FAQ – Erection and Installation

Return to FAQ

Can bolted bridging be welded in lieu of bolting?
Yes, Erection bridging must be installed prior to the hoisting cable being released, consequently if welding is being placed on erection bridging, the welding must be done prior to the hoisting cables being released.


How much force can a bridging resist?
Bridging is only designed for the lateral stability forces in the joists.  In general those values are in the SJI bridging tables in the specification.  If bridging is intended to brace other components of the structure the size and connections must be indicated on the contract documents.  Normally these systems are independent of the joist system.


What kind of information is provided on the joist tag and is it helpful in identifying the capacity of the joist?
Typically, the joist tag provides information that is useful to the erector in matching a particular joist in the field to a location on the placing plan. If the placing plan or approved field use drawings from the joist manufacturer are available, then the tag information could be useful. If plans are not available, it is possible that the manufacturer may still have helpful information. When all else fails, contact the manufacturer.


Can the bridging be removed after the joists are erected, the deck is in place and construction of the building is completed?
The bridging that is required only for erection stability can be removed. However the bridging needed for lateral stability during the life of the joist cannot be removed without an analysis. Generally the deck provided the lateral stability of the top chord so it might be able to be removed. The bridging generally provides the lateral stability of the BC. The removal of this bridging will require an analysis of the loading as well as consultation with the manufacturer.


What should happen if the bearing seat bolts are not installed?
The seat should be welded.


Why can’t hole to hole bearing seat connections be used?
Slots are used due to fabrication and field tolerances. Also, hole to hole connections would encourage using joists to plumb the building.


How far can I extend the top chord?
That depends on the loads and the configuration of the TCX. Refer to the Top Chord Extension section in the current Specification.


How large of an additional top chord axial load can I have in my joist?
That depends on the bearing depth and type of joist. The manufacturer can provide this information.


How much extra capacity is built into a joist?
Almost none. Joists are designed for efficiency and a very high strength to weight ratio.


Can concentrated loads be placed between panel points on KCS joists without reinforcement?
No, KCS joists must be reinforced if the concentrated load is between panel points just like all other joists, unless the load is less than or equal to 100 pounds.


Return to FAQ