Deformation, stress, and strain problem.

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SUMMARY

The forum discussion focuses on the analysis of a 24-inch diameter concrete column subjected to a wind uplift load of 50 kips and a factored compressive force of 120 kips. The column, 10 feet long, has a concrete elasticity of 4200 ksi, with ultimate compressive and tensile strengths of 2.400 ksi and 0.2000 ksi, respectively. Key calculations include axial compressive stress (0.2653 ksi), axial tensile stress (0.1105 ksi), and net stress (0.1547 ksi). The discussion emphasizes the need to calculate deformation, strain, and the factor of safety to determine if the column can safely support the roof slab.

PREREQUISITES
  • Understanding of axial stress calculations in structural engineering
  • Knowledge of concrete material properties, including elasticity and strength
  • Familiarity with deformation and strain formulas for structural members
  • Ability to assess factors of safety in structural design
NEXT STEPS
  • Research formulas for calculating deformation and strain in concrete columns under axial loads
  • Study the concept of net stress and its implications in structural safety
  • Learn how to compare actual ultimate stresses to allowable ultimate stresses for safety assessments
  • Explore software tools for structural analysis, such as SAP2000 or ETABS
USEFUL FOR

Civil engineers, structural designers, and students studying structural analysis who need to understand the behavior of concrete columns under various loads.

vac
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Homework Statement


A 24in diameter concrete column, at tenth story of an office building, is supporting the flat roof slab is subjected to a wind uplift load of 50.00kips while carrying a factored
compressive force of 120.0kips. the column is 10.00ft long. Assume elasticity of concrete
to be 4200ksi and the ultimate compressive and ultimate tensile strength as 2.400kis and 0.2000ksi respectively. Determine:


Diameter: 24 in
Wind uplift load: 50 kips
Compressive force: 120 kips
Colums length: 10 ft
Concrete elasticity: 4200 ksi

Area (A): 452.39 in^2


Homework Equations


a) The axial compressive stress from compressive force only
b) The axial tensile stress from wind action only
c) The net stress
d) The deformation of the column
e) The strain in the column
f) The factor of safety? Is the column safe? Check whether the roof is carried away or not?


The Attempt at a Solution


A = 0.2653 ksi
B = 0.1105 ksi
C = 0.1547 ksi

Sorry, but I am not sure if my answers are correct.
Also I don't know how to solve d, e, and f.

Thanks in advance.
 
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vac said:

Homework Statement


A 24in diameter concrete column, at tenth story of an office building, is supporting the flat roof slab is subjected to a wind uplift load of 50.00kips while carrying a factored
compressive force of 120.0kips. the column is 10.00ft long. Assume elasticity of concrete
to be 4200ksi and the ultimate compressive and ultimate tensile strength as 2.400kis and 0.2000ksi respectively. Determine:


Diameter: 24 in
Wind uplift load: 50 kips
Compressive force: 120 kips
Colums length: 10 ft
Concrete elasticity: 4200 ksi

Area (A): 452.39 in^2


Homework Equations


a) The axial compressive stress from compressive force only
b) The axial tensile stress from wind action only
c) The net stress
d) The deformation of the column
e) The strain in the column
f) The factor of safety? Is the column safe? Check whether the roof is carried away or not?


The Attempt at a Solution


A = 0.2653 ksi
B = 0.1105 ksi
C = 0.1547 ksi

Sorry, but I am not sure if my answers are correct.
Also I don't know how to solve d, e, and f.

Thanks in advance.
Your answers A and B look good, also C, but you should indicate for C whether net stress is compression or tension.

For deformation and strain, there are formulas you should look up for members under axial tensile or compressive loads.

For F, compare actual ultimate stresses to allowabale ultimate stresses to see if the column is safe.
 

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