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One corner of a trench for a strip foundation is shown in the sketch - Leaving Cert Construction Studies - Question 4 - 2013
Question 4
One corner of a trench for a strip foundation is shown in the sketch. Describe, using notes and neat freehand sketches, the setting-out of a typical strip foundation... show full transcript
Worked Solution & Example Answer:One corner of a trench for a strip foundation is shown in the sketch - Leaving Cert Construction Studies - Question 4 - 2013
Step 1
levelling the profiles
Answer
To level the profiles for setting out the foundation:
- Setting Out: Begin by establishing a datum point that is usually taken from a defined reference height.
- Using Levels: Employ spirit levels or laser levels to ensure that the profiles are vertical and horizontal at all points.
- Water Levels: Where sustainability is needed, a water level can also be used, ensuring a precise transfer of height.
- Adjustments: Make necessary adjustments based on the finished floor level to maintain accuracy.
Step 2
locating the position of the trench
Answer
To locate the trench's position:
- Identify Corners: Mark the corners of the building using string lines stretched between the markers in the ground.
- External Wall Layout: Confirm the external wall's outline with measurements taken from the identified corners.
- Width Marking: Clearly indicate the trench width on profile boards to guide excavation.
Step 3
squaring the corner of the trench
Answer
To square the corner of the trench:
- Define the Rectangle: The first step is to outline a rectangle based on the building's layout and location.
- Right Angles: Use a 3-4-5 triangle method to ensure accurate right angles at the corners.
- Check Alignment: Verify the notation against the drawn rectangle to make sure it corresponds properly.
Step 4
locating the finished level of the concrete in the foundation
Answer
To locate the finished level of the concrete:
- Driving Pegs: Place pegs at the required height in line with the finished level of the concrete.
- Top of the Trench: Ensure these pegs are level with the top surface of the proposed foundation.
- Using Laser Levels: Employ laser levels for consistent accuracy in measuring the concrete's required height above the physical trench.
Step 5
Sketch of a typical strip foundation
Answer
In the sketch, depict a strip foundation for a 350 mm concrete block wall:
- Foundation Dimensions: Clearly illustrate the foundation base, with a width of at least 350 mm.
- Reinforcement Bar Positioning: Indicate the location of reinforcing bars within the foundation.
- Three Dimensions: Include and label at least three typical dimensions, such as the width, depth, and spacing of reinforcement.