
What is STATICS
"mechanics dealing with the relationship of forces that produce equilibrium among material bodies"

State of Equilibrium
 There are no unbalanced forces acting on the structure
 The sum of all external and internal forces must equal zero
 If the sum does not equal zero then movement exists


Vectors in Statics
 Forces expressed as vectors
 Vector has two components, magnitude (6k, 15lbs, etc) and direction (vertical, horizontal, 60 degrees)

Simply Supported Beam, single span beam supported at each end, shear connection

Free Body Diagram
 Beam, loads and reactions drawn as isolated "free body"
 Shown with a uniformly distributed load
 Other load types include; varying, concentrated and movement
 Supports replaced with reactions (R)

Shear Diagram
 Shear stresses in the Y direction, vertical shear (V) are graphically represented
 Shear stress is greatest at the supports
 Shear stress is zero at midspan

Moment Diagram
 Moments  bending stresses  graphically represented
 Moment stress is zero at the reactions
 Moment is greatest at mid span

Moment Diagram
 Interestingly, the shape of this diagram is the same as that of the formactive shape for a distributed load. This indicates that the intensity of the bendingtype internal force (bending moment) at any crosssection is directly proportional to the distance of the crosssection from the equivalent point on the formactive shape.


