Preformed manhole base section construction

In a prefabricated concrete unitary manhole base section for providing access to and connection of a plurality of standard subterranean drainpipe conduit at the location thereof, said section having at least one inlet and one outflow, interior structure defining a flow channel from each inlet to the outflow, and annular flange means at periphery of the top of said section for engaging a cylindrical concrete pipe section thereon, the improvement comprising:

• a polygonal exterior wall structure having a thickness greater than said annular flange means and a plurality of substantially vertical faces with each face aligned in a different direction than the other faces;
• said outflow being a substantially cylindrical lateral opening provided at one of said faces and defined by and extending through said exterior wall structure;
• at least one of said inlets being a substantially cylindrical lateral opening provided at another of said faces and defined by and extending through said exterior wall structure, said other face being at least at right angles to said face having said outflow opening therein;
• each of said openings being sized and shaped to receive an end portion of a said standard drainpipe conduit directly in a secure closely fitting engagement therewithin;
• resilient sealing means compressed between each said opening and said end portion therein for providing a watertight seal therebetween.