Construction Technology (L3) Market Weighton Depot Flashcards
What defects did you identify?
- Cracking to the brickwork
- Gaps to the perps
- Slippage of the wall at approximately 450mm high from ground level
What was the pattern of the cracking?
Vertical cracking
How did you carry out the inspection?
- I carried out a visual inspection taking notes of the positioning of the wall and the purpose it was serving.
- I took notes on the type of brickwork, height and type of the ground levels and extent of the damage.
What conclusion did you make following your inspection?
- I concluded the wall was unstable and not fit-for-purpose. This was due to a lack of weep holes causing lateral movement to the wall.
- Also, the use of calcium silicate bricks and lack of movement joints had caused extensive cracking.
How did you conclude the bricks were calcium silicate?
- The appearance of the bricks which were a creamy, off-white colour
- Small particles of flint were visually noticeable upon close inspection.
- To be certain, I could have sent one of the bricks to be sampled by XRD (X-ray diffraction), however, the wall was beyond repair and needed replacing so it was not necessary
What advice did you provide your client?
I advised the client that the area be closed with immediate effect and to remove and replace the wall.
What design options did you consider and why?
Engineered Brick Wall
- Well established form of construction with minimal maintenance, weatherproof, easy to obtain and relatively cheap.
Issues: Time consuming, weather dependant
Reinforced Concrete Wall
- Excellent compressive and tensile strength
- Can withstand the lateral soil pressure
- Very low maintenance
Issues: Time consuming, costly due to both the formwork and concrete, disruptive and it produces extensive carbon emissions due to production and transportation.
Gabion Stone Baskets
- Quick and easy to install, they do not require extensive excavations or concrete foundations. They can be laid directly on top of a well-compacted and levelled hardcore base.
- They are cheap in comparison to the other methods mentioned
- There are no wet trades involved, so the installation is not weather dependant
- Shorter programme and minimal disruption for the site users.
Issues: Require firm ground and the stability relies upon the quality of installation.
Were there any limitations on when the work could be undertaken and did the limitations impact your design decision?
Yes. The site is in operation from morning to evening and is continually in active operation from heavy load vehicles, particularly waste vehicles. This was a key consideration when recommending a design.
Which option did you recommend to the client and why?
Gabon Stone Baskets
- Quick and easy to install, they do not require extensive excavations or concrete foundations. They can be laid directly on top of a well-compacted and levelled hardcore base.
- They are cheap in comparison to the other methods mentioned
- There are no wet trades involved, so the installation is not weather dependant
- Shorter programme and minimal disruption for the site users.
Can you draw a sketch showing the installation detail?
What was your main design considerations?
- Health and Safety
- Time
- Cost
- Maintenance
What was the budget estimate; did you provide the client with an estimate in the first instance?
I had no information from previous projects and no other colleague had either. I decided to speak with our internal civil engineers for a cost. However, the issue I found was their scheme was much larger, so they had a better rate per metre. For that reason, I increased the cost slightly per linear metre to account for this, so my budget estimate was more accurate.
