I'm stuck with how to work out the total pressure and centre of pressure in this example. Hmm, ocean water pressure, take a boat out on duh water… any drain tiles out there? rev 2020.11.11.37991, Sorry, we no longer support Internet Explorer, The best answers are voted up and rise to the top, Engineering Stack Exchange works best with JavaScript enabled, Start here for a quick overview of the site, Detailed answers to any questions you might have, Discuss the workings and policies of this site, Learn more about Stack Overflow the company, Learn more about hiring developers or posting ads with us. Sealing leaks from the OUTSIDE is the way to be happy down the road and a lot less $. 2 0 obj just because someone gets water through a crack in foundation wall, it’s not hydrostatic pressure, it’s later soil pressure, saturated soil forcing water through the crack. Find the total pressure per meter length of the wall and the point at which the resultant cuts the base. You no longer have to convince me that: The one thing that I don’t understand is why you seem to feel the presence or absence of a well functioning exterior perimeter drain tile maters not as long as the above practices are followed. Category theory and arithmetical identities. Pipe placement should be at or below the bottom of the footing, gravel should be clean (no fines). If your building department has abrogated its responsibility, this is what CON MEN are allowed to do to your home…”, U S Army Corps, lateral soil pressure, backfill with gravel etc etc Lateral Earth Pressure And Wall Movement Lateral earth pressure are the direct result of horizontal stresses in the soil. (I know, I know… now) Anyway when I do my hose test should I pull back my plastic “foundation roof” and lay the hose on the soil right up against the wall? Why thin metal foil does not break like a metal stick? In order to understand the lateral earth pressure we have to define the Coefficient of lateral earth pressure, K. 8. loll Let’s say we COULD put, install drain tiles around our boats, lets say the Titanic had BIGLY drain tiles around it… would the drain tiles keep the boats from taking on water, sinking? Laws and Treaties for Activities in Outer Space. You could pull it back a little, then run the water/hose test right where the crack is. The equations for the maximal pressure are the same for each side:$ q_{clay} = k * \gamma_{clay} * H \\ q_{water} = k * \gamma_{water} * H $. An interior perimeter drain tile system won’t prevent water from saturated soil adjacent to my foundation wall from entering a crack 5ft up from the slab. in-part they write, 'Typically, the failure is NOT from hydrostatic pressure but from the SOIL re-expanding…. stain appears to migrate down to slab floor. If you had a few cracks in the basement floor and one day you come home while its raining and see water coming UP through the floor cracks then, for me, one could call that hydrostatic pressure. The pressure loss depends on the height of the water. Because you don’t want the soil to CONTRACT… see that Donan Engineering link again. Gravel backfill reduces wall pressure from 3.) which waterproofing techniques have the lowest failure rates when subject to long term exposure of water saturated gravel? You can easily design a basement wall to hold back saturated soil. Concrete formwork - best approach to counter uplift forces, for a freestanding pour? Well, if 1+ openings in the boat occurs aka hits an iceberg! by replacing material immediately next to the wall with stuff that doesn’t swell. The seam at footer key looking at it from the outside seemed to me to be a very high resistance flow path for relieving exterior wall hydrostatic pressure. For those who have a horizontal piece of concrete up-against their vertical foundation wall then, one needs to get the water UNDERNEATH the slab(s) to deduce if they have a crack etc that allows water in… those often take longer, have to run hose a bit longer to get water under the slabs or porch etc. Quoting proper slope, larger diameter ADS and more pumps! –Severity of problem… each year SHRINKING or swelling inflict$$damages to houses, building, roads etc-- more than twice the damage from floods, hurricanes, tornadoes and earthquakes…, The U S Army Corps link previously posted… causative factors… one is “shrinkage & swelling of clay”. How can I label segments of a smooth curve through some nodes? North foundation wall is below grade and South foundation wall is above grade. weight of water in the soil, The take away I am getting is walls are typically designed for 1.) Never charged anyone one damn cent. Usually for safety, we also put the water table all the way up to the level of the ground, since this can easily happen after a storm in non-draining clay. but maybe not for 2.) Got lots of quotes from basement waterproofing companies that want to install interior perimeter drain. The soil UNDER the footing helps hold the footing in-place, you don’t want it to dry out. If you have enough movement to mobilise active pressure on the right and passive pressure on the left, then you can simply use the same equations with$k_a$on the right and$k_p\$ on the left. The wall may tilt away from the soil that is retained (Figure b). Benefits/pitfalls of defining function that is discontinuous at a point "explicitly" vs using piecewise? As an FYI, John (aka, Mark) is an expert at sealing basement water entry in SE Michigan…and, you would do well listening to his advice. The first two page and…page 19… Backfill, lateral pressure problems are exasperated by using unsuitable backfill materials, usually from on-site excavation… expansive clay soil… generally NOT recommend for backfill, Page 21, modeling results demonstrate that granular backfills (gravel etc) can reduce lateral pressures. Powered by Discourse, best viewed with JavaScript enabled, hydrostatic lateral foundation wall pressure, https://www.youtube.com/watch?v=5dpGpiB7kQI, https://www.youtube.com/watch?v=AyVA73ILPUM, https://www.youtube.com/watch?v=Q7jprh5f2p8, https://www.youtube.com/watch?v=h-GaOiWZPYM, Basement Wall Failures - Donan - Forensic Engineering Experts, Forces Harmful to House Foundation & Footers - Ask the BuilderAsk the Builder, http://www.amherst.ny.us/pdf/building/soilsstudy/TOASFS_section3.pdf, https://www.youtube.com/watch?v=jLjltBxHKfU, https://www.youtube.com/watch?v=INFPk66SG1g, https://www.youtube.com/watch?v=cLzdt6wkS24, https://www.youtube.com/watch?v=AHqScpQQqZI, https://www.youtube.com/watch?v=3KFycoizC84, A Definition | Colorado Geological Survey, https://www.youtube.com/watch?v=c4Ozr64HKsc, https://www.youtube.com/watch?v=owwskmlN388, https://www.youtube.com/watch?v=FK6PW6AyHig.