- #1

anthonyk2013

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**20t**. The overall cross section area of the column is 0.1m^2 and the steel bars accounts for 3% of this area.

Find the stress in the concrete

If the length is 4m< how much does it shorten.

E of steel 200GN/m^2

E of concrete 20 GN/m^2

Load=20*1000=20000*9.81=196200 or 19.6*10^4

Area of concrete =.1*97%/100=.097m^2

Area of steel=.1*3%/100=.003m^2

Area of concrete=.1*97%/100=.097m^2

steel=s

concrete=c

σs/Es=σc/Ec→σs=σc*Es/Ec→σs=σc*200/20→

**σs=10*σc**

F=σs*As+σc*Ac

19.6*10^4=(10*σc*.003)+(σc*.097)

19.6*10^4=σc(10*.003+.097)

19.6*10^4=σc(.127)

19.6/.127=154.3*10^4

**σc=154.3*10^4**

**My question is, the answer I have in my notes is 1.54MN/m^2. Why is my decimal point wrong?**