AD.2007-08.3.1 API 2A WSD 21st Ed. Update

Joint checking for tubular members per the American Petroleum Institute 2A-WSD code has been updated to the 21st Edition (December 2000) of that code, including errata and supplements 1 to 3 (latest: Supplement 3 - March 2008). Additionally, the process of joint design has been simplified.

Note: Only simple joints and overlapping joints will be considered by the program. Other type such as grouted joints, joints with ring stiffeners etc are not be considered.

The clauses/sections in the API code that have been dealt with are:

4.2.1 Material strength
4.2.3 Minimum Capacity
4.2.4 Joint Classification
4.3 Simple joints
4.4 Overlapping joints

Refer to D1.J. American Codes - Steel Design per API 2A-WSD 2000 for additional information on the methodology used.

External Joint Data File

In previous versions, the LEG design parameter was used to direct the program to generate a separate joint data file or to check a user-specified file. This file is now automatically generated or checked as needed.

As the API code allows for mixed joint types, the PUNCH column in the input file has been replaced with K, X, and Y columns which are used to designate fractional contributions of each joint class. Similarly, overlapping joints are indicated by using a negative value for the GAP between braces and the member number of the overlapping member in the OB column (replaces THETAT used in previous versions).

If the filename.PUN file is not detected in the same folder as the current STAAD input file (where "Filename" is the same as the .STD file), then the program assumes this is the initial joint design and this file is created. If, however, this file is detected, the program assumes that the that the joint design has been performed at least once and will use this file to perform the joint checks.

To check tubular member joints per API

The checking of joints is an iterative process done by means of an automatically generated text file.

Model a structure as you normally would.

Note: Only circular pipe members are considered.

Tip: Using TRUSS specifications helps to reduce analysis time.
In the Steel Design - Whole Structure dialog box, select API as the design code.
(Optional) Specify the factor of safety used for joint checks using the new FSJ design parameter.
(Optional) Specify all other necessary design parameters.

The LEG parameter is no longer used to generate or check joint data files.
Specify CODE CHECK or SELECT MEMBER commands as needed and perform the analysis.

If this the filename.PUN file is not detected in the same folder as the input file, the program assumes this is the first time the structure is being analyzed and generates this input file with default data for the detected joints. Each joint is assumed to be a Y joint by default.
Modify the default joint data in the filename.PUN as needed to describe the actual joint conditions.

A text editor can be used to make changes to this file. Be sure to save changes once complete.
Re-analyze the STAAD input file.

Joint check results follow the steel design output.
Repeat steps 3 through 7 as needed to make changes in the structure.