Untitled - Future Pipe Industries

More documents

Recommendations

Info

4.2: Maximum particle size for gravel and crushed rock/stones The following limits should be observed with regard to the maximum particle size for the above materials Nominal <strong>Pipe</strong> Maximum Diameter (DN) Particle Size Up to 12” fi ” 14 – 36” fl ” 42” and larger 1 ” 4.3: Migration When backfill materials such as gravel and crushed rocks are placed in a trench adjacent to finer native material, the finer material may migrate into the coarser material under the flow pressure force of the ground water table. Migration can also occur when selected sand is used as backfill in a trench where the native soil is coarser. Significant hydraulic gradients may arise in the pipeline trench during construction, when water levels are controlled by various pumping or well-pointing methods. Gradients may also arise after construction, when permeable under drainpipes or when the open graded bedding and backfill materials act as a French drain under high ground water levels. Migration can result in significant loss of pipe support and increasing pipe deflections that may eventually exceed the design limits of the pipe. The gradation and relative size of the embedment and adjacent native soils must be compatible in order to minimize migration. In general, where significant ground water is anticipated above the foundation or bedding of the pipe, avoid using open graded materials such as type A or B backfill material (crushed rocks and gravel) when the native soil is a finer type such as sand, unless a geotextile filter media is used to line the trench bottom and sides. The following gradation criteria may be used to restrict the migration of finer material into a coarser material under a hydraulic gradient. • D15 / d85 < 5 where D15 is the sieve opening size passing 15 percent by weight of the coarser material and d85 is the sieve opening size passing 85 percent by weight of the finer material. • D50 / d50 < 25 where D50 is the sieve opening size passing 50 percent by weight of the coarser material and d50 is the sieve opening size passing 50 percent by weight of the finer material. (This criteria doesn’t apply if the coarser material is well graded {See ASTM D2487}) 4.4: Determination of native soil properties In order to choose the appropriate installation type and to identify the allowed burial depth limits, it is necessary to determine native soil properties. Proper soil investigation along the pipeline route is an engineering practice that should be executed by the Contractor in case no soil data is provided by the end user. When no soil data is available, borehole samples should be taken along the pipeline route at intervals of not more than 1500 feet. If the native soil properties and appearance are not consistent over this distance, shorter intervals for sampling should be adopted. Soil samples must be taken from a representative burial depth in order to provide the necessary information of the bedding and pipe zone level of the pipeline. Important properties for soils • Physical characteristics, appearance, and gradation • Water table location • Blow counts (N) per ASTM D1586 (Standard Penetration Test) • Unconfined compressive strength qu, 9
4.5: Classification of native soils Native soils can be classified into four main groups (1,2 3 and 4) and two sub groups, cohesive and granular as shown in table (4). Table 4: Soil Groups 1 2 3 4 Cohesive soils stiff medium soft very soft E’n (psi) > 3000 1500 700 200 Unconfined compressive strength qu (Tons/sf) >1 0.50-1.0 0.25-0.5 Good native soils > Poor native soils Granular soils Blow counts (N) (ASTM D 1586) Unconfined compressive strength qu (Tons/sf) • Installation type I: Full gravel/crushed stones surround, compacted. (E’b = 3000 psi ) 0.125- 0.25 1 2 3 4 S compact • Installation type II: Full clean sand surround compacted to 90% SPD. (E’b = 2000 psi) • Installation type III: Full excavated granular material, free from rocks and organic material, compacted to 90% SPD. (E’b = 1000 psi). • Installation type IV: Sand compacted to 90% SPD or gravel/crushed stones up to 70% of pipe diameter. (E’b = 700 psi) • Installation type V: Lightly tamped clean sand to 80% SPD. (E’b = 250 psi) loose loose very loose >8 5-8 3-4 1-2 > 3000 2500 700 200 Good native soils > Poor native soils Note: Native soils with a low blow count (N) of less than 2 will generally be unsuitable for installation of Fiberglass pipe utilizing standard installation practices. A soil specialist should be consulted on recommended alternative installation procedures when this type of native soil is found. 4.6: Installation selection Installation selection, unless otherwise specified by the end user, shall be based on the native soil properties, pipe stiffness class (SN), burial depths and any vacuum requirements. Figure 5 illustrates five installation types (I through V). Tables 5, 6, 7 and 8 are the installation selection tables for pipe with a stiffness class of SN 18, 36, 46, and 72 psi respectively. See figure 6 for installation schemes in poor soil condition, where a wide trench is required by the installation selection tables. Cement stabilized sand (backfill type F) may also be used in a normal trench configuration as an alternative to a wide trench construction, and an E’b value of 10,000 psi may be used for deflection calculations. 10
Page 2 and 3: All information was correct at the
Page 4 and 5: 1.0: Introduction This manual deals
Page 6 and 7: 2.5: Storing pipes on site 2.5.1 Di
Page 9 and 10: Figure 4: Pipes in the same trench
Page 11: 4.0: Backfilling and installation s
Page 16 and 17: Installation type I ASTM D1586 Blow
Page 18 and 19: Installation type I ASTM D1586 Blow
Page 20: Installation type I ASTM D1586 Blow
Page 23 and 24: 5.1.1: Joint lubricant For lubrican
Page 25: Mechanical lowering is used for lar
Page 28: 5.6: Pipes with locked joints For s
Page 31 and 32: Caution: Always provide a standard
Page 34 and 35: Figure 20 6.2: Pipe zone backfillin
Page 36 and 37: 6.3: Backfilling where temporary sh
Page 38 and 39: 7.0: Hydrostatic testing of pipelin
Page 40 and 41: 7.2: Bracing test-ends and set-up D
Page 42 and 43: 7.6: Final pressure test After all
Page 44 and 45: 7.9.2: Low head water test The Cont
Page 46 and 47: 9.0: Tapping water mains Pressure p
Page 48 and 49: APPENDIX II: Design considerations
Page 51 and 52: APPENDIX III AIR IN PIPELINES, AIR-
Page 53 and 54: APPENDIX IV FLANGE INSTALLATION INS
Page 55 and 56: Table 1a If connected to raised fac
Page 57 and 58: APPENDIX V: LIST OF REFERENCES The

Untitled - Future Pipe Industries

Create successful ePaper yourself

Delete template?

Save as template?