Looking to see if anyone has any guidance...
I have looked through the threads and seen a good bit on reinforcing joists along their length with rod and angle, and have the "Designing with Steel Joists..." book at my disposal, but unfortunately my situation is a little different. I have a situation in which joists span about 22', are 20" on center, can only be accessed by the basement, and there are probably over 100 that need to be reinforced...quickly...
Unfortunately, due to the time constraints, removing and replacing the whole system is not a feasible option. There is not enough time to get new concrete cured and ready to recieve floor coverings. "Fortunately", the owner is willing to tolerate a new intermediate post and girder system slightly off of midspan. The joists are Kalmantruss circa the late 1940's and I was able to get tags off them to use with the SJI load tables.
I know I will need to add vertical reinforcing and cross bracing at the new bearing points, but am not sure how to address the very significant change/reversal in shear diagram with respect to the original envelove due to the new supports. Also not sure how to handle the negative moment or if the chord should be cut to avoid that concern.
Background- this is a revovation under construction and it was discovered during the construction that some significant (undocumented of course) modifications had been made to the floor, including the addition of a topping which renders the floor over-stressed as-is, not including the new work that was scheduled, based on code loads.
Any thoughts on how to handle the design and detailing of this is appreciated.
Sorry for such a long post...
I have looked through the threads and seen a good bit on reinforcing joists along their length with rod and angle, and have the "Designing with Steel Joists..." book at my disposal, but unfortunately my situation is a little different. I have a situation in which joists span about 22', are 20" on center, can only be accessed by the basement, and there are probably over 100 that need to be reinforced...quickly...
Unfortunately, due to the time constraints, removing and replacing the whole system is not a feasible option. There is not enough time to get new concrete cured and ready to recieve floor coverings. "Fortunately", the owner is willing to tolerate a new intermediate post and girder system slightly off of midspan. The joists are Kalmantruss circa the late 1940's and I was able to get tags off them to use with the SJI load tables.
I know I will need to add vertical reinforcing and cross bracing at the new bearing points, but am not sure how to address the very significant change/reversal in shear diagram with respect to the original envelove due to the new supports. Also not sure how to handle the negative moment or if the chord should be cut to avoid that concern.
Background- this is a revovation under construction and it was discovered during the construction that some significant (undocumented of course) modifications had been made to the floor, including the addition of a topping which renders the floor over-stressed as-is, not including the new work that was scheduled, based on code loads.
Any thoughts on how to handle the design and detailing of this is appreciated.
Sorry for such a long post...
