Construction Tech

Question 1

1. Do you know any MMC?

Answer 1

a. MMC stands for modern methods of construction, examples include solar panels, recycled and reclaimed materials, green roofs, air source heat pumps

Question 2

2. Can you name any building regulations?

Answer 2

a. O – Overheating in buildings
b. M – Access to and use of buildings
c. L – conservation of fuel and power

Question 3

3. What is your current industry knowledge of the building regs?

Answer 3

a. New process in place October 2023
b. Additional requirements being set out for higher risk buildings that are 18+ metres in height or have 7 or more storeys and have at least two residential dwellings

Question 4

4. What are the different types of foundations?

Answer 4

a. Strip, Pile, Pad, Raft

Question 5

5. What are the advantages and disadvantages of Strip foundations?

Answer 5

a. Used to transfer continuous loads
b. Where ground conditions are good
c. Good for clays and seasonally changing soils
d. Not good for really tall buildings
e. Takes a lot of time due to excavation and curing time, a lot of concrete so costs a lot, complicated formwork

Question 6

6. What are the advantages and disadvantages of Pile foundations?

Answer 6

a. Good for large structures and very poor ground conditions
b. Expensive
c. Can be very noisy and intrusive
d. Expensive due to the plant hire required and need for piling mat and rig
e. Bored takes a long time due to the boring of the hole
f. CFA is quite quick as excavation and pouring is consecutive
g. Transporting pre cast piles is difficult

Question 7

7. What are the advantages and disadvantages of Pad foundations?

Answer 7

a. Good for point loads like columns in warehouse or ground beams
b. don’t need a full circumference of foundations
c. requires lots of smaller excavations
d. not good for poor ground conditions or large structures

Question 8

8. What are the advantages and disadvantages of Raft foundations?

Answer 8

a. Good for poor ground conditions and small buildings
b. Not good for large loads
c. Requires lots of concrete
d. Requires lots of sturdy formwork

Question 9

9. Can you give me the advantages of pre-cast concrete?

Answer 9

a. Better QAQC in the factory.
b. Reduces time on site and therefore associated preliminaries costs
c. Reduces the time you need to wait for it to cure on site, better programme

Question 10

10. How big is a window board?

Answer 10

a. This depends on the size of the window opening and the design, how recessed is the window, and how thick the wall is.

Question 11

11. What are section 38 works?

Answer 11

a. Construction of new estate road that will be adopted by the public highway

Question 12

12. What is S278 works?

Answer 12

a. These consist of alterations to existing highways

Question 13

13. Is there any RICS literature relating to MMC you are aware of?

Answer 13

a. I am aware of the report prepared by RICS on MMC looking at the forward lookahead for MMC.

Question 14

14. What are the British Standards (BS)?

Answer 14

a. Recommendations to minimum standards for construction and design

Question 15

15. What are the International Standards (ISO)?

Answer 15

a. Same as above but international and compatible with BS

Question 16

16. You mentioned ponds and swales as a drainage solution, are you aware of any other drainage solutions?

Answer 16

a. These are classed as Sustainable Urban Drainage Systems. I also know about traditional drainage systems composing of pipes and manholes etc. I understand there is symphonic drainage which is used on large roof spans

Question 17

17. A Client has a large area of land and is looking to develop a warehouse, how would you advise him between using a Concrete structural frame or a steel structural frame.

Answer 17

a. I would advise the client of the advantages and disadvantages of both. However a steel portal frame would traditionally suit a warehouse.
b. This is because of the long spans able to be achieved with steel as well as its quick erection on site, thus reducing cost of preliminaries
c. Steel is lightweight also, meaning it can support its own weight and the roof structure, whereas concrete would not achieve this.
d. A warehouse requires large open spaces (tall) for racking, which concrete could not do.
e. Steel is stronger, more tensile and compressive
f. Lighter so requires smaller foundations

Question 18

18. Steel vs concrete?

Answer 18

a. Steel is more Lightweight
b. Steel has better Large spans
c. Steel is Recyclable/sustainable
d. Both can be prefabricated and have quality control (moreso steel)
e. Steel is erected quicker on site, no drying time
f. Steel requires less foundation as its lighter
g. Concrete requires lots of maintenance, can be damaged just from air
h. Concrete is fireproof, steel needs protection
i. Concrete can usually be more local (steel from abroad)
j. Concrete has better sound and heat insulation
k. Cost – it depends!

Question 19

19. On the Cromwell Lane Housing Dev, you note that the ground conditions were poor, what does this mean for the Client? And can you advise on the differences between deep strip foundations and piled foundations?

Answer 19

a. For the client this means that foundations are going to have to be built to withstand and counteract this poor ground. Or additional excavation, earthworks or stabilisation will be required to the area, which is going to cost a lot of money.
b. Piles for houses are generally more expensive at £12-15k per house and strip foundations at £180/m3 so £4-7k per house.
c. Deep strip are linear and distribute loads from continuous walls whereas piles are long concrete structures distributing the load to the ground, or end bearing to the rock bed. Or in the case of house piles, sheet piles can be used which are made of steel, and can be re used when the house is demolished.

Question 20

20. You delivered a seminar on foundations, therefore talk me through the different options of foundations and when you’d advise a client to use them?

Answer 20

a. Foundations are the concrete mass in which a building sits on, between the ground, transferring the lode of the building into them.
b. The different types and when they’d be used are:
i. Strip foundations, I would advise a client to use these where the building is at a certain size (small) as they are usually not suited to larger building lodes. Where there is horizontal or continuous loading to be spread by external and internal loadbearing walls, and where the ground conditions are suitable for them. If the ground conditions are a bit poorer, I would advise deep strip.
ii. Piled foundations (CFA, bored, driven and sheet). I would advise to use these where ground conditions are poor and a suitable stratum needs to be reached in order to spread the lode, I would also advise this when the building is very large as there would be a massive amount of lode imposed which needs distributing deep into the ground and surrounding earth.
iii. Pad foundations. I would advise the use of pad where the building construction calls for point lodes, such as steel columns in a warehouse, usually cheaper than strip as it isn’t used across the entire perimeter
iv. Raft foundations. I would advise on the use of these where the building needs to spread the lode over the whole area, this is good for smaller buildings or very poor ground conditions, this can also act as a floor slab, saving on additional cost and time

Question 21

21. On Cromwell lane, did you get any input from the structural engineer?

Answer 21

a. We had a GI report which detailed the ground conditions, and that some areas of the site were worse than others, and that due allowance should be made for pile foundations, I then presented some options to the client based on different % of houses that need piles on site.

Question 22

22. Is it wise to use past experience to assume the CBR, and what was the assumption?

Answer 22

a. I used very similar previous projects that were all greenfield sites so had a similar CBR (Greenfield sites are generally softer and require a higher CBR). I used 3%. I advised my client of this assumption, and to undertake a further GI.

Question 23

23. On Cromwell Lane, what did you actually advise, and what was the outcome?

Answer 23

a. I advised on the costs of different options of foundations, and the impact that different % splits of foundations would have on the total cost of the project, taking into account the GI report findings where some plots need strip, and some need piles.

Question 24

24. Have you got any other advice on construction tech?

Answer 24

a. I noted on the Mills & Reeve project that the client had selected a rolled carpet for their new office fit out, this was a new client who hadn’t done a lot of projects. I suggested early on in the design stage that carpet tiles better suit an office environment due to access for the RAF. I proposed 2 different costs for the client consideration and requested input from the architect.

Question 25

25. You have worked on projects where planning was involved, do you know what reserved matters are?

Answer 25

a. They are essentially a planning application with increasing detail on the project, taking into account any conditions that have been incorporated.

Question 26

You’ve mentioned about poor ground conditions, can you outline a few ways in which the ground could be tested to assess the conditions?

Answer 26

Boreholes/trial pits. LIDAR, radar penetration. Soil and rock tests

Question 27

Why do ground conditions affect the type of foundation utilized?

Answer 27

As different foundations suit different soil conditions, although this will also be dependant on the type of building. For example piles are often considered for poor ground conditions as they can transfer load to deeper more stable strata. Rafts are also good for small buildings as they float on the ground distributing the load over a large surface area

Question 28

Can you explain the typical build up for an adopted road construction?

Answer 28

Capping, Sub-Base, Base Course, Binder, Surface Course, Tack Coat

Question 29

Can you give me a rate for a road?

Answer 29

£125 per m2, generally including all excavation, testing, kerbs

Question 30

How would you construct a standard 2m x 2m pad foundation?

Answer 30

Remove vegetation and topsoil, reduce level dig, foundation excavation, BCO sign off, level and compact, formwork, reinforcement, concrete pour, vibration and level, cure concrete, remove formwork

Question 31

You provided costs for piles and strip foundations, how did you do this and what were the rates you used?

Answer 31

Using previously tendered rates and in house cost data i used an average of £12,000 per plot, due to the level of design available, using the average plot size to get this figure. I used a rate of £180m2 for the trench including excavation and all other associated costs, and applied this to an average length of strip per plot.

Question 32

You have done a lot to do with drainage and delivered a seminar, can you give me a rate of a drain run and manhole?

Answer 32

This would heaviliy depend on depth and size of pipe, but a 150mm pipe at 1.5m is £160/m, and a manhole at 1.5m wide and 1.5m deep is £2.5k

Question 33

With the shortfall in excavation and fill on Rugby S278, what wad the outcome?

Answer 33

I advised the client we need to hold a meeting to run through this. I facilitated discussion between the two different engineers on each phase. This was then rectified prior to sending the documents out to tender, as the designers agreed there was an error.

Question 34

What are the main components of surface a water drainage network?

Answer 34

Storm drain runs, manholes, gullies, attenuation tanks, syphonic drains, SUDS.

Question 35

How did you advise your client the most suitable example road build up if none were available? Can you give on example of when you advised this?

Answer 35

For example on Cromwell lane and Horsham, i assumed the depth of carriageway as 750mm thick in total, including testing, excavation and formation in my rates.

Question 36

Why did you make the allowances and give the advice you chose to give on the Horsham project when CBRs were unavailable?

Answer 36

Because the CBR usually influences the depth of carriageway needed.

Question 37

What considered advice did you give the client when the ground was poor on Cromwell lane housing development?

Answer 37

I advised the client that poor ground conditions would have an effect on the type of foundations used, and the GI report included a note to say piles may be required on some areas of the north of the site.

Question 38

On Cromwell Lane, what investigations did you advise and consider?

Answer 38

testing such as boreholes, trial pits, lidar

Question 39

What ground stabilisation techniques are there?

Answer 39

lime stabilisation, vibro compaction

Question 40

Talk me through different frame types and when you’d use them?

Answer 40

Timber, Steel, Concrete - then go into detail

Question 41

What can you tell me about HVAC systems?

Answer 41

Stands for Heating, ventilation and air conditioning, and constitutes the main part of the mechanical installations.

Question 42

How is a swale constructed?

Answer 42

Using cut and fill model to excavate material in a ditch, install headwalls to the surface water drainage in correct locations and heights, then planting, signage.