Steel Roof Joist Chord Reinforcement

All vulcraft joists and joist girders are designed and manufactured in accordance to the exacting specifications of the steel joist institute.

Steel roof joist chord reinforcement.

Screw the metal joist to the existing wood ceiling joist and to each plate and you have very effectively reduced the load deflection of any stored attic loads for little cost. Depending on loads and spans c joists are typically spaced at 12 16 19 2 or 24 on center spacing. For a steel joist in your roof this may mean it can support your rtu or not. Open web steel joists are an engineered truss like construction component used to support loads over short and long spans alike.

Chord reinforcement typical reinforcement details top chord more difficult to reinforce since the floor or roof. For a grade 50 steel chord this changes the force capacity up or down by 3000 lbs. New sji rule on steel joists. Adding new joists or beams.

One of the structural components that is highly impacted by any change in loading is the open web steel joist. Loads are small 20 50 pounds so additional reinforcement by susan bady contributing editor a new rule from the steel joist institute clarifies when local reinforcement of joists is required for chord loads away from panel points. Sji members offer guidance about how and when to specify loads. Evaluation of joists and their typical reinforcement in steel framed buildings unforeseen changes often occur in the design loads on a building either during construction or afterwards in the existing structure.

Steel joist institute publication technical digest no. Reinforcing the existing joists. Joists can be strengthened by welding steel rods and plates to the flanges similar to how we would strengthen a steel beam see blog post how to strengthen an existing support beam. There are three basic methods of reinforcing a joist system for additional loading.

Typically used in non residential construction steel joists and joist girders provide an economical system for supporting floors and roofs. One 32nd of an inch thickness variance on a 1 3 4 x 1 3 4 steel angle adjusts the area up or down by about 1 10 square inch. Structural track usually in the same gauge as the. Provide a lightweight low cost rigid floor assembly c joist components provide an economical lightweight alternative to open web trusses bar joists engineered lumber cast in place or hollow core floor assemblies.

Typically existing joists do not have a lot of extra load carrying capacity especially if they are already supporting an existing rooftop unit. However this doesn t result in large increases in capacity.