LARSA 4D Introductory Training Manual for Bridge ... - LARSA, Inc.

LARSA 4D Introductory Training Manual for Bridge Projects
Accessing Results
To access results, click the name of the case and use graphical or spreadsheet results. While each case
individually does not provide the final values necessary for AASHTO LRFD (see below), they are the
first step.
Click the first influence case “Right Lane” in the Analysis Results Explorer.
Turn on graphical member force diagrams and change the report to Moment Mz.
This graph represents the envelope of forces for all possible positions of the truck, tandem, or two trucks
plus lane load, including variable axle spacing.
Moment Diagram
Accessing results in the spreadsheets works as usual, except you must choose an envelope column.
In this case, you would choose the Mz column to envelope on. The rows of the spreadsheet then show
the min and max Mz values for each station along the girder, plus corresponding forces in the other
directions. Mz refers to member local coordinate system directions.
You may check where LARSA 4D decided to place the truck and lane load to produce the extreme effect
for any point on the structure using several methods. The first method is to look at the Result Case
column on the spreadsheet. It indicates the station number (in coordinate units) from the start of the
lane at which each vehicle is placed (refering to the front of the vehicle).
Numerical Influence Results and the Context Menu
It is also possible to right-click a row in an influence analysis spreadsheet and use either the Create
Input Load Case or Create Result Case commands to create a new case that contains the loading
configuration that produced the effect shown in the chosen row. Creating an input load case creates a
new load case with member or plate loads for the vehicle axles and UDL. Creating a result case makes
a new linear result combination out of the already-analyzed unit load result cases. It is then possible
28