8.1s PRINCIPLES OF CONSTRUCTION

Question 1

S1 - 2 TYPES OF LOADS

Answer 1

Ching 2.08

STATIC & DYNAMIC

Question 2

S2 - 2 TYPES OF STATIC LOADS

Answer 2

Ching 2.08

DEAD & LIVE

Question 3

S3 - 4 TYPES OF LIVE LOADS

Answer 3

Ching 2.08

1 - OCCUPANT & MOVEABLE FURN/EQUIPMENT

2 - SNOW

3 - RAIN

4 - IMPACT (KINETIC LOADS OF SHORT DURATION - CONSIDERED STATIC BY CODE - AMPLIFY LOAD TO COMPENSATE FOR DYNAMIC NATURE)

Question 4

S4 - 2 COMMON TYPES OF DYNAMIC LOADS

Answer 4

Ching 2.09

WIND & SEISMIC

Question 5

S5 - NEWTON’S 3RD LAW

Answer 5

Ching 2.12

For every force acting on a body (building) there is an equal force of opposite magnitude.

Question 6

S6 - LIST & DEFINE THE 3 TYPES OF FORCES WHICH MAY IMPACT A STRUCTURAL BODY.

Answer 6

Ching 2.11

1 - COLLINEAR = along the same line of action *sum of vectors = magnitude along same line of action

2 - CONCURRENT = vectors that intersect at one point *sum of vectors with parallelogram polygon method

3 - NON-CONCURRENT = moment or rotation forces *sum of vectors = moment arm = F X d

Question 7

S7 - SHEAR & MOMENT FORCES ARE BEST RESISTED WITH WHICH CONSTRUCTION TYPES.

Answer 7

• RIGID CONNECTIONS (Least efficient, only good for small buildings)
• SHEAR PLANES
• BRACING

Question 8

S8 - 3 TYPES OF STRUCTURAL SYSTEMS & MATERIALS TYPICALLY USED FOR EACH

Answer 8

1 - LINEAR - columns & beams (steel/timber/concrete beams)

2 - PLANAR - walls & slabs (light wood/steel framing/masonry/concrete walls & slabs)

3 - COMPOSITE - columns/walls & beams/slabs

Question 9

S9 - 3 MAIN TYPES OF SHEAR STRENGTH IN HIGH RISE CONSTRUCTION

Answer 9

1 - CONVENTIONAL - shear walls/bracing &or rigid frames

2 - CORE - vertical circulation key to lateral strength

3 - TUBE - lateral bracing along perimeter

Question 10

S10 - BEST CONSTRUCTION TYPE FOR TALL BUILDINGS IN SEISMIC ZONES

Answer 10

STEEL = DUCTILE & LIGHT

NOT CONCRETE FOR EXAMPLE = HEAVY & BRITTLE

Question 11

S11 - 2 TYPES OF DAMPENING

Answer 11

1 - TUNED MASS DAMPER - heavy mass on rollers towards the top of a tall building

2 - BASE ISOLATION - isolate the base from the ground so building can ‘float’ - prevents resonance

Question 12

S12 - Define underpinning.

Answer 12

rebuilding / strengthening foundation of existing buillding

Question 13

S13 - Describe 5 main types of excavation support systems

Answer 13

1 - SHEET PILING steel (corrugated), timber or precast planks driven vertically into ground

2 - SOLDIER PILES steel h-sections driven down vertically to support horizontal lagging

2 - TIE BACKS used if rakers would interfere with const. steel cables anchored into predrilled soil or rock

3 - CROSS BRACING sheet piling and soldier beams are supported by horizontal steel cross bracing or by steel rakers bearing on heal blocks

4 - SLURRY WALL poured into a trench and often becomes permanent wall

Question 14

Describe the dimensions shown below:

Answer 14

width of foundation wall = W

projection = 1/2 W

height of footing = W

width of footing = 2 W

Question 15

Describe the cone of bearing, how in impacts footing spacing, and what angle is shaped by rock and soil/sand respectively.

Answer 15

1. Cone of bearing is the compacted soil below the footing
2. each footing must be separated by the width of two footings @ min.
3. rock results in an angle of 60deg
4. soil and sand results in an angle of 30deg

(see below)

Question 16

S16 - What building/soil type are floating foundations used for, and why are they successful?

Answer 16

1. used for tall buildings in yeilding soil
2. they use a mat (or raft) foundation the is deep enough in the ground that the weight of the excavated soil is equal to or greater than the construction supported.

Question 17

S17 - When siting a building near the top or base of a slope what sort of setback can be used as a rule of thumb for stability of the foundation?

Answer 17

1. at the base = H/2 (height of the slope/2) or 5m max
2. at peak = H/3 or 12m max

Question 18

S18 - Describe the typical assembly for a concrete slab:

Answer 18

TOP

1. 100min slab thickness
2. welded wire fabric reinforcement midway
   
   • controls thermal stress: shrinking /cracking
   • grid of bars needed for heavy floor loads
3. 6 mil poly
4. 50mm sand
   
   • soak up water during curing
5. 100mm min base course of gravel/crushed stone
6. stable uniformly dense soil
   
   • prevents capillary rise of groundwater

Question 19

S19 - What are the 3 main concrete joints?

Answer 19

1. Isolation (aka expansion)
   
   • allows MVMT btwn concrete slab + adj. columns walls
2. Construction (also serve as control/isolation)
   
   • allows a place for construction to stop and start again @ later time
   • keyed or doweled
3. Control
   
   • ​​creates lines of weakness so cracking from tensile stress occurs along predetermined lines

Question 20

Describe the typical spacing of control joints, and 3 common types.

Answer 20

typ. spaced 4500-6100(15’-20’) or where required:

• irregular slab shape
• openings

1. Sawn Joint
2. Premolded or metal strip inserted into concrete
3. Keyed Joint
   
   • prevent bond by applying metal or plastic joint material or applying curing agent to one side

Question 21

M10 - Radiant heat cannot provide _______ to the space and it cannot _____ _____. For these reasons, radiant heating should be supplemented.

Answer 21

Radiant heat cannot provide ventilation to the space and it cannot react quickly. For these reasons, radiant heating should be supplemented.