AD.2007-07.3.5 Transverse IRC Loading in STAAD.Beava

For the specific bridge width, IRC (Indian Road Congress) chapter 6-2000, table 2, clause 207.4 defines the rules to combine the live loads. This new feature allows you to either use these IRC live load rules or use an iterative, custom method. If the IRC rule option is selected, this function uses the appropriate live loads and number of design lanes and the generates all the possible load combinations as stated for this particular bridge width. Otherwise, you can select a specific live load and design lane to generate combinations.

Loading rules per IRC Chapter 6 are applied in much the same way as previous codes. The defined roadway for the selected deck(s) is divided into design lanes and the selected load class is applied to the structure achieve the specified actions.

To specify loading per IRC Chapter 6

Open an analyzed bridge model in the Bridge Deck mode.
Create Deck and Roadway definitions.
Generate influence surfaces for the structure.
Select Loading > Run Load Generator….

The Load Generation Parameters dialog General tab opens.
Select IRC Chapter 3 for the Design Code and select the appropriate Limit State.

The <code> tab updates to display IRC Loading.
Select the IRC Loading tab.
Select the appropriate Loading Class.

Note: Combinations of the AA, B, and 70R vehicles have been added to the included vehicle definitions. These may be reviewed in the Vehicle Database dialog.
(Optional) Specify an impact factor or modify the Multiple Presence Factors as needed.
Specify the decks for consideration on the Decks tab and the load effects to dictate load placement on the Node Displacements, Support Reactions, Plate Center Stresses, and Beam End Forces tabs.
Click the OK button.

The program places the selected loads in design lanes to produce the maximum or minimum effects requested. A text file containing a summary of the generated loads and corresponding effects is opened in a text editor for review.