I'm doing a structural design of a base plate holding a steel column supporting electrical equipment in a substation on a column pedestal. I'm using post-installed bolts, using a Hilti Hit-RE 500 V4 resin and HAS-U 8.8 bolts.
The column pedestal is 800x800 which seem to be fine for 500x500mm base plate (200mm bolt edge distance, 400mm bolt spacing). Unfortunately, no matter how long the bolts are, the resistance does not seem to increase past 133mm embedment (since Ccr,N = 1.5 hef; 200/1.5=133mm).
Using Hilti Fastening Technology Manual 2005 issue, I was able to verify the arrangement with M30 with 350mm Embedment length.
Please let me know if there any way to verify the baseplate without increasing the size of the pedestal if it is possible.
Thank you for your enquiry, would it be possible to upload your.pe please see we can see the full details. From looking at your screen shot going deeper close to an edge is not beneficial as you are encountering a larger reduction factor. I also wouldn't be using a manual from 2005 (Unless you need a door stop or a paperweight ).Certainly HILTI would not support any current designs using obsolete products and data. It's important to keep in mind the simplified design method from that time period was based upon an estimation of the then forthcoming state of the art design process . This was before the European Technical Approval Guide and later formally adopted Eurocode 2 Design of concrete structures Part 4 Design of fastenings for use in concrete.
I'd suggest at this moment you let the software run at the optimised embedment depth and not a fixed depth criteria and select all options for the anchor calculations.
I've used the optimize depth but it isn't much help either, it just stops at the maximum depth and it will still be failing.
One thing I forgot to mention is that the pedestal does have 12 16mm bars bent on top, that might help with cone failiar.
Please find my .pe file so you could have a look
Thanks for your pe file. Looking at the detail the area of concrete is too small to resist the load you wish to safely transfer, As an example I looked at your file and I saw you didn't have any supplementary reinforcement selected now what I did was reduce the diameter of the anchors down to M24 and added an extra pair whist just slightly increasing your baseplate dimensions. This allowed for the selection for activation of the supplementary option and, I selected 16mm rebar yet as can be seen the additional steel was not capable of resisting as well as the bond your applied loads from the moment load being applied. I've attached this pe file as an indication for you so you can review if your loads are conservative , if supplementary reinforcement is available and as an illustration larger diameter anchors in close edge spacing criteria is not always the best assumption in trying to come up with a workable solution. Hopefully the above and the file is enough to help you going forwards to achieve a resolution.
Here's a different option again within 1992 using 8 bolts M24 and this works in relation to the supplementary reinforcement the issue remains re the bond strength and the combined concrete utilisation even when additional reinforcement is activated to deal with the shear condition.