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Resin fixed reinforcement
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civilperson
Structural
Yes, one of the best and costly methods of insertion into existing concrete. Works best if the holes are brushed and blown clean.
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I am in the process of preparing a departure for the use of resin fixed reinforcement. I have been predominately looking at Hilti HIT-RE-500 system.
The job involves breaking out the back face of a small wingwall, resin fixing some bars into the abutment, then recasting the back of the wingwall. This is to give the wingwall the required capacity to resist parapet impact loading.
I am a little unsure about the method of using Hilti's quoted loads with the draft HA document 'The anchorage of reinforcement and fixing in hardened concrete'.
Due to the small number of bars to be fixed in each wingwall (5no.), I expect the application to be considered safety critical. The IAN states that for a safety critical application the maximum force in the bar should not exceed a) 35% of the typical failure load (or ultimate capacity), b) characteristic yield strength of bar divided by material factors, c) 70% of test load (test load < 95% characteristic yield strength). Criteria b) and c) seem fairly straight forward, but I am having a problem with a).
I have been using the Hilti EXBAR spreadsheet which gives design loads for various embedment depths. This spreadsheet modifies the output based on bar spacing, edge distance, partial safety factors etc. This spreadsheet also gives a corresponding bond stress.
The IAN states that clause 5.8.6.3 of BS5400 pt.4 can be used as a worst case for bond stress, but is this still true regardless of bar spacing?
I am just seeking a bit of clarification on the method as it seems that numerous assumptions can be made which would affect the final design.
The job involves breaking out the back face of a small wingwall, resin fixing some bars into the abutment, then recasting the back of the wingwall. This is to give the wingwall the required capacity to resist parapet impact loading.
I am a little unsure about the method of using Hilti's quoted loads with the draft HA document 'The anchorage of reinforcement and fixing in hardened concrete'.
Due to the small number of bars to be fixed in each wingwall (5no.), I expect the application to be considered safety critical. The IAN states that for a safety critical application the maximum force in the bar should not exceed a) 35% of the typical failure load (or ultimate capacity), b) characteristic yield strength of bar divided by material factors, c) 70% of test load (test load < 95% characteristic yield strength). Criteria b) and c) seem fairly straight forward, but I am having a problem with a).
I have been using the Hilti EXBAR spreadsheet which gives design loads for various embedment depths. This spreadsheet modifies the output based on bar spacing, edge distance, partial safety factors etc. This spreadsheet also gives a corresponding bond stress.
The IAN states that clause 5.8.6.3 of BS5400 pt.4 can be used as a worst case for bond stress, but is this still true regardless of bar spacing?
I am just seeking a bit of clarification on the method as it seems that numerous assumptions can be made which would affect the final design.
civilperson
Structural
The Hilti "Ultimate Loads" are the answer to your question in (a). These are divide by FS to give allowable. Use 0.35 x Ultimate for a comparison.
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