- #1
curious_iza
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Hi I have tried this question and am struggling to work it out;
A concrete concrete tunnel with 2m x 2m dimensions on the outside (in cross section) with a uniform wall thickness of 200mm, is used to support a live load of 4kN/m^2 on its top surface. The density of the concrete is 25kN/m^3. The structure has 4 supports.
a) Calculate the dead load (G) and live load (Q) along its length in kN/m.
b) Calculate the ultimate state design load in kN/m of the concrete tunnel by applying the appropriate load factors of 1.2 and 1.5.
Obviously I have do work...
1) I got the cross section of the area which worked out to be 4m^2...
2) I then worked out the 'hollow' part since the thickness is only 200mm I got the 'empty' area as (2 - 0.2 -0.2)^2 = 2.56.
3) I subtracted this to get the actual cross section of the concrete.
4) I then made the length of the beam = Lm. And using the cross section and the Lm length I multiplied the cross section by the length to get the volume. Since density was given I multiplied volume by density and got 36L kN/m.
5) I then divided by L to get the force per m...
I don't know if I did all above right ... if so how do I tackle this question!
Thankyou for your time.
Kind regards, Isabelle
A concrete concrete tunnel with 2m x 2m dimensions on the outside (in cross section) with a uniform wall thickness of 200mm, is used to support a live load of 4kN/m^2 on its top surface. The density of the concrete is 25kN/m^3. The structure has 4 supports.
a) Calculate the dead load (G) and live load (Q) along its length in kN/m.
b) Calculate the ultimate state design load in kN/m of the concrete tunnel by applying the appropriate load factors of 1.2 and 1.5.
Obviously I have do work...
1) I got the cross section of the area which worked out to be 4m^2...
2) I then worked out the 'hollow' part since the thickness is only 200mm I got the 'empty' area as (2 - 0.2 -0.2)^2 = 2.56.
3) I subtracted this to get the actual cross section of the concrete.
4) I then made the length of the beam = Lm. And using the cross section and the Lm length I multiplied the cross section by the length to get the volume. Since density was given I multiplied volume by density and got 36L kN/m.
5) I then divided by L to get the force per m...
I don't know if I did all above right ... if so how do I tackle this question!
Thankyou for your time.
Kind regards, Isabelle
