Strip footings are the continuous spread footings of foundation wall.
Rules of thumb
The lowest part of the foundation are called footings. They are made from reinforced concrete. The concrete is allowed to have as minimum compressive strenght of 17 kPa at 28 days.
The footing should project more than hald othe foundation wall thickness and 150 mm minimum above stell reinforcement 75 mm minimum between reinforcing bars and concrete surface. (Ching, 2014) The footing should have the following proportions in order to afford the loads and distibute them in the soil.
(T)Thickness of the foundation wall : 200 mm Projection : 1/2 T Thickness of the footing : T Width of the footing : 2T (Ching, 2014,) To minimize the effects of ground heaving the footings are required to be placed below the depth of frost penetration.
The effect of ground heaving is when the groundwater freezes. Frostline is the average depth at which soil is frozen.( 305 mm below 0,0) (Ching, 2014) |
Materials
Brick (Masonry Strip)
Concrete
Assymetrical load
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Stone (Masonry Strip)
Reinforced Concrete
Lighweight concrete
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Construction
In situ Reinforced concrete
The work flow begins by digging out the trench to a level aggres with the constructor then blinding concrete is poured in order to cuver the defects 0f the soil, Then, the concrete is poured in the trench and also the reinforcement. The trench is stabilized by using formwork usually made by wood. (https://www.homebuilding.co.uk/foundations-explained/)
Prefabricated concrete
The construction of a strip foundation can be done with prefabricated pieces of concrete in the dimensions that the constructor has set. The parts of the strip are casted in the industry and the reinforcement is already added. At the construction site a few reinforcement bars are placed in order to unite tha parts.(http://www.ekt.bme.hu/ArchEng/Foundations%20%28S-D%29-s.pdf)
(Video 01 : https://www.youtube.com/watch?v=vX5tNMGpsfQ)
Detail of Strip Foundation
Strip foundations on sloping ground |
Rubble Trench Foundation
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Stepped footings that change level according to the levels of the soil in order to transfer the loads of the stucture in the soil and maintain the required depth. ( Ching,2014)
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Rubble trench foundation uses loose stone or rubble in order to reduse the use of concrete.. It is an enviromental friendly type of foundation and it is used for ancient times. Also it is not manufactured.(http://www.slideshare.net/bakhtzamin/foundation-29063799)
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(JV)