The normal values for gravitational acceleration used in physics and engineering are: g = 9.8066 m/s2 g = 32.1740 ft/s2 Poles and Equator Because g varies from the poles to the equator, here are the extreme values: North and South Poles: g = 9.832 m/s2 = 32.26 ft/s2. Equator: g = 9.780 m/s2 = 32.09 […]
How to Calculate Relative Density
December 20, 2013 by Leave a Comment
Relative Density is the ratio of the density of a substance to a specified reference density. Where: Dr = Relative Density (dimensionless) ρs = bulk density of soil (kg/m3 or lb/ft3) ρref = bulk density of reference (kg/m3 or lb/ft3) Often, the reference density is that of water, 62.4 lbs/ft3 or 1000 kg/m3. Alternatively, the […]
How to Calculate Specific Gravity
December 19, 2013 by Leave a Comment
Specific Gravity is the ratio of the density of a soil to the density of water. Where: SG = Specific Gravity (dimensionless) ρs = bulk density of soil (kg/m3 or lb/ft3) ρw = bulk density of water (kg/m3 or lb/ft3) = 1000 kg/m3 (62.4 lb/ft3) Specific Gravity of Various Substances Substance Specific Gravity Water 1.0 […]
How to Calculate Bulk Density
December 18, 2013 by Leave a Comment
Bulk density, also called soil density, is the ratio of the total mass of a soil to the total volume. Where: ρ = bulk density (kg/m3 or lb/ft3) mt = Total mass (kg or lbs) mw = Mass of water (kg or lbs) ms = Mass of solids (kg or lbs) Vt = Total Volume […]
How to Calculate Degree of Saturation
December 17, 2013 by Leave a Comment
The degree of saturation is the ratio of the volume of water in a soil to the volume of voids. Where: S = Degree of Saturation Vw = Volume of water (m3 or ft3) Vv = Volume of voids (m3 or ft3) Vg = Volume of air (m3 or ft3) The degree of saturation is […]
How to Calculate Moisture Content
December 13, 2013 by Leave a Comment
The moisture content of a soil is the ratio of the mass of water in a soil to the mass of solids. Where: mw = Mass of water (kg or lbs) ms = Mass of solids (kg or lbs) The moisture content is thus a ratio which can be greater than 1. It can also […]
How to Calculate Soil Porosity
December 12, 2013 by Leave a Comment
The soil porosity, also called the void fraction, is the ratio of the volume of voids (open spaces, i.e. air and water) in a soil to the total volume. Where: Vv = Volume of voids (m3 or ft3) Vt = Total Volume (m3 or ft3) Vg = Volume of air (m3 or ft3) Vw = […]
Concrete Slump: Explanation, testing and Interpretation
December 6, 2013 by Leave a Comment
Concrete slump is a definition of the consistency, often called workability, of concrete. Slump Test The slump test is defined by ASTM C143 and AASHTO T119 in the United States, and EN 12350-2 in Europe. There is no significant other testing method for concrete workability in industry use today. A standard size cone (Base diameter […]
How to Design Guardrail
November 29, 2013 by Leave a Comment
The design guidelines for all barriers is taken from the AASHTO Roadside Design Guide. Determining if Guardrail is Required It is necessary to calculate a “clear zone” which is a distance from the pavement edge within which there should be no hazards. If a non-breakaway appurtenance must appear within the clear zone, a barrier is […]
How to Calculate the Water Cement Ratio
November 28, 2013 by Leave a Comment
The water to cement ratio is the most important factor in concrete strength. The ratio is, as it’s name implies, the ratio of water to cement. If you can measure the volume of water, a common conversion is: The higher the water cement ratio, the lower the strength. But the lower the ratio, the more […]