8.1mec PRINCIPLES OF CONSTRUCTION Flashcards
C1 - Soil testing is needed for what kinds of buildings?
All buildings except single family dwellings
C2 - Describe the function of and difference between test pits and boring.
The geotech Engineer generates a soil profile to show the strata (horizons) of varied soil types.
Test Pit (<3)
Boring (>3)
C3 - Describe the 2 broad classes of soil.
- coarse grain (particles visible to naked eye)
- gravel
- sand
- fine grain
- silt
- clay
C4 - How does ASTME define soil types. (4)
1 - description (ex: silty gravel)
2 - bearing capacity (ex: 5000 psf)
3 - susceptibility slight (ex: slight)
4 - permeability + drainage (ex: poor)
C5 - Define ALLOWABLE BEARING CAPACITY.
Max unit pressure a foundation is permitted to impose VERTICALLY or LATERALLY on soil mass.
C6 - Define a standard penetration test.
Measures density of granular soils by recording the number of blows required to advance a standard soil sampler
C7 - Describe the shearing strength of cohesive and granular soils when unconfined.
- Cohesive - maintain strength when unconfined
- Granular - require a confining force for their shear resistance
C8 - Describe 6 potential soil problems.
1 - SETTLEMENT - dead load causes structure to compact soil and ‘settle’
2 - DIFFERENTIAL settlement causes cracks
3 - FROST action heaving during freeze thaw = stress on footing .: footing must be 12” below frost line
4 - EARTH MVMT prevalent w clay soils .: footings lower than 5’ subject to less mvmt
5 - soil DRAINAGE moisture content impacts bearing capacity .:must know water level & drain properly
6 - WATER TABLE foundation must be well above water table to avoid • hydrostatic pressure • capillary action
C9 - Describe 5 potential soil interventions.
1 - SOIL MODIFICATION - to improve consitancy/bearing etc.
2 - INCREASE BEARING CAPACITY - deepening of footing - increase bearing area of footing
3 - IMPROVE DRAINAGE - increase bearing capacity
4 - REMOVE/REPLACE UNSUITABLE SUBSOIL - typ. replaced w compacted granular engineered mix
5 - COMPACTION - w rollers
C10 - Describe 4 types of earthwork in order of execution.
1 - ROUGH GRADING - permanently filled slopes stable @<2:1
2 - EXCAVATION - removal of existing - permanently cut slopes are stable @ <1.5:1
3 - BACKFILL - earth replaced around foundations + footings - deposit in 6-12” layers - tamp to avoid settlement
4 - FINISH GRADING - final distribution of earth @ conclusion of construction - accurate win 1”
C11 - If soils are not adequately dense for a foundation to bear upon, what can be done?
The soil may need compaction in order to achieve optimum density or soaking to achieve optimum moisture content.
C12 - Silt and sandy soils are typically _____ and susceptible to _____.
- impervious
- frost
C13 - Ideal soil type for construction?
Clean (no silt or clay) sand or gravel
C14 - Which soil types have either very poor or unsuitable bearing capacity.
All organic soils:
- Organic silt-clay
- Organic clay and silt
- Peat (highly organic = unsuitable)
M1 - WHAT IS THE WATER PRESSURE IN CITY SUPPLY SYSTEMS AND HOW MANY STOREYS CAN BE SUPPLIED WITHOUT A PUMP?
50 PSI - 6 STOREYS
M08 - Describe a radiator and a fin-tube convector.
Radiator
- series /coil of pipes w steam or hot water inside
- heats space by radiating heat
Fin-Tube Convector (baseboard)
- series of thin vertical tubes spaced closely to max heat transfer to air
- cool air drawn in from below by convection, and heated by contact with fins and discharged out the top
