Design Code SNiP Steel Structures –as is the case in the majority of modern codes– is based on the method of limit states. The following groups of limit states are defined in the Code.
- The first group is concerned with losses of general shape and stability, failure, qualitative changes in configuration of structure. Appearance of non-allowable residual deformations, displacements, yielding of materials or opening of cracks.
- The second group is concerned with states of structures making worse normal their service or reducing durability due to not allowable deflections, deviations, settlements, vibrations, etc.
Analysis of structures for the first limit state is performed using the maximum (design) loads and actions, which can cause failure of structures.
Analysis of structures for the second limit state is performed using service (normative) loads and actions. Relation between design and normative loads is referred to as coefficient of load reliability, which is defined in SNiP 2.01.07.- 85 Loads and Actions.
Coefficient of reliability for destination GAMA n according to SNiP 2.01.07.- 85 shall be taken in to account determining loads or their combinations.
In this version of the program only members from rolled, tube and roll-formed assortment sections and also from compound such as double angles of T-type sections, double channels are presented. Design of other members of compound section will be presented in other versions of the program.
Economy of selected section is indicated by ratio (RATIO) σ/Ryyc presented in calculation results. A section is economical when said ratio equals to 0,9 – 0,95.