Tie Joist Requirement? 1

[Ian999]

OSHA: Subpart R - Steel Erection (Sect. 1926.751c Structural Steel Assembly) states: "In steel framing, where bar joists are utilized, and columns are not framed in at least two directions with structural steel members, a bar joist shall be field-bolted at columns to provide lateral stability during construction."

Case: Residential/Townhouse construction(Two stories) typically one end bears on steel(Welded or shot to beam) and the other end bears on concrete tie beam or lintel U Block.

Is there any loopholes against this section? It seems this section was written for large commercial jobs considering in residential construction by the time the tie joist is bolted off the welder is already welding it down. Also the end bearing on masonry is not bolted down. (Should installation bolts be put into an embed plate for the masonry side?)

 

[JAE]

The OSHA reasoning is that a steel beam, supporting bar joists, usually has zero lateral stability during erection of the joists, and therefore, can laterally slide out from under the joists as they are placed on the beam.

OSHA requires that a single joist be bolted in the field to create a fixed link between beam and adjacent beams or walls. For a CMU wall, there is usually much more lateral stability than a single column/beam arrangement.

 

[Watermelon]

Adding tie joists (bottom chord bolted)to any project is a good idea. It helps the erection crew to align and plumb the steel. It also helps to keep the structure stable during installation and so is a great safety feature.

Does it add anything to the completed structure? No, not really, unless the joists have been specially designed to carry frame-type forces. But it does add a bit of unaccounted-for stiffness and strength.

All the best.