A beam with a wide-flange cross section (see figure) has the following dimensions: b = 5 in., t = 0.5 in,, ft = 12 in., and /?, = 10.5 in. The beam is simply supported with span length L = 10 ft and supports a uniform load q = 6 kips/fL
Calculate the principal stresses *rl and
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3 ft from the left-hand support at each of the following locations: (a) the bottom of the beam, (b) the bottom of the web, and (c) the neutral axis
(a).
Find principal stresses and maximum shear stress at top of beam.
Answer to Problem 8.4.15P
Principal stresses
Maximum shear stress
Explanation of Solution
Given Information:
Beam length
Uniform load
Concept Used:
Bending stress
Shear stress
Principal normal stresses
Maximum shear stress
So bending moment at point
Shear force at point
Moment of inertia,
First moment of area at the top of beam shall be zero,
So bending stress at top,
And shear stress at that point,
For this situation no stress in
Principal normal stresses are given by following equation,
Maximum shear stress,
Conclusion:
Hence we get,
Principal stresses
Maximum shear stress
(b).
Find principal stresses and maximum shear stress at top of web.
Answer to Problem 8.4.15P
Principal stresses
Maximum shear stress
Explanation of Solution
Given Information:
Beam length
Uniform load
Concept Used:
Bending stress
Shear stress
Principal normal stresses
Maximum shear stress
So bending moment at point
Shear force at point
Moment of inertia,
First moment of area of flange,
So bending stress at top of web,
And shear stress at that point,
For this situation no stress in
Principal normal stresses are given by following equation,
Maximum shear stress,
Conclusion:
Hence we get,
Principal stresses
Maximum shear stress
(c).
Find principal stresses and maximum shear stress at neutral axis.
Answer to Problem 8.4.15P
Principal stresses
Maximum shear stress
Explanation of Solution
Given Information:
Beam length
Uniform load
Concept Used:
Bending stress
Shear stress
Principal normal stresses
Maximum shear stress
So bending moment at point
Shear force at point
Moment of inertia,
First moment of area for the section above the neutral axis,
So bending stress at neutral axis,
And shear stress at that point,
For this situation no stress in
Principal normal stresses are given by following equation,
Maximum shear stress,
Conclusion:
Hence we get,
Principal stresses
Maximum shear stress
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Chapter 8 Solutions
Mechanics of Materials - Text Only (Looseleaf)
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