Agenda packet — San Carlos City Council, June 27, 2022 (part 4 of 6)

Grades above the central part of the wall generally slope gently to the south and east at inclinations of about 5:1. Level grades above the wall at the northern and western/southern ends extend between 3 and 4-feet to existing, 2- to 3-foot high concrete landscape walls beyond. Below the wall, about 12-inches of level grade exists between the roadway’s concrete gutter pan and the base of the wall.

Exposed slopes at the failed section of wall are underlain by near-vertically bedded, very hard, and very strong Franciscan chert bedrock, which strikes nearly perpendicular to the face of the wall.

Locally, we noted evidence of up to about 1-foot of apparently silty/clayey backfill soil in a small wedge near the top of the wall. No significant evi dence of expansive soils or instability or native soil/rock materials was observed. A Site Plan, show ing the extent of the wall to be replaced, the extents of the failed portion, and a typical cross section is presented on Figure 2.

Regional Geology and Topography
The project site is located in the Coast Ranges geomorphic province of California, which is typified by generally northwest-trending ridges and intervening valleys formed as a result of movement along a group of northwest-trending fault systems, including the San Andreas Fault. The San Andreas Fault Zone effectively bisects San Mateo County in a northwesterly direction. East of the fault, bedrock geology is dominated by complex ly deformed and altered sedimentary, igneous, and metamorphic rock of the Jurassic-Cretaceous age (65 to 190-million years old) Franciscan Complex, which is locally overlain by geologically young alluvial and colluvial deposits, including Bay Mud. Geology west of the fault is dominated by Cretaceous granites of the Salinian block, which are locally overlain by younger sedimentary and lesser igneous rocks.

Regional geologic mapping
1 indicates that the project site is primarily underlain by chert commonly associated with the Franciscan Formation. It is described as white, green, red, and orange chert, in places interbedded with reddish −brown shale. Chert and shale commonly are rhythmically banded in thin layers, but chert also crops out in very thick layers. A surface trace of the inactive Belmont Hill Fault is mapped about 400-feet east of the site, passing on a north-northwesterly trend. A regional geologic map is shown on Figure 3.

Geologic Hazards Evaluation
The principal geologic hazard which could potentially affect the project site is strong seismic shaking. Other hazards, such as fault surface rupture, liquefaction, flooding, settlement, et cetera are not considered to have a significant impact to the current project. Geologic hazards, their impacts, and recommended measures are discussed below.

Seismic Shaking
The site will likely experience seismic ground shaking from future earthquakes in the San Francisco Bay Area. Earthquakes along several active faults in the region, as shown on Figure 4, could cause moderate to strong ground shaking at the site.

Deterministic Seismic Hazard Analysis (DSHA) predicts the intensity of earthquake ground motions by analyzing the characteristics of nearby faul ts, distance to the faults and rupture zones,

1 E.E. Brabb, et all. 1998. “Geology of the Onshore Part of San Mateo Coun ty, California: Derived from a Digital Database Open File 98-137” by United States Geological Survey. Map Scale 1:62500 BLD2021-00899

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earthquak
e magnitudes, earthquake durations, and site-specific geologic conditions. Empirical relations (Campbell and Borzognia, Chiou and Youngs, 2014) for the very stiff soil/soft rock (?)subsurface conditions were utilized to provide approximate estimates of median site peak ground accelerations (PGA). A summary of the principal active faults affecting the site, their closest distance, maximum moment magnitude, probable median PGAs, and 84 th Percentile PGA which an
earthquake on the fault could generate at the site are shown in Table 1 Table 1 – Deterministic Peak Ground Accelerations for Active Faults Fault
Moment
Magnitude for
Characteristic
Earthquake
Closest
Estimated
Distance (km)(1)
Median Peak
Ground
Acceleration (g)(2)
Median PGA
+1 Std Dev (g)(2)
San Andreas 8.0 5.2 0.47 0.85
San Gregorio 7.4 18.1 0.22 0.39
Hayward 7.3 24.5 0.17 0.30
Monte Vista-
Shannon 6.4 14.1 0.18 0.32
Cascade 6.7 18.9 0.16 0.29
(1) Estimated using CalTrans Google Earth Faul t Database (2013), accessed on September 22, 2020.
(2)
Estimated using Campbell & Bozorgni a, and Chiou & Youngs 2014 NGA models using Vs30=560 m/s.

The calculated bedrock accelerations should only be considered as reasonable estimates. Many factors (soil conditions, orientation to the fault, etc.) can influence the actual ground surface accelerations.

Ground shaking can result in structural failure and collapse of structures or cause non-structural building elements, such as light fixtures, shelves, cornices, etc., to fall, presenting a hazard to building occupants and contents. Compliance with provisions of the California Building Code (CBC) should result in structures that do not collapse in an earthquake. Damage may still occur, and hazards associated with falling objects or non-structural building elements will remain.

The potential for strong seismic shaking at the project site is high. Due to proximity and/or historic seismic activity, the San Andreas, San Gregorio, and Monte Vista-Shannon Faults present the highest potential for ground shaking. The significant adverse impact associated with strong seismic shaking is potential damage to structures and improvements.

Evaluation: Less than significant with mitigation.

Mitigation: Mitigation measures should include designing the improvements and structures in accordance with the most recent (2019) version of the California Building Code.

The new wall should be designed in consideration of seismic surcharge loads.

Recommended CBC seismic coefficients and spectral accelerations are provided in the Seismic Design section of this report.

Conclusions
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Based
on our observations, we judge that wall failure is likely the result of a combination of factors, primarily age, a lack of internal reinforcement, and a lack of adequate drainage provisions. Several options may be considered for retaining wall replacement, depending on desired aesthetics and level of cost.

We understand that on a preliminary basis, the City is interested in lowering the effective wall height via excavation above the wall to create steeper back-slopes. Note that this approach is generally feasible from a geotechnical standpoint, and may be combined with any of the following structural wall options as a means of reducing the required retaining wall height. For design purposes, permanent slopes at the site should be inclined no steeper than 1:1 (horizontal:vertical), and new surface drainage (concrete ditch or earthen swale) should be provided at the back of the wall.

Detailed discussion of each structural wall option is provided in the following sections OPTION 1 – SOLDIER PILE AND TIMBER LAGGING RETAINING WALL For a timber lagging wall, drilled pier shafts would be drilled in front of the existing wall (or in-line, if the existing wall is demolished entirely) and fitted with steel H-beams. Pressure-treated timber would be placed between the H-beams, and the narrow void between the new wall and the existing wall or cut slope would be filled with drainage materials and backfill. Advantages to this option include the ability to construct such a wall in a “modular” fashion, which may allow for phased implementation if the cost of replacing the entire wall at once is of concern. Provided that steel H-beam elements are appropriately corrosion-protected, this wall should provide a reasonable service life of at least 40- to 50-years or more, with maintenance generally limited to replacement of timber lagging elements as needed due to age/rot on anticipated 15 to 30-year intervals.

The primary disadvantage to this option is the potential for time-consuming and expensive hard rock drilling to achieve the necessary pier embedments, especially if the maximum wall height is not reduced. A soldier-pile and timber lagging retaining wall is expected to cost on the order of $150 per square foot based on bids collected over the last several years. Assuming replacement of the entire 150-foot section (and based on an average retained height of 5-feet), we anticipate this option would cost on the order of $100,000 to $125,000 to construct, depending on ultimate wall height and attendant required pier depths.

OPTION 2 – REINFORCED CONCRETE RETAINING WALL
A reinforced concrete wall could also be considered. Concrete walls could be supported on a shallow footing foundation, thereby omitting the drilling cost associated with timber walls. However, concrete walls are more labor-intensive due to the need for construction of forms and steel rebar reinforcement. Excavation would need to extend into the roadway to accommodate the retaining wall footing, thereby necessitating ancillary replacement of the concrete gutter pan and disturbed asphalt areas. Concrete walls may generally be provided with a variety of aesthetic finishes if desired. Provided that quality materials are used and sufficient concrete cover over rebar is provided, concrete walls may be expected to provide a reasonable service life of 40 to 50 years.

Costs are expected to be slightly higher than a soldier-pile wall, on the order of about $200 per square foot. Assuming replacement of the entire 150-foot section (and based on an average retained height of 5-feet), we anticipate this option would cost on the order of $150,000 to construct.

OPTION 3 – SOIL NAIL AND SHOTCRETE RETAINING WALL
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This option would include drilling sub-horizontal tiebacks (soil nails) into the exposed chert cut slope (or through the remaining portions of the existing wall facing), then filling drilled holes with grouted, corrosion-protected rebar. These soil nails are then structurally connected to a rebar wall facing and shallow footing, and geocomposite drainage panels are applied to the back of the wall prior to shotcrete placement.

This option could be advantageous in that soil-nail drilling is typically very efficient in hard rock.

Footing dimensions would likely be reduced versus a “traditional” cantilevered retaining wall, and as such may require less disturbance to the gutter pan and roadway. This option is judged especially advantageous in the event wall heights cannot be reduced. This option could be implemented in phases if needed, and could also be provided with a variety of textures and aesthetic finishes. As with Option #1, a soil nail and shotcrete retaining wall is expected to cost on the order of $150 per square foot based on bids collected over the last several years. Assuming replacement of the entire 150-foot section (and based on an average retained height of 5-feet), we anticipate this option would cost on the order of $100,000 to construct.

OPTION 4 – GRADE SLOPE AND OMIT OR SHORTEN WALL
This option would entail excavating existing chert bedrock to lay the slope back to an acceptable permanent inclination. For planning purposes, we recommend that permanent slopes be designed no steeper than 1:1. Depending on the limits of grading at the top of the slope, this option could be designed to completely omit the retaining wall, or could be used in conjunction with a shorter soldier pile or reinforced concrete wall.

This option may in advantageous in that it would omit or lessen costs associated with retaining wall construction. However, as not ed, the bedrock underlying the site is very hard, and special excavation techniques and equipment, such as medium to heavy excavators equipped with jackhammers or hoe-rams, could be required to complete the excavation. Excavation spoils will need to be offhauled and disposed of. Other non-geotechnical considerations may include the need for easements or other arrangements if grading work is proposed on private property, and safety of creating a steep slope adjacent to the private yard.

Recommendations
Based on our evaluation, we judge that Option #3 (Soil Nail and Shotcrete Retaining Wall) is likely the most cost-effective option if the planned wall height will remain unchanged. If grading work is performed to reduce the effective required wall height, then Option 2 is likely the most cost-effective.

Note that the extents of the public right-of-way and the City’s ability to perform work on private property may impact the feasibility of laying back the slope.

We are available to consult with you to assist in selection of the “preferred” retaining wall option, if desired. As discussed above, we anticipate performing supplemental calculations to design the new wall and provide construction details and technical specifications once the “preferred” option has been identified.

We trust that this letter contains the information you require at this time. Please do not hesitate to contact us of there are any questions or concerns.

Very truly yours,

MILLER PACIFIC ENGINEERING GROUP
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Mike Jewett
Engineering Geologist #2610
(Expires 1/31/21)
Attachments: Figures 1-4
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Attachment: 447 Hillcrest Wall Replacement Plans and Specifications (Approve Plans and Specs for the 447 Hillcrest Rd Wall Replacement REFERENCE: Google Earth, 2019
SITE LOCATIONN.T.S.

NORTH
SITE
FIGURE
Drawn
Checked
Project No. Date: 9/14/2020
504 Redwood Blvd.Suite 220Novato, CA 94947T 415 / 382-3444F 415 / 382-3450 www.millerpac.comFILENAME: 1465.095 Standard Figures.dwgA CALIFORNIA CORPORATION, © 2020, ALL RIGHTS RESERVED 1 SITE LOCATION MAP447 Hillcrest RoadSan Carlos, California 1465.095
ZMS
SITE COORDINATESLAT. 37.5029°LON. -122.2691°
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Attachment: 447 Hillcrest Wall Replacement Plans and Specifications (Approve Plans and Specs for the 447 Hillcrest Rd Wall Replacement A
A'
Existing Wall
Gutter Pan
Collapsed Section
Existing Stairs

SITE PLAN

AA' TYPICAL CROSS SECTION
DrawnChecked
Designed
Project No.Date: 8/3/2016FIGURE
504 Redwood Blvd.Suite 220Novato, CA 94947T 415 / 382-3444F 415 / 382-3450www.millerpac.comA CALIFORNIA CORPORATION, © 2016, ALL RIGHTS RESERVED FILE: 1465.095 Standard Figures.dwg
447 Hillcrest RoadSan Carlos, California1465.095

SITE PLAN
ZMSZMS
MFJ2
SCALE0102040 FEET
N
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fg
Belmont Hill Fault

REGIONAL GEOLOGIC MAP
SITE
NORTH
FIGURE
Drawn
Checked
Project No. Date: 9/14/2020
504 Redwood Blvd.Suite 220Novato, CA 94947T 415 / 382-3444F 415 / 382-3450 www.millerpac.comFILENAME: 1465.095 Standard Figures.dwgA CALIFORNIA CORPORATION, © 2020, ALL RIGHTS RESERVED 3 REGIONAL GEOLOGIC MAP447 Hillcrest RoadSan Carlos, California 1465.095
ZMS
Sandstone - Greenish gray to buff, fine to coarse−grainedsandstone (graywacke), with interbedded siltstone andshale.

Greenstone - Dark green to red altered basaltic rocks,including flows, pillow lavas, breccias, tuff breccias, tuffs,and minor related intrusive rocks, in unknown proportions.

Chert - White, green, red, and orange chert, in placesinterbedded with reddish−brown shale. Chert and shalecommonly are rhythmically banded in thin layers, but chertalso crops out in very thick layers.

Geologic Contact: Depositional or intrusive Contact,dashed where approximate, dotted where concealed Fault: Dashed where approximate, dashed where inferred,dotted where concealed Artificial Fill - Loose to very well consolidated gravel, sand,silt, clay, rock fragments, organic matter, and man−madedebris in various combinations.

Alluvial Fan and Fluvial Deposits − Alluvial fan deposits arebrown or tan, medium dense to dense, gravely sand or sandygravel that generally grades upward to sandy or silty clay.

Alluvial Fan and Fluvial Deposits - Brown dense gravely andclayey sand or clayey gravel that fines upward to sandy clay.These deposits display variable sorting and are located alongmost stream channels in the county.They are distinguishedfrom younger alluvial fans and fluvial deposits by highertopographic position, greater degree of dissection, andstronger soil profile development.

LEGEND
Reference: E.E. Brabb, et all. 1998. “Geology of the Onshore Part of San Mateo County, California: Derived from a Digital Database Open File98-137” by United States Geological Survey. Map Scale 1:62500 BLD2021-00899

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0 12.525 50 MILES
SITE
25 MILES
50 MILES
NORTH
FIGURE
Drawn
Checked
Project No. Date: 9/14/2020
504 Redwood Blvd.Suite 220Novato, CA 94947T 415 / 382-3444F 415 / 382-3450 www.millerpac.comFILENAME: 1465.095 Standard Figures.dwgA CALIFORNIA CORPORATION, © 2020, ALL RIGHTS RESERVED 4 ACTIVE FAULT MAP447 Hillcrest RoadSan Carlos, California 1465.095
ZMS
SITE COORDINATESLAT. 37.5029°LON. -122.2691°
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APPENDIX C

STRUCTURAL DESIGN CALCULATIONS

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STRUCTURAL DESIGN CALCULATIONS

SOIL NAIL WALL FOR WALL STABILIZATION
447 Hillcrest Road
San Carlos, CALIFORNIA 94070

Prepared for:

Bellecci & Associates, Inc.
2290 Diamond Boulevard, Ste. 100
Concord, California 94520

Project No. 1465.095

October 19, 2021

Prepared by:

MILLER PACIFIC ENGINEERING GROUP REVIEWED BY

Ronald Burgess Ben Pappas
Geotechnical Engineer No. 2786
(Expires 9/30/23)

Reviewed for Code Compliance
CSG CONSULTANTS, INC.
02/04/2022
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October 2021 1 Miller Pacific Engineering Group
3 Design Summary and Calculations

To: Mr. Robert Broestl, P.E. Project: 447 Hillcrest Road Soil Nail Wall From: Ben Pappas, GE cc: Mr. Manny Abucay, P.E.

Date: September 30, 2021 Job No.: 1465.095
Subject: Design Summary for Soil Nail Wall

Revision Log
Revision No. Date Revision Description
0 October 19, 2021 Issued for 100% Review

Attachments
Attachment
1 Design Calculations SNAIL output (54 Pages)
2 Technical Specifications Sections 2210, 2286, and 3360 (16 Pages) 3 100% Plans and Details Sheets 1 through 5
4 Geotechnical Evaluation Letter dated 9/24/2020 (10 Pages)

Mike Jewett Ben Pappas
Engineering Geologist No. 2610 Geotechnical Engineer No. 2789 (Expires 1/31/23) (Expires 9/30/22)
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Attachment: 447 Hillcrest Wall Replacement Plans and Specifications (Approve Plans and Specs for the 447 Hillcrest Rd Wall Replacement 447 Hillcrest Road, San Carlos Design Summary for Soil Nail Wall October 2021 2 Miller Pacific Engineering Group

1.0 Introduction
This technical memorandum summarizes Miller Pacific Engineering Group’s engineering approach and design calculations for the new soil nail wall planned at 447 Hillcrest Road in San Carlos, California. The new concrete retaining wall will be approximately 55 feet long and up to about 9 feet tall. The purpose of the new wall is to retain a steep cut that was formerly supported by an unreinforced grouted -rock wall that has failed. We previously performed a Geotechnical Evaluation for the project, as summarized in our letter report dated September 24, 2020. The new soil nail wall and associated details are shown on the Design Drawings included in Appendix A.

2.0 Geotechnical Design Criteria
We previously performed a site reconnaissance to observe existing conditions and develop conceptual options for wall design and construction, as summarized in our Geotechnical Evaluation for the project, as summarized in our letter report dated September 24, 2020. As noted therein, site observations indicate that the site is underlain by Franciscan chert bedrock, which is typically hard, strong, and bedded near-vertically. Minor sandy to clayey residual soil and wall backfill overlying the chert was observed to be typically less than 1- foot thick. Based on our observations, we conservatively modelled the retained materials (chert and minor overlying soil) with a unit weight of 130 pcf, a friction angle of 30 degrees, and a cohesion of 200 psf. The horizontal seismic coefficient for the site is 0.47.

3.0 Calculations
Our calculations included analyzing wall sections which are generally representative of the maximum loading conditions that are anticipated along the wall alignment. The maximum wall height of 9 -feet, intermediate wall height s of 7-feet, 5-feet, 4-feet, 3-feet, and 2 -feet were the considered scenarios. Our calculations were performed in general accordance with the guidelines outlined in the FHWA Soil Nail Wall Reference Manual (FHWA, 2015). We analyzed the internal stability of the soil nail wall using the computer software Snail developed by Caltrans (Caltrans, 2015). The soil nail wall was checked under static and seismic loading conditions. The horizontal seismic coefficient used in our analysis was calculated through deterministic seismic hazard analysis for a latitude/longitude of 37.50°/-122.27° to be 0.47 g.

The calculated maximum demand for the soil nails within the wall was 11.7 kips, which equates to 14.8 ksi within the soil nail bar , including resistance factors within the SNAIL program. We calculated this demand in the lowest factor of safety failure conditions during seismic conditions on the soil nail wall. The planned soil nails are to have a strength of 75 ksi. See the attached details on the outputs for the various loading cases and calculation details.

4.0 References
Caltrans, “Snail” Soil Nail Wall Design Software, 2015.

Federal Highway Administration, Soil Nail Walls Reference Manual (FHWA GEC 007), Publication No. FHWA-NHI-14-007, February, 2015.

Miller Pacific Engineering Group (2020), “Geotechnical Evaluation, Retaining Wall Replacement, 447 Hillcrest Road, San Carlos, California”, dated September 24, 2020.

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Attachment: 447 Hillcrest Wall Replacement Plans and Specifications (Approve Plans and Specs for the 447 Hillcrest Rd Wall Replacement ====================================================================================================== Snail

Version: 2.2.2

====================================================================================================== File Information
======================================================================================================

File Name: 1465.095 SNAIL.snz
Run Date: 09/24/21
Run Time: 16:08:07

====================================================================================================== Project Information
======================================================================================================

Description: Retaining Wall Repai
Location: 447 Hillcrest Road
EA:

Project ID: 1465.095
Wall No.:

Structure No.:

Station:

Engineer: RGB
Designer

Comments:

====================================================================================================== Geometry
======================================================================================================

Layout:

Reference Point:

At: Toe of Wall
Distance From Origin: 10.00 feet
Elevation Above Origin: 10.00 feet

Wall Dimensions:

Wall Height: 9.00 feet
Facing Angle: 90.00 degrees
Facing Batter: 0.000 :12 H:V

Ground Surface:

Number of lines that define the ground surface above the wall: 1

Angle Distance
No. degrees feet
------------------------
1 0

Number of lines that define the ground surface in front of the toe: 1

Angle Distance
No. degrees feet
------------------------
1 0

Soil Layers:

Number of Layers: 1

Ground Water:

Include Ground Water: No

====================================================================================================== Soil Nails
======================================================================================================

Dimensions and Properties:

Maximum Vertical Spacing: 6.00 feet
Number of Soil Nail Rows: 2

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Attachment: 447 Hillcrest Wall Replacement Plans and Specifications (Approve Plans and Specs for the 447 Hillcrest Rd Wall Replacement Soil Nail Design Parameters: Uniform Throughout Cross-Section Soil Nail Length: 9.00 feet
Inclination From Horizontal: 15 degrees
Vertical Distance from Top of Wall
to First Row: 1.50 feet
Vertical Spacing: 6.00 feet
Horizontal Spacing H: 6.00 feet
Nail Bar Diameter Ø: 1.000 inches
Nail Bar Yield Strength fy: 75.0 ksi

Facing Resistance:

Temporary Permanent Seismic
ASD Allowable Facing Resistance: 25.6 12.8 17.5 kips

====================================================================================================== Soil Properties
======================================================================================================

Unit Weight Friction Angle Cohesion
γ φ' c'
Layer Description pcf degrees psf ----------------------------------------------------------------------------------- 1 Retained 130 30.0 200

====================================================================================================== Loads
======================================================================================================

Applied Loads:

Seismic:

Horizontal Seismic Coefficient Kh0.47:

External Load:

Apply external load: No

Surcharges:

Apply surcharges: No

====================================================================================================== Factors of Safety
======================================================================================================

Temporary Permanent Seismic
Pullout (Distal): 2.00 2.00 1.50
Pullout (Proximal): 2.00 2.00 1.50
Nail Bar Yield: 1.80 1.80 1.35

====================================================================================================== Search Options
======================================================================================================

Search Limits:

Begin: 1.00 feet
End: 50.00 feet

Below Toe Searches (BTS):

Perform below Toe Search: No

Advanced Search Options:

Use Advanced Search Options: No

====================================================================================================== Results
======================================================================================================

Analysis:

Method: ASD
Scenario: Temporary

Factor of Safety:

Minimum: 2.58
Found at Search Point: 3
Found at Grid Point: 54

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Attachment: 447 Hillcrest Wall Replacement Plans and Specifications (Approve Plans and Specs for the 447 Hillcrest Rd Wall Replacement Found at Search Level: Toe of the wall

Load at Soil Nail Head:

Calculated Service Load at Soil Nail Head (Empirical), To: 9.1 kips Allowable Facing Resistance, F_allowable (Entered): 25.6 kips F_allowable ≥ To OK

Nominal Pullout Resistance:

Nominal Pullout Resistance
Layer Description klf
----------------------------------------------
1 Retained 3.167

Results by Search Level:

** Indicates Minimum Factor of Safety

Search Level: At the toe of the wall Facing Design Force = 9.1 kips (Clouterre) ------------------------------------------------------------------------------------------------------ | | | | Failure Planes | Reinforcement | | | | |---------------------------------------|-------------------------------| | | Minimum | Distance | Lower | Upper | | | | | | Factor | From Toe |---------------------------------------| | | Controlling | |Search | of | of Wall | Angle | Length | Angle | Length | | Stress | Resistance | |Point | Safety | feet | degrees | feet | degrees | feet | Level | ksi | Failure Mode | ------------------------------------------------------------------------------------------------------ 1 3.17 1.00 81.87 6.36 87.88 2.70 1 16.2 Pullout 2 17.7 Pullout

2 2.72 5.90 50.67 9.31 90.00 1.80 1 7.6 Pullout 2 16.0 Pullout

** 3 2.58 10.80 36.87 13.50 -90.00 0.90 1 2.8 Pullout 2 15.1 Pullout

4 2.78 15.70 29.82 18.10 0.00 0.00 1 0.0 Pullout 2 14.4 Pullout

5 3.36 20.60 23.60 22.48 0.00 0.00 1 0.0 Pullout 2 13.7 Pullout

6 3.97 25.50 19.44 27.04 0.00 0.00 1 0.0 Pullout 2 13.1 Pullout

7 4.58 30.40 16.49 31.70 0.00 0.00 1 0.0 Pullout 2 12.6 Pullout

8 5.12 35.30 0.00 3.53 15.82 33.02 1 0.0 Pullout 2 8.7 Pullout

9 5.65 40.20 0.00 4.02 13.97 37.28 1 0.0 Pullout 2 8.0 Pullout

10 6.18 45.10 0.00 4.51 12.50 41.58 1 0.0 Pullout 2 7.5 Pullout

11 6.71 50.00 0.00 5.00 11.31 45.89 1 0.0 Pullout 2 7.0 Pullout

======================================================================================================

END OF REPORT
======================================================================================================

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Attachment: 447 Hillcrest Wall Replacement Plans and Specifications (Approve Plans and Specs for the 447 Hillcrest Rd Wall Replacement ====================================================================================================== Snail

Version: 2.2.2

File Name: 1465.095 SNAIL.snz
Run Date: 09/24/21
Run Time: 16:08:31

Description: Retaining Wall Repai
Location: 447 Hillcrest Road
EA:

Project ID: 1465.095
Wall No.:

Structure No.:

Station:

Engineer: RGB
Designer

Comments:

Layout:

Reference Point:

At: Toe of Wall
Distance From Origin: 10.00 feet
Elevation Above Origin: 10.00 feet

Wall Dimensions:

Wall Height: 9.00 feet
Facing Angle: 90.00 degrees
Facing Batter: 0.000 :12 H:V

Ground Surface:

Number of lines that define the ground surface above the wall: 1

Angle Distance
No. degrees feet
------------------------
1 0

Number of lines that define the ground surface in front of the toe: 1

Angle Distance
No. degrees feet
------------------------
1 0

Soil Layers:

Number of Layers: 1

Ground Water:

Include Ground Water: No

Dimensions and Properties:

Maximum Vertical Spacing: 6.00 feet
Number of Soil Nail Rows: 2

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Attachment: 447 Hillcrest Wall Replacement Plans and Specifications (Approve Plans and Specs for the 447 Hillcrest Rd Wall Replacement Soil Nail Design Parameters: Uniform Throughout Cross-Section Soil Nail Length: 9.00 feet
Inclination From Horizontal: 15 degrees
Vertical Distance from Top of Wall
to First Row: 1.50 feet
Vertical Spacing: 6.00 feet
Horizontal Spacing H: 6.00 feet
Nail Bar Diameter Ø: 1.000 inches
Nail Bar Yield Strength fy: 75.0 ksi

Facing Resistance:

Temporary Permanent Seismic
ASD Allowable Facing Resistance: 25.6 12.8 17.5 kips

Unit Weight Friction Angle Cohesion
γ φ' c'
Layer Description pcf degrees psf ----------------------------------------------------------------------------------- 1 Retained 130 30.0 200

Applied Loads:

Seismic:

Horizontal Seismic Coefficient Kh0.47:

External Load:

Apply external load: No

Surcharges:

Apply surcharges: No

Temporary Permanent Seismic
Pullout (Distal): 2.00 2.00 1.50
Pullout (Proximal): 2.00 2.00 1.50
Nail Bar Yield: 1.80 1.80 1.35

Search Limits:

Begin: 1.00 feet
End: 50.00 feet

Below Toe Searches (BTS):

Perform below Toe Search: No

Advanced Search Options:

Use Advanced Search Options: No

Analysis:

Method: ASD
Scenario: Seismic

Factor of Safety:

Minimum: 1.15
Found at Search Point: 3
Found at Grid Point: 51

Page 2 of 3 ends

BLD2021-00899

7.h.2
Packet Pg. 660
Attachment: 447 Hillcrest Wall Replacement Plans and Specifications (Approve Plans and Specs for the 447 Hillcrest Rd Wall Replacement Found at Search Level: Toe of the wall

Load at Soil Nail Head:

Calculated Service Load at Soil Nail Head (Empirical), To: 11.7 kips Allowable Facing Resistance, F_allowable (Entered): 17.5 kips F_allowable ≥ To OK

Nominal Pullout Resistance:

Nominal Pullout Resistance
Layer Description klf
----------------------------------------------
1 Retained 3.167

Results by Search Level:

** Indicates Minimum Factor of Safety

Search Level: At the toe of the wall Facing Design Force = 11.7 kips (Clouterre) ------------------------------------------------------------------------------------------------------ | | | | Failure Planes | Reinforcement | | | | |---------------------------------------|-------------------------------| | | Minimum | Distance | Lower | Upper | | | | | | Factor | From Toe |---------------------------------------| | | Controlling | |Search | of | of Wall | Angle | Length | Angle | Length | | Stress | Resistance | |Point | Safety | feet | degrees | feet | degrees | feet | Level | ksi | Failure Mode | ------------------------------------------------------------------------------------------------------ 1 2.99 1.00 81.87 6.36 87.88 2.70 1 21.6 Pullout 2 22.9 Facing

2 1.66 5.90 42.47 8.00 90.00 3.60 1 7.8 Pullout 2 20.7 Pullout

** 3 1.15 10.80 30.26 12.50 -90.00 2.70 1 0.0 Pullout 2 19.3 Pullout

4 1.19 15.70 24.64 17.27 -90.00 1.80 1 0.0 Pullout 2 18.4 Pullout

5 1.25 20.60 19.27 21.82 90.00 1.80 1 0.0 Pullout 2 17.4 Pullout

6 1.31 25.50 15.77 26.50 -90.00 1.80 1 0.0 Pullout 2 16.6 Pullout

7 1.36 30.40 13.32 31.24 90.00 1.80 1 0.0 Pullout 2 15.9 Pullout

8 1.40 35.30 11.53 36.03 90.00 1.80 1 0.0 Pullout 2 15.3 Pullout

9 1.43 40.20 10.15 40.84 90.00 1.80 1 0.0 Pullout 2 14.9 Pullout

10 1.45 45.10 0.00 4.51 12.50 41.58 1 0.0 Pullout 2 10.0 Pullout

11 1.47 50.00 5.14 30.12 17.48 20.97 1 0.0 Pullout 2 12.5 Pullout

======================================================================================================

END OF REPORT
======================================================================================================

Page 3 of 3 ends

BLD2021-00899

7.h.2
Packet Pg. 661
Attachment: 447 Hillcrest Wall Replacement Plans and Specifications (Approve Plans and Specs for the 447 Hillcrest Rd Wall Replacement ====================================================================================================== Snail

Version: 2.2.2

File Name: 1465.095 SNAIL.snz
Run Date: 09/24/21
Run Time: 16:07:06

Description: Retaining Wall Repai
Location: 447 Hillcrest Road
EA:

Project ID: 1465.095
Wall No.:

Structure No.:

Station:

Engineer: RGB
Designer

Comments:

Layout:

Reference Point:

At: Toe of Wall
Distance From Origin: 10.00 feet
Elevation Above Origin: 10.00 feet

Wall Dimensions:

Wall Height: 9.00 feet
Facing Angle: 90.00 degrees
Facing Batter: 0.000 :12 H:V

Ground Surface:

Number of lines that define the ground surface above the wall: 1

Angle Distance
No. degrees feet
------------------------
1 0

Number of lines that define the ground surface in front of the toe: 1

Angle Distance
No. degrees feet
------------------------
1 0

Soil Layers:

Number of Layers: 1

Ground Water:

Include Ground Water: No

Dimensions and Properties:

Maximum Vertical Spacing: 6.00 feet
Number of Soil Nail Rows: 2

Page 1 of 3 ends

BLD2021-00899

7.h.2
Packet Pg. 662
Attachment: 447 Hillcrest Wall Replacement Plans and Specifications (Approve Plans and Specs for the 447 Hillcrest Rd Wall Replacement Soil Nail Design Parameters: Uniform Throughout Cross-Section Soil Nail Length: 9.00 feet
Inclination From Horizontal: 15 degrees
Vertical Distance from Top of Wall
to First Row: 1.50 feet
Vertical Spacing: 6.00 feet
Horizontal Spacing H: 6.00 feet
Nail Bar Diameter Ø: 1.000 inches
Nail Bar Yield Strength fy: 75.0 ksi

Facing Resistance:

Temporary Permanent Seismic
ASD Allowable Facing Resistance: 25.6 12.8 17.5 kips

Unit Weight Friction Angle Cohesion
γ φ' c'
Layer Description pcf degrees psf ----------------------------------------------------------------------------------- 1 Retained 130 30.0 200

Applied Loads:

Seismic:

Horizontal Seismic Coefficient Kh0.47:

External Load:

Apply external load: No

Surcharges:

Apply surcharges: No

Temporary Permanent Seismic
Pullout (Distal): 2.00 2.00 1.50
Pullout (Proximal): 2.00 2.00 1.50
Nail Bar Yield: 1.80 1.80 1.35

Search Limits:

Begin: 1.00 feet
End: 50.00 feet

Below Toe Searches (BTS):

Perform below Toe Search: No

Advanced Search Options:

Use Advanced Search Options: No

Analysis:

Method: ASD
Scenario: Permanent

Factor of Safety:

Minimum: 2.58
Found at Search Point: 3
Found at Grid Point: 54

Page 2 of 3 ends

BLD2021-00899

7.h.2
Packet Pg. 663
Attachment: 447 Hillcrest Wall Replacement Plans and Specifications (Approve Plans and Specs for the 447 Hillcrest Rd Wall Replacement Found at Search Level: Toe of the wall

Load at Soil Nail Head:

Calculated Service Load at Soil Nail Head (Empirical), To: 9.1 kips Allowable Facing Resistance, F_allowable (Entered): 12.8 kips F_allowable ≥ To OK

Nominal Pullout Resistance:

Nominal Pullout Resistance
Layer Description klf
----------------------------------------------
1 Retained 3.167

Results by Search Level:

** Indicates Minimum Factor of Safety

Search Level: At the toe of the wall Facing Design Force = 9.1 kips (Clouterre) ------------------------------------------------------------------------------------------------------ | | | | Failure Planes | Reinforcement | | | | |---------------------------------------|-------------------------------| | | Minimum | Distance | Lower | Upper | | | | | | Factor | From Toe |---------------------------------------| | | Controlling | |Search | of | of Wall | Angle | Length | Angle | Length | | Stress | Resistance | |Point | Safety | feet | degrees | feet | degrees | feet | Level | ksi | Failure Mode | ------------------------------------------------------------------------------------------------------ 1 3.15 1.00 81.87 6.36 87.88 2.70 1 16.2 Pullout 2 16.7 Facing