Tek-Tips is the largest IT community on the Internet today!

Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!

  • Congratulations TugboatEng on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Different approach

Status
Not open for further replies.

Bert2

Mechanical
Joined
Feb 17, 2010
Messages
80
Location
GB
I have a question regarding cast in situ bridge girders relative to a load imposed considering pre-tensioning and ultimate elongation of strands.

Specific details;

Length of span = 30M
Grade of Strands = 270k / 0.6”
Pre tension imposed = 19500kg / Strand
Neglect compression effects of concrete girder.
Load = UDL of 270Te (270000Kg)
Neglect any Dynamic inputs – only consider as a static load.

I’am aware of AASHTO std however using Hooke’s law principles is there a way to calculate Sigma / Epsilon / x elongation; given the pre-load applied..? guess it won’t be as simple as to ‘-‘ the pre-load off the imposed load…

Thanks for any replies! – I know it’s a bit different.
 
I guess you could do a deflection based on load and obtain the equation of that curvature. Then the elongation would be the arc length of that geometry less the length of the undeflected member. This is the classical approach to beam design taught in static courses with a little bit of calculus.

Regards,
Cockroach
 
Status
Not open for further replies.

Part and Inventory Search

Sponsor

Back
Top