Thanks RAPT
Yes. You are right. Another reason scared me off using equivalent frame method is a lack understanding of these torsional members. Do you mean “torsional member” does not physically exist and ain’t need shear links to withstand the twisting arising from a) unequal frame span on both...
Thanks Kikflip and Rapt
We are designing to ACI 318, rather than BS 8110. RAPT slab member (two way strips) gives identical numerical model compared to that required by clause 13.7 of ACI 318 for the equivalent frame method for two-way slabs (without beams). There is a reduction factor, 75%...
Thanks Kikflip
I had read the paper done by Concrete Centre and used it as the guide through the FEA. General purpose FE software was used. Pattern loading was done manually, loads were applied on the appropriate bays to achieve the worst output. I did use Australian software RAPT to design...
ACI 318-8, clause 13.7.6 gives requirement for arrangement of live load on 2-way slab:
1) Pattern loading is not necessary if unfactored live load is less than ¾ of the unfactored dead load.
2) 75% of the full factored live load on appropriate panels is required if pattern loading has to be...
Ev=0 is required for those load combinations containing Eh-Ev when checking “soil-structure interface of foundations”. I am not sure about this terminology at all. Does soil-structure interface demand cover all checks such as ground bearing, overturning and sliding?
My second question is: why...
Clause 2.1.2.3 ACI530-05: allowable stresses increase by 1/3 for masonry
Three load combination C) D) and E) are allowed for this strength increase, besides those “permitted by the legally adopted building code”:
1. D+L+(W or E)
2. D+W
3. 0.9D+E
My load combination has an extra ingredient...
Thanks Kikflip
I plan to determine the reaction forces in slabs (by taking into consideration the penetration effects) rather than sizing rebars. The latter has to be done manually, or using a spreadsheet. This can be done by using nearly all 3D structure analysis software packages. The...
Thanks Hokie66
I agree with you.
But we have hundreds of elongated openings (typically >2m long) for air services and risers. This means 100% of the reinforcing bars will have to be packed within 2/3~3/4 of the span which varies between 6m and 8m.
I plan to run a ‘global’ analysis to slabs...
“ACI 318: 13.4.2.1 – Openings of any size shall be permitted in the area common to intersecting middle strips, provided total amount of reinforcement required for the panel without the opening is maintained.”
I totally agree with the first part of the sentence. My interpretation about the...
12.1.5 Foundation design section of ASCE7-5 does say that “foundation shall be designed to resist the forces developed and accommodate the movements imparted to structure by the design ground motions”. Does this mean that flexural and shear rebars shall be sized to carry this seismic load apart...
Thanks!
Uplift - yes, as a part of stability.
ACI 318 for bending and shear strength - do you mean use seismic load combo to size reinforcing bars? But in chapter 21 of ACI 318-08, only foundations of structures to SDC D, E or F are required to resist earthquake induced forces, see 21.12.1.1.
He might only ask for a favour from you.
By the way, it may not be conservative to have one ‘worst’ case to check. I did have combo reaction forces from my colleague who worked on superstructures. But I have to make my judgement to figure out the worst cases, e.g. a smaller vertical reaction is...
Apart from the settlement and overturning requirements (12.13.3 and 12.13.4 of ASCE7-5) for footings as parts of structures assigned to seismic design category B, are their other requirements for concrete isolated or combined footings in terms of strength and detailing?
Thanks
