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anthonyk2013

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A cast iron pipe is filled with concrete and used as a column to support a load

Take E for concrete as one tenth that of cast iron.

σ

Area of concrete is 3.14*150

Area of pipe is 3.14*200

σ

σ

σ

σ

σ

F=F

F=σ

F=(.5*10

F=8835.5*10

F=77555.5N*10

F=77555.5N/9.81=7905kg=7.9tons

**W**.If the outside diameter of the pipe is 200mm and the inside diameter is 150mm, what is the maximum permissible value for**W**if the compressive stress in the concrete is limited to 5 KN/m^{2}.Take E for concrete as one tenth that of cast iron.

σ

_{c}=5KN/m^{2}Area of concrete is 3.14*150

^{2}/4=17671*10^{-3}mm^{2}Area of pipe is 3.14*200

^{2}/4=31415-17671=13744*10^{-3}mm^{2}σ

_{p}/E_{p}=σ_{c}/E_{c}σ

_{p}=σ_{c}*.1N**E of concrete one tenth that of cast iron=.1**σ

_{p}=σ_{c}*.1Nσ

_{p}=5*10^{6}N*.1Nσ

_{p}=.5*10^{6}NF=F

_{c}+F_{p}F=σ

_{p}*A_{p}+σ_{c}*A_{c}F=(.5*10

^{6}N*17771*10^{-3}mm)+(5*10^{6}N*13744*10^{-3}MM^{2})F=8835.5*10

^{3}N+68720*10^{3}NF=77555.5N*10

^{6}F=77555.5N/9.81=7905kg=7.9tons

**The answer in my notes is 79tons, where have I gone wrong with my decimal point**
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