I need an engineer to help design residential bridge over creek

I need an engineer to provide drawings and weight limit of residential bridge over creek. Creek span is approximately 35 feet. I have already pre-purchased 37 foot 18" steel I-Beams and can provide those details. I want the bridge to be 15 feet wide with a poured concrete deck with 8-inch concrete curbs on edges so that I can attach wood railings. We would use a pier and beam system.