Soldiers rebuilt a bridge (7)
I believe the answer is:
brigade
'soldiers' is the definition.
(I've seen this before)
'rebuilt a bridge' is the wordplay.
'rebuilt' is an anagram indicator.
'a'+'bridge'='abridge'
'abridge' is an anagram of 'BRIGADE'.
(Other definitions for brigade that I've seen before include "Body of troops" , "Soldiers" , "Part of an army division" , "Rig a bed (anag)" , "Company" .)