North American Pile Driving drove piles for CN Railways at a timber

PROJECT HISTORY: RESONANT PILE DRIVING TIMBER TRESTLE REPLACEMENT
FRASER RIVER DELTA, VANCOUVER, BC, CANADA
North American Pile Driving drove piles for CN Railways at a timber trestle replacement project
located within the delta of the Fraser River in Vancouver, BC, Canada. The trestle carries two
heavily travelled tracks into and out of the port of Vancouver. The project involved the driving
of HP 360 x 132 kg (HP 14 x 89lbs) piles 36 m (120 ft) in length in tight 4 pile clusters. The
vertical piles were driven as close as 600 mm (24 inches) centre to centre. The piles were driven
with either a 3800 kg (8000 lbs) drop hammer or an ICE I 30 diesel hammer. The site soils
consisted of saturated sands, sandy silts and silts in a compact to dense condition. SPT blow
counts varied from 5 to 30 per 300 mm. CPT’s indicated typical qc of 150 to 200 bar. Typical
blows per 300 mm with the impact hammers were on the order of 10 increasing to 20 to 35 bl at
the end of driving. Typical end of drive set was considered 5 blows per 50 mm. The impact
driving resulted in densification of the soils with associated higher resistance of subsequent piles
driven within the group. Those piles that were driven first suffered down drag during driving of
adjacent piles.
Further problems associated with the impact driving including settlement of the trestle. During
the day piles were driven adjacent to the timber pile supported trestle. The driving resulted in
densification and settlement of the soils on one side of the trestle with down drag on the shorter
timber piles. Evening and night train traffic caused vibration and differential settlement of the
trestle, throwing the tracks out of tolerance. The pile driving was halted and the contractor’s
work restricted both in scope and timing; demanding that piles be driven simultaneously and to
similar depths on either side of the trestle. This method reduced the differential settlement issues
for the trestle but severely reduced production.
A 140 kW (200 Hp) Resonant Pile Driver was introduced to the site in an effort to remedy the
driving restrictions and improve production. Conventional vibrators were not permitted at the
site for fear of increased vibration levels and related settlements. The Resonant Pile Driving
method results in near imperceptible ground vibrations and no vibration related densification or
settlement of the surrounding soils. The impact hammers required between 40 and 80 minutes of
driving time to complete a pile. The Resonant Driver completed the piles in 8 - 12 minutes of
driving. To prove the capacity of the Resonant Driven piles impact hammer re-taps were
conducted that compared well with the original, impact driven piles. PDA testing of the
Resonant Driven piles was conducted after two weeks of set up. The PDA results indicate the
Resonant Driven piles exhibit a capacity between 2300 and 3000 kN. Typical driven piles on
site varied in CAPWAP capacity from 2200 to 4000 kN. Vibration monitoring during Resonant
Driving indicated particle velocities of 1/5 to 1/10th of acceptable vibration levels at just 1 m.
Conventional vibration monitoring equipment typically will not even trigger during Resonant
Driving. Accelerometers placed beyond 5 m are dominated by construction vibration such as
power pack or crane vibration as opposed to Resonant Driving. Monitoring during impact
driving exceeded 10 mm/sec at 1 m.
INNOVATIVE GEOTECHNICAL & FOUNDATION CONSTRUCTION EQUIPMENT
51 Leeder Avenue, Coquitlam, B.C., V3K 3V5 Canada
Tel: (604) 395-6845 Fax: (604) 395-6846
e - m a i l : i n f o @ r e s o n a n c e t e c h n o l o g y. c a w w w . r e s o n a n c e t e c h n o l o g y. c a
GST 875160202 - PST R456340
RTI Resonant Driver installing a 36 m long HP 360 x 132 pile adjacent to a trestle.
Piles required 8 to 12 minutes to install using the RTI RD 140 kW Driver.
Conventional drop hammer in the background required 40 to 80 minutes to drive and caused
vibration related bridge settlements that interrupted rail service.
INNOVATIVE GEOTECHNICAL & FOUNDATION CONSTRUCTION EQUIPMENT
51 Leeder Avenue, Coquitlam, B.C., V3K 3V5 Canada
Tel: (604) 395-6845 Fax: (604) 395-6846
e - m a i l : i n f o @ r e s o n a n c e t e c h n o l o g y. c a w w w . r e s o n a n c e t e c h n o l o g y. c a
GST 875160202 - PST R456340
Piles were driven on 600 mm c/c spacing.
Pile capacity proven by CAPWAP is on the order of 2300 to 3000 kN.
INNOVATIVE GEOTECHNICAL & FOUNDATION CONSTRUCTION EQUIPMENT
51 Leeder Avenue, Coquitlam, B.C., V3K 3V5 Canada
Tel: (604) 395-6845 Fax: (604) 395-6846
e - m a i l : i n f o @ r e s o n a n c e t e c h n o l o g y. c a w w w . r e s o n a n c e t e c h n o l o g y. c a
GST 875160202 - PST R456340
Piles are driven free hanging, on line and plumb since the Resonant Driver can pull and adjust
pile placement during driving. Free hanging arrangement allows less slung weight and ease of
orienting pile flanges or pile batter where required.
INNOVATIVE GEOTECHNICAL & FOUNDATION CONSTRUCTION EQUIPMENT
51 Leeder Avenue, Coquitlam, B.C., V3K 3V5 Canada
Tel: (604) 395-6845 Fax: (604) 395-6846
e - m a i l : i n f o @ r e s o n a n c e t e c h n o l o g y. c a w w w . r e s o n a n c e t e c h n o l o g y. c a
GST 875160202 - PST R456340