Civil Engineering math?

How much math is used in civil engineering?

• I have always heard that mathematics is heavily involved in engineering, but I've never seen actual equations that civil engineers do. Where, when, and how do these equations apply? An example of an equation an engineer might see on a random day would be awesome.

• Answer:

  It really depends on what sub-branch of Civil you are referring to. Transportation folks have equations to describe traffic flow. Structural folks have equations to describe loading on beams and structures Environmental folks have equations to describe chemical reactions in lakes and streams Geotech folks have equations to describe soil loading behavior. Hydrologists have equations to describe surface water flow. The thing is, nowadays, most of the final work is done by computer or is constrained by codes and the day to day equation hacking is done to get a ballpark estimate or to make sure that you're going the right direction before plugging things into the computer. That means that most of the equations are pretty simple. For example: (transportation) If you have two bridges across your local body of water (river, lake, bay) and you have to close one of them for the weekend to do repair work, you would be interested in knowing if the other one will be congested. So, you make up a really simple equation based on what you know. Demand = Normal hourly demand on bridge 1 + normal hourly demand on bridge 2 If Demand exceeds capacity on the open bridge, you have problems! See, I told you it would be simple.. The next step would be to quantify how much excess demand you have, estimate average delays, expected diversion rates and develop alternate routes. Another example: If you have a uniform distributed wind load of X, and a cross sectional area of Y, then the force (F) on a sign will be X*Y and can be treated as though it was a point load at the sign's centroid. Assuming that the sign is symmetrical and supported from the middle, The bending load /bending moment (or overturning moment) at the base of the sign is H*F and you'd better be sure that whatever post you are putting it on can hold it up when the wind blows. (and yes, 90% of the time you just look at the table that says "use a 4x4 wood post for signs between this area and this area") But when you have a structure that was put in place 10 years ago that you now want to replace the signs with some that are larger (to save the $200,000 a new signbridge would cost) you do the math yourself and then plug it into your software.