Author Archives: Conrad
Irony of Age
I know I don’t usually post things like this on here, but the idea of this came up at work and I thought other engineers might like it. I present to you, the irony of age! Done in Excel (well, Google Spreadsheets in this case).
energy time and money; pick two
I dare you to defy the chart! I want to be able to place a check next to all three both as an adult and later on when I am elderly, and I hope that many others can as well given that society is so advanced and all. Click here to continue reading
Closed Conduit Hydraulics – Bernoulli Equation
The Bernoulli Equation is used to analyze flow in closed pipe systems and is one of the most used equations in hydraulics (that I can remember!).
The base form of the equation relates energy between two or more points in a system. I think it is easier to remember and use in terms of head loss(ft or m).
$$ h_f = \frac{V_1^2}{2g}+\frac{p_1}{\rho g} + z_1 = \frac{V_2^2}{2g}+\frac{p_2}{\rho g} + z_2 $$ Click here to continue reading
Closed Conduit Hydraulics – Hazen Williams Equation
Hazen-Williams can be used to determine the flow characteristics in closed conduits (pipe systems).
For Velocity
$$ V = 1.318CR^{0.63}S^{0.54} \text{ (US)}$$
$$ V = 0.849CR^{0.63}S^{0.54} \text{ (SI)}$$
S = slope, in decimal form. This is equivalent to \( h_f/L\)
R = hydraulic radius, \(\text{(Area of flow)}/\text{(wetted perimeter)}\)
C = Roughness Coefficient, get this from a table (available in both the AIO and CERM) Click here to continue reading
Earthwork Cut and Fill Calculations
I spent some time reviewing the earthwork sections that will appear on the construction breadth AND depth portions of the test and realized that the books are kind of confusing in their presentation of the formulas. I figured out a way that helps me to remember the formulas easily and these problems should be straightforward free points on the actual test.
First, a few definitions (these go by a lot of different names that mean the same thing).
In Situ, bank measure: soil as it is currently on-site. This is soil that has supposedly been at rest for a while. Even if it was compacted initially it has expanded gradually over to time to be at its current at-rest condition.
Bulk Size, Swell, Transport Size, Loose, Expanded, Excavated: This is soil that has been excavated and is loose. This is used to calculated the volume used while transporting or while sitting loosely in a pile. Click here to continue reading
