Abstract

Introduction

This report presents the theory that was used to determine influence lines for statically

indeterminate structures, and the use of the influence lines to determine reactions and moments

in a structure. The apparatus and methodology used for the experiment are described. The

experimental results are then presented and analyzed in comparison to the theoretical

calculations. Conclusions with regards to the experiment’s correlation with theoretical

computation of influence lines are then drawn.

Theory

The Muller-Breslau principle and the principle of virtual work were used to determine the

influence lines for the pin-ended and fixed-ended arches. Muller-Breslau principle states that the

influence line for a variable of interest is to some scale the deflected shape of the structure when

the constraint (e.g. reaction) is removed and its conjugate is applied to the structure. The value of

the influence line of the variable of interest at any point is given by;

Ri=δX

δB

The displacements were calculated using the Principle of Virtual Work as,

δ=muMp

EI dx

where mu = unit moment applied to virtual system, Mp = applied moment to real system, EI =

flexural rigidity of the material.

The theoretical bending moment diagram for the rigid-jointed portal frame was obtained using

Prokon frame analysis.

Apparatus

Methodology

Results and Discussion

Conclusion

LAB 4 - experiment 4 report

Structural Engineering IA (CIVN3014)