Load Factors for Concrete Wall Pipe Penetrations With a Wall Mounted Welded Plate

The bending moments imposed on welded plate anchors that are part of embedded pipe wall penetrations are often overestimated in the structural evaluations of these penetrations. For this type of restraint, the pipe is embedded in a concrete wall penetration with a welded plate mounted on the surface of the wall. This penetration is typically modeled with a single 6 degree of freedom (DOF) restraint at the plate in the pipe stress analysis. This approach can lead to overestimated loads on the welded plate and the mounting anchor bolts because no credit is taken for reaction on the embedded portion of the pipe. A significant portion of the bending moments from piping on both sides of the penetration is transferred directly to the concrete wall by the normal reaction on a fully grouted pipe, thus reducing loads on the steel plate and the mounting anchored bolts. The objective of this study is to determine load factors for bending moments from both sides of the pipe penetration on the anchored steel plate. A parametric study is performed using ANSYS models of a pipe fully embedded in a concrete wall penetration with a welded plate mounted on one side of the wall by anchor bolts. Various pipe diameters, concrete wall thicknesses and plate thicknesses are considered. For each model, the loading on the plate is compared to the loading applied at the free end of the pipe. Load factors are developed for use in the structural evaluation of the welded plate and the mounting anchor bolts. The maximum compressive bearing pressure at the concrete wall is also calculated for use in the structural evaluation of these types of pipe supports.