The warehouse of a major Bismarck construction company was damaged in the early morning hours on Thursday. Bismarck Fire officials say a truck in the shop of Northwest Contracting caught fire, triggering the building’s sprinkler system. Investigators say the system kept the fire under control by the time fire crews arrived around 3 a.m. Firefighters found heavy smoke and heavy fire and smoke damage to the truck and ceiling in the shop on the 2800 block of Valley Forge Street. No one was injured. Investigators believe the vehicle fire was accidental.