Good Evening All,
I am using RAM Concept to assess and existing reinforced concrete slab to AS 3600 for a partial demolition and restoration job we are working on. The slab dates from the 1930s but I actually have all the original structural documentation and it seems to check out on site so we are trying to reverse engineer to confirm that we can achieve the floor loading requirements of the current version of AS 1170.1.
The model generally reports favorable results with the odd failure reported here and there, mostly at bar terminations. We do a lot of work involving existing slabs and we always find RAM Concept reports failures at locations such at as bar terminations and near support faces which is to be expected as many of the slabs we work with would predate current code requirements.
This latest one however appears to be behaving somewhat strangely in that there are four beams which report failures at all cross sections in spite of the moment and shear capacity diagrams both show that there is more than sufficient moment and shear capacity, a result which is validated by looking at the cross-section audits (refer screenshots).
This is somewhat strange as the reinforcement generally is pretty consistent from one beam to the next and the 3D perspectives show that all reinforcement and design cross-sections appear to be as you would expect.
Troubleshooting I have already tried but did not resolve the issue are as as follows:
- Deleted and re-modelled the beam elements by copying the nearest, similar beam element that this error does not appear to occur on.
- Deleted and re-modelled the design strip and strip boundaries by copying the nearest, similar span segments that this error does not appear to occur on.
- Deleted and re-modelled the reinforcement by copying the nearest, similar reinforcement that this error does not appear to occur on.
However, I tried stretching the slab edge out past one of the beams and sure enough, this problem disappears (see attached screenshot). All other beams have the slab edge flush with the outside faces of the beams. Does anyone have an explanation as to why this is occurring?
