that is being undertaken by the Italian construction firm Salini Custruttori SpA.
With a trailer specifically geared to transport the shipment, the transformer on January 28, 2008, passed over the 110m long, 40-year-old bridge that has a maximum carrying capacity of 50tns a week after it set out from Port of Djibouti.
“The transformer is crucial for the country’s development and the bridge lies on the main route for the country’s goods,” a senior government official told Fortune. “Though it was a difficult choice, we had to find a way to proceed.”
Both the transformer and the truck trailer were manufactured by Spanish CYMI-SOCOIN. The design of the 22-axle trailer was undertaken by Negussie Tebeje (Engineer.), a 63-year-old retired professor from the Technology Faculty of Addis Abeba University (AAU).
“The 20mm stretch will have no impact on the current and future life of the bridge,” Negussie told Fortune.
According to a civil engineer, if the numbers of axels are increased when the load of a cargo on a truck trailer is high the bridge could handle the weight as the load would be distributed evenly.
“It is because of the many axles of the trailer the bridge handled four times its recommended capacity,” said the engineer.
Negussie for over a year has been studying ways to transport the transformer on the bridge.
The vigilance came following the threat posed by the Tunnel Boring Machines (TBM) that crossed Abay Bridge, the country’s largest bridge (145m) that stretches over the Nile River, in July 2006 after they were stranded for over three weeks. The machines were brought for the Beles Hydropower project underway in the Amhara Regional State.
Of the four trucks blocked at the gate of the bridge at the time, two trucks carrying 62tns and 64tns were allowed to cross the bridge that only is dubbed to carry 40tns following a recommendation by Negussie after a 10-day study on the bridge. The other two trucks that collectively had carried over 100tns of shipments were forced to reach their destinations through different route via Wollega in a bid to protect the 57-year-old bridge.
Salini, which hired Negussie to study the passage on Abay Bridge, has been working with the veteran since then.
Salini has been constructing Gilgel Gibe II as an extension to Giglel Gibe I with a project cost of 400 million Br. Prior to the latest passage two equipments weighing 107tns have crossed Awash Bridge.
For this project, two transformers weighing 213tns each are needed including the one that crossed recently. The transformer crossed on the bridge at a snail pace of five kilometres per hour. The other transformer is expected to arrive soon.
By ISSAYAS MEKURIA - FORTUNE STAFF WRITER
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