Atlas-Helical &
ATLAS RESISTANCE PIERS
CASE STUDY 110-9
Atlas-Helical Slab Piers and
Atlas Resistance Piers are Used
to Restore and Stabilize a New House
Atlanta, Georgia
Installed by:
Atlas Piers of Atlanta
Alpharetta, Georgia
Designed by:
Peach State Building Consultants, Inc.
Lawrenceville, Georgia
LOOK OUT! New House Headed South!
This is a view of the front elevation of the residence.
The ATLAS RESISTANCE PIERS
were installed on the rear of the structure and Atlas-Helical Slab Piers
inside.
Description of Site: This house is situated on a sloping
lot. The cut and fill lot slopes at approximately one foot in five feet. Behind the
structure the grade drops to a swale 15 feet below the lot at a slope of 1 to 1. The rear
of the structure is constructed upon graded fill. The engineers found evidence of active
slope movement of the fill. Standard Penetration Test values indicated values of 2 or less
over vertical expanses of 5 feet or more in the area of fill.
Description of Structure: This new two story house has a
full basement that is below grade at the front of the house and above grade at the rear.
The upper levels of the structure and the rear wall of the basement are of wood frame
construction. The front of the house is brick veneer while the rear and sides have siding.
The house showed settlement of up to 5 inches with respect to the front of the house. The
basement slab and the rear porch footing both show fractured concrete.
Description of Findings: The engineers recommended permanent
stabilization and restoration of the foundation and slab. Soils with minimum safe bearing
pressures of 5,000 psf were found at depths ranging from 5 to more than 15 feet. ATLAS
RESISTANCE PIERS and Atlas-Helical Slab Piers were chosen to
support and restore the structure. The recommendation to stabilize the soil mass was the
construction of a 6 foot high crib wall and slope modification of the back yard.
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The photograph above shows the rear of the structure where settlement
occurred. ATLAS RESISTANCE PIERS were installed from the air conditioning units to
the rear and across the back of the house.
The technician is shown in both photos installing the pier pipe. The
system uses a quiet hydraulic pump for a smooth installation that is without vibration.
Each pier is carefully driven to a suitable load bearing stratum. Before
the structure is restored, each pier is individually tested to a load greater than the
working load required. This verifies a factor of safety against future settlement. |
After
the ATLAS RESISTANCE PIERS are installed to the load bearing stratum, hydraulic
lifting rams are installed on each Pier. The rams are gently actuated together through a
manifold arrangement. The photograph below shows a lift of over 5 inches.
The photograph above show an ATLAS RESISTANCE PIER installed on the
side of the structure. The ATLAS RESISTANCE PIER is ideal for installation in tight
locations; only a small, hand dug excavation is required. This is Pier location number 14.
Atlas Piers Installation Summary |
| Design
Engineer: |
Peach State Building
Consultants, Inc., Lawrenceville, Georgia |
| Installed
By: |
Atlas Resistance
Piers of Atlanta -- Alpharetta, Georgia |
| Atlas
Resistance Pier Product: |
AP2S-3500 Two Piece ATLAS
RESISTANCE PIER |
| Number of
Resistance Piers: |
18 |
| Average
Drive Force: |
32,700 pounds |
| Average
Lift Force: |
14,160 pounds |
| Average
Factor of Safety: |
2.30:1 [130% above
actual lift force] |
| Amount of
Lift: |
up to 5 inches |
| Average
Depth: |
14’ - 5" |
|
Atlas-Helical Installation Summary |
| Installed
By: |
Atlas Resistance
Piers of Atlanta -- Alpharetta, Georgia |
| Atlas-Helical
Foundation Pier Product: |
AHS-SPSP-SQ150 /8/ x
[5’-0"] Screw Activated Slab Pier AHE-SQ150 x [5’-0"] Extension
Assembly |
| Number of Atlas-Helical
Slab Piers: |
17 |
| Installation
Torque: |
3,000 ft-lbs |
| Depth to Design
Torque: |
10 to 15 feet |
| Amount of Lift: |
up to 2 inches |
|
The photograph above
shows the technicians installing an ATLAS-Helical Slab Pier at
location "P" inside the structure. The pier is installed until the design torque
is achieved.
 Once the ATLAS-Helical Slab
Pier is installed to design torque, the Sub-slab support Assembly is installed. The
floor is then restored to as close to original elevation as construction permits by
applying torque to the Lifting Bolts evenly across the floor. In the photograph at right
show ATLAS-Helical Slab Pier locations "F", ‘G",
"H", & "J" after restoration. |
The
photograph at left shows the preparation required ATLAS-Helical Slab Piers
installations. Eight inch diameter holes are drilled through the concrete slab. A
technician then excavates and prepares the lower side of the slab to receive the Sub-slab
Support Assembly. Following this careful preparation, the ATLAS-Helical Slab
Pier is installed using a quiet hydraulic torque motor. This is a view of Pier
locations "H", "G", "F" & "E". 
|
Atlas Piers
INSTALLATION SUMMARY
Pier Installation Log
Pier
Section |
Location and Driving
force -- pounds |
| Pier #1 |
Pier #2 |
Pier #3 |
Pier #4 |
Pier #5 |
Pier #6 |
Pier #7 |
Pier #8 |
Pier #9 |
| Sect. #1 |
33,160 |
33,160 |
13,264 |
11,606 |
8,290 |
7,461 |
12,435 |
8,290 |
8,290 |
| Sect. #2 |
|
|
23,212 |
16,580 |
16,580 |
13,264 |
14,922 |
14,922 |
8,290 |
| Sect. #3 |
|
|
33,160 |
24,870 |
16,580 |
16,580 |
19,896 |
33,160 |
12,435 |
| Sect. #4 |
|
|
|
31,502 |
31,502 |
33,160 |
18,238 |
|
13,264 |
| Sect. #5 |
|
|
|
|
|
|
31,502 |
|
14,922 |
| Sect. #6 |
|
|
|
|
|
|
|
|
14,922 |
| Sect.#7 |
|
|
|
|
|
|
|
|
31,502 |
Factor of Safety
| Location |
Lifting
Force, lb |
Driving
Force, lb |
Ultimate
Cap. - lb |
Working
F.S. |
Ultimate
F.S. |
| Pier #1 |
12,875 |
33,160 |
85,000 |
2.58 : 1 |
6.60 : 1 |
| Pier #2 |
12,875 |
33,160 |
85,000 |
2.58 : 1 |
6.60 : 1 |
| Pier #3 |
12,875 |
33,160 |
85,000 |
2.58
: 1 |
6.60
: 1 |
| Pier #4 |
14,420 |
31,502 |
85,000 |
2.18 : 1 |
5.89 : 1 |
| Pier #5 |
14,420 |
31,501 |
85,000 |
2.18 : 1 |
5.89 : 1 |
| Pier #6 |
15,450 |
33,160 |
85,000 |
2.15
: 1 |
5.50
: 1 |
| Pier #7 |
15,450 |
31,502 |
85,000 |
2.04 : 1 |
5.50 : 1 |
| Pier #8 |
15,450 |
33,160 |
85,000 |
215 : 1 |
5.50 : 1 |
| Pier #9 |
15,450 |
31,502 |
85,000 |
2.04 : 1 |
5.50 : 1 |
|
Results
| Location |
Approx.
Lift - in. |
Depth to
Bearing |
| Pier #1 |
0" |
3' - 6" |
| Pier #2 |
0" |
3' - 6" |
| Pier #3 |
0" |
10'
- 6" |
| Pier #4 |
2" |
14' - 0" |
| Pier #5 |
2" |
14' - 0" |
| Pier #6 |
3" |
14'
- 0" |
| Pier #7 |
3" |
17' - 0" |
| Pier #8 |
3" |
10' - 6" |
| Pier #9 |
3-1/2" |
24' - 6 |
|
Pier
Section |
Location and Driving force -- pounds |
| Pier #10 |
Pier #11 |
Pier #12 |
Pier #13 |
Pier #14 |
Pier #15 |
Pier #16 |
Pier #17 |
Pier #18 |
| Sect.
#1 |
8,290 |
11,606 |
11,606 |
9,948 |
11,606 |
9,948 |
11,606 |
12,435 |
12,435 |
| Sect.
#2 |
8,290 |
11,606 |
11,606 |
11,606 |
13,264 |
12,435 |
12,435 |
23,212 |
20,725 |
| Sect.
#3 |
11,606 |
16,580 |
13,264 |
12,435 |
13,264 |
27,357 |
16,580 |
33,160 |
33,160 |
| Sect.
#4 |
13,264 |
23,212 |
33,160 |
16,580 |
18,238 |
33,160 |
33,160 |
|
|
| Sect. #5 |
18,238 |
33,160 |
|
21,554 |
33,160 |
|
|
|
|
| Sect. #6 |
19,896 |
|
|
24,870 |
|
|
|
|
|
| Sect.#7 |
31,502 |
|
|
33,160 |
|
|
|
|
|
Factor of Safety
| Location |
Lifting
Force, lb |
Driving
Force, lb |
Ultimate
Cap. - lb |
Working
F.S. |
Ultimate
F.S. |
| Pier #10 |
15,450 |
31,502 |
85,000 |
2.04 :1 |
5.50 : 1 |
| Pier #11 |
15,450 |
33,160 |
85,000 |
2.15 : 1 |
5.50 : 1 |
| Pier #12 |
14,420 |
33,160 |
85,000 |
2.30
: 1 |
5.89
: 1 |
| Pier #13 |
14,420 |
33,160 |
85,000 |
2.20 : 1 |
5.89 : 1 |
| Pier #14 |
14,420 |
33,160 |
85,000 |
2.20 : 1 |
5.89 : 1 |
| Pier #15 |
12,875 |
33,160 |
85,000 |
2.58
: 1 |
6.60
: 1 |
| Pier #16 |
12,875 |
33,160 |
85,000 |
2.58 : 1 |
6.60 : 1 |
| Pier #17 |
12,875 |
33,160 |
85,000 |
2.58 : 1 |
6.60 : 1 |
| Pier #18 |
12,875 |
33,160 |
85,000 |
2.58 : 1 |
6.60 : 1 |
|
Results
| Location |
Approx.
Lift - in. |
Depth to
Bearing |
| Pier #10 |
3-1/2" |
24' - 6" |
| Pier #11 |
3" |
17' - 6" |
| Pier #12 |
2" |
14'
- 0" |
| Pier #13 |
1-1/2" |
24' - 6" |
| Pier #14 |
1" |
17' - 6" |
| Pier #15 |
1/2" |
14'
- 0" |
| Pier #16 |
0" |
14' - 0" |
| Pier #17 |
0" |
10' - 6" |
| Pier #18 |
0" |
10' - 6" |
|
Slab Pier
Installation Log
Slab
Pier
Depth |
Location and Installation Torque - ft-lbs |
| Pier A |
Pier B |
Pier C |
Pier D |
Pier E |
Pier F |
Pier G |
Pier H |
Pier J |
| 5' |
1,500 |
1,500 |
1,500 |
1,500 |
1,500 |
1,500 |
1,500 |
1,500 |
1,500 |
| 10' |
1,500 |
3,000 |
3,000 |
1,500 |
1,500 |
1,500 |
1,500 |
3,000 |
1,500 |
| 15' |
3,000 |
|
|
3,000 |
3,000 |
3,000 |
3,000 |
|
3,000 |
|
Slab
Pier
Depth |
Location and Installation Torque - ft-lbs |
| Pier K |
Pier L |
Pier M |
Pier N |
Pier P |
Pier Q |
Pier R |
Pier S |
| 5' |
1,500 |
1,500 |
1,500 |
1,500 |
1,500 |
1,500 |
1,500 |
1,500 |
| 10' |
3,000 |
1,500 |
1,500 |
1,500 |
3,000 |
1,500 |
1,500 |
1,500 |
| 15' |
|
3,000 |
3,000 |
3,000 |
|
3,000 |
3,000 |
3,000 |
|
Results
| Location |
Approx.
Lift - in. |
Depth to
Torque |
| Pier A |
0" |
15' |
| Pier B |
0" |
10' |
| Pier C |
0" |
10' |
| Pier D |
0" |
15' |
| Pier E |
0" |
15' |
| Pier F |
0" |
15' |
| Pier G |
0" |
15' |
| Pier H |
0" |
10' |
| Pier J |
0" |
15' |
|
Results
| Location |
Approx.
Lift - in. |
Depth to
Torque |
| Pier K |
2" |
10' |
| Pier L |
2" |
15' |
| Pier M |
2" |
15' |
| Pier N |
2" |
15' |
| Pier P |
2" |
10' |
| Pier Q |
1" |
15' |
| Pier R |
0" |
15' |
| Pier S |
0" |
15' |
|
Force
Lifting
14 |
Force
Driving
33 |
Capacity
Ultimate
85 |
 |
|
Chance
Civil Construction
1026-B South Powell Road
Independence, MO 64056
Office: (816) 796-6800
Fax: (816) 796-0919
Toll Free: (877) 285-2739
Email: info@atlassys.com
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