Structural Adequacy Of Existing Pipe Sleepers & Structural Bridges

To check the adequacy of existing pipe sleepers and structural grid for the inclusion of new 20” MEG line, which travels over 700 meters in the loading arm and CTMS Metering Skid. The inlet line paves from PIG LAUNCHER AREA – AG/UG interface to the Custodial Metering Skid ranges 350 meters. The Outlet line paves parallel to inlet pipe which has a length of 350 meters which travels to Loading Arm area. The line routed along with other existing lines in same pipe sleepers, cross over bridge and structural supports. Therefore, to check the adequacy of existing sleeper, structural bridge and support location along with existing and as well new loads on it.

The Design Assumptions are made to check the adequacy of existing sleeper and structural bridge as follows,

  • To check the adequacy of existing sleeper and structural bridge or structural support location along with existing and new loads on it, we have done with structural modelling software and typical sleepers load calculation (manual) using macros developed internally.
  • The operating temperature of all existing / new lines on structure / sleepers is assumed to be close to the ambient temperature. Thermal expansion loads are assumed to be insignificant.
  • It is assumed that no anchor or partial anchor supports are provided for the existing / new lines on the structures / sleepers.
  • It is assumed that guides, if any, are provided with adequate gaps so that the guide loads in operating condition are less than the frictional loads.
  • It is assumed that all lines are bare lines and no insulation loads are considered.
  • Pipe wall thickness of lines are considered as per PMS.

The analysis and design as per IS 800 codal provision using software has been carried out for Pipe Bridge portion with piping loads and for pipe sleeper’s location we have done with manual calculations developed internally using macros.

From the analysis it is found that, actual stress ratios of existing members are safe except at few existing members’ location where the utilization ratio is marginally on higher side. We have provided solution for those selected members by means of either provision of strengthening plates or bracing to existing vertical members in order to adequately support the new pipe loads.

From the serviceability and stability point of view the pipe bridge structure found to be satisfactory and the utilization ratio of the existing beam along Grid for the proposed bracing arrangement is found safe. Hence it is concluded that impact of 20” MEG new pipe loads on the pipe bridge is safer and hence it is confirmed that Pipe Bridge or structural support location is found safe and adequate for 20” MEG new piping loads with the inclusion of new arrangement.

From the calculation, it’s found that the prevailing pipe sleeper locations are adequate for the extra piping loads for new line (20” MEG Line) with no modifications on sleeper area.