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D1.J.8.2 Joint File Format

The data contained in the filename .PUN file should meet the following format. The overall process of performing punching shear checks consists of two steps which are explained in D1.J.8.1 Joint Checking.

When the API design module is invoked, the program will initially check for the presence of a filename .PUN file (where filename is the name of the .std file) in the same folder as the input file. If the program does not find such a file, it assumes that the joint design is being run for the first time and will create this file. If the program does find this file, it will assume that the joint design has been run at least once and will attempt to read the input data from this file. Not that modifying and saving the main structure (i.e., any changes to the main model using GUI or text editor) will invalidate all design results and the program will automatically delete all design related files including the *.PUN file. Hence if the user wises to keep an existing version of the *.PUN file, he/she must make a separate copy of this file before making any changes to the model.

Note: Units used in this file must be kips and inches.

General Format

 b# c# K% X% Y% Dc Tc db tb gap fy ob tw swap


  • b# = the brace member number
  • c# = the chord member number
  • K%, X%, and Y% = The fractional contributions of K-type, X type and Y-type, respectively. Initially the joints will be classed as Y (i.e., K=0, X=0 and Y=1).
  • db, tb = Diameter and thickness of BRACE member
  • Dc, Tc = Diameter and thickness of CHORD member
  • gap = Distance required to calculate gap factor for K bracing. Initially, the value of GAP is assumed as 0. An overlap can be specified by setting the gap to a negative value.
  • fy = the yield stress to be used in the joint capacity checks
  • ob = member number of the overlapping brace in an overlap joint (i.e., a gap value less than zero)
  • tw = Used in overlap K-joint, taken as the lesser of the weld throat thickness or thickness t of the thinner brace in inches
  • swap = If parameter SWAP 0 is used then major moment Mz is taken for In Plane Bending (IPB). SWAP 1 uses the minor moment My as the IPB.


*BRACE  CHORD   K      X      Y       D      T       d      t      GAP   FYLD OBRACE TW SWAP
    10      7  0.000  0.000  1.000  16.000  0.394  16.000  0.394   0.00  36.0  0.0  0.00 0
    13      7  0.000  0.000  1.000  16.000  0.394   7.626  0.315   0.00  36.0  0.0  0.00 0
    14     11  0.000  0.000  1.000  16.000  0.394   7.626  0.315   0.00  36.0  0.0  0.00 0