Mohr’s Circle is used to graphically determine the principal normal and shear stresses. First, some definitions: Tensile stresses are positive. Compressive stresses are negative. Clockwise shear stresses are positive. Counterclockwise shear stresses are negative. To draw Mohr’s circle, and find the principal normal and shear stresses, you must know the stresses applied to the object, […]
Archives for November 2013
What is Rock Quality Designation?
November 7, 2013 by Leave a Comment
Rock Quality Designation (RQD) is a test used by geotechnical engineers to indicate the degree of fracture of a drill core. It is a simple process which involves counting up the pieces of drill core which are more than 10 cm long and fully intact. The percentage of the whole drill core length is the […]
How to Calculate the First Moment of Area
November 6, 2013 by Leave a Comment
In structural engineering applications, the first moment of area is a calculation that is used to determine shear stress distributions. It is a relatively simple concept which involves the moment of a surface around an axis. $latex Q_y = x_c A\newline\newline Q_x = y_c A&s=2$ Where: Qx = first moment around the x axis (ft3 […]
Soil Particle Size Distribution
November 4, 2013 by Leave a Comment
Soil contains four primary components, for engineering purposes: gravel sand silt clay Organic material can be present in surface samples as well but this has no relevance to engineering applications. Gravel and sand are classified as coarse-grained, whereas silt and clay are classified as fine-grained. Various classification schemes exist which attempt to define the grain […]
Types of Guard Rail
November 2, 2013 by Leave a Comment
Guard rail absorbs the impact of out-of-control vehicles while guiding the vehicle to safer stops. There are three types of guard rail in primary use today. Flex Beam Thrie-beam Cable barrier Flex Beam Also called W-beam, flex beam is the cheapest and easiest to install, and thus the most popular guard rail in use today. […]