Glencoe: 18 Flashcards
Porosity:
measure of the ability of water to flow through the soil
What happens if the soil does not drain well?
Material may have to be excavated and replaced with better soil.
Test borings will also:
identify problems that could significantly affect the cost of the house. Such as rock ledge and high water table
Types of earth moving equipment used for basement excavations:
power shovel, backhoe.
Topsoil is often stockpiled by a
bulldozer, front-end loader, or a grader.
Why is topsoil stockpiled?
for future use as in grading the site.
X are often used in excavating the slab footings or shallow foundation walls
power trencher.
It is best to excavate only until
the top of the foundation foots are the bottom of the basement floor.
When is it advisable to make the final excavation for footings and why:
When its nearly time to pour to concrete.
Because some soil becomes soft upon exposure to air or water.
Excavation must be:
wide enough to do work. such as install and remove concrete forms, lay up block and waterproof the exterior surface of the walls, install foundation drainage.
Overdig:
additional excavation needed to provide clearance for the work.
Backslope:
Sides of the excavation are sloped to prevent them from caving.
Footing:
the base that provides a surface that distributes weight over a wide area of soil.
Footings are generally made of
concrete
Footings are usually built
first and then foundation wall is built later
Monolithic wall:
the footing and the foundation wall are built as a single unit
The depth and width of a footing is based upon
weight the footing must bear, the bearing and capacity of the soil, and local building codes.
If the building official thinks the bearing capacity of the soil may be less than X lbs / sq. ft., he or she may require a soil test for the soils actual capacity
1,500 lbs. sq. ft
Footings must always rest on X and why
undisturbed soil (soil that has not been dug up previously). Because it lowers the chance of the foundation settling unevenly.
If a site for footing has been dug too deep it should
never be filled back in with soil, but be filled with concrete
Who determines the strength and minimum footing depth
local building codes
footings should be placed at least
12” below grade.
In cold climates, footings should be placed far enough below finished grade to
protect from frost
Generally, the width of the footing should be X the foundation wall, And project out Y of the thickness of the foundation wall on each side.
2 times
1/2 the thickness of the wall
Footing height should be equal to
the foundation wall thickness
what is placed in footing to increase strength
two lengths of 1/2” #4 rebar.
The rebar in footings must be X above the bottom of footing
3 inches
The exact location of footings is determined by
plumb bombs hung from the foundation batter boards.
Once the location of the footing is known the X
size and shape of the footing can be established.
What is in the center of the surface of a footing
keyway
