What is the volume of a cylinder if the diameter equals 3 feet and the length equals to 12 feet?
84.78 cubic feet
Explanation:
There are two ways to
... [Show More] solve the problem. However, regardless of which method is used, you need to first determine the area of the circle then multiply it by the length.Traditional MethodUse the following formula:Area of the circle = π x r x rWhere π = 3.14 and radius (r) = 1.5 feet (half of the diameter length)Area = 3.14 x 1.5 x 1.5Area = 7.065 sq. ft.Multiply area by the length to find the volume.7.065 x 12 = 84.78Shortcut MethodArea of the circle is 78.5% of the square. Treat the circle as a square and solve for the area.Find the area of the square instead of the circle.3' x 3' = 9 sq. ft.Since circle is 78.5% of the square, multiply area of the square by 78.5% (or .785 if there is no percentage sign on the calculator).9 sq. ft. x .785 = 7.065 square feetMultiply area by the length to find the volume.7.065 x 12 = 84.78 cubic feet
Where are spiral rebar ties used?
In round columns
Control joints in sidewalks should be spaced at what intervals?
Equal to the width of the slab
Explanation:
Generally the control joints in sidewalks should be spaced equal to the width of the slab, but not more than 6 feet apart.
One cubic foot of cement weighs approximately:
95 lbs
How many cubic yard of concrete is required for a 4" slab with the diameter of 15 feet?
2 ½ cubic yards
Explanation:
Traditional MethodUse the following formula:Area of the circle = π x r x rWhere π = 3.14 and radius (r) = 7.5 feet (half of the diameter length)Area = 3.14 x 7.5 x 7.5Area = 176.625 sq. ft.Multiply area by the depth of the slab (in feet) to find the volume in cubic feet.176.625 x .333 = 58.82 cubic feetConvert cubic feet into cubic yards.58.82 ÷ 27 = 2.18 cubic yardsSince 2.18 is not a given option, round up the number to 2.5 cubic yardsShortcut MethodThis problem can be solved using a much simpler method. First is to find the area of the square, then convert it into the area of the circle by multiplying it by 78.5%.Area of the square = 15' x 15' = 225 square feetArea of the circle = 225 x .785 = 176.625 square feetDivide the volume by 81 to solve for the cubic yards for a 4" slab.176.625 ÷ 81 = 2.18 cubic yardsSince 2.18 is not a given option, round up the number to 2.5 cubic yards
The normal tolerance for the location of bends and ends of reinforcing bar is:
+/- 2 inches
How many cubic yards of backfill are required for a 3' x 5' trench, 1500 ft long, with a 1 foot diameter pipe?
789.72
Explanation:
Step 1. Find the net face area of the trench deducting for pipe.Face area including pipe: 3 x 5 = 15 square feetArea of the pipe: 𝐴=𝜋𝑟2A = 3.14 x .5 x .5A = 0.785Find the face area of the trench minus area of the pipe, which will give you the net area for the backfill.15 - 0.785 = 14.215Step 2. Find the total volume of the backfill.14.215 x 1500 = 21322.5 cubic feetConvert the volume into cubic yards.21322.5 ÷ 27 = 789.72 cubic yards
When can the live load be calculated by multiplying the height, width and length of a pour and dividing by the deadload?
Never
Tensile strength in concrete is achieved by:
The use of steel reinforcement.
Refer to the house plan. What is the total cost for the foundation slab if the contractor charges $3.54 per square foot?
$6524.90
Explanation:
The easiest way to solve for the area of the slab is to image a full rectangle of the slab and subtract void areas from the area of the slab.
Rectangle area: 28.167' x 71.5'= 2013.94 sq ftLeft void area: 6.667' x 1.83' = 12.2 sq ftCenter void area: 11.5' x 1.83' = 21.045 sq ftRight void area: 9.167' x 15' = 137.505Net area of the foundation slab: 2013.94 - 12.2 - 21.045 - 137.505 = 1843.19 sq ft.Calculate the price of the slab.1843.19 sq ft x $3.54 = $6524.90
What is the minimum spacing of parallel reinforcing bars placed in two or more layers?
1 inch
Explanation:
According to the American Concrete Institute, where parallel reinforcement is placed in two or more layers, bars in the upper layers shall be placed directly above bars in the bottom layer with clear distance between layers not less than 1 inch.
When applying concrete to concrete there are several factors to consider. Which is most important?
In most cases the most important is the bond.
What is the purpose of the rebar?
To increase the tensile strength
There are many ornamental uses of concrete, including casting architectural elements, ornaments, and faux finishes. How would you describe terrazzo in the simplest terms?
A special combination of colored rock and glass for floors.
What is the minimum size of anchor bolt can be used in seismic category E?
#5
The building code requires 5/8" anchor bolt to be used in seismic category E.
Construction loads are:
The maximum loads to which a structure will ever be subjected.
In some cases it may be necessary to use stronger or double ties. Why?
As a safety precaution when workers may need to climb on reinforcement.
What size of rebar is used to reinforce stem wall?
#4
Explanation:
The code requires ½ inch rebar to be used in stem walls.
On concrete paving or roadway, it is normal to use transverse joints at regular intervals. These joints are best filled and sealed. Why?
To reduce risk of exposure to the reinforcing.
When batching concrete, what percentage of concrete powder is commonly used?
25% to 40% cement powder
The sides of the main field of the slab must be reinforced with an ___ by ___ grid.
15"...18"
How long can a batch of concrete be in the truck before considerations of quality arise?
45 minutes
Pitch in a spiral reinforcing is a measure of:
Spacing between turns.
The anchor bolt must be embedded ___ into the slab.
7"
What is the purpose of the deformed rebar?
Deformations improve the bond between steel and concrete
What would be the easiest way to avoid puddling under a slab?
Careful grading
Air-entraining:
Improves the working life of concrete.
What is the maximum number of parallel bars that can be bundled together and still be considered a single unit?
4 bars
Explanation:
According to the American Concrete Institute, groups of parallel reinforcing bars bundles in contact to act as a unit shall be limited to four in any one bundle.
Shotcrete can be wet or dry. What are the advantages of wet?
Exact batching
What is the maximum spacing of the rebar in the stem wall?
18"
Explanation:
The code requires additional rebar to be used if the spacing between rebar in the stem wall exceeds 18".
What is the area of the circle if the diameter is 20 feet?
314 sq. ft.
Explanation:
There are two ways to solve for the area of the circle.Traditional MethodUse the following formula:Area of the circle = π x r x rWhere π = 3.14 and radius (r) = 10 (half of the diameter)Area = 3.14 x 10 x 10Area = 314 sq. ft.
Shortcut MethodArea of the circle is 78.5% of the square. Treat the circle as a square and solve for the area.Step 1. Find the area of the square instead of the circle.20' x 20' = 400 sq. ft.Step 2. Since a circle is 78.5% of the square, multiply the area of the square by 78.5% (or .785 if there is no percentage sign on the calculator).400 sq. ft. x .785 = 314 sq ft
A standard truck load of concrete is around 10 cubic yards of material. In a pour with an average depth of 8 inches, and a width and length of 12 by 32 feet, how much will the second truck need to bring?
One load was enough
Explanation:
Step 1. Solve for the volume of the pour: 12 x 32 x 8/12 (or 0.667) = 256.128 cubic feetStep 2. Convert cubic feet into cubic yards.256.128 ÷ 27 = 9.49 cubic yardsSince one truck carries 10 cubic yards of concrete, one truck will be enough for the pour.
To ensure proper grounding, the grounding electrode must be encased by how many inches of concrete?
2"
Explanation:
To ensure proper grounding, the electrode must meet the following criteria:1. Must be encased by 2 or more inches of concrete2. Electrode must be at or near the bottom of the footing or foundation3. Concrete must be in contact with the ground4. At least 20 feet of rebar that is at least ½" thick or 20 feet of solid copper as a conductor
Required reinforcement bar splicing length or lap length is a function of:
ALL
-Diameter of the reinforced bar.
-Stress in the reinforced bar at the cross section of splicing.
-Bond-strength between the reinforcing bar and the concrete.
Bundled reinforcing bars are normally required to have a minimum cover of at least the diameter of the bundle, except in the case of permanent proximity to earth where the minimum will be:
3 inches
Releasing agent is used on forms, why is over use a problem?
Oil in the water makes concrete that is less strong.
There are many surface finishes that can be applied to smooth finished concrete, including: Stain, Paint, Stenciling Oil, Varnish, Epoxy. What considerations should be taken into account before application?
Depends on finish to be applied.
Strength tests are normally:
The average of 2 tests at a specified time, taken from the same pour.
A mix with a higher percentage of rock has the advantage of:
Being less expensive. [Show Less]