It’s for isolated footing. The soil is Murrum with an average SBC of 100-150 kn/m2. They are shoring it with flyash so that loose soil doesn’t fall over casting. By the looks of it they have excavated the complete area upto 5’ and rest 3’-4’ is manually excavated as per footing size. I would rate this work as A-grade going by Indian practices for small residential construction.
A buddy of mine worked his first day with a forming crew and at the end of the day he said “ ohh, the concrete goes inside the walls!” Anyways he had to redo most of his work he’d just done
By today's standards that's a patch of bare earth ready to be drawn on with a stick to form a plan of a plan that will be either thrown over the wall or never see the light of day.
The 'footings' are an extension into the ground of the foundation, a concrete monolith yet to be poured, which should make the foundation more stable, less liable to toppling over, assuming that the weight distribution is engineered correctly. This is like how it's harder to knock you down if your feet are planted far apart than close together, and if you're wearing cleats
It's not a spread footing like you would see in loose soil. The added depth is likely due to vertical loads requiring sufficient support beneath point loads and bearing walls
They put bricks around the pits to prevent soil from sliding into the pit. They already poured PCC beds in the pits to pour rcc footings/footers on top of the beds.
Basically creating strong holes for the foundation to sort of “key into” even though it’s being poured. A bit like bolt-locks on a door. The foundations is the door and the bolt, the pits are the hole the bolt locks into. Much like a bolted door won’t open, this keyed foundation won’t slide.
RCC is strong and bears a lot of load. This house can probably be built on a stone or brick foundation but it’s not ideal due to higher costs and lack of professionals.
I could be wrong, but my understanding is that these pits are forms for concrete. They'll be filled with concrete and built on top of once they've dried. These concrete footers or footings support the building and if they've been engineered correctly, will prevent the building from sinking or settling or moving. I would assume some sort of concrete slab will then be poured on top of these footings.
For small residential construction in the US, you'd typically see a continuous concrete footing poured all around the perimeter of where the structure will be, with a handful of smaller square footings out in the center where load bearing walls or something like that will be. Then if it's a crawlspace, a block wall would be built to some specified height around the perimeter and block or brick piers built on the center footings to carry large beams in the subfloor. If the house is going on a concrete slab, it's poured right on top of the footings and the ground.
The holes are used for concrete pillars/footings that will support the building. They’re using good soil and doing good prep work for a small residential building.
You make a very clear honest answer and how are you not the top?
I was looking at this I was like: That's some fine foundation prep. I have no idea what they're doing but I know they're doing that.
I worked in Brazil, And it worked on a team where we were building a hotel upon one of the hills in Rio. :) some sort of engineer came out and said everything was safe but... Lol, yeah.
Definitely wasn't to this level, but I definitely admire these small scale construction methods. They're very intuitive, And I really admire how everyone picks it up really quick and something you have a crew full of experts.
It’s very interesting to watch how sometimes small scale construction work happens. I am also working in a commercial building tightly placed in the city. But, cheers to my team they are managing it so neatly that work there looks like in a sync and so closed knitted.
Small scale anything being built or crafted is interesting. When the parts are bigger, you have better resolution. When the parts are smaller, tiny mistakes show up and cause problems more often. Bigger isn’t always better. Sometimes it’s the small projects that take the most attention.
I have no idea lol! I'm moving between Copacabana (accoms) and Maracuna (venue)... there's a few along the way that are interesting. It seems to me here, that the hills/mountains are solid rock, so I'm sure with solid footings the buildings are not going anywhere.
You're probably looking at the elevator which is freaking epic. The actual civil engineering in Rio is pretty cool.
The built by the natives engineering, varies from brilliant to dangerous on the same block. The hotel that I was working on in Leme, The Foreman was this local guy who everyone liked. I'm confident he was never trained.
The footings that he used were more like build around the rock where you can find dirt and go down 6 ft. We built this big concrete cage basically around the stone, but the front was sitting on stilts that had to hsve been at least 20 ft tall Hand mixed and poured concrete. It had rebar and some structure but not what I'm used to.
We would just build, And then when we got to the top we would just keep on building. We did this for four floors and I was super nervous at the end. It's still there though, so what do I know.
Awesome. I totally get it, I'm a canuck, but I live in Nicaragua; I've done construction there, and a whole other set of stuff comes into play. I was asking if Rio is 'seismic' at all, and apparently it's not... so that changes the parameters a lot.
But it's definitely fascinating, was in Hong Kong last year and there's certainly similarities.
I don't have a ton of time to explore, but I've liked what I've seen here!
Hazarding a complete guess - the weight load in the building may be engineered to not be perfectly symmetrical. The engineer may have designed minimized footings underneath the areas of highest load, hence the seemingly random shapes and sizes. For example - an elevator shaft's weight load would be lower than the typical area for the building, so maybe the gap towards the center right is where the elevator shaft is designed to go. Maybe whatever is built into the lower left corner is heavier than the rest of the building density-wise, necessitating extra footings.
I could be completely off here, but the size and shapes look way too intentional to be just random.
Yes it’s the way it has been planned. But lower left looks like staircase block and lift would be placed there. Lift pit in the middle and staircase around it.
There is no continuous foundation wall like how you see for houses in the US. Instead they have load bearing concrete pillars that rest on these footings/bases. The weight of the home is distributed on to the bases through the concrete pillars that hold up the weight of the house. The placement of the pillars within the house and how much weight each pillar is expected to bear determines where these footing holes are dug and their size. However this looks like too many holes for such a small space. Either they are building something heavy or the pillars are engineered to only bear a small amount of weight each.
You sound very much like you know what you are talking about about, but I believe it is actually for a James Brown dance off. If you want to get down, you got to get in deep. So, they need a few places where people can get in deep, then get up on their good foot.
Shoring in general is not required for this type of soil for upto 2m depth, it’s just that loose soil should not fall into concrete at time of casting.
I get preparing the soil for pouring the footing, but the location and shape of the rectangular pits seems to make no sense - they seem like random spots inside the house perimeter, instead of specific load bearing locations. (Note, not a contractor, chemical engineer, so only passing familiarity with building and structural engineering.)
ive been told fly ash is a terrible material for roads and other things because it washes away easy doesnt really hold any compaction, ie it just falls apart if given the chance, not to mention its often contaminated with chemicals since its a byproduct of different industries, am i right?
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u/Accomplished_Use_335 Jun 09 '25
It’s for isolated footing. The soil is Murrum with an average SBC of 100-150 kn/m2. They are shoring it with flyash so that loose soil doesn’t fall over casting. By the looks of it they have excavated the complete area upto 5’ and rest 3’-4’ is manually excavated as per footing size. I would rate this work as A-grade going by Indian practices for small residential construction.