The following information should be specified in all design modes when preparing data in the Concrete tab: concrete type, concrete class, service factors for concrete, conditions of hardening, and the hardening factor.
A class of heavy-weight or fine-grained concrete is selected from the Concrete class list. For lightweight concrete, you have to select its grade by average density first, and then its class and aggregate.
If the analysis is performed according to SP 52-101-2003, only heavy-weight
concrete will be available because this document does not provide rules
for designing from other types of concrete.
If
the analysis is performed according to SP 63.13330, lightweight concrete
can not be selected because the deformation characteristics should be
taken according to the special instructions.
The service factor for concrete, γb2 (or γb1 if the analysis is performed according to SP 52-101-2003 and SP 63.13330), allows for the load duration. The value of the factor is set equal to either 1 or 0.9 (item 2a in Table 15 of SNiP 2.03.01-84* and Sec. 5.1.10a of SP 52-101-2003 and Sec. 6.1.12 of SP 63.13330), the default value is 1. In cases when a different value has to be used for this factor according to conditions of the analysis, it can be specified directly in the list field.
If a combination of loadings includes short-term loads, the analysis will use γb2 = 1.1 (regardless of the specified value) in compliance with regulations of item 2b in Table 15 of SNiP 2.03.01-84*.
The service factor for concrete, γb, is a product of all service factors for concrete from Table 15 of SNiP 2.03.01-84* (Section 5.1.10 of SP 52-101-2003 and Sec. 6.1.12 of SP 63.13330), except for γb2 (γb1). The default value of it is 1 (0.9 in the Strength of Concrete Sections mode).
If the initial elastic modulus of concrete is different from its table value, then a hardening factor should be specified; it is used to adjust the value of the modulus (it is set only for natural hardening).