In A 400mm x 650mm x 7.2m long prestressed concrete cantilever beam carries a concentrated livel oad of 18.68kN at free end and a uniform dead load due to its own weight. Unit weight of concrete is2 5kN/m3. The strands are 12 mm in.-diameter with total prestressing force of 550.23kN applied at an eccentricity “e” above the neutral axis of the gross section. a. What is the maximum stress in the bottom fiber of the beam at free end when the eccentricity e =0, in MPa? Use Basic Concept Method. b. What is the maximum stress in the top fiber of the beam at the fixed end when the eccentricity e =120mm, in MPa? Use C-line Method. c. What is the required eccentricity e such that the stress in the top fiber of the beam at the fixed end is zero, in mm? Use Load-balancing Method.
In A 400mm x 650mm x 7.2m long prestressed concrete cantilever beam carries a concentrated livel oad of 18.68kN at free end and a uniform dead load due to its own weight. Unit weight of concrete is2 5kN/m3. The strands are 12 mm in.-diameter with total prestressing force of 550.23kN applied at an eccentricity “e” above the neutral axis of the gross section.
a. What is the maximum stress in the bottom fiber of the beam at free end when the eccentricity e =0, in MPa? Use Basic Concept Method.
b. What is the maximum stress in the top fiber of the beam at the fixed end when the eccentricity e =120mm, in MPa? Use C-line Method.
c. What is the required eccentricity e such that the stress in the top fiber of the beam at the fixed end is zero, in mm? Use Load-balancing Method.
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