- Why Bridges Don’t Sink (practical.engineering)
The essence of a bridge is not just that it goes over something, but that there’s clear space underneath for a river, railway, or road. Maybe this is already obvious to you, but bridges present a unique structural challenge. In a regular road, the forces are transferred directly into the ground. On a bridge, all those forces on the span get concentrated into the piers or abutments on either side. Because of that, bridge substructures are among the strongest engineered systems on the planet. And yet, bridge foundations are built in some of the least ideal places for heavy loading. Rivers and oceans have soft, mucky soils that can’t hold much weight. Plus, obviously, a lot of them are underwater.
Stanford Encyclopedia of Philosophy
- Algebra (plato.standford.edu)
Algebra is a branch of mathematics sibling to geometry, analysis (calculus), number theory, combinatorics, etc. Although algebra has its roots in numerical domains such as the reals and the complex numbers, in its full generality it differs from its siblings in serving no specific mathematical domain. Whereas geometry treats spatial entities, analysis continuous variation, number theory integer arithmetic, and combinatorics discrete structures, algebra is equally applicable to all these and other mathematical domains.
- Algebra (Wikipedia)
Algebra is the branch of mathematics that studies algebraic structures and the manipulation of statements within those structures. It is a generalization of arithmetic that introduces variables and algebraic operations other than the standard arithmetic operations such as addition and multiplication.