1968 CONCRETE PIPE NEWS

DESIGN OF A NON-PRESSURE SEWERAGE SYSTEM REQUIRES SELECTION OF ADEQUATELY SIZED PIPE TO CARRY MAXIMUM PREDICTED FLOW, AT A GIVEN SLOPE, WITHOUT FLOODING. A COMPARISON OF PIPE DIAMETER WITH DIFFERENT SURFACE ROUGHNESS COEFFICIENTS IS AN IMPORTANT DESIGN CONSIDERATION FOR EQUIVALENT FLOW CAPACITY. THE MANNING FORMULA IS PRESENTED WITH RECOMMENDED VALUES OF ROUGHNESS COEFFICIENTS FOR ALL SMOOTH-WALLED PIPE AND CORRUGATED METAL PIPE. THE EQUATION IS SIMPLIFIED TO ILLUSTRATE THAT THE RELATIVE PIPE SIZES ARE DEPENDENT ON THE RATIO OF THE RESPECTIVE ROUGHNESS COEFFICIENTS. THE EQUATIONS ARE PRESENTED FOR COMPARING RELATIVE PIPE SIZES. AN EXAMPLE IS PRESENTED SHOWING DIRECT COMPARISON OF REQUIRED CORRUGATED METAL PIPE SIZES TO ASSURE THAT THE HYDRAULIC CAPACITY IS AT LEAST EQUIVALENT TO CONCRETE OR OTHER SMOOTH-WALLED PIPE. DESIGN DATA ARE PRESENTED TO DETERMINE LIVE LOAD ON CONCRETE PIPE CULVERTS FOR: LIVE LOAD DISTRIBUTIONS FOR VARIOUS HEIGHTS OF COVER, AND LIVE LOAD PRESSURE DISTRIBUTIONS ON UNDERGROUND CONDUITS. INPACT FACTORS ARE DESCRIBED AND DISCUSSED FOR TRAFFIC LOADS. THE MOST WIDELY ACCEPTED FORMULA FOR EVALUATING THE HYDRAULIC CAPACITY OF NON-PRESSURE SEWERS IS THE MANNING FORMULA. THE FORMULA IS EXPRESSED TO SELECT A SEWAGE SIZE FOR A GIVEN DESIGN FLOW AND PIPE SLOPE. TABLES ARE PRESENTED GIVING VALUES FOR: THE ROUGHNESS COEFFICIENT, CIRCULAR CONCRETE AND CORRUGATED METAL PIPE, HORIZONTAL ELLIPTICAL CONCRETE PIPE, CONCRETE ARCH PIPE AND CORRUGATED METAL PIPE ARCH. THE FORMULA IS PRESENTED FOR CONCRETE PIPE SELECTION UNDER EARTH LOADS. THE LOAD TRANSMITTED TO A CONCRETE PIPE LINE INSTALLED IN A POSITIVE PROJECTING ENBANKMENT CONDITION CAN BE COMPUTED BY THE EQUATION. TABLES ARE PRESENTED FOR LOAD FACTORS FOR CIRCULAR PIPES, AND WEIGHTS OF PRISM OF FILL ABOVE THE PIPE FOR SOIL DENSITY OF 100 POUNDS PER CUBIC FOOT. DESIGN DATA ARE PRESENTED FOR CONCRETE PIPE SELECTIONS FOR TRENCH INSTALLATIONS. THE BACKFILL LOAD ON A CONDUIT INSTALLED IN A TRENCH CONDITION IS EQUAL TO THE WEIGHT OF THE MASS OF FILL MATERIAL WITHIN THE TRENCH LESS THE SUBMATION OF THE FRICTIONAL LOAD TRANSFERS. THE EQUATION IS PRESENTED BY WHICH THIS IS COMPUTED. TRENCH CONDUIT LOAD CHARTS ARE PRESENTED FOR THE FOLLOWING SOILS: SAND AND GRAVEL, SATURATED TOP SOIL, DRY CLAY AND WET CLAY. MEANS FOR CULVERT ANALYSIS ARE PRESENTED WHICH ENABLES THE SELECTION OF REQUIRED PIPE SIZE WITHIN THE PRACTICAL RANGES OF ALLOWABLE HEADWATER DEPTHS AND DESIGN DISCHARGES. THE MAJOR FACTORS AFFECTING THE HYDRAULIC CAPACITY OF A CULVERT ARE PRESENTED. EXAMPLES ARE PRESENTED FOR VARIOUS TYPE SIZES AND TYPES. STRUCTURAL DESIGN ANALYSIS IS PRESENTED OF A 96-INCH CONCRETE PIPE CULVERT WHICH HAD 230 FEET OF COVER ON TOP. THE STRUCTURAL DESIGN OF THIS CULVERT WAS NECESSITATED BY RELOCATION OF INTERSTATE FIVE THROUGH THE TEHACHAPI MTS. IN CALIFORNIA.

  • Supplemental Notes:
    • Vol 20, No 1, 127 PP, FIGS, TABS, PHOTS
  • Publication Date: 1968

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  • Accession Number: 00204213
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Sep 2 1994 12:00AM