How to Reinforce Beams
- 1). Add mass to the bottom of the beam to increase deflection and its carrying ability. Cut 1/2-inch to 1-inch- thick, steel plates to the width and length of the beam you want to reinforce and weld in place.
- 2). Cut new plates approximately 2 inches shorter than the beam's depth so it has a snug fit to the vertical area of the beam that is connecting the horizontal pieces. This area is referred to as the web. They should be about 2 or 3 inches wide and a 1/4 or 3/4-inch thick.
- 3). Attach the web plates in intervals of 2 to 3 feet, welding them into place. Clean the surfaces to be welded and clamped together. Put on your welding goggles before welding. With a torch, heat the areas you want to weld. Heat a welding rod(s) and press along the seam, melting the rod into the seam and locking the pieces in place. Allow the the weld to cool before working on the section again. Check for gaps, and re-weld if needed. Once completed, the web plates will lower deflection, allowing for a higher carry capability.
Source...