Design of 24 & 30 inch pipe struts 2

[jdonville]

The project specifications for a braced excavation support structure require that we prestress the excavation strut members that are in excess of 50ft in length to 50% of the design load. We have determined that pipe sections of 24 and 30 inch diameters @ fy=42ksi will be suitable for use as the struts. We will be using welded-on flange plates with holes to bolt up to 40ft pipe sections together.

How would you prestress the strut in-place? We have thrown around several ideas, without a very satisfactory conclusion. Any suggestions or help appreciated. Sketches would also be appreciated.

J

 

[dgkhan]

http://www.deepexcavation.com/braced_excavations_struts_crosslot.htm

 

[PEinc]

Check your e-mail.

http://www.PeirceEngineering.com

 

[jdonville]

Thanks to you both. I believe that we can work up a feasible solution from here.

J

 

[dcarr82775]

Design one end of the strut so that you can install a flat jack of sufficient capacity to preload the pipe. Then either shim or grout it solid. We have done it multiple times.