- #1
daphnelee-mh
- 62
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I am confused why positive value of bending moment is plotted under the axis?
Question about plotting a Bending Moment Diagram
- Context: Engineering
- Thread starter daphnelee-mh
- Start date
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SUMMARY
The discussion clarifies that in structural engineering, particularly in concrete design, the convention dictates that positive bending moments are plotted below the axis on the tension side of a member. This practice simplifies the analysis of frames and clearly indicates the deformation shape. It also provides guidance on rebar placement, as concrete is weak in tension. The references to Wikipedia articles on bending moments and shear and moment diagrams reinforce these conventions.
PREREQUISITES- Understanding of structural engineering principles
- Familiarity with bending moment diagrams
- Knowledge of concrete design conventions
- Basic grasp of rebar placement in structural members
- Research the principles of bending moment diagrams in structural analysis
- Study the role of rebar in concrete design and its placement strategies
- Explore the differences between positive and negative bending moments
- Learn about software tools for structural analysis, such as SAP2000 or ETABS
Structural engineers, civil engineering students, and professionals involved in concrete design and analysis will benefit from this discussion.
I am confused why positive value of bending moment is plotted under the axis?
- #2
Lnewqban
Homework Helper
Gold Member
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It is just a convention.
Please, see:
https://en.m.wikipedia.org/wiki/Bending_moment
https://en.m.wikipedia.org/wiki/Shear_and_moment_diagram
"In structural engineering and in particular concrete design the positive moment is drawn on the tension side of the member. This convention puts the positive moment below the beam described above. A convention of placing moment diagram on the tension side allows for frames to be dealt with more easily and clearly. Additionally placing the moment on the tension side of the member shows the general shape of the deformation and indicates on which side of a concrete member rebar should be placed, as concrete is weak in tension."
Please, see:
https://en.m.wikipedia.org/wiki/Bending_moment
https://en.m.wikipedia.org/wiki/Shear_and_moment_diagram
"In structural engineering and in particular concrete design the positive moment is drawn on the tension side of the member. This convention puts the positive moment below the beam described above. A convention of placing moment diagram on the tension side allows for frames to be dealt with more easily and clearly. Additionally placing the moment on the tension side of the member shows the general shape of the deformation and indicates on which side of a concrete member rebar should be placed, as concrete is weak in tension."
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