Browse Forums Building A New House 1 Apr 24, 2022 3:54 pm Re: Building on a dam 3Apr 25, 2022 12:06 am YES! Soils expand approx 10mm for every 1000mm. If your fill is equal, say 2000mm deep on the left side of you house and 2000mm deep on the right side, then the heave will be approx 20mm to both sides! dams are built like a cone, deep in the centre shallower near the sides which means your fill will not be even. This can cause the slab to tilt eg 2000mm on the left = 20mm heave (upward movement) and 3500mm on the right = 35mm heave. Therefore most engineers will pier through the fill to stable ground, basically placing the house on stilts, so whatever happen in the fill doesn't effect the structure. Deepish piers are about 2500 - 3000mm long and mostly screw piers (like a corkscrew), deeper than this the piers start costing quite a bit of money as obviously they are longer but the wall of the tube needs to increase in thickness to prevent the pier from corkscrewing the shaft due to the friction. I would be getting a siting of the house to workout your pads position and getting a soiltest within the pad area asap We are Expert Consultant's, and we are here to help. Re: Building on a dam 4Apr 25, 2022 9:28 am Hey vidhya Ramamoorthy Welcome to the forum Also check stormwater requirements, sounds like you are in a possible flood prone area LOL, peirs won't help when the gyprock turns to mash (humour) Goodluck Designer,Engineer (Civil,Const & Envir),Builder,Concrete & Masonry Contract.Struct Repairs Re: Building on a dam 5Apr 25, 2022 3:35 pm BuildingandLegal YES! Soils expand approx 10mm for every 1000mm. If your fill is equal, say 2000mm deep on the left side of you house and 2000mm deep on the right side, then the heave will be approx 20mm to both sides! dams are built like a cone, deep in the centre shallower near the sides which means your fill will not be even. This can cause the slab to tilt eg 2000mm on the left = 20mm heave (upward movement) and 3500mm on the right = 35mm heave. Therefore most engineers will pier through the fill to stable ground, basically placing the house on stilts, so whatever happen in the fill doesn't effect the structure. Deepish piers are about 2500 - 3000mm long and mostly screw piers (like a corkscrew), deeper than this the piers start costing quite a bit of money as obviously they are longer but the wall of the tube needs to increase in thickness to prevent the pier from corkscrewing the shaft due to the friction. I would be getting a siting of the house to workout your pads position and getting a soiltest within the pad area asap I agree with what you say that it is most likely going to be screw piles and will be significantly more expansive than a non filled block but not with your comments about soil expanding 10mm for every 1000mm regardless of soil type etc. Re: Building on a dam 6Apr 25, 2022 7:01 pm groundzero what would say a simple quick calc number would be? We are Expert Consultant's, and we are here to help. Re: Building on a dam 7Apr 25, 2022 9:10 pm BuildingandLegal groundzero what would say a simple quick calc number would be? BuildingandLegal There is no simple calculation for example a sand won't heave, a highly reactive clay will and it will depend on the change in soil suction which depends on the soil type and changes in moisture. Usually fill settlement will override heave in moderately or less reactive soil fill material. Filled in dams have the additional problem of the actually still retaining water at the base so bored piers are more of a construction risk then screw piles where a perched water table won't effect the screw pile installation.So your conclusion is right in my opinion. The Australian standards have a triangle model to calculate ground movement but it doesn't really take into account the effect of fill material in the calculations. I could crap on for hours about soils but you probably would fall asleep like most people do. Re: Building on a dam 8Apr 25, 2022 9:29 pm Groundzero are you Jason (Vic) We are Expert Consultant's, and we are here to help. Thanks for your reply. I will just wait and see I guess. Trying to get some more information from our builder. 9 30235 go upvc window frames ensure insulation under colorbond. not just sarking, lighter color roof also not sure if you have seen this viewtopic.php?t=5823 last couple of pages… 4 110524 |