Beam analysis calculators from AccessEngineering
These Excel workbooks (in SI and US units) calculate maximum values, plots and tables of beam deflections, shear, and moments. The external reactions acting on the beam are also calculated. The user specifies beam length, load (concentrated forces, distributed forces, and concentrated moments) values and positions, and elastic modulus, and results appear in clearly labeled output cells, tables, and plots.
Interactive graphs from AccessEngineering
AccessEngineering provides interactive graphs that allow users to enter data points in order to analyze structures. Interactive graphs are identified by this icon: 
Strength of materials calculators from Knovel
Knovel provides a number of interactive equations to analyze the strength of materials in bars, beams, columns, and shells. Sample equations are also provided.
Deformation calculators from Knovel
Knovel provides equations for failure and stress/strain, including sample equations.
Structural Engineering Calculators
These calculators are from buildersguide.com