Code Checking and Member Selection
The purpose of code checking is to check whether the provided section properties of the members are adequate to carry the forces transmitted to it by the loads on the structure. The adequacy is checked per the GB 50017-2017 requirements.
Code checking is done using forces and moments at specified sections of the members. General they are calculated at every twelfth point along the beam. The code checking output labels the members as PASSED or FAILED. In addition, the critical condition, governing load case, location (distance from start joint) and magnitudes of the governing forces and moments are also printed.
The member selection process basically involves determination of the least weight member that PASS the code checking procedure based on the forces and moments of the most recent analysis. The section selected will be of the same type as that specified initially. For example, a member specified initially as a channel will have a channel selected for it. Selection of members whose properties are originally provided from a user table will be limited to sections in the user table.
Use of Design Parameters
Users can modify the design parameters and control the whole design process by checking the specified parameters before. These parameters are used by design engineers to communicate their design decisions to computer programs. The default values of all these parameters are selected as the common values which are more inclined to the security design. For a specific design requirement, some or all of the parameters need to be changed to meet the actual design requirements. Therefore, specifying design parameters is often an indispensable step.
There are some default assumptions in the program when performing specification checking.
- Biaxial symmetry and uniaxial symmetry are specified in the code. When different terms are adopted, the proportion of area difference between upper and lower flanges shall be taken as the judgment basis for H-section program judgment (mainly for H-section with unequal upper and lower flange and H-section with adhesive plate). When the area difference is less than 30%, the cross section is considered to be biaxially symmetric.
- When calculating the post buckling strength of H-section with plate, the program considers that the laminate on the compression side is invalid, and the effect of the veneer is not considered when calculating the effective section.