IL of Reaction,shear,moment for indeterminate structure
Pre-stressed Concrete Lab.
Course Teacher: MR. GALIB & MS. SABRINA
Influence Line for Reaction ,Moment & Shear
for Indeterminate Structure
Md. Enamus Salahin.
Dept. of Civil Engineering
Ahsanullah University of Science &
An influence line is a plot of the magnitude of the resulting
reaction/axial force/shear/moment generated in a beam or
structure as a unit load travels across its length. Influence
lines can be generated for any of these actions
(reactions, axial forces, shears, or moments) in a structure.
* Dead loads are fixed in positions ---- Live loads can change their positions
* Our objective is to establish how to position live loads (a truck or a train) to maximize
the value of certain type
of force (Shear or moment in a beam or axial force in a truss) at a designated section of a
* To establish maximum design forces at critical sections produced by moving loads, we
METHODS FOR CONSTRUCTION OF INFLUENCE LINE
BRUTE FORCE METHOD[USES STATICS/MECHANICS TO CALCULATE THE
INTERNAL LOAD OR REACTION]
MULLER BRESLAU PRINCIPAL[DRAW INFLUENCE LINES BY APPLYING UNIT
****MULLER BRESLAU PRINCIPAL IS THE MOST GENERAL METHOD FOR
CONSTRUCTING INFLUENCE LINE DIAGRAMS.
TYPES OF STRUCTURE