Full Issue (17 MB) - Pile Driving Contractors Association

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Vibration Standards-Steady State (Vibratory Hammer) Below is a summary of information on vibration limits for steady state vibration levels for pile driving and other construction activities (Dowding, C.H., 1996): • Vibrations from steady state sources are typically limited to a PPV of 12.7 mm/sec (0.5 in/sec) or less. • Greater potential for resonance due to number of cycles/duration • Fatigue cracking a concern due to the number of cycles • Low frequency vibrations typically occur during ramping up and down at start up and stop (vibratory hammer) • Objects “walking” across shelves are more of a concern with steady state vibrations, even well below safe structure standards Soil Settlement There are two possible foundation related effects from vibrations; direct vibration effects on a house and effects on the foundation soils, which can then affect the house (Siskind, 2000). Saturated cohesionless soils, like poorly graded beach sand, are known to be susceptible to a vibration effect called liquefaction (beach sand is the best known example of this). Required are susceptible soils (saturated and cohesionless), long duration vibration (tens to hundreds of cycles), and high vibration amplitudes (Siskind, 2000). The concern is not vibration velocity, but acceleration and the conditions that sometimes occur in earthquakes, yet seldom in blasting or dynamic compaction. The lowest known examples of vibration induced liquefaction were 80 cycles of vibration at 0.165 g (equivalent to 63.5 mm/sec (2.5 ips) at 4 Hz) and observed liquefaction at a PPV of 50.8 mm/sec (2.0 ips) (Siskind, 2000). Because liquefaction concerns are earthquake driven, frequencies required to induce liquefaction are very low and therefore strain levels are very high (displacements and strains are inversely proportional to frequency). Therefore, it is reasonable to assume that the accelerations associated with the observed liquefaction examples apply only to low frequencies, likely below 4 Hz (Siskind, 2000). Dowding (1985) describes the blast densification of loose sand. He reiterates that very high velocities are required to induce liquefaction or settlement. He presents an example where a five-kg bundle of high explosives was detonated in loose to medium-dense sands and measurable settlement occurred out to a distance of <strong>17</strong>.98 meter. The estimated PPV at <strong>17</strong>.98 meter from the blast was between 25.4 and 76.2 meter per second (mm/sec). These sands were extremely loose and had standard penetration resistance below count numbers (N) of less than 10. Oriard (2002) reports that the minimum threshold for ground shear strain to induce liquefaction is about 0.02 percent for a very wide variety of soil conditions independent of the duration of the shaking. In the case of construction activity, this would mean that the dynamic compaction source would have to be located in the immediate area, within the 92 • Q4 • 2009
deposit itself. Strain is equal to particle velocity divided by shear wave velocity. Buried Utilities • Restrained in-ground resonance unlikely • Less susceptible to vibration effects than above ground structures • PPV limits published for pressurized gas transmission pipelines and for fiber optics-101.6 to 127 mm/sec. Engineered Commercial Structures • PPV standards two or three times safe levels for residences • Can be up to 76.2 to 127 mm/sec. • Displacement of 0.020 mm can be applied Toppling of Loose Objects Movement of pictures, items on shelves, dishes rattling, and toppling of tall knick-knacks occurs at PPV levels below cracking thresholds. Oriard (1999) indicates that based on Table 1 – Vibration Effects on Loose Objects (Oriard, 1999) Vibration Effects on Loose Objects TOPPLING OBJECTS Construction Claim Consultants Foundation and underground construction claim consultants provide construction claims analysis and monitoring during performance of project. • Experts on foundation specifications and plans • Experts in differing site condition claims • Experts on public work contracts • Litigation consulting 35 years of experience constructing thousands of foundation projects as foundation drilling and piling subcontractors. PARTICLE VELOCITY (IPS) Rare Under 0.1 Occasional 0.1 to 1 Common 1 to 4 Extensive Above 4 Note: Sensitivity depends on the mass and shape of the object. In general, objects will topple more readily at lower frequencies and longer durations. Ph: 949-419-5202 | Ph: 562-577-3926 Fax: 619-216-9390 www.constructionsclaim.com altamiranosa@aol.com • Q4 • 2009 93
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THE OFFICIAL PUBLICATION OF THE PIL
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PILE DRIVING CONTRACTORS ASSOCIATIO
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We Service You From Mill Rollings W
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PORT OF HOUSTON EXPANSION BUILT ON
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and Wayne Waters (president, Ed Wat
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Executive Director’s Message Exec
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meeting in Orlando, FL. The meeting
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With nearly 200 acres of stock and
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Charlie Gibson Manson Construction
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Annual Membership Directory As a me
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PDCA MEMBERSHIP APPLICATION Step St
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A Driving Force in the Foundation E
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Chapter Updates Chapter Updates PDC
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THE SHAPE OF THE FUTURE... Port of
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Member Profile Footing piles for po
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Member Profile Johnson Bros. Many M
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The company is a “F.A.S.T.” (Fo
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Independent Pipe and Steel, Inc. Me
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Taking the Lead in over40 countries
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DRIVEN PILE COST COMPARISON for two
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on hammerhead piers, incorporating
Page 44: We Get Thousands of Tons of New Pil
Page 47 and 48: The results of the DPH test did con
Page 49 and 50: The vibration compacts the concrete
Page 51 and 52: THE NEW IMPORTANCE OF RECORDS RETEN
Page 53 and 54: information needed for the ongoing
Page 55 and 56: RoyOMartin-Colfax Treating speciali
Page 57 and 58: JD & Company, Inc. the supply of St
Page 59 and 60: Driven Treated Timber Piles Lead th
Page 61 and 62: Steel piles take the LEED® in a GR
Page 63 and 64: MARINE AND HEAVY CONSTRUCTION 711 E
Page 65 and 66: The Inner Harbor Navigation Canal B
Page 67 and 68: pumped from the top of the pile to
Page 69 and 70: “MAFCO” - Your one stop shoppin
Page 71 and 72: AZ / Larssen U AZ / Larssen U Ball
Page 73 and 74: The Harvey Canal Project: Saving Ti
Page 75 and 76: Project Spotlight Miles and Miles o
Page 77 and 78: Project Spotlight Safety Procedures
Page 79 and 80: Project Spotlight Kremer carries
Page 81 and 82: Project Spotlight “It’s interes
Page 83 and 84: Project Spotlight Seeing the waters
Page 85 and 86: THE BUSINESS OF BUSINESS THE BUSINE
Page 87 and 88: in English while performing specifi
Page 89 and 90: PDCA 14 th Annual Conference and Ex
Page 91 and 92: 2010 PROJECT OF THE YEAR Awards Put
Page 93: Monitoring Pile Driving Vibrations
Page 97 and 98: Recordkeeping Good record keeping i
Page 99 and 100: 2009 New PDCA Members Contractor Me
Page 101 and 102: 2009 New PDCA Members SK Geotechnic
Page 104: A.P.E. AMERICAN PILEDRIVING EQUIPME
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Full Issue (17 MB) - Pile Driving Contractors Association

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