How do you measure excavation depth?
To transform this for use with our excavation, Ab will be the area of the bottom of the excavation, At will be the area of the top of the excavation, and D will be the depth. So, the formula is: Ab = Wb * Lb, where Wb and Lb are the width and length of the bottom of the excavation.
How deep do you have to dig foundations?
Strip, trench fill or pad foundations must be cast at a minimum depth of 750mm in low plasticity clays, 900mm depth in medium, and British Standard 8004 recommends a minimum depth of 1m for foundations in the highest risk areas. If there are, or were, trees nearby, depths of up to 3m may be necessary.
Do you need rebar in concrete footings?
Plain concrete deck foundations without rebar are acceptable under the minimum standards of construction established in the International Residential Code. Footings with large bearing areas or unstable soil can benefit from adding rebar to prevent cracking.
How do you dig up concrete footings?
You can use a shovel and a post hole digger to excavate your footings by hand. The size of your footing will be determined by the amount of weight or load the footing will need to support and the type of soil in your yard. You will need to dig the footings to a depth below the frost line.
How are concrete foundations and footings are designed?
Reinforced concrete foundations, or footings, transmit loads from a structure to the supporting soil. Footings are designed based on the nature of the loading, the properties of the footing and the properties of the soil.
Where is the critical section on a concrete footing?
The footing acting basically as a wide beam, with a potential diagonal crack intending in a plane across the entire width, the critical section for this condition shall be assumed as a vertical section located from the face of the column, pedestal or wall at a distance equal to the effective depth of the footing in case of footings on soils.
Do you need a contractor to design a footing?
Footing design is something your normal concrete contractor or general contractor does not care much about, it is not required of them. Usually a contractor shows up in the picture after the footing design, concrete footing detail, and continuous footing are complete.
How is a beam carried on a footing?
This beam was carried by a 4 stud column at each end which in turn transfers the load to the footings. Here are the steps and thought process that went into footing design: Concrete footing design requires estimating the dead load, the load of building material, in this case all the material for the floor.