Between Mosul and Irbil stretches the four span, 120m long Khazir Bridge. This demands complete replacement of one span which traffic continues to use.
For the Al Mat bridge between Baghdad and Jordan, isolated replacement of longitudinal beams, deck slab and transverse members is needed. A Kuwaiti precaster was originally sourced to produce replacement beams. But as the project progressed it was felt local firms could benefit instead.
The original 20m long beams were 1,124mm deep prestressed I-sections. Suitable replacements that are buildable by local industry have been detailed to allow for the materials and methods used.
'These replacements are 100mm deeper than the originals, but by shaving the top of the beam over the bearing point and the plinth beneath the bearing, we were able to squeeze them in.'
Designers were able to play with the 150mm clearance between beam and column because flat jacks - not available at the time of original construction - mean less room is now needed for any maintenance jacking.
At Tikrit, two of the 19 spans were destroyed. One of these was neighbouring the central box girder spans. To isolate this from the more complex structure and prevent damage, US forces blasted the collapsed members free.
A cracked hammerhead pier supports the concrete box girder spans in Tikrit. This was shored up with sacrificial steel props, scabbled back and recast as a solid leaf pier in emergency works designed by Halcrow.