![influence line structural analysis examples influence line structural analysis examples](https://image.slidesharecdn.com/influencelines-180824045855/95/influence-lines-structural-analysis-theories-86-638.jpg)
Many loads are distributed rather than concentrated. Rear axle, B, is three feet behind front axle, A, then the effect of A at x feet along the structure must be added to the effect of B at ( x – 3) feet along the structure-not the effect of B at x feet along the structure. For example, a truck load is applied to the structure. When adding the influence lines together, it is necessary to include the appropriate offsets due to the spacing of loads across the structure.
![influence line structural analysis examples influence line structural analysis examples](https://3.bp.blogspot.com/-MBIBeohq1UA/UtKFpqP9LwI/AAAAAAAACY0/KoJ5rM59LjQ/s1600/www.sut.ac.th_engineering_civil_courseonline_430331_pdf_06_InfluenceLineBeams_026.png)
In cases where multiple loads may be in effect, influence lines for the individual loads may be added together to obtain the total effect felt the structure bears at a given point. The scaled maximum and minimum are the critical magnitudes that must be designed for in the beam or truss. The entire influence line can be scaled, or just the maximum and minimum effects experienced along the line. To find the effect of any non-unit load on a structure, the ordinate results obtained by the influence line are multiplied by the magnitude of the actual load to be applied. This means that they can be used even when the load that will be applied is not a unit load or if there are multiple loads applied. Influence lines are both scalar and additive. The influence lines show where a load will create the maximum effect for any of the functions studied. Influence lines are important in designing beams and trusses used in bridges, crane rails, conveyor belts, floor girders, and other structures where loads will move along their span. Common functions studied with influence lines include reactions (forces that the structure’s supports must apply for the structure to remain static), shear, moment, and deflection (Deformation). felt in a structural member) at a specific point on a beam or truss caused by a unit load placed at any point along the structure. In engineering, an influence line graphs the variation of a function (such as the shear, moment etc. Its influence lines for four different functions: (b) the reaction at the left support (denoted A), (c) the reaction at the right support (denoted C), (d) one for shear at a point B along the beam, and (e) one for moment also at point B. Figure 1: (a) This simple supported beam is shown with a unit load placed a distance x from the left end.