coolad2007
Structural
Hello everyone!
I am currently designing a 35 foot high warehouse with LFRS system consisting of precast wall panels and with roofing made up of precast/prestress double T joists which would be interconnected along joint lines as per MFR design guidelines. I have assumed that the diaphragm is going to be rigid but the catch is that there is no topping slab over it. Now my question is how to ensure that this double T joist slab would behave as a rigid diaphragm. These joists run from wall to wall (almost 88’-0” long) with joints along parallel line between them. I have never encountered this situation before. Am I supposed to give MFR connection forces (it may be either due to drag, shear or bending) to connect these joist along panels joint lines to make sure that the rigidity behavior holds true. In general these connections are by MFR but not sure what is the industry standard to approach this type of problem. I am not sure how to check deflection of such diaphragm to see whether this would be rigid or flexible.
The reason for this concern is due to the fact that I have varying rigidity along shearlines. There is lot of load getting dragged into stiffer walls and if this rigidity concept won’t hold good I would end with lot of shear in other walls which are relatively less stiffer but have a very large trib area.
Any reference material or theory guidelines would do. I did talk to my principal about it but was not convinced with his response so wanted to check opinions of rest of the engineers.
Thanks in advnace!
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I am currently designing a 35 foot high warehouse with LFRS system consisting of precast wall panels and with roofing made up of precast/prestress double T joists which would be interconnected along joint lines as per MFR design guidelines. I have assumed that the diaphragm is going to be rigid but the catch is that there is no topping slab over it. Now my question is how to ensure that this double T joist slab would behave as a rigid diaphragm. These joists run from wall to wall (almost 88’-0” long) with joints along parallel line between them. I have never encountered this situation before. Am I supposed to give MFR connection forces (it may be either due to drag, shear or bending) to connect these joist along panels joint lines to make sure that the rigidity behavior holds true. In general these connections are by MFR but not sure what is the industry standard to approach this type of problem. I am not sure how to check deflection of such diaphragm to see whether this would be rigid or flexible.
The reason for this concern is due to the fact that I have varying rigidity along shearlines. There is lot of load getting dragged into stiffer walls and if this rigidity concept won’t hold good I would end with lot of shear in other walls which are relatively less stiffer but have a very large trib area.
Any reference material or theory guidelines would do. I did talk to my principal about it but was not convinced with his response so wanted to check opinions of rest of the engineers.
Thanks in advnace!
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