Rory2405
Structural
- Apr 15, 2024
- 1
I'm looking for advice on a niche scenario.
Bit of background about the project I'm working on. I work on a nuclear decommissioning site for an engineering team, where various other teams on the site come to us for engineering work/projects that need done. The client I'm working for now previously had a design for the structural decommissioning of their facility by an external designer, which involves the removal of walls, foundation, roof and external cladding etc.
Part of the original design was to core through reinforced concrete walls of one area and install 6No. circular hollow sections, pour mass fill concrete between the RC walls, and then cut up the area into blocks. A Dywidag threadbar is to be inserted through the CHS/concrete block and fixed both sides to end brackets. These end brackets are to be connected to a lifting beam by threaded rods. I don't think I can show a drawing for security reasons/site policy, but I have provided a sketch to help visualise what I tried to describe.
For various reasons the client had to deviate from the design and did not install the circular hollow sections. They are now opting to core through the full length of the concrete block after pouring the concrete, and they have asked me to confirm if the beams can still be removed safely without the CHS being installed.
I have carried out some basic checks currently, (shear/bending resistance of the threadbar, and bending resistance of the concrete) all of which are OK. However, my main concern is there will be no bond present at the join between the mass fill concrete and existing RC walls. My thoughts are that it is likely to shear at this joint, and this was the external designers reason for the CHS - to provide shear resistance against de-bonding of these two parts while maintaining lifting access.
For the last few days I've been trying to prove that the compressive force induced by the torquing of the end bolts is enough to prevent shear at this location, but I'm struggling to find anything of relevance in the Eurocodes. Is there anything in the Eurocodes (or any code for that matter) that can prove shear resistance for two separate blocks being compressed together?
Part of me thinks I'm overthinking things. The lifting arrangement will pin the three blocks together during lifting, and they will only come apart once the threadbar is removed. The client has said this won't be an issue, they just want to make sure that removal of the CHS will not cause collapse during removal (which I've effectively done through the shear/bending checks). We have talked about specifying an anchor plate to fix the threadbar post lift, pinning the blocks together.
Anyway I'd be curious to know what anyone's thoughts are on this, any help is appreciated.
Bit of background about the project I'm working on. I work on a nuclear decommissioning site for an engineering team, where various other teams on the site come to us for engineering work/projects that need done. The client I'm working for now previously had a design for the structural decommissioning of their facility by an external designer, which involves the removal of walls, foundation, roof and external cladding etc.
Part of the original design was to core through reinforced concrete walls of one area and install 6No. circular hollow sections, pour mass fill concrete between the RC walls, and then cut up the area into blocks. A Dywidag threadbar is to be inserted through the CHS/concrete block and fixed both sides to end brackets. These end brackets are to be connected to a lifting beam by threaded rods. I don't think I can show a drawing for security reasons/site policy, but I have provided a sketch to help visualise what I tried to describe.
For various reasons the client had to deviate from the design and did not install the circular hollow sections. They are now opting to core through the full length of the concrete block after pouring the concrete, and they have asked me to confirm if the beams can still be removed safely without the CHS being installed.
I have carried out some basic checks currently, (shear/bending resistance of the threadbar, and bending resistance of the concrete) all of which are OK. However, my main concern is there will be no bond present at the join between the mass fill concrete and existing RC walls. My thoughts are that it is likely to shear at this joint, and this was the external designers reason for the CHS - to provide shear resistance against de-bonding of these two parts while maintaining lifting access.
For the last few days I've been trying to prove that the compressive force induced by the torquing of the end bolts is enough to prevent shear at this location, but I'm struggling to find anything of relevance in the Eurocodes. Is there anything in the Eurocodes (or any code for that matter) that can prove shear resistance for two separate blocks being compressed together?
Part of me thinks I'm overthinking things. The lifting arrangement will pin the three blocks together during lifting, and they will only come apart once the threadbar is removed. The client has said this won't be an issue, they just want to make sure that removal of the CHS will not cause collapse during removal (which I've effectively done through the shear/bending checks). We have talked about specifying an anchor plate to fix the threadbar post lift, pinning the blocks together.
Anyway I'd be curious to know what anyone's thoughts are on this, any help is appreciated.
