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The images below present embankment bedding class A for circular concrete pipe (both in inches and millimeters). (Image: Embankment bedding circular pipe (inches) according to [ACPA] [Image: visaplan GmbH] – Class A, concrete cradle) (Image: Embankment bedding circular pipe (millimeters) according to [ACPA] [Image: visaplan GmbH] – Class A, concrete cradle) |
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The images below present embankment bedding class B for circular concrete pipe (both in inches and millimeters). (Image: Embankment bedding circular pipe (inches) according to [ACPA] [Image: visaplan GmbH] – Class B, shaped subgrade with granular foundation and granular foundation) (Image: Embankment bedding circular pipe (millimeters) according to [ACPA] [Image: visaplan GmbH] – Class B, shaped subgrade with granular foundation and granular foundation) |
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The images below present embankment bedding class C for circular concrete pipe (both in inches and millimeters). (Image: Embankment bedding circular pipe (inches) according to [ACPA] [Image: visaplan GmbH] – Class C, granular foundation) (Image: Embankment bedding circular pipe (millimeters) according to [ACPA] [Image: visaplan GmbH] – Class C, granular foundation) |
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The images below present embankment bedding class D for circular concrete pipe (both in inches and millimeters). (Image: Embankment bedding circular pipe (inches) according to [ACPA] [Image: visaplan GmbH] – Class D, flat subgrade) (Image: Embankment bedding circular pipe (millimeters) according to [ACPA] [Image: visaplan GmbH] – Class D, flat subgrade) |
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The images below present trench beddings for non-circular concrete pipe. (Image: Trench beddings (inches) horizontal elliptical pipe according to [ACPA] [Image: visaplan GmbH]) (Image: Trench beddings (inches) vertical elliptical pipe according to [ACPA] [Image: visaplan GmbH]) (Image: Trench beddings (inches) arch pipe according to [ACPA] [Image: visaplan GmbH]) |
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The following image presents the terminology used in PE pipe installation using the open cut method according to the [[Plastic Pipe Institute]]. (Image: Pipe trench for PE piping according to [Plastic Pipe Institute] [Image: visaplan GmbH]) 1- Final backfill |
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The Plastic Pipe Institute recommends that [[ASTM D2321–05]], [[AASHTO Section 30]] and [[CAN/CSA B182.11]] should be followed for good practices for the installation of thermoplastic pipes. Accordingly, any organization or agency, such as federal, state, county and city, have the task to determine their own set of governing standards applicable to the installation of HDPE pipes. Bedding is required to establish line and grade and to provide firm, … |
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Class IA materials should not be used where groundwater flow is anticipated unless a geotextile trench wrap is used to prevent soil migration. Class III materials are suitable when moisture content is controlled [[Plastic Pipe Institute]]. To equalize load distributions along the invert of the pipe, 4 in (0.1 m) of bedding should be placed and compacted on the foundation [[Plastic Pipe Institute]]. Generally, the bedding equal to one-third the pipe … |
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Jan 09, 2017 AE-02 Open Cut Method: Embedment Zone and Pipe Installation Creation of the Bedding for Various Pipe Materials in the US According to [[ASTM D2321–05]], the soil types applied in foundation can be identically suitable in other processes of embedment. In pipe bedding process, soil IA, IB, II, and III are installed and compacted in 6 in maximum layers. Level final grade by hand. Minimum depth is 4 in (6 in in rock cuts). Soil IV is only suitable in dry trench conditions and other parameters are identical with the above. Please refer back to page 259 for an overview of … |
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Jan 09, 2017 AE-02 Open Cut Method: Embedment Zone and Pipe Installation Creation of the Bedding for Various Pipe Materials in the US Pipe bedding must be level throughout the pipe’s foundation and the material shall be placed and consolidated under the pipe, avoiding both vertical and lateral displacement [[HOBAS CCFRPM Guide]]. In the case of saturated soil with groundwater, the bedding material must be free of fines. The trench shall be refilled and backfilled in 12 in (30 cm) layers. Each layer must be compacted separately. The pipes must be stable and proper compaction achieved. … |
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Mar 01, 2017 AE-02 Open Cut Method: Embedment Zone and Pipe Installation Creation of the Bedding for Various Pipe Materials in the US For proper installation of Centrifugally Cast Fiberglass Reinforced Polymer Mortar (CCFRPM) pipe, bell holes have to be provided at each joint for proper joint assembly and alignment. If the trench bottom is excavated below grade, it should be backfilled to grade and compacted as required to provide firm pipe support [[HOBAS CCFRPM Guide]]. The image on the right presents the correct vs. incorrect installation of bell holes. Special care must be taken … |
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Feb 06, 2017 AE-02 Open Cut Method: Embedment Zone and Pipe Installation Creation of the Bedding for Various Pipe Materials in the US (Image: Glass fibre reinforced plastic pipe (GRP pipe)) The minimum bedding thickness for glassfiber reinforced pipes (GRP) is given by [[ATV-DVWK-A 127]] standard, and must be at least 0.1 x Pipe OD, or at least 6 in (15 cm). If the soil is soft or not load bearing, another 6 in (15 cm) of the bedding has to be replaced with soils in groups G1 or G2. Requirements for bedding material:
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Jan 09, 2017 AE-02 Open Cut Method: Embedment Zone and Pipe Installation Creation of the Bedding for Various Pipe Materials in the US (Image: Attention!) Bedding for ductile iron pipe depends on its laying condition, as per [[ANSI/AWWA C150/A21.50]] [[DIPRA Installation Guide]]. More information about DIP installation will be presented in later sections. All soil compaction must follow [[AASHTO T99]]. |
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According to an extensive laboratory and field research conducted by the National Clay Pipe Institute, documented in the [[VCP Engineering Manual]], an ideal bedding system prevents pipe movement, which was found to be the leading cause of structural problems. Not all bedding materials provide the same longitudinal and circumferential pipe support. The following table presents the allowable bedding material and initial backfill per bedding class for … |
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(Image: Vitrified clay pipes, class D bedding according to [NCPI] [Image: visaplan GmbH] – Load factor = 1.1) When using Class D bedding, the pipe is placed on a firm and unyielding trench bottom with bell holes provided. The bottom of the entire pipe barrel will have a continuous and uniform bearing support. The initial backfill can be either Class I, II, III or IV soil. The maximum particle size of the initial backfill material shall be 1 in [[VCP … |
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(Image: Vitrified clay pipes, class C bedding according to [NCPI] [Image: visaplan GmbH] – Load factor = 1.5) For Class C bedding, the bedding material can be either Class I or II soil, when the maximum particle size of the material is 1 in. Class I, II, III or IV soil type shall be used for the initial backfill, with a maximum particle size of 1 1/2 in. The minimum thickness of the bedding must be 4 in or 1/6th of the pipe OD (whichever is greater). … |
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(Image: Vitrified clay pipes, class B bedding according to [NCPI] [Image: visaplan GmbH] – load factor = 1.9) For Class B bedding, the bedding material is either Class I or II soil. Class I, II, III or IV soil type shall be used for the initial backfill, with a maximum particle size of 1 1/2 in. The minimum thickness of the bedding must be 4 in., or 1/6th of the pipe OD (whichever is greater). The bedding must extend up to the haunches of the pipe … |
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(Image: Vitrified clay pipes, crushed stone encasement bedding according to [NCPI] [Image: visaplan GmbH] – Load factor = 2.2) The bedding material can be either Class I or II soil. Class I, II, III or IV soil type shall be used for the initial backfill, with a maximum particle size of 1 1/2 in. The minimum thickness of the bedding must be 4 in or 1/6th of the pipe OD (whichever is greater). The bedding must extend up the top of the pipe barrel, in … |
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The bedding material can be either Class I or II soil, placed on firm and unyielding trench bottom, with a minimum thickness of 1/6th of the pipe OD, but not less than 4 in. The following table shows the minimum width of CLSM on each side of the pipe barrel as a function of the pipe OD. (Table: Minimum width of Controlled Low Strength Material) (Image: Vitrified clay pipes, controlled low strength material (CLSM) bedding according to [NCPI] [Image: … |
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According to the [[VCP Engineering Manual]], the optimal mix for Controlled Low Strength Material (CLSM) used in gravity sewer applications is one that has the fastest curing time over a maximum of 6 hours. The table below presents the optimal mix components and their corresponding quantities. (Table: Optimal mix components for use in Controlled Low Strength Material for VCP bedding) |
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(Image: Vitrified clay pipes, concrete cradle bedding according to [NCPI] [Image: visaplan GmbH] – Load factor = 3.4) When having a reinforced concrete cradle as bedding, the thickness of the bedding under the pipe barrel is at least 6 in or 1/4th of the pipe OD, whichever is greater. The initial backfill shall be either Class I, II, III, or IV, with a maximum particle size of 1½ in. Also, the cradle has to extend up the haunches to a height of a … |
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(Image: Vitrified clay pipes, concrete encasement according to [NCPI] [Image: visaplan GmbH]) Concrete encasement has to fully surround the pipe, and must have a minimum thickness of 1/4th the pipe OD or 4 in, whichever is greater, at any point [[VCP Engineering Manual]]. |
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Each bedding class offers a different load supporting capability for the pipe. Accordingly, load factors have been determined for each bedding class [[VCP Engineering Manual]]. The load factor is used to compute the field supporting strength (FSS) of VCP with any designated bedding class, which is obtained by multiplying the minimum three-edge bearing strength [[ASTM C700]] by the appropriate load factor. FSS = Minimum Pipe Bearing Strength x Load … |
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