Structure Design The Foundation of all RCP Attributes

Structure & Design The Foundation of all RCP Attributes Hank Gottschalk Concrete Pipe & Precast, LLC

Pipeline Functions What 2 functions must an underground pipe provide? Conduit Structure www. concrete-pipe. org 2

All Buried Pipelines… Are Structural Systems That Incorporate: The Properties of the Pipe The Properties of the Soil

All Buried Pipelines… Pipe Strength Allowable System Load = + Soil Strength

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Soil Strength Soil Type Soil Density (Compaction)

Soil / Pipe System Flexible pipe – embedment soil must carry most of the load. Flexible Stiff Dead load Live load Rigid pipe – the pipe carries the majority of the load. 7

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Reinforced Concrete Pipe n Structural System – RCP Pipe Wall = Majority of Strength § 60% - 90% of System Strength – Bedding & Haunch § 40% - 10% of System Strength Cover Pipe ID

Rigid Pipe Traffic Load Earth Load Final Backfill Loads Haunching Initial Backfill Bedding Foundation Supporting Strength

Flexible Pipe Traffic Load Earth Load Final Backfill Initial Backfill Haunching Bedding Foundation

Flexible Pipe • Structural System § Flexible Pipe Wall • 5% - 10% of System Strength § Structural Backfill Carries Majority of Load • 90% - 95% of System Strength Cover Pipe ID

Strength vs. Stiffness Rigid Pipe (i. e. Reinforced Concrete) • Strength: Designed to resist stress and transmit the loads on the pipe through the pipe walls to the foundation soil beneath. Flexible Pipe (i. e. HDPE) • Stiffness: Designed to transmit part of the load to the soil at the sides of the pipe and resist deflection. www. concrete-pipe. org

Concrete Pipe

Pipe Classification = Strength Options ASTM C-76 D 0. 01 Dult CLASS I 800 1, 200 CLASS II 1, 000 1, 500 CLASS III 1, 350 2, 000 CLASS IV 2, 000 3, 000 CLASS V 3, 000 3, 750

56, 000 lbs/ft/ft 42” Pipe (CL IV)

Pipe Strength – 48” Diameter – ASTM C 76 Class IV Class III D-0. 01 1350 D-Ult D-0. 01 2000 43, 200# 64, 000# D-Ult 3000 64, 000# 96, 000# f’c=4000 psi Class V D-0. 01 3000 D-Ult 3750 96, 000# 120, 000# f’c=6000 psi Asi=. 24 Asi=. 42 Asi=. 73 Aso=. 14 Aso=. 25 Aso=. 44 ASTM C 76 – Recipe Conc. + Wall Thickness + Steel Reinforcement for Each Size and Strength Class

Weak Pipe + Strong Soil or Strong Pipe + Soil / Pipe System Weak Soil 19

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Soil Properties: Composition • Soil is an aggregate of loose mineral and organic particles. • Rock exhibits strong and permanent cohesive forces between mineral particles. • Soil’s primary components are: • • Gravel Sand Silt Clay 23

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Standard Installations Bedding/Structural Embedment l l Type 1: Highest Quality installation using select granular soils with high compaction requirements for haunching and bedding. [A 1, A 3] Type 2: Allows silty granular soils with less compaction required for haunching and bedding. [A 2, A 4] Type 3: Allows use of soils with less stringent compaction requirements for haunching and bedding. [A 5, A 6] Type 4: Allows use of onsite native material for haunching and bedding with no compaction required. (6” of Bedding is required if rock foundation) Class II-A 1, A 3 TYPE 1 Class III-A 2, A 4 TYPE 2

Weak Pipe + Strong Soil or Strong Pipe + Soil / Pipe System Weak Soil 31

TOOLS - Calculate Required Pipe Strength n Blue book – Formulas n Fill height tables n Computer software – Pipe. Pac 2000 American Concrete Pipe Association www. concrete -pipe. org

Installation Type Trench Negative Positive Projecting Tunnel

Examples n 48” RCP – 18’ of fill (cover) –Class of pipe for Type 2 bedding

Examples n 48” RCP – 18’ of fill (cover) –Class of pipe for Type 4 bedding

Examples n 84” RCP - 30’ fill (cover) –Class of pipe for Type 1 bedding

Examples n 84” RCP - 30’ fill (cover) –Class of pipe for Type 3 bedding

Examples n 15” RCP - 5’ fill (cover) –Class of pipe for Type 2 bedding

Fill Height Design Tool Re-Cap n Fill Ht Tables: n Pros: – Fast & Easy – Can Provide Safe and conservative design If you know how to use and the limitations – Can use for most day to day designs n Cons: – Limited Live Load Application – Only one Installation Type = Embankment – Can be overly Conservative