Pipe Deflection

This depends on the spans and the bore spacer locations within the spans but provided that there was a bore spacer at the center of the span, the combination would be correct, the load would be shared in proportion to the Moments of Inertia. If the spacers were not on center span, the the deflection would be smaller by a negligable amount.

The objective is we want to achieve as much deflection as practical without sacrificing the integrity of the pipe. We have control of where the bore spacers are located. We are boring under a railroad and want to come up to a more practical depth as soon as we get out of the bore casing under the railroad.

The piping going into the bore is a double wall pipe 6" in the middle and 10" as the outer wall pipe, we haven't determined our method of bore spacing for the pull/tug yet, we however, have kicked some various ideas around.

Thanks for the input

P.I.

My best estimate (WITHOUT CALCULATING) is the deflection of the assembly under uniform loading ( assembly weight in open spans )will be determined by the SUM of the bending resistances calculated for each for the two pipes (neglecting the coating). The spacers every 6.6 feet will effective couple the two pipes. However, crush strength from weight on supports or overburden/trench fill is strictly outer pipe limited.