Assuming linear elastic bending with small deformations and planes perpendicular to the neutral axis remain plane after bending, then for a rectangular beam:
Moment = (Yield Stress)*(Second Moment of Area)/(Distance of surface to Neutral Axis)
For Ultimate Bending Moment, assume stress is uniform throughout the beam, and acting through half the distance from surface to neutral axis, then:
Moment = Stress * (Area/2)*(h/4 + h/4)
For a better visualization check out Popov's textbook, Engineering Mechanics of Solids, Chapter 6, Section 6.10
The maximum bending moment is located at the point where shear is zero. This occurs because shear is the mathematical derivative of bending moment, and the maximum bending moment occurs when its derivative (i.e. Shear) is zero.
Steel I beams
Allowable stress would normally refer to design using Allowable Strength Design, also known as working strength design. In this the allowable stress is usually a fraction of the yield strength and can be different for uniform tension and bending. Typically mild steel has a yield strength of about fy=250MPa with allowable stresses in Tension, 0.6fy=150MPa Bending, 0.66fy=165MPa
The "W" in steel I-beam designations refers to wide-flanged beams. Most wide-flanged beams are symmetric about both the vertical and horizontal axes.
Elevator!
you may have 2 kinds of failures. there is the buckling and the bending. in the bending there is compression and tension, while in the buckling there i torsion and shear. if the beam is restrained but not stiffened you may have Lateral Torsional Buckling, but if it is restrained and stiffened throughout, then you will have Tension Field Action and this would result in a higher load durability.
Curtailment is optimizing steel w.r.t changes in Bending moment over a section
to prevent the beam from failing immediately when a crack occurs. If the ultimate resisting moment is less than the crcking moment the beam wold fail, but by putting a minimum percentage of steel i the concrete this can be avoided.
Structural steel members are the I-beams which consist second moments of area (moment of inertia of plane area), it allow them to be very stiff in respect to their cross-sectional area.
Steel I beams
bar cranking is the process of bending up the bottom steel bars in upward direction. it is mainly to prevent upward bending moment near the joint. also useful for attaching stirrup bar efectivly. cranking is also used in two way slabs
Steel is stronger than concrete. By adding some reinforcement in the compression zone of a beam, it's bending strength can be increased without increasing the size of the beam. The steel increases the compression strength, while the concrete prevents the slender steel bars from buckling.
composite deck
Allowable stress would normally refer to design using Allowable Strength Design, also known as working strength design. In this the allowable stress is usually a fraction of the yield strength and can be different for uniform tension and bending. Typically mild steel has a yield strength of about fy=250MPa with allowable stresses in Tension, 0.6fy=150MPa Bending, 0.66fy=165MPa
Among our handy steel beam tables you can find standard beams' dimensions and beams' weights, steel hollow sections tables and other steel profiles data.
As I would interpret the question, I would refer to the nature of reinforcing to be placed within the concrete. Often in large beams, the reinforcing steel may be made up separately in "cages" and set in place for the concrete pour. The reinforcing may be comprised of shear, bending, torsional, and specialized support components.
The "W" in steel I-beam designations refers to wide-flanged beams. Most wide-flanged beams are symmetric about both the vertical and horizontal axes.
Elevator!