ground support pllc - pavilion construction apartments... · ground support pllc the following...

2

Ground Support PLLC

BACKGROUND:

The planned project consists of a prefabricated modular apartment building with underground

parking, located on the site bounded by Dexter Avenue N. to the east, multi-story

residential/commercial structures to the north and south, and an alley to the west. The site slopes to

the east, with the alley at elevation 128-130 feet and Dexter Avenue ranging from elevation 103 feet

in the north to 99 feet in the south. The buildings to the north and the south, as well as the structure

presently located on the northern portion of the site, are benched into the steep slope that is adjacent

the alley. The parking lot within the south portion of the site is separated from the steep slope to the

west by a 10-foot-high cast–in-place concrete retaining wall.

The excavation will cover essentially the entire site with setbacks of 2 feet from the north and south

property lines to accommodate shoring. In addition, the basement excavation will be set back from

the east property line such that the building footprint will be 146 feet long by just over 100 feet wide

(east-west). The excavation will extend to elevation 88 to 96 feet, with maximum depths of

excavation along the west (alley) side of 37 feet.

This design addendum addresses the re-design of the central section of the west wall, replacing

anchored soldier pile shoring with internally-braced soldier piles, as a result of a lack of a temporary

construction easement for the associated property to the immediate west of the alley.

SUBSURFACE CONDITIONS:

The geotechnical information indicates that the subsurface materials consist of fill/colluvium and

landslide deposits overlying very stiff to hard glacially over-ridden silt and clay. The groundwater

table is located below the planned base of excavation but perched groundwater seepage can be

anticipated during construction.

SHORING SYSTEM:

The replacement shoring will consist of soldier piles supported by rakers and associated walers. The

rakers will in turn be supported by toe piles and the rakers will be pre-loaded to control displacements

of the alley. A single row of rakers will be employed. After installing the soldier piles, the

construction sequence will consist of sequential excavation of the face and placement of the wood

lagging. A berm will be left in place, starting at just below the planned elevation of the raker

supports. Following excavation to the planned base of the excavation and installation of the toe piles,

the rakers will be installed and pre-loaded. The berm will then be removed from beneath and

between the installed rakers. In addition to the above, small bar anchors will be installed and attached

to each of the internally braced soldier piles. These anchors will not contribute to overall stability,

which will be provided by the raker supports, but will simply reduce the flexural demand on the

soldier piles until the rakers can be installed.

DESIGN PARAMETERS:

Design earth pressures corresponding to the soil self-weight are recommended in the geotechnical

report. For the raker supported soldier piles, the soil self-weight was modeled using an equivalent

fluid density of 45 psf/ft, per the recommendations of the geotechnical report.

Live load lateral surcharge pressures were taken as 100 psf.

3

Ground Support PLLC

The following design values were used to evaluate the depth of embedment of the soldier piles below

the base of the excavation:

Passive Equivalent Fluid Density 300 pcf over 2 pile diameters

150 pcf over 2 pile diameters for berm

300 pcf over 3 pile diameters for toe pile

Active Equivalent Fluid Density 45 pcf over 1 pile diameter Allowable Pile Skin Friction 0.75 ksf

Raker Loads:

Individual raker loads are developed from the design earth pressure diagrams presented on the Plans,

using a tributary area method to assign loads to the rakers and to the toe shear in the piles. The results

are presented in Appendix A (Table A1). Loads indicated are per pile, with the raker loads being

twice these loads as each raker supports two adjacent soldier piles. Design calculations for the raker

and associated walers are shown in Table 1.

Soldier Piles:

Soldier pile loadings were determined from the design earth pressure diagrams and the locations and

inclinations of the raker supports. The spreadsheet output presented in Appendix A (Table A2)

summarizes the following design aspects for the final condition following completion of the

excavation:

Calculation of soldier pile loads and bending moments, consistent with the design apparent earth

pressure diagrams provided on the Plans. For each soldier pile, the calculated shear force, axial

load and bending moment are provided. Representative earth pressure diagrams, together with

calculated shear force and bending moment diagrams, are also shown for a number of piles, in

Appendix A.

Calculation of pile toe embedment requirements (for lateral support and uplift resistance) using

the criteria indicated on the Plans.

Pile structural steel sizing in accordance with the AISC 360-05 Specification for Structural Steel

Buildings. Combined flexure and axial load, shear, and compact section steel design checks are

performed for the critically loaded section of each pile along the length of the wall. The

spreadsheet output summarizes the minimum steel section required for each pile.

Also shown in Appendix A are the corresponding design calculations for the toe piles that support the

rakers (Table A3 and Figure A4).

Table A4 and Figure A5 show design calculations for the intermediate condition where the soldier

piles act in a cantilevered condition, prior to the installation of the rakers, and where small bar

anchors provide nominal support.

Lagging:

Timber lagging will be used to support the soil between adjacent soldier piles. The average design

earth pressures for the lagging are indicated in Appendix A, and these design earth pressures are

derived directly from the design earth pressure diagrams. Hem-Fir No. 2 lagging (4-inch) or

equivalent will provide adequate support for the soil between the soldier piles, per the

recommendations of the FHWA Engineering Circular No. 4.

4

Ground Support PLLC

TABLES

Available Available Flexure Available

Axial Bending Maximum Axial Flexural & Flexure Shear

Load Shear Moment Span Steel Strength Axial Strength Axial & Strength Shear

P V M L Steel Grade Pa Design Ma Design Axial Va Design Shear

Case Analysis Case (k) (k) (ft-k) (ft) Section (ksi) (k) Ratio (ft-k) Ratio Status (k) Ratio Status

1 Waler 0.0 170.0 380.0 5.0 W14x132 50.0 1,156.3 0.00 585.0 0.65 OK 190.6 0.89 OK

2 Waler Stubout 170.0 0.0 30.0 3.0 HSS12x6x3/8 46.0 324.1 0.52 103.0 0.78 OK 136.1 0.00 OK

3 Raker Type 1 260.0 0.0 45.5 56.0 Pipe18x5/8 36.0 393.1 0.66 339.8 0.91 OK 221.1 0.00 OK

4 Raker Type 2 310.0 0.0 33.4 48.0 Pipe18x5/8 36.0 464.4 0.67 339.8 0.83 OK 221.1 0.00 OK

TABLE 1

STRUCTURAL ELEMENT DESIGN

5

Ground Support PLLC

APPENDIX A

DESIGN CALCULATIONS

Design Pile Top Pile Toe Pile Toe Pile Lagging

L=NH2

Unif. Press. Elevation Angle Anchor Load No. of Total Length Bond Length Beam Elevation Embed Elevation Length Pressure

Pile ID Station (ft) Height (ft) Spacing (ft) No. Anchors N (psf/ft) P (psf) (feet) (degrees) (kips) Strands (feet) (feet) (feet) (feet) (feet) (feet) (psf)

W8 255.5 36.2 5 1 22.5 100 113.00 -29.75 136 4 91.8 54.4 W21x111 128.0 13.4 77.0 51.0 1728

W8A 260.5 36.3 6.25 1 22.5 100 113.00 -29.75 172 5 106.2 68.7 W21x132 128.0 16.5 74.0 54.0 1732

W9 268 36.4 6.25 1 22.5 100 113.00 -29.75 173 5 106.8 69.3 W21x132 128.0 16.6 74.0 54.0 1738

W9A 273 37.0 4.25 1 22.5 100 113.00 -29.75 122 4 87.2 48.9 W21x101 128.0 12.9 77.0 51.0 1764

W10 276.5 39.0 4.25 1 22.5 100 113.00 -31.1 134 4 96.6 53.7 W21x132 128.0 13.8 74.0 54.0 1857

W10A 281.5 36.6 4.5 1 22.5 100 113.00 -31.1 129 4 90.9 51.7 W21x101 128.0 13.3 77.0 51.0 1748

W11 285.5 36.7 4.5 1 22.5 100 113.00 -31.1 130 4 91.1 51.9 W21x101 128.0 13.4 77.0 51.0 1751

W12 290.5 34.5 5 1 22.5 100 113.00 -31.1 131 4 88.4 52.5 W18x97 128.0 13.5 79.0 49.0 1651

Anchor 1

TABLE A1

RAKER DESIGN LOADS

2

Axial Free Pile Pile Pile Pile Pile End Skin Axial Embed

Design Load Moment Length Steel Flex/Ax Diameter End Area Skin Area End Bear Skin Frict Bearing Friction Load Length

Pile ID Beam (kips) (ft-kips) (feet) Section Ratio (ft) (ft^2) (ft^2/ft) (ksf) (ksf) (kips) (klf) (kips) (ft)

W8 W21x111 -67 630 22.00 W21x111 0.94 2.50 4.91 7.85 12.00 0.75 0.0 5.9 -67 13.4

W8A W21x132 -85 799 22.00 W21x132 1.00 2.50 4.91 7.85 12.00 0.75 0.0 5.9 -85 16.5

W9 W21x132 -86 802 22.00 W21x132 1.00 2.50 4.91 7.85 12.00 0.75 0.0 5.9 -86 16.6

W9A W21x101 -61 597 22.50 W21x101 0.98 2.50 4.91 7.85 12.00 0.75 0.0 5.9 -61 12.3

W10 W21x132 -69 745 24.50 W21x132 0.93 2.50 4.91 7.85 12.00 0.75 0.0 5.9 -69 13.8

W10A W21x101 -67 588 22.00 W21x101 0.97 2.50 4.91 7.85 12.00 0.75 0.0 5.9 -67 13.3

W11 W21x101 -67 589 22.00 W21x101 0.97 2.50 4.91 7.85 12.00 0.75 0.0 5.9 -67 13.4

W12 W18x97 -68 474 19.69 W18x97 0.94 2.50 4.91 7.85 12.00 0.75 0.0 5.9 -68 13.5

Pile Vertical Load Analysis Toe Dist. Depth (ft)

Soldier Beam Loads-Below Anchor 1

TABLE A2

SOLDIER PILE DESIGN

Axial Free

Design Load Moment Length Steel Flex/Ax

Pile ID Beam (kips) (ft-kips) (feet) Section Ratio

TP W30x292 150 2483 0.50 W30x292 0.97


TABLE A3

TOE PILE DESIGN

Axial Free

Axial Load Shear Force Steel Shear Design Load Moment Length Steel Flex/Ax

Pile ID (kips) (kips) Section Ratio Beam (kips) (ft-kips) (feet) Section Ratio

C 9 31 W14x34 0.38 W18x86 9 425 16.50 W18x86 0.95


TABLE A4

SOLDIER PILE DESIGN LOADS

STAGE 1 PRIOR TO RAKER INSTALLATION

Depth (ft)

0

0.098

0.197

0.295

0.394

0.492

0.591

0.689

0.787

0.886

0.984

1.083

1.181

1.280

1.378

1.477

1.575

1.673

1.772

1.870

1.969

2.067

2.166

2.264

2.362

2.461

2.559

Wall Height (ft) 36.4

Pile Spacing (ft) 6.25

FIGURE A1 SOLDIER BEAM - W9

-6000

-4000

-2000

0

2000

4000

0 10 20 30 40 50 60

(ps

f)

Depth (ft)

Eart

h P

res

su

re

-150

-100

-50

0

50

100

0 10 20 30 40 50 60

(kip

s)

Depth (ft)

Sh

ea

r F

orc

e

-1000

-800

-600

-400

-200

0

200

400

0 10 20 30 40 50 60(f

t-k

ips

)

Depth (ft)

Ben

d.

Mo

men

t

Point Depth Pressure Width Force Depth(CG) Moment

A 0.00 0.0 6.25 FAB 186233 24.26 4647686

B 36.39 1637.6 6.25 FBC 0 0.00 0

C 36.39 1637.6 6.25 FCD 0 0.00 0

D 36.39 0.0 6.25 FAD 186233 24.26

36.39 0.0

E 36.39 1637.6 2.50 FEF 61762 43.12 376295

F 49.22 2214.8 2.50

49.22 0.0

G 38.39 0.0 5.00 FGH 0 0.00 0

H 38.39 -600.0 5.00 FHI -120376 45.12 -492987

I 49.22 -3847.7 5.00 FIJ 0 0.00 0

J 49.22 -3847.7 5.00 FJK 0 0.00 0

K 49.22 -3847.7 5.00 FGK -120376 45.12

49.22 0.0

0.00 0.0

L 0.00 100.0 6.25 FLM 22745 18.20 705569

M 36.39 100.0 6.25

36.39 0.0

0.00 0.0

N 0.00 0.0 6.25 FNO 0 0.00 0

O 0.00 0.0 6.25

0.00 0.0

0.00 0.0

P 0.00 0.0 6.25 FPQ 0 0.00 0

Q 0.00 0.0 6.25

0.00 0.0

0.00 0.0

R 0.00 0.0 6.25 FRS 0 0.00 0

S 0.00 0.0 6.25

0.00 0.0

T 36.39 0.0 6.25 FTU 0 0.00 0

U 36.39 0.0 6.25 FUV 0 0.00 0

V 36.39 0.0 6.25 FVW 0 0.00 0

W 46.39 0.0 6.25 FTW 0 0.00

46.39 0

Anchor 1 150365 14.39 5236564

Amchor 2 0 0.00 0

Anchor 3 0 0.00 0

Anchor 4 0 0.00 0

Load 1 0 0.00 0

S Forces 0 S Moments 0

FIGURE A1 (cont'd) SOLDIER BEAM - W9

F AD

F EF

F GK

F LM

F TWF NOF PQ

F RS

A 1

A 2A 3A 4L 1

-5000.0

-4000.0

-3000.0

-2000.0

-1000.0

0.0

1000.0

2000.0

3000.0

4000.0

5000.0

6000.0

0.00 10.00 20.00 30.00 40.00 50.00 60.00

Pre

ssu

re (

psf

)

Depth (ft)

Depth (ft)

0

0.106

0.211

0.317

0.423

0.528

0.634

0.740

0.845

0.951

1.057

1.162

1.268

1.374

1.479

1.585

1.691

1.796

1.902

2.007

2.113

2.219

2.324

2.430

2.536

2.641

2.747




-6000

-4000

-2000

0

2000

4000

0 10 20 30 40 50 60

(ps

f)

Depth (ft)

Eart

h P

res

su

re

-150

-100

-50

0

50

100

0 10 20 30 40 50 60

(kip

s)

Depth (ft)

Sh

ea

r F

orc

e

-800

-600

-400

-200

0

200

0 10 20 30 40 50 60

(ft-

kip

s)

Depth (ft)

Ben

d.

Mo

men

t

Point Depth Pressure Width Force Depth(CG) Moment

A 0.00 0.0 4.25 FAB 145738 26.03 3906142

B 39.04 1756.8 4.25 FBC 0 0.00 0

C 39.04 1756.8 4.25 FCD 0 0.00 0

D 39.04 0.0 4.25 FAD 145738 26.03

39.04 0.0

E 39.04 1756.8 2.50 FEF 71258 46.28 466726

F 52.83 2377.3 2.50

52.83 0.0

G 41.04 0.0 4.25 FGH 0 0.00 0

H 41.04 -600.0 4.25 FHI -118671 48.40 -525431

I 52.83 -4136.9 4.25 FIJ 0 0.00 0

J 52.83 -4136.9 4.25 FJK 0 0.00 0

K 52.83 -4136.9 4.25 FGK -118671 48.40

52.83 0.0

0.00 0.0

L 0.00 100.0 4.25 FLM 16592 19.52 552652

M 39.04 100.0 4.25

39.04 0.0

0.00 0.0

N 0.00 0.0 4.25 FNO 0 0.00 0

O 0.00 0.0 4.25

0.00 0.0

0.00 0.0

P 0.00 0.0 4.25 FPQ 0 0.00 0

Q 0.00 0.0 4.25

0.00 0.0

0.00 0.0

R 0.00 0.0 4.25 FRS 0 0.00 0

S 0.00 0.0 4.25

0.00 0.0

T 39.04 0.0 4.25 FTU 0 0.00 0

U 39.04 0.0 4.25 FUV 0 0.00 0

V 39.04 0.0 4.25 FVW 0 0.00 0

W 49.04 0.0 4.25 FTW 0 0.00

49.04 0

Anchor 1 114916 14.54 4400090

Amchor 2 0 0.00 0

Anchor 3 0 0.00 0

Anchor 4 0 0.00 0

Load 1 0 0.00 0

S Forces 0 S Moments 0

FIGURE A2 (cont'd) SOLDIER BEAM - W10

F AD

F EF

F GK

F LM

F TWF NOF PQ

F RS

A 1

A 2A 3A 4L 1

-6000.0

-4000.0

-2000.0

0.0

2000.0

4000.0

6000.0

0.00 10.00 20.00 30.00 40.00 50.00 60.00

Pre

ssu

re (

psf

)

Depth (ft)

Depth (ft)

0

0.098

0.197

0.295

0.393

0.491

0.590

0.688

0.786

0.885

0.983

1.081

1.179

1.278

1.376

1.474

1.573

1.671

1.769

1.868

1.966

2.064

2.162

2.261

2.359

2.457

2.556




-6000

-4000

-2000

0

2000

4000

0 10 20 30 40 50 60

(ps

f)

Depth (ft)

Eart

h P

res

su

re

-100

-50

0

50

100

0 10 20 30 40 50 60(kip

s)

Depth (ft)

Sh

ea

r F

orc

e

-800

-600

-400

-200

0

200

0 10 20 30 40 50 60

(ft-

kip

s)

Depth (ft)

Ben

d.

Mo

men

t


Depth of Embed (ft) 25.45

Depth to Top of Passive (ft) 2.50

moment moment

Force p (psf) Kg (psf) h (ft) w (ft) phw (lbf) Kg h2w/2 (lbf) depth (ft) arm (ft) (ft-lbf)

A1 0.0 0.50 10.00 260000 0.00 25.95 6746636

A2 0.0 0.50 10.00 0 0.33 25.62 0

A3 0.0 25.45 3.50 0 13.22 12.72 0

A4 0.0 25.45 3.50 0 17.47 8.48 0

P1 600.0 23.45 10.00 140692 14.22 11.72 1649511

P2 300.0 23.45 10.00 824755 18.13 7.82 6446453

P3 0.0 0.00 10.00 0 25.95 0.00 0

P4 0.0 0.00 10.00 0 25.95 0.00 0

Moments about pile toe Sum of resisting moments (ft-lbf) 8095963

Sum of driving moments (ft-lbf) 6746636

FS 1.20

Depth to Zero Shear (ft) at "M" 13.82

moment moment


a1 0.0 0.50 10.00 260000 0.00 13.82 3592331

a2 0.0 0.50 10.00 0 0.33 13.48 0

a3 0.0 13.32 3.50 0 7.16 6.66 0

a4 0.0 13.32 3.50 0 9.38 4.44 0

p1 600.0 11.32 10.00 67900 8.16 5.66 384200

p2 300.0 11.32 10.00 192100 10.04 3.77 724643

p3 0.0 0.00 10.00 0 0.00 13.82 0

p4 0.0 0.00 10.00 0 0.00 13.82 0

Moments at Zero Shear Point Sum of shear forces (lbf) at "M" 0

Sum of moments (ft-lbf) at "M" 2483487

FIGURE A4 SOLDIER BEAM - TP

Re

sis

tin

gD

rivin

gR

esis

tin

gD

rivin

g

A1

A2

A3

A4

P1

P2

M

P3

P4

A5

A6

A7

A8

A9

A10

W1

W2 W

4W

3W

2a

-10000.0

-8000.0

-6000.0

-4000.0

-2000.0

0.0

2000.0

4000.0

0.0 5.0 10.0 15.0 20.0 25.0 30.0

Pre

ssu

re (

psf)

Depth (ft)

Earth Pressure


Depth of Embed (ft) 25.90

Depth to Top of Passive (ft) 18.50

moment moment moment moment

Force p (psf) Kg (psf) h (ft) w (ft) phw (lbf) Kg h2w/2 (lbf) depth (ft) arm (ft) (ft-lbf) Force p (psf) Kg (psf) h (ft) w (ft) phw (lbf) Kg h

2w/2 (lbf) depth (ft) arm (ft) (ft-lbf)

A1 100.0 16.50 5.00 8250 8.25 34.15 281732 A5 0.0 0.00 5.00 -12000 8.00 34.40 -412792

A2 45.0 16.50 5.00 30628 11.00 31.40 961703 A6 0.0 0.00 5.00 0 0.00 42.40 0

A3 742.5 25.90 2.50 48076 29.45 12.95 622564 A7 0.0 0.00 5.00 0 0.00 42.40 0

A4 45.0 25.90 2.50 37731 33.77 8.63 325737 A8 0.0 0.00 5.00 0 0.00 42.40 0

P1 300.0 23.90 5.00 35849 30.45 11.95 428384 A9 0.0 0.00 5.00 0 0.00 42.40 0

P2 150.0 23.90 5.00 214192 34.43 7.97 1706349 A10 0.0 0.00 5.00 0 0.00 42.40 0

P3 0.0 0.00 5.00 0 42.40 0.00 0

P4 0.0 0.00 5.00 0 42.40 0.00 0

Moments about pile toe

Moments about pile toe Sum of resisting moments (ft-lbf) 2134733

Sum of driving moments (ft-lbf) 1778944 moment moment


FS 1.20 a5 0.0 0.00 5.00 -12000 8.00 21.29 -255436

Depth to Zero Shear (ft) at "M" 29.29 a6 0.0 0.00 5.00 0 0.00 29.29 0

moment moment a7 0.0 0.00 5.00 0 0.00 29.29 0

Force p (psf) Kg (psf) h (ft) w (ft) phw (lbf) Kg h2w/2 (lbf) depth (ft) arm (ft) (ft-lbf) a8 0.0 0.00 5.00 0 0.00 29.29 0

a1 100.0 16.50 5.00 8250 8.25 21.04 173550 a9 0.0 0.00 5.00 0 0.00 29.29 0

a2 45.0 16.50 5.00 30628 11.00 18.29 560077 a10 0.0 0.00 5.00 0 0.00 29.29 0

a3 742.5 12.79 2.50 23735 22.89 6.39 151740

a4 45.0 12.79 2.50 9196 25.02 4.26 39196

p1 300.0 10.79 5.00 16180 23.89 5.39 87259 Moments at Zero Shear Point

p2 150.0 10.79 5.00 43630 25.69 3.60 156868

p3 0.0 0.00 5.00 0 0.00 29.29 0

p4 0.0 0.00 5.00 0 0.00 29.29 0 moment moment


W1 0 0.00 2.50 0 16.50 25.90 0

Moments at Zero Shear Point Sum of shear forces (lbf) at "M" 0 W2 0.0 0.00 2.50 0 16.50 25.90 0

Sum of moments (ft-lbf) at "M" 424999 W3 0.0 10.00 2.50 0 19.83 22.57 0

W4 0.0 10.00 2.50 0 21.50 20.90 0

W2a 0.0 0.00 2.50 0 16.50 25.90 0

Moments about pile toe

moment moment


w1 0 0.00 2.50 0 16.50 12.79 0

w2 0.0 0.00 2.50 0 16.50 12.79 0

w3 0.0 12.79 2.50 0 20.76 8.52 0

w4 0.0 12.79 2.50 0 22.89 6.39 0

w2a 0.0 0.00 2.50 0 16.50 12.79 0

Moments at Zero Shear Point

FIGURE A5 SOLDIER BEAM - C

Re

sis

ting

Dri

vin

gR

esis

ting

Dri

vin

g

A1

A2 A3

A4

P1

P2

M

P3

P4

A5

A6

A7

A8

A9

A10

W1

W2 W

4W

3W

2a

-5000.0

-4000.0

-3000.0

-2000.0

-1000.0

0.0

1000.0

2000.0

3000.0

0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 45.0

Pre

ssu

re (

psf)

Depth (ft)

Earth Pressure

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