COMBINED AXIAL AND BENDING

https://www.mesubjects.net/wp-admin/post.php?post=2310&action=edit                Q. Ans. Simple stresses-1

https://www.mesubjects.net/wp-admin/post.php?post=6112&action=edit                 Q. Ans. simple stresses-2

https://www.mesubjects.net/wp-admin/post.php?post=7658&action=edit                MCQ Simple stresses

https://www.mesubjects.net/wp-admin/post.php?post=6335&action=edit            Question bank simple stresses & strains

https://www.mesubjects.net/wp-admin/post.php?post=6333&action=edit             Formulas simple stresses Simple strains

https://www.mesubjects.net/wp-admin/post.php?post=3503&action=edit              Q. ANs on bending

https://www.mesubjects.net/wp-admin/post.php?post=3454&action=edit                Bending stresses-2

 

COMBINED AXIAL AND BENDING

It is applicable for a beam column. A beam carries transverse loads (bending loads) and a column carries an axial compressive load. Examples of beam column are chimneys, dams, retaining wall, trees, poles and building structures. Axial compressive load is due to the self weight and the bending is due to the wind affect.

STRESSES IN A BEAM COLUMN

(i) Axial stresses are compressive stresses of CONSTANT value, σA =W/A

(ii) Bending stresses are both simultaneously tensile and compressive stresses and are of VARYING values

σb = (M/I) y

(iii) Maximum compressive stress      σmax =  σA + σb

(iv)Maximum tensile stress σmax =  σb – σA i.e. tensile stress is there only if σb > σA.

There are three possible cases

Case 1   σb > σA

σmax =  σA + σb  Compressive

σmax =  σb – σA   Tensile

Neutral axis will not coincide with the centroid axis. Neutral axis is towards compressive fibers.

Case 2  If   σb = σA

σmax =  σA + σb  Compressive

σmax =  σb – σA = 0 

Neutral axis will coincide with the centroid axis. 

Case 3   σb < σA

σmax =  σA + σb  Compressive

σmax =  σb – σA  Compressive

Neutral axis will not coincide with the centroid axis. Neutral axis will be towards tensile fibers.