Army Engineers Dig Deep to Restore Key Iraqi Bridge (6/30/03)
By Thomas F. Armistead in Tikrit
Army Engineer bridge builders, trained to build medium girder bridges from kits, have used every tool in their box to reopen a bomb-damaged concrete-beam-and-arch bridge across the Tigris River in Tikrit to normal civilian and military traffic.
Air strikes breached the deck at two points on the 680-m-long structure. The 565th Engineer Battalion arrived April 23 to reopen the crossing by first throwing a 556-m float bridge across the river. It was the largest float bridge built in combat theater since World War II, according to the Army.
Under its contract with USAID to rebuild Iraq's infrastructure, San Francisco-based Bechtel National Inc. has assigned the bridge third priority and will not be able to start reconstruction for some months. So army engineers began temporary repairs to reopen the fixed bridge to normal traffic. They set about spanning the ragged gaps with prefabricated Mabey & Johnson bridges, like dentists bridging molars.
The mission has taxed the combat engineers to the utmost. "This project has grown immensely since we started. Every time we go out there, there's something else wrong," says Capt. Carrington Stoffels, commander of the 38th Engineer Co.
Bombs pierced half the deck on the upstream side at Spans 7 and 10. The bomb on Span 7 struck near a pier, destroying the two outermost of five stringers, cracking the third, blowing out the bearings and dropping the deck onto the pier cap. At Span 10, the deck was left hanging by prestressing cables. The bearings were canted and the entire deck shifted 5 to 8in. downstream.
The 38th demolished the damaged deck sections. Lacking tools for time-delayed detonation, they made do with C4, using detonation cord and time-fuse igniter. Careful placement seasoned with "Kentucky windage" brought down the decks with minimal additional damage. The company began erecting the 130-ft steel bridge at Span 7 at night on May 9.
Settling and cracking developed in Pier 7's cap after a couple of days and construction was halted. Stoffels called on the Forward Engineer Support Team (FEST) attached to the 4th Infantry Division occupying Tikrit, and FEST and the Engineers separately assessed the bridge. They distilled their findings into a 35-page report with photos and was emailed to the Corps of Engineers' Engineering Research & Development Center in Vicksburg, Miss.
ERDC recommended an I-beam structure to support the frame in place of the missing Pier 7 bearings. But before going ahead, the engineers load-tested the badly cracked pier cap with 35-ton jacks from the Mabey & Johnson bridge kits. They placed four on the pier cap, jacked them nearly to failure and left them overnight. With no further settling by morning, work began on the support structure. The Span 7 bridge and the 240-ft Span 10 bridge were completed May 16, raising capacity from class 30 to class 70. Work since has increased that to class 80 for tracked vehicles and class110 for wheeled--a rating that will carry M1 tanks. The engineers' next goal is to shift the deck back to normal alignment.