How does the span between support points effect a simply supported beam when it is loaded?

Question

How does the span between support points effect a simply supported beam when it is loaded?

Answer 1

The shear, bending moment, deflection angle and deflection of a beam ( not just a simply supported beam but any beam with any other method of support) are functions of the length. These are given by the expressions:

V = SUM wdx

M = SUMVdx

EI A = SUM Mdx

EI D = SUM A dx

Where:

SUM means integral of

w = unit load

V = shear

M = bending moment

A = deflection angle

D = deflection

dx = element of length

E = the modulus of elasticity of the beam material

I = the moment of inertia of the beam cross-section

When the integration is performed, the span or unsupported length comes into play when the constant of integration is determined so that if maximum values are to be calculated, the resulting equations are expressed in the length of the unsupported span.

Answer 2

you will get deflection on the beam, this is ok as long as it is within safety limits, usually a percentage of  the span, this deflection will depend on whether the load is a point load or spread over the length & what beam you are using.

Answer 3

With a greater span (and therefore distance between the effective point of loading, and support), the bending moments are increased, and stress and strain in the beam is increased.