A precast concrete manhole structure features a twenty-four inch diameter heavy-duty lid and ring with a solid traffic-rated cover set within a concrete collar in paved areas. Grade rings of variable thickness support the heavy-duty lid and ring assembly above a standard H-twenty concrete lid. The precast structure varies from four to six feet in diameter and rests on an eight-inch base course compacted to ninety-six percent per ASTM D-one thousand five hundred fifty-seven. Precast riser sections are joined using joint mastic at horizontal joints. The bottom of the manhole includes a mortar shelf constructed with a slope of one and one-half inches in twelve inches over a channel where the upper one-third of the pipe within the manhole is removed.
Members view this detail in full resolution, download the CAD files (SVG, PDF), and can adapt it in the built-in CAD editor — export DXF, DWG, or PDF.
Start membership