Limit State Method
The criteria governing the capacity of Tension members are based on:
- Design Strength due to Yielding in Gross Section
- Design Strength due to Rupture of Critical Section
- Design Strength due to Block Shear (does not apply to solid rods)
STAAD.Pro calculates the tension capacity of a given member based on these three limit states.
The limit state of yielding in the gross section is intended to prevent excessive elongation of the member, and the corresponding check is done as per section 6.2 of the code.
The Design strength, involving rupture at the section with the net effective area, is evaluated as per section 6.3 of the code. Here, the number of bolts in the connection may be specified through the use of the design parameter ALPHA.
The Design strength, involving block shear at an end connection, is evaluated as per section 6.4 of the code. This criteria is made optional by the parameter DBS. If the value of DBS is specified as 1, additional design parameters AVG, AVN, ATG, and ATN must be supplied to the program for that member.
The Net Section Area may be specified through the use of the parameter NSF.
Working Stress Method
The criteria governing the allowable stress from tension in members are based on Section 11.2.1 of the code:
- Yielding of Gross Section - to prevent excessive elongation of the member due to material yielding.
- Rupture of Net Section - to prevent rupture of the net effective section area. The number of bolts in the connection may be specified through the use of the design parameter ALPHA. The code parameter, γM1, is taken as 1.25 per Table 5, Clause 5.4.1 of the code.
Block Shear — to prevent block shearing at the end connection. This check is made option through use of the DBS parameter. Additional design parameters AVG, AVN, ATG, and ATN must be supplied to the program for any member which is to be checked for block shear. The code parameters,, γM0 and γM1, are taken as 1.10 and 1.25, respectively, per Table 5, Clause 5.4.1 of the code.
These criteria are dependent on the steel material yield stress parameter, FYLD, and ultimate tensile strength parameter, FU.