Concrete Joist Diaphragm Strength
Concrete Joist Diaphragm Strength
(OP)
I am analyzing an existing building with concrete joist floor system. The joists are 5in wide by 8in below the slab. The slab is only 2 or 2.5 in thick. The joist spacing is 20in and the spans are 10-12ft. I am in a high seismic area and the diaphragm strength is being evaluated. The slab alone has minimal strength due to the small thickness.
What is the typical practice with a system such as this? Can you take an effective depth for evaluation which would take advantage of the joists? If possible, can this approach only be used perpendicular to the joists?
In the direction parallel to the joists can you take advantage of supporting beams and bridging between joists to add to your diaphragm strength? There is a bridging member or beam every 5-6 ft.
Any input on this topic is appreciated.
What is the typical practice with a system such as this? Can you take an effective depth for evaluation which would take advantage of the joists? If possible, can this approach only be used perpendicular to the joists?
In the direction parallel to the joists can you take advantage of supporting beams and bridging between joists to add to your diaphragm strength? There is a bridging member or beam every 5-6 ft.
Any input on this topic is appreciated.





RE: Concrete Joist Diaphragm Strength
RE: Concrete Joist Diaphragm Strength
For example at a 32 ft long perimeter shear wall i have roughly 500k coming in from the diaphragm based on deformation control and 2/3 MCE (IO level) (15k/ft) which is twice my capacity considering only 2in slab.
RE: Concrete Joist Diaphragm Strength
RE: Concrete Joist Diaphragm Strength
RE: Concrete Joist Diaphragm Strength