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Re: crack control

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Crack control is to protect reinforcing from corrosion, therefore, IMO it 
applies to *all* flexural members.

Service loads = unfactored loads.

Flexural stress in concrete is:

f(c) = 2*M/[b*k*j*d^2]

Flexural stress in reinforcing is:

f(s) = M/[A(s)*j*d]

k = sqrt{[rho*n]^2 + 2*rho*n} - rho*n

j = 1 - k/3

rho = A(s)/[b*d]

Hope this helps.

A. Roger Turk, P.E.(Structural)
Tucson, Arizona

. > The issue of crack width, brings the following questions to my mind of:
. > 
. > (1) Do most people check crack width for only beams and one-way slabs as
. > implied by the 
. > section title where crack provisions are given or is crack width checked 
. > for other 
. > concrete members like footings, walls, and two-way slabs also.
. > 
. > (2)  When checking rebar service stresses do most people use the load 
. > factors like 1.4 
. > and 1.7, or do they use 1.0 or do they use something else.
. > 
. > 
. > Mark Ahlskog
. >