Cracking Check (Distribution of Flexural Reinforcement Check)

Cracking check is performed only if at least one service load group is selected along with the ultimate load group.

The program follows the crack width as per Article 8.12.3.1 and checks the maximum crack width against the maximum crack width as defined in Table 8.6 . In this approach, program calculates min. tension area of concrete bounded by a depth which is lesser of 2.5*d1 and 1/3*d2 where

d1	=	the depth of the centroid of tension steel from the extreme tension fiber
d2	=	the depth of the neutral axis from the extreme tension fiber

The provided rebar is computed based on service moments. Using the stress in rebar, program calculates ε_sm using:

ε_{s m} = \frac{f_{s}}{E_{s}} [1 - {(\frac{f_{w}}{f_{s}})}^{2}]

If ε_sm is negative, then crack width is -ve, then section is treated as uncracked. If f_s (that is rebar stress due to service moment) is greater than f_w that is stress in rebar when extreme tension fiber is f_cr section is treated as cracked. The program compares the calculated crack width against the maximum allowed. The program uses the maximum crack width as defined in CHBDC table 8.1. You can customize this value in the A/D parameter dialog. If the calculated crack width is greater than the maximum allowed, it flags the location.