A simply supported beam has dead load, prestressing and Creep & Shrinkage (CS) at STG1
The internal forces (STG-SUM at the end of STG1: STG1E-SUM) are as below (e.g. node 112 at element 111)
The corresponding stresses are as below (e.g. node 112 at element 111)
The section is as below
Based on the internal forces and section properties extracted from RM Bridge, the stress at bottom center can be calculated as follows
stress due to N, σN=-4275kN / 8.9e5mm2 = -4.8MPa
stress due to Mz, σMz=-3007.3kN*m * 1.333e3mm / 4.293e11mm4 = -9.3MPa
stress due to My, σMy=-26.1kN*m * 0 mm / 1.938e11mm4 = 0MPa
total stress = σN + σMz + σMy = -14.1MPa, I get similar result from other software, like LUSAS, Midas Civil and Sofistik
But RM Bridge shows -30494 (-30.494MPa)
Why?
The TCL files are attached
1.zip
RM Bridge results are correct:
Ana Carla Peres
Senior Technical Support Engineer
Bentley BrIM
For using the plain CS properties, in RM>Recalc>Extending Settings you need to use the following options.
Hi Peres,
Thank you for pointing out that the plain CS instead of updated CS (excluding duct, including tendon, grouting) is used in stress calculation by hand.
The reason I use plain CS is because the area of the duct (0.0129 m2) is small compared to the area of the girder section (0.89 m2).
Therefore the stress results from plain CS and from updated CS should have small differences, this conclusion has been verified by hand calculation and other softwares as show below.
In the "Hand Calculation", plain CS are used, while in the "Software Calculation", all 4 softwares use updated CS.
The σ1 is the top corner stress and σ2 is the bottom corner stress.
It can been found that the stresses from plain CS is very close to those from updated CS in Midas Civil, Lusas and Sofistik.
But RM Bridge shows very large difference.
Hi netsonic,
The duct area that you introduced is wrong. Because you're placing the tendon area of one strand, the duct area needs to be according to one strand area value. Or you introduce the total area of 8 or 9 strands and the correspondent duct area.
Please,review the values introduced.
Answer Verified By: netsonic