- #1
anthonyk2013
- 125
- 0
A concrete column is reinforced with steel bars and carries a load of 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?
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?