HomeMy WebLinkAboutBY3.pdf1.0 Temporary Ground Nail Wall Materials
1.1 Ground Nails - Grade 75 threadbar or equivalent in accordance with ASTM A615, or Williams 32mm injection bar.
fy=75,000 psi
1.2 Grout - Grout may be neat-cement or with sand, with Type II cement in accordance with ASTM C150. Water-cement ratio should be between 0.4 and 0.6.
f'c=1,500 psi minimum 3 day
f'c=3,000 psi minimum 28 day
1.3 End hardware - Nuts and washers shall be in accordance with ground nail manufacturer's recommendations. Bearing plate shall be in accordance with ASTM A36, Grade 36.
1.4 Shotcrete - Shotcrete mix shall consist of Type II cement in accordance with ASTM C150, potable water and normal weight aggregate in accordance with ASTM C33.
Admixtures, if used, should be non-corrosive to steel.
f'c=4,000 psi (28-day strength)
1.5 Welded wire mesh shall be in accordance with ASTM A185.
1.6 Walers and vertical bearing bars shall be in accordance with ASTM A615.
fy=60,000 psi
1.7 Strip drains consist of 12" wide dimpled cores wrapped in geotextile. The compressive strength of the core should be at least 20 psi when tested in accordance with ASTM
D1621, and it's in-plane flow capacity should be at least10 gpm/ft when tested in accordance with ASTM D4716
1.8 Centralizers should be plastic that will provide free passage of grout and attached to the nails in accordance with the manufacturer's recommendations. Centralizers not
required for injection bars.
2.0 Temporary Ground Nail Underpinning Construction Sequence
PANEL EXCAVATION SEQUENCE
2.1 Excavate panels 1 - 4. Excavation shall be stopped if backfill materials or retained soils begin to ravel. At no time shall unretained excavations be left overnight.
2.2 Install ground nails at the locations and to the lengths shown on the plans. Ground nail location may vary by up to 6". Tremie the grout from the bottom of the hole up.
2.3 Install strip drains, welded wire mesh, walers and bearing bars as shown on the drawings. Use chairs to hold the welded wire mesh away from the soil as necessary.
2.4 Install shotcrete to the minimum thickness shown on the drawings and to attain the minimum coverages specified herein. Give special attention to filling the void in the
borehole above the grout line.
2.5 Install the ground nail end hardware after the minimum inside coverage specified herein has been attained. While the shotcrete is still wet, embed the plate into the shotcrete
surface until there is no void behind the plate. Handtighten the nut.
2.6 Once the grout and shotcrete have attained 80% of their specific strengths, excavate panels 5 - 8 and repeat 2.2 - 2.5.
2.7 At the bottom of wall, complete strip drains to daylight as shown on the drawings.
3.0 Temporary Ground Nail Wall Design Parameters
3.1 The ground nail wall has been designed in general accordance with procedures contained in the FWHA "Manual for Design and Construction Monitoring
of Soil Nail Walls", Report No. FHWA-SA-96-069R.
3.2 The following strength parameters walls were assumed for the subsoils based on our experience in the area with similar projects.
The following values were assumed for soil design parameters:
I c J
Qult
(deg) (psf) (pcf) (psi)
Overburden 28 100 125 20
An experienced geotechnical engineer should verify the above design parameters during construction.
3.3 Groundwater level was assumed to be below the base of the wall.
3.4 Factors of safety
Global - FS > 1.2 (temporary)
Nail Tension Strength Factor - QN = 0.55
Nail Pullout Resistance Factor - QQ = 0.50
Nail Head Strength Factor - QF = 0.67
3.5 Surcharge loading
The excavation shoring is designed to accommodate normal construction surcharge of material and light trucks, not heavy loads such as cranes
(wheels and outriggers), excavators, concrete trucks, concrete pumpers (wheels or outriggers) or large stockpiles. Heavy loads shall not be placed
within 10 feet of the top of the ground nail wall facing.
3.6 Corrosivity was assumed to be low.
3.7 The maximum design life of the temporary shoring is 12 months.
4.0 Special Notes
4.1 Wall geometry used in design was based on information from plans provided by B&Y Drilling, Inc.
4.2 This design is valid only for B&Y Drilling, Inc. at the subject site.
4.3 RJ Engineering is not responsible for maintaining slope stability above and below the ground nail wall during construction.
4.4 RJ Engineering is not aware of any utility conflicts. The contractors are responsible for field locating all nearby utilities. Conflicting utilities may require
ground nail wall redesign at RJ Engineerings' discretion.
4.5 RJ Engineering is not responsible for quality control, quality assurance, changed conditions or problems resulting from improper construction techniques,
and construction site safety.
4.6 RJ Engineering is not responsible for wall layout. Wall layout shall be performed by the contractor or contractor's representative.
5 1 2 7
6 3 4 8
18.0'
4.5'
3.0'
6.5'
Ground Nail Wall
General Notes
March 13, 2015
Hovey Residence
1339 Westhaven Circle
15-015G-D1
BY-3
of 4
RDJ
Project Number:
Date: Sheet Number:
Prepared by:
Project:
Sheet Revisions
Date Revision/Issue Prepared by B&Y Drilling, Inc.
Designed For:
Seal:
266 Red Cliff Circle Glenwood Springs, CO 81601
Phone: (970) 230-9208
03/30/15