{Test Problem
name = Section cuts in moving load analysis |
description = Verification of section cuts in moving load analysis. |
keyword = section cut; moving load; correspondence |
program = SAP2000 |
version = V11.0.8 |
status = done |
id = ok/moving load - correspondence and section cuts}} |
The section cut forces for moving load analysis represent realistic forces for the given section cut. Extreme forces from individual section cut elements that occur for different placements of the live load are not combined together as this would result in overestimating the section cut forces. This can be illustrated by a simple model that I have attached.
In the attached model, the lane Section-cut forces for moving-load analysis represent the actual forces that occur at any given section cut. For various configurations of live-load applications, extreme resultant forces which occur within a section cut are not combined as this would overestimate section-cut forces. This concept is demonstrated in the attached model, where lanes and section cuts are defined as shown in the figure belowFigure 1:
Unit load "vehicle"
Figure 1 - Lane and section-cut definition
A vehicle of unit load is applied to travel the structure such that it travels along the lane, which results in producing the moment diagram shown belowin Figure 2:
Figure 2 - Moment diagram
Since each of the two main beams girder is 10m long, the maximum moment at the midspan due to the unit moving load is (0.5 kN midspan moment under unit loading is calculated as 0.5kN (reaction) * (0.5 m support to midspan location5m (length) = 2.5 kN5kN-m as indicated in the above screenshot.
Now, two Two section cuts (, one using groups and the other one using a quadrilateral cutting plane) , are defined such that they cut both beams at the midspan. The section cut moments are again 2.5 kN-m, which indicates that the results are as expected:
See Also
Attachments
...
through each midspan location. As expected, the section-cut moments reported are also 2.5kN-m (Figure 3), indicating consistency between theoretical and software-generated results.
Figure 3 - Section-cut moments reported
Attachments
SAP2000 V11.0.8 model (zipped .SDB file)
Metadata
Name: Moving-load analysis section cuts
Description: Verification of section-cut forces generated during moving-load analysis.
Program: SAP2000
Program Version: 11.0.8
Model ID: na