I am reviewing a 1930's era floor in a NY city building that was designed using the empirical formula in the NY code of that time. Having some difficulty deciding how to rationally decide when a hole in the floor of what size needs to be reinforced with steel angles etc under the slab.
The mesh reinforcing is supposed to be acting as catenary cables rather than as tension reinforcing in the normal modern engineering sense of the word. My understanding is that the empirical formula for determining the slabs reinforcing was based on testing. I can assume that the load formerly carried by cut wires spreads to adjacent undamaged slab and reinforcing, but to what extent?
Is anyone aware of a design method or approach for dealing with post-construction holes in this type of floor slab? My particular slab has 1/4" dia wires at 4" o/c, typical spans of 5' to 6.5', overall thickness of 4" of cinder concrete. There are existing intermittent holes up to 15" +- wide in the slab now and new ones contemplated the same size or slightly smaller. No strengthening has been done to the floor and it has held up ok so far. The live load on the floor is not going to increase, I just am trying to understand and want to be able to justify rationally how much intervention and strengthening is needed for these holes.
The mesh reinforcing is supposed to be acting as catenary cables rather than as tension reinforcing in the normal modern engineering sense of the word. My understanding is that the empirical formula for determining the slabs reinforcing was based on testing. I can assume that the load formerly carried by cut wires spreads to adjacent undamaged slab and reinforcing, but to what extent?
Is anyone aware of a design method or approach for dealing with post-construction holes in this type of floor slab? My particular slab has 1/4" dia wires at 4" o/c, typical spans of 5' to 6.5', overall thickness of 4" of cinder concrete. There are existing intermittent holes up to 15" +- wide in the slab now and new ones contemplated the same size or slightly smaller. No strengthening has been done to the floor and it has held up ok so far. The live load on the floor is not going to increase, I just am trying to understand and want to be able to justify rationally how much intervention and strengthening is needed for these holes.