I am trying to understand if sustained loads are included in the design of post installed bars in profits software. I tried to define two load cases with and without sustained loads and noticed that the utilization are the same. Please refer to the screen shot that i attached. Also I created separate reports for these two cases and saw that all the coefficients used in combined pull-out & concrete con failure.
Could you please advise if i am missing something?
Hi Yasam,
Thank you for your question and apologies for the delayed response to your post here on Ask Hilti.
Firstly, sustained loads are definitely checked by PROFIS Engineering. In fact, as the anchor design check in PROFIS Engineering is programmed according to AS5216, the sustained loading is addressed according to AS5216 Section 6.2.5.2 - thereby only applying to the calculation of the capacity of chemical anchors in the "Combined pull-out and concrete cone failure"
Might I suggest taking another look at your model example and expanding the tension failure modes being calculated? The reduction in the aforementioned failure mode affected by the introduced sustained load may still result in the overall utilisation being less than your concrete cone, hence it still showing the results of the governing failure in concrete cone.
Otherwise, more than happy to look at this closer with you directly. Feel free to either post your model here or reach out to us at our Anchor Design Centre
Hope this helps,
Ask Hilti Team
Australia
Hi Tony,
Thanks for your reply. I already checked all utilization values and all coefficients considered for combined pull-out and cone failure from the reports for both load cases. I couldn't see any difference for the load cases with and without sustained load. I am attaching the model. Could you please clarify if psi_sus is considered in the assessment? and if it is considered why there is no difference between the results of two load cases with and without sustained loads?
Regards,
Hi Yasam,
Thank you for your response and the additional information. Your model is actually not utilising AS5216 due to the layout being out of scope of the design standard according to Section 2.1
The design rather is opting for the SOFA design method which is an extended design method based on additional testing and research, involving engineering judgement. The particular method selected as appropriate to your design is relying on European EOTA TR029, where the combined pullout and cone failure does not account for sustained loading.
Please see below attached snips for comparison of AS5216 and TR029. As sustained loading is not covered in your calculations, I'd suggest a manual calculation applying a similar reduction according to sustained loading to the TR029 calculations as a workaround.
The sustained load factor is also dependent on the product used as well as the usage conditions (information can be found in the ETA approval). If you require assistance with this, please reach out to our Anchor Design Center on the link above.
