Construction Technology

Question 1

What are pad foundations?

Answer 1

• Shallow isolated footings • Typically square or rectangular • Single point loads from columns • Where would you use them? o Ideal for strong, lowbearing soils o Used in buildings with wide light spans such as warehouses • Advantages o Cost effective o Quick to install • Disadvantages o Not suitable for weak soils o Load limitation

Question 2

What are raft foundations?

Answer 2

• Concrete slabs which span the entire building footprint • Designed to distribute heavy weight across weak soils • When would you use them? o When the soils weak • Advantages o Less excavation required o Can be used as the floor slab o Cost and time effective • Disadvantages o Can crack o Not ideal for heavy loads o Can involve lots of concrete

Question 3

What are strip foundations?

Answer 3

• Concrete poured into trenches to transfer loads • Usually span along walls • When would you use them? o Residential homes o Under load bearing walls o Stable ground conditions • Advantages o Cost effective o Simple to install o Suitable for small projects • Disadvantages o Requires strong soils o Labour intensive o Limited load capacity

Question 4

What are pile foundations?

Answer 4

• Deep concrete cylinders fitted with rebar • Driven or drilled into the ground • When are they used? o When soils are weak o Highrise buildings o Building with heavy loads • Advantages o Suitable for weak soils o Can work with heavy structures • Disadvantages o Expensive o Logistically difficult to install in tight areas o Can take time o Disruptive

Question 5

What are the differences between driven and bored piles?

Answer 5

• Driven o Prefabricated piles are forced into the ground o Very loud and disruptive o Quicker • Bored o Drilled into the ground o Takes longer o Less noise

Question 6

What is a steel frame?

Answer 6

• Metal structural frame consisting of beams and columns • When to use? o Used in highrise buildings o Used in industrial buildings o Used in large residential buildings • Advantages o Very strong o Offers programme benefits due to prefabrication off site o Quick to construct o Sustainable • Disadvantages o Expensive o Expensive to fire protect o Difficult to implement changes

Question 7

What is an RC frame?

Answer 7

• A structural frame made of concrete, either precast or insitu • Reinforced with rebar • Usually includes the slabs • When to use? o Multi storey residential buildings o Basements o Complex architectural shapes o Infrastructure project • Advantages o Fire resistant o Versatile when poured insitu • Disadvantages o Very heavy loads o Expensive o Takes long to install o Environmental impact o Logistical issues at certain heights

Question 8

What are some examples of temporary propping systems?

Answer 8

• Titan props • GASS Props • Steel props • Megashore props

Question 9

What is plasma cutting?

Answer 9

• Carefully burning through steel with a flame • Pros o Its quicker than dismantling • Cons o Less quality for scrapping

Question 10

What is the difference between a proprietary system and steel system?

Answer 10

• Steel is fixed into position and unable to move • Prop system can be moved around freely

Question 11

Waterproofing grades

Answer 11

• Grade 1 o Seepage and damp areas are acceptable o Used for carparks etc • Grade 2 o No seepage is allowed, but some dampness may be tolerated o Used in basements • Grade 3 o No seepage or dampness is allowed o Needs to be ventilated o Completely dry