1AFTHAP m2 10.03

Luis A. Agudo Fernández

AFTHAP CONFERENCE www.afthap.com

REINFORCED AND PRESTRESSED CONCRETE PIPE, STEEL CYLINDER TYPE

Module 2:Structural designHydraulic design

Protection measures in special cases

Pressure› Steady state, design pressure (DP)› Transient. Maximum design pressure (MDP)› System test pressure (STP)› Factory test pressure (PP)

External loads› Steady, earths› Accidental, traffic› Special, tunnels, footings, and so.

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Actions

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Support conditions

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Example 1, gravity pipeline

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Example 2, forced main

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Trench, compacted or non-compacted

Negative projection embankment

Embankment

Types of installation - Marston

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Live - traffic

Tunnel excavation Footings loads Other loads

The software allows to replace the load calculated according to Marston by a surface load calculated by any other method (i.e. in the case of tunnels)

Really local loads, such as footings, are usually solved by filling the trench with concrete in the involved area.

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Special loads

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Maximim design pressure (MDP) + dead loads

Design pressure (DP) + dead loads + live loads

Factory test pressure (PP)

System test pressure (STP) + dead loads corresponding to 1 m of earth height

Pressure zero + dead loads + live loads

DESIGN HYPOTHESIS reinforced concrete:the allowable stresses will not be exceeded (2/3 Elastic Limit) in the following design hypothesis

Hypothesis Stress in core

Design Pressure DP + dead loads ≥0.5 Mp

Max Design Pressure MDP+0.1 Mp + dead loads ≤ fct,k

Design Pressure DP + dead loads + live loads ≥0.0 Mp

Max Design Pressure MDP ≥0.5 Mp

Factory Test Pressure PP ≥0.5 Mp

System Test Pressure + 1 m tierra ≥0.5 Mp

Dead + Live loads, without pressure ≥0.5 Mp

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• During the manufacturing and evolution of the prestressed concrete the allowable values of compressive and tensile strengths in the active reinforcement will not be exceeded

Prestressed concrete

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Diameter 1200, the biggest of the following values:

Diameter > 1200, the biggest of the following values:

Maximum design pressure (MDP) + 0.2 Mpa

PMaximum design pressure (MDP) + 0.1 Mpa

1.2 times the maximum design pressure (MDP)

1.2 times the maximum design pressure (MDP)

FACTORY TEST PRESSURE (PP)Reinforced concrete steel cylinder type

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Pressure that produces a stress of – 0.5 MPa on the pipe wall

FACTORY TEST PRESSURE (PP)Prestressed concrete steel cylinder type

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CALCULATED

Water Hammer

NOT CALCULATED

Water hammerthe LOWER of the following values

Maximim design pressure (MDPc) + 100 kPa

1.5 * Maximum design pressure (MDPa)

Maximum design pressure (MDPa) + 500 kPa

System test pressure (STP)

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It can be free downloaded from › www.afthap.com

For any doubts regarding the use of the software, please contact the association through our web site

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Software for pipes design

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Hydraulic design

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Author Year

Manning 1890

Scimemi 1925

Hazen-Williams 1905

Meyer-Peter ~ 1930

Ludin ~ 1920

Scobey 1931

Darcy - Weisbach 1775

Colebrook 1939

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Anachronisms of the correlations• Short pipes, more joints (2.5 m against current 6-7)• Worse quality concretes• Tests for small diameters

TIME LINE

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Aggressive enviroments Aggressive fluids to be carried Low-resistivity soils Stray currents

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Extraordinary protection measures

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The discontinuity of the elastic joint makes currents circulation difficult and benefits the pipe (IET 07 2.4 appendixe 3)