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Strip foundations are widely used for modern dwelling houses - Leaving Cert Construction Studies - Question 2 - 2008
Question 2
Strip foundations are widely used for modern dwelling houses. (a) Using notes and neat freehand sketches, show the construction of a strip foundation for the extern... show full transcript
Worked Solution & Example Answer:Strip foundations are widely used for modern dwelling houses - Leaving Cert Construction Studies - Question 2 - 2008
Step 1
depth of trench
Answer
The depth of the trench must be sufficient to accommodate the type of foundation being used. Generally, the minimum depth for strip foundations is 600 mm, particularly for a building in freezing climates. The trench should also be deeper if the soil type requires it, ensuring it is below the frost line to prevent heaving.
Step 2
width of foundation
Answer
The width of the foundation should be at least three times the wall thickness. For a 300 mm wall, this means the minimum width for the foundation should be at least 900 mm. Properly sizing the foundation is crucial to evenly distribute the weight of the structure.
Step 3
Step 4
Step 5
design detail to ensure foundation strength
Answer
To reinforce the foundation, additional design elements should include:
- The projection "P" should be less than the thickness "T" to prevent shear failure.
- Using reinforcing steel mesh within the concrete enhances its tensile strength.
- Typical dimensions, such as three steel rods with a diameter of 12 mm, should be embedded where tensile strength is critical.
- It is crucial that the concrete is poured and compacted properly around the reinforcing steel to ensure effective load distribution.