SteelPE
Structural
- Mar 9, 2006
- 2,759
I have wrapped up the design of a warehouse recently. The project was a single story warehouse/lt manufacturing facility with an internal mezzanine. The project was tough to get through as the owner hired an independent construction manager and placed him in-between the design team and contractor. The project was designed using IBC 2015.
Unfortunately I have been dealing with slab on grade issues on the project. Getting the client to nail down the specific design criteria has been impossible. The client has varied their design criteria throughout the project and has even gone so far as to change the criteria after the slab was poured (we were told we had final information but then they changed it).
Now the client is requesting an allowable capacity for the slab… an allowable capacity in “psi” for loads placed on the slab. The client wants to take the new load, divide by the allowable “psi” and then come up with a plate size to support that load. I have never heard of such a method. Has anyone else ever given the client this type of number before? How would one go about calculating this.
I am used to designing slabs in accordance with the book “Designing Floor Slabs On Grade” by Ringo and Anderson. This book goes through different types of load (forklifts, isolated columns, racks etc) and give you methods to either come up with slab thickness or calculate capacities. Similar methods can be found in ACI 360R. The problem is, there is no magical number as the methods presented are based upon nomographs and logarithmic equations.
I just don’t know who is being obtuse, myself, or the owners CM. This is now beginning to cause major issues with closing out the project.
Unfortunately I have been dealing with slab on grade issues on the project. Getting the client to nail down the specific design criteria has been impossible. The client has varied their design criteria throughout the project and has even gone so far as to change the criteria after the slab was poured (we were told we had final information but then they changed it).
Now the client is requesting an allowable capacity for the slab… an allowable capacity in “psi” for loads placed on the slab. The client wants to take the new load, divide by the allowable “psi” and then come up with a plate size to support that load. I have never heard of such a method. Has anyone else ever given the client this type of number before? How would one go about calculating this.
I am used to designing slabs in accordance with the book “Designing Floor Slabs On Grade” by Ringo and Anderson. This book goes through different types of load (forklifts, isolated columns, racks etc) and give you methods to either come up with slab thickness or calculate capacities. Similar methods can be found in ACI 360R. The problem is, there is no magical number as the methods presented are based upon nomographs and logarithmic equations.
I just don’t know who is being obtuse, myself, or the owners CM. This is now beginning to cause major issues with closing out the project.
