The pilot in the tailwheel-equipped airplane reported that, during the takeoff roll, the wind was variable and gusting from the left. He initiated the takeoff roll and applied left aileron and right rudder pedal pressure. The tailwheel lifted from the ground about 40 knots ground speed and the airplane veered to the left. Subsequently the pilot applied full right rudder and simultaneously applied full left aileron, but the airplane exited the left side of the runway. The pilot continued the takeoff roll as he believed that the airplane would start to climb. However, the airplane collided with a drainage culvert located about 25 ft from the left side of the runway. The airplane sustained substantial damage to the right-wing spar and ribs. The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operations. The METAR located at the accident airport reported that about the time of the accident, the wind direction was from 230° with a velocity of 20 knots and gusting to 25 knots. The pilot was departing from runway 23.