Floor Strengthening with Buildability Concerns 1

[Aytacoglu]

Hi,

I am currently working to strengthen an existing floor slab where new heavy equipment will be installed on the floor above.

I have attached the plan view of the area below for reference. The 3no. beams shown are actually not supporting the slab and they are there to only support the high voltage cables(I also attached the photo of the area).

Due to heavy equipment that is going to be installed above, this area needs to be strengthened. My initial thought was to just provide some trimmer beams in order to reduce the slab span from 3.310m to around 1.000m where the slab would be sufficient. However, the problem is the buildability part in this area. Due to the presence of high voltage cables underneath, there is no way of building a scaffold to install the trimmer beams. I am really struggling to come up with a solution that would strengthen the floor without actually working above the HV cables.

Is there any ideas/suggestions for potential solution for this issue?

Please let me know if you require any further details and I can provide them here.

Thanks

 

[GeorgeTheCivilEngineer]

Client builds a snake pit then can't get rid of the snakes... if they can't turn the HV cables off then I guess the only other way is to build a new floor above the existing one.

 

[phamENG]

Strengthening from above does sound like the best option - though that will of course depend on head clearance in the room and minimum clearance for the new equipment.

If you do somehow manage to squeeze beams in underneath, beware of the negative moment you'd be generating in the slab and potential top-of-slab cracking at the beam locations.

 

[Eng16080]

As noted by others, I would try to provide support above and not mess with the "snake pit." This may well be your only realistic option. If I was the contractor, I wouldn't want to be anywhere near those HV lines. Hopefully it's possible to turn the power off while the new work is being done.

 

[Enable]

Looking at the orientation of the cables it appears possible to erect construction aids and add additional support. We work in Hydro Vaults quite a bit and this kind of work is certainly done with active and inactive lines. Ideally you shut everything off and bring in temp generators if necessary. But if you cant then work in live hydro vaults is possible.

Before contemplating a new support structure from below you will need to contact your local utility (here it would be Toronto Hydro or similar) for a site meeting to determine their requirements. They decide what can and cannot happen inside their vault and that will have huge implications (basically dictate) any design you create. They should have procedures for repairs (or upgrades) as things do deteriorate with time so it'll be a matter of getting to the right people, which is not always so easy.

Here we go through electricians who have previously done vault repairs that have the relationship with individuals at Hydro to facilitate all this. They know who to talk to and can get it done much quicker than you can working on behalf of the owner.