In cases when the analysis of the formation and opening of cracks is required, the user should provide data about a category of crack resistance, an allowable crack opening width etc. All these data are entered on the Crack Resistance tab.
If the 1st category of crack resistance is selected (no cracks), then no additional information is required in this tab.
If the analysis is performed according to SNiP 2.03.01-84* and the 3rd category of crack resistance is selected, then you have to use the respective lists to select the conditions of operation, the mode of concrete humidity, and the humidity of environmental air. Next, specify an allowable width of short-term and long-term crack opening (the default values are those recommended by SNiP 2.03.01-84*, KMK 2.03.01-96 on the basis of conditions of operation and humidity parameters).
If the analysis is performed according to SP 52-101-03 and the Limited crack opening width item is selected in the drop-down list, you have to specify the requirements to the crack opening width (based on preservation of reinforcement or based on limitation of the structural permeability). This will automatically set the maximum allowable widths of long-term and short-term crack opening recommended by Sec. 7.2.3 of SP 52-101-03. The user can edit these values when necessary.