The pilot stated that he positioned his feet on the toe brake pedals during engine start. After starting, the engine accelerated to a higher rpm than the pilot expected, and the airplane began to roll forward. The pilot pressed down with his feet, but the airplane continued to roll. After reducing the throttle to idle, the pilot attempted to steer the airplane with the rudder pedals, but they were fixed and would not move. As the airplane neared a hangar, the pilot shut down the engine with the fuel mixture control and turned the magneto switch off. The airplane then impacted the hangar, resulting in substantial damage to both wings. Postaccident examination revealed no anomalies with the rudder pedal or toe brake systems. In a postaccident statement, the pilot offered that, rather than placing his feet on the brake pedals, he inadvertently pressed on the torque tube assembly, which is part of the airframe structure located above the toe brake pedals.