Juliette Substation SVP Design Standards.pdf

BACKFILL MATERIAL

FOR SUBSTATIONS

ISSUING DIVISION: Electric Engineering Signed by ___ Kevin Keating______ SVP SPONSOR: Kevin Keating, Manager Date Signed ___28 September 2023___ Revision: 0 Sheet 1 of 5

SECTION: Earthwork Material Requirements MS-7110

Scope of Document Purpose of the Revision References Rescissions Definition of Terms Background Backfill Source Requirements Class 1 Aggregate Base Class 2 Aggregate Base Installation Inspection and Testing

Table 1: Class 1 Aggregate Base Material Gradation Requirements Table 2: Class 2 Aggregate Base Material Gradation Requirements

By: SVP Staff Backfill Material for Substations

Silicon Valley Power

Drawn By: k² Approved: 09/28/23 SHEET 2 of 5

MS-7110

Rev.

Scope of Document

This document outlines and details the requirements for gradation requirements for aggregate base under asphalt paving in a substation and bedding for use under boxes, vaults, manholes and pads. This document is intended for use by City forces and by Contractors on SVP projects.

Purpose of the Revision

This is a new document in the Earthwork Material Requirements section of the Substation Design and Construction Manual. There is no revision at this time.

References o AASHTO Standard M 43, “Standard Specification for Sizes of Aggregate for Road and Bridge Construction”, most recent version o CALTRANS, Standard Specification (NEWEST RELEASE) Section 68-2.02F, “Permeable Material” o SVP Standard document SD-5505, “Substation Grading Design Guide”, most recent version o IEEE Standard 80 – 2013, “Guide for Safety in AC Substation Grounding”, 11 December, 2013

Rescissions

This is an original document that has not been previously issued by the SVP Electric Engineering Division.

Definition of Terms o Aggregate Base: A permeable material that consists of hard, durable, clean sand, gravel, or crushed stone and must be free from organic material, clay balls, or other deleterious substances.

o Contractor: The person or persons, firm, partnership, corporation or combination thereof, who has entered into a contract with the City of Santa Clara.

o City: City of Santa Clara or the City Council of the City of Santa Clara.

o Silicon Valley Power (SVP): Municipal Electric Department of the City of Santa Clara.

o SVP Inspector: Silicon Valley Power Inspector responsible for verifying proper installation of electric facilities installed for use of SVP.

o Virgin Material: Unused raw material that is sourced directly from nature in its raw form and has never been subjected to any processing other than for its production.

Approved: 09/28/23 SHEET 3 of 5

Background SVP standard document SD 5505, “Substation Grounding Design Guide,” requires SVP substation grades to be relatively flat. From a maintenance and operations perspective, a flat substation grade will allow for best access to the station by tractor-trailer vehicles with low ground clearances. To achieve a relatively flat substation grade, substation construction projects may require excavation and removal of existing soil from the site. This may be due to uneven site contours, removal of existing hazardous materials, and / or removal of any existing development elements from previous use of the site. Additional aggregate base may be required to meet grading requirements, as a base layer under asphalt paving, or for placement under boxes, enclosures, foundations, manholes, or vaults.

Properly sourced, imported backfill material can increase the contact resistance between a person’s foot and the substation subsurface ground grid. With higher contact resistance levels, the electrical current that may flow through a person’s body is reduced. For electrical substations, it is desired to have the highest surface resistivity possible in order to provide the highest level of personnel safety. This document specifies the requirements for imported backfill used in SVP substations.

Backfill Source Requirements Backfill for SVP substations may not use reclaimed materials and shall consist of 100% virgin material free from organic matter and other deleterious substances.

Typical reclaimed materials are asphalt concrete, portland cement concrete, lean concrete base, cement treated base, or combination of these materials up to a maximum of 100% of the total volume. Reclaimed materials may contain metals and other non-cementitious products. The non-homogeneity of the reclaimed materials is not suitable for use in an electrical substation because the electrical resistivity is inconsistent per unit volume.

Class 1 Aggregate Base Class 1 aggregate base (AB) is to be utilized as base material under equipment pads, boxes, manholes, and vaults, unless otherwise determined by the design engineer. Class 1 AB shall consist of ¾” maximum size of permeable material. Class 1 aggregate base material must have a sand equivalent value of not less than 50. Class 1 base shall have a Durability Index of not less than 40. The material in place must comply with the percentage passing gradation requirements shown in Table 1.

CLASS 1 - 3/4" Max.

Sieve Sizes % Passing

1" 100 3/4" 90-100 No. 4 35-60 No. 30 10-30 No. 200 2-9

Table 1: Class 1 Aggregate Base Material Gradation Requirements

Approved: 09/28/23 SHEET 4 of 5

Class 2 Aggregate Base

Class 2 aggregate base (AB) is typically to be utilized as base material under asphalt paving and any other location specified on the project plans, unless otherwise determined by the design engineer. Class 2 AB shall consist of 11/2” maximum size of permeable material. Class 2 aggregate base material must have a sand equivalent value of not less than 75. Class 2 base shall have a Durability Index of not less than 40. The AB material in place must comply with the percentage passing gradation requirements shown in Table 2.

CLASS 2 - 1 1/2" Max.

Sieve Sizes % Passing 2” 100 1 1/2" 90-100 3/4" 50-85 No. 4 25-45 No. 30 10-25 No. 200 2-9

Table 2: Class 2 Aggregate Base Material Gradation Requirements

Installation

The Contractor is to review the SVP substation project plans and specifications to verify if imported backfill is required for the project. If imported backfill is required for any work inside the substation perimeter, or within 10 feet of the exterior face of the substation perimeter wall, the Contractor shall provide a sample of the proposed backfill material.

Material sample shall be submitted in accordance with material submittal requirements as described in SVP standard document MS 7020.

Prior to placement of imported backfill, the native soil is to be compacted to 95% relative compaction (RC). Class 1 AB material is to be placed in 6-inch maximum lifts. Class 2 AB material is to be placed in 12” maximum lifts. The thickness of AB layers shall be as described in the appropriate SVP substation project documents. AB material shall be compacted between lifts to 95% RC, under watering and rolling, to form a firm, stable base.

Approved: 09/28/23 SHEET 5 of 5

Inspection and Testing

SVP’s Inspector shall be informed at least 24 hours in advance before commencing any item of construction or installation of material in order to permit proper inspection of materials and workmanship. No work shall be embedded, backfilled or otherwise covered until such time as it has been inspected and approved by the Inspector. Any materials and/or workmanship failing to meet the requirements of the project documents, SVP standard documents, good acceptable engineering or construction practices, or installed without prior notice to Inspector shall be subject to rejection. If required by the Inspector, the Contractor shall, at his own expense, remove rejected work, finish, and install approved material and /or workmanship.

SVP’s Inspector arranges for the appropriate materials compaction testing to be performed on all aggregate base materials installed on the project site, unless otherwise specified in the project documents.

SVP’s Inspector will review the test results for compliance with SVP’s requirements. Before any further work can be performed within the test area, SVP’s Inspector must confirm that compaction requirements have been achieved.

Rock for Oil Containment Pits

ISSUING DIVISION: Electric Engineering Signed by ____Kevin Keating_______ SVP SPONSOR: Kevin Keating, Manager Date Signed __28 September, 2023_____ Revision 0 Sheet 1 of 5

SECTION: Earthwork Material Requirements MS-7120

Scope of Standard Purpose of Revision References Rescissions Definition of Terms Background Granite Ballast Rock Requirements Installation Approved Granite Ballast Rock Source

Table 1: Ballast Rock Gradation

Figure 1: Granite Rock Filled Oil Containment Pit

By: SVP Staff Rock for Oil Containment Pits

Approved: 09/28/2023 SHEET 2 of 5 Kevin Keating

MS-7120

Scope of Standard

This document outlines and details the specifications for ballast rock used in oil containment pits around SVP substation transformers. This document is intended for use by Designers of SVP substation facilities, Contractors under contract to the City of Santa Clara, and City forces.

Purpose of Revision

This is a new document in the Earthwork Material Requirements section of the Substation Design and Construction Manual. There is no revision at this time.

References o IEEE Standard 100 – “The Authoritative Dictionary of IEEE Standards Terms”, 7th

Edition, 2000 o IEEE Standard 80 – 2013, “Guide for Safety in AC Substation Grounding”, 11

December, 2013 o IEEE Standard P980-2013, Guide for Containment and Control of Oil Spills in

Substations” o T&D World, “Risk Equals Probability Times Consequences”; Arne Petersen; April 1, 2014; (www.tdworld.com/substations/article/20964130/risk-equals-probability-times-consequences)

Rescissions

This is an original document that has not been previously issued by the SVP Electric Engineering Division. No documents are rescinded with the issuance of this document.

http://www.tdworld.com/substations/article/20964130/risk-equals-probability-times-consequences http://www.tdworld.com/substations/article/20964130/risk-equals-probability-times-consequences

Approved: 09/28/2023 SHEET 3 of 5 Kevin Keating

MS-7120

Definition of Terms o Aggregate Base: A permeable material that consists of hard, durable, clean sand, gravel, or crushed stone and must be free from organic material, clay balls, or other deleterious substances.

combination thereof, who has entered into a contract with the City of Santa Clara.

Oil containment pits are secondary oil containment structures inside most SVP substations.

In the event of the failure of a transformer tank, the oil containment pit is intended to hold the transformer oil and keep it from leaking into the surrounding soil. The containment pits have a sump drain that connects to an oil water separator before discharging the separated water into the storm water drain system. The oil water separator has coalescing plates that trap oil, while allowing storm water to pass through.

Transformer fires are a serious concern to utilities as all major components needed for a fire to burn, (fuel, heat, oxygen) are typically present when a transformer fails in service.

According to T&D World, “…2.4% to 4% of all transformers can be expected to cause a fire during a 40-year service life.” Above grade level secondary oil containment structures, such as oil containment pits, create an area that can provide all three fire components in the event of a transformer tank rupture.

To mitigate the potential fire hazard associated with oil containment pits, SVP fills the oil containment pits with granite ballast rock. If hot, or burning, oil falls into the rock, the rock cools the oil below its flame point. In addition, the amount of rock in the pit prevents oxygen from getting to the oil. Both passive measures act together to effectively eliminate the oil containment pits as significant substation fire hazards.

This document specifies the requirements for granite ballast rock to be installed in SVP’s substation transformer oil containment pits.

Approved: 09/28/2023 SHEET 4 of 5 Kevin Keating

MS-7120

Granite Ballast Rock Requirements

Ballast rock shall be washed, evenly graded mixture of crushed granite stone. Granite ballast rock shall be virgin material, free from any organic material, clay balls, or other deleterious substances. Ballast rock for use in transformer containment pits and gravel areas shall have the following physical properties:

Gradation:

Sieve Sizes, inches Cumulative Percent Passing

2 100 1 ½ 90 – 100 1 20 – 55 ¾ 0 – 15 3/8 0 – 5

#200 0 – 1 % Pass #200 <= 1%

Table 1: Ballast Rock Gradation

Bulk Specific Gravity ≥ 2.60

Absorption ≤ 1.0%

Clay Lumps and friable Particles ≤ 0.5%

Resistance to Degradation (L.A. Rattler) ≤ 35% at 500 revolutions

Durability Index ≥ 60

Sodium Sulfate Soundness ≤ 5.0%

Flat or Elongated Particles (3:1) ≤ 5.0%

Resistivity (ohm-m) ≥ 6,688

Fines can build up in the substation storm drain system and reduce the effectiveness of the oil coalescing plates in the oil water separator system. Therefore, no fines are permitted to be mixed with the ballast rock.

Installation

Figure 1 shows an SVP substation transformer oil containment pit that is filled with granite ballast rock. The pits are to be filled to the brim of the containment pit with the granite ballast rock before the substation transformer is set on the foundation pad. Ballast rock is to be placed into the pits loose and without compaction to avoid damage to conduits and sump drain. Refer to specific project specifications and drawings for any additional ballast rock installation requirements.

Approved: 09/28/2023 SHEET 5 of 5 Kevin Keating

MS-7120

Figure 1: Granite Rock Filled Oil Containment Pit

Approved Granite Ballast Rock Source

Granite ballast rock shall come from A.R. Wilson Quarry (1900 Quarry Road, Aromas, CA)

If the contractor chooses to make a substitution of the ballast rock from a different quarry, the contractor shall have the rock tested by a certified lab to confirm that the rock resistivity meets the minimum requirements and submitted to SVP for approval. Substitutions may be rejected at SVP’s sole discretion.

Trench Backfill Material

ISSUING DIVISION: Electric Engineering Signed by ____ Kevin Keating _______ SVP SPONSOR: Kevin Keating, Manager Date Signed ____ January 18, 2024____ SHEET: Sheet 1 of 7

SECTION: Earthwork Material Requirements MS 7130

Scope of Standard Purpose of Revision References Rescissions Definition of Terms Inspections:

Permits:

Guarantee:

Sand Backfill Concrete Slurry Backfill Mixes Fluidized Thermal Backfill

By: SVP Staff Trench Backfill Requirements

Drawn By: K²

Approved: 01/18/2024 SHEET 2 of 7

MS 7130

The UG 1000 Document includes information regarding standard backfill requirements for electric trenches outside of SVP substations. This document is intended to provide guidance and direction to installers of SVP electric conduit systems about the acceptable trench backfill methods and related material specifications inside SVP substations. Please refer to specific design and construction drawings for details and locations where one of these backfill mixes may be required.

This is a new document in the Earthwork Material Requirements section of the Substation o Occupational Safety and Health Administration (OSHA), Publication OSHA 2226, 2002 (Revised), “Excavations” o National Ready Mixed Concrete Association (NRMCA), CIP-17, 2000, “Flowable Fill Materials” o State of California Department of Transportation (CalTrans), Standard Specifications, 2010, Section 19, “Earthwork”, Subsection 19-3.02 “Structure Backfill” o SVP standard document MS-7110 “Substation Backfill Material”, latest revision.

o SVP standard document SD-5510, “Cable Trench Systems”, latest revision.

o SVP standard document SD-5555, “Water Hose Bib Connection”, latest revision.

o SVP standard document UG-0345, “Electric Trench Backfill”, lastest revision.

o SVP Standard Document UG 1000, “Installation of Underground

Substructures by Developers”, latest revision.

o Transmission & Distribution World, April 1, 2003, “Underground Cables

Need a Proper Burial”, Deepak Parmar and Jan Steinmanis

Rescissions

None – This is an original document that has not been previously issued by the SVP Electric Engineering Division.

Approved: 01/18/2024 SHEET 3 of 7 o Backfill: Compacted material required over and around substructures, such as conduits and enclosures, to prevent damage to the substructures from vehicles or heavy equipment operating over or near the substructures.

o Building Inspector: City of Santa Clara Building Dept. Inspector, responsible for verifying proper installation and repair of all private building facilities. This includes the electric service entrance and meter service panel.

o Developer: A developer is any person who causes land to be divided into two or more parcels for himself or others; or is engaged in the development of property, in whole or in part, by the placing of any improvements thereon, whether the property was previously developed in whole, in part, or at all.

combination thereof, who has entered into a contract with the City of Santa Clara, as a party or parties of the second part of his or their legal representative.

o City Engineer: City Engineer of the City of Santa Clara.

o Flowable Fill: A self-compacting low strength material with a flowable consistency that is used as an alternative backfill material to granular fill (sand).

Flowable fill is a self-leveling material, placed with minimal effort, that does not require vibration or tamping. It hardens into a strong material with minimal subsidence. Also known as Controlled Low Strength Material (CLSM) o Public Works Inspector: City of Santa Clara Public Works Dept. Inspector, responsible for verifying proper installation and repair of all facilities within City right of ways and easements.

o SVP Inspector: Silicon Valley Power Electric Inspector responsible for verifying proper installation of electric substructures installed for use of SVP.

o Thermal Backfill: Engineered backfill designed to maintain a relatively constant thermal resistivity less than 90°C-cm/W when placed around distribution and transmission cables.

o Trench: A narrow below grade excavation that is deeper than it is wide. Typical

SVP width is 2 feet, but wider widths, up to 15 feet are possible.

Approved: 01/18/2024 SHEET 4 of 7

Inspections:

A. Inspector Notification

The Inspector shall be informed at least 24 hours in advance before commencing any item of construction or installation of material in order to permit proper inspection of materials and workmanship. No work shall be embedded, backfilled or otherwise covered until such time as it has been inspected and approved by the Inspector. Any materials and / or workmanship failing to meet the requirements of this Specification, good acceptable engineering or construction practices, or installed without prior notice to Inspector shall be subject to rejection. If required by the Inspector, the Developer or Contractor shall, at his own expense, remove rejected work, finish and install approved material and /or workmanship.

B. Private Electric Equipment

For all work performed on the "Service Entrance" and other private-electrical equipment, a permit shall be obtained from the City Building Inspectors Division.

C. Safety Regulations

It is the Developer's and Contractor's responsibility to comply with all State and OSHA Safety Regulations.

Permits:

For all work performed within a public right of way, electric easement, or public easement, an encroachment permit shall be obtained from the City Engineer’s Office.

An encroachment permit is not required for work outside of a public right of way, electric easement or other public easement.

Guarantee:

It shall be the responsibility of the Developer or Contractor to repair and correct any defects or deficiencies in a backfilled trench excavation (the Work), due to workmanship or material, which are discovered within one year from date of acceptance by the City. Repairs and corrections will be made at no charge to SVP or the City of Santa Clara.

If the Contractor defaults or neglects to carry out the Work in accordance with the Contract Documents and fails within 48 hours after receipt of written notice from the SVP to commence and continue correction of such default or neglect with diligence and promptness, the SVP may, after 48 hours following receipt by the Contractor of an additional written notice and without prejudice to any other remedy make good such deficiencies. SVP reserves the right to make the necessary repairs or replacements at the expense of the Developer or Contractor. SVP will, as much as it is practicable, preserve the available evidence of cause of the failure for examination by the Developer or Contractor.

The City also reserves the right to perform any portion of the work due to an emergency threatening the safety of the Work, the Public, City, and any property or equipment.

Approved: 01/18/2024 SHEET 5 of 7

Sand Backfill

Sand is the typical and preferred trench backfill component. Sand that is backfilled around electric substructures should be a significantly different color so as not to get confused with surrounding soils. A sudden and drastic color change in soils can serve as a visual alert to anyone excavating in the area that an electric utility trench is in the immediate vicinity. This does not replace any need for marking and locating electric utilities. Rather, it is intended to serve as an additional visual reminder of the presence of electric substructures, reduce the chance of an accidental dig-in, and damage to SVP substructure facilities.

Sand is to be clean with no clay or organic materials. Sand is to be free of toxic constituents at or above State or Federal hazardous waste levels. Manufactured, or recycled, sand is not approved as a backfill material inside an SVP substation facility. The total chloride content shall be less than 500 ppm. The maximum total sulfate content shall be 150 ppm. The minimum pH of the sand shall be 4.5. The maximum pH shall not exceed 9.

Approved sand sources are:

Quail Hollow “Utility Trench Sand” Decker Island “DI Fill Sand”

When sand is used as a trench backfill component, it is to be installed in such a manner so as not to displace, damage, or collapse the trench substructures. A minimum compaction of 90% is required in landscaped areas. A minimum compaction of 95% is required in asphalt paved areas. Higher compaction in all areas may be required by appropriate permits or inspectors. Compaction may be achieved utilizing mechanical means in 8-inch lifts.

Compaction around electrical conduits may also be accomplished by jetting with pressurized water, with prior approval of the SVP Inspector. Compaction methods employed shall not cause damage or displacement of any substructures.

A concrete cap is required over sand backfilled conduits installed in landscaped areas or in areas where the depth of cover is less than 24 inches. The concrete cap is to cover the full width of the trench for the length of the applicable trench segment. The concrete cap shall be a minimum of 3 inches thick, have a minimum strength of 2500 pounds psi, and be red in color.

Within a substation, perforated pipe may be used as subdrains in the storm drainage system. An example is shown in Figure 5 of SD 5510, “Cable Trench Systems.” Backfill around perforated pipe shall use sand that complies with the requirements of this document. Since the sand is intended to allow storm water to percolate directly into the soil, no other backfill material shall be used around perforated pipe. Only mechanical compaction means are allowed around perforated pipe.

Approved: 01/18/2024 SHEET 6 of 7

Concrete Slurry Backfill Mixes

In cases where trenching is done in asphalt paved areas or areas with a higher probability of trench settling in the future, other types of backfill or encasement may be required. Some acceptable alternatives to sand for backfilling around SVP’s electric conduits include flowable fill, controlled density fill, and concrete encasement. Flowable fill and controlled density fill may be used in asphalt paved areas. Concrete should be used for conduit encasement when the minimum amount of soil cover is less than 24” or when making a transition from a bridge abutment to a concrete bridge. Approved mix designs for the alternate backfills are listed below.

Flowable Fill Mix:

Slump: 10” Maximum aggregate size: No. 4 Minimum strength: 60 psi Maximum strength: 120 psi (must be able to dig) Minimum water/cement: 2.5 lbs/lb Minimum cement/yd3: 94 lbs/yd3 Type II cement

Controlled Density Fill (CDF):

Controlled Density Fill shall consist of clean sand (no clay or organic material), water, flyash, and cement in the following proportions:

Clean sand: 71.6% by volume Water: 23.7% by volume Flyash: 2.4% by volume Type II Cement: 2.3% by volume

Conduit Encasement Concrete Mix:

Maximum slump: 4” Maximum aggregate size: ¾” Minimum strength: 2000 psi Maximum water/cement: 0.85 lbs/lb Minimum cement/yd3: 453 lbs/yd3

Type II cement

Red dye is added to the concrete encasement mix to indicate that electric conduits are encased within the concrete.

Approved: 01/18/2024 SHEET 7 of 7

Fluidized Thermal Backfill

Fluidized Thermal Backfill is a form of controlled low-strength material specially designed to dissipate the heat generated by underground transmission cables within urban streets. It is a free flowing and non-segregating slurry that provides consistent heat dissipation along the full length of the underground transmission line. It provides a consistent structural embedment support for the conduits while also serving as a medium with low thermal resistivity. The expected 28-day compressive strength is approximately 300 psi. The maximum thermal resistivity of Fluidized Thermal Backfill in a totally dry condition is 100°C-cm/W.

The approved mix design for Fluidized Thermal Backfill is:

#8 Elliot 3/8” (Cemex) 1420 lb/yd³ Blended Sand 1985 lb/yd³ Fly ash “Type F” 235 lb/yd³ Portland Cement Type II/V 95 lb/yd³ Potable water 425 lb/yd³

The dry density is not to exceed 138 pcf. The Thermal Resistivity at a set moisture content of 11% is 39°C-cm/W. Air entraining agents are not to be used in Fluidized Thermal Backfill.

Red dye is added to the thermal backfill mix to indicate that electric conduits are encased within the backfill.

Asphalt Concrete

ISSUING DIVISION: Electric Engineering Signed by ____Kevin Keating______ SVP SPONSOR: Kevin Keating, Manager Date Signed _____31 May, 2024____ Revision 0 Sheet 1 of 16

SECTION: Concrete Material Requirements MS 7210

Scope of Standard Purpose of Revision References Rescissions Definition of Terms Background Submittals Aggregates Asphalt Asphaltic Emulsion Aggregate Base Course Installation Asphalt Emulsion Installation Asphalt Concrete Installation Field Quality Control

Table 1: Type A Asphalt Concrete Aggregate Grading Requirements Table 2: Aggregate Quality Requirements Table 3: Asphalt Concrete Mixture Quality Requirements Table 4: Hot Mix Asphalt Design Requirements Table 5: Performance Graded Asphalt Binder Requirements Table 6: Anionic Asphaltic Emulsion Requirements

Figure 1: Aggregate Base Installed in a Substation Figure 2: Asphalt Emulsion Applied in a Substation Figure 3: Applying Liquid Primer Coat Figure 4: Installing Hot Mix Asphalt in a Substation

By: SVP Staff Asphalt Concrete

Approved: 05/31/2024 SHEET 2 of 16 Kevin Keating

MS 7210

This document outlines and details the requirements for asphalt concrete used for paving inside SVP substations. This document is intended for use by Designers of SVP substation facilities, Contractors under contract to the City of Santa Clara, and City forces.

This is a new document in the Concrete Material Requirements section of the Substation o ASTM D2172, “Quantitative Extraction of Bitumen from Bituminous Paving

Mixtures,” most recent revision.

o IEEE Standard 100 – “The Authoritative Dictionary of IEEE Standards Terms”, 7th

Edition, 2000 o IEEE Standard 80 – 2013, “Guide for Safety in AC Substation Grounding”, 11

December, 2013 o SVP Standard document SDC-5040, “60kV Single Customer Junction Design Guide”, most recent version o SVP Standard document MS-7020, “Material Submittal Requirements”, most recent revision.

o SVP Standard Document MS-7110, “Substation Backfill Material,” most recent revision.

o US Department of Transportation, Federal Highway Administration Information

Series 128, “HMA Pavement Mix Type Selection Guide,” most recent revision.

o California Department of Transportation, (Caltrans) “California Tests (CT)”, https://dot.ca.gov/programs/engineering-services/california-test-methods

Engineering Division. No documents are rescinded with the issuance of this document.

Approved: 05/31/2024 SHEET 3 of 16 Kevin Keating

MS 7210

o Contractor: The entity who has entered into a contract with the City of Santa o California Tests: A series of material tests and standardized testing methods, prepared and promulgated by Caltrans. Tests are used to verify materials utilized in a project comply with project specifications.

o Engineer: The person designated by the City as the project engineer in charge of the overall project. May be the same person identified as the project manager for the project.

o Final Grade: The grade of the substation at the conclusion of all grading efforts.

o Hot Mix Asphalt: An impermeable mixture of asphalt binder and a graded aggregate ranging from coarse to very fine particles.

o Slope: An inclined surface, the inclination of which is expressed as a ratio of horizontal distance to vertical distance.

Electric utility substations are designed to provide as safe a work environment as possible for all personnel inside of a substation switchyard. One of the safety measures is to minimize the chance of personnel getting an electric shock by walking across the substation switchyard.

In addition to substation grounding grids, uniform surface coverings are utilized to create a consistent substation switchyard surface.

Surface material coverings, such as crushed granite, help reduce drying of moisture from the topmost soil layers during lengthy dry weather seasons. This helps to maintain a constant moisture level for ground grid stability. In addition, the surface material can increase the contact resistance between a person’s foot and the earth’s surface. With higher contact resistance levels, the electrical current that may flow through a person’s body is reduced. For electrical substations, it is desired to have the highest surface resistivity possible in order to provide the highest level of personnel safety. Therefore, covering a substation switchyard with a material with a high value of resistance will greatly reduce the magnitude of any electrical shock currents experienced by personnel in the switchyard. According to IEEE Standard 80-2013, a 3- to 6-inch-thick layer of asphalt concrete has resistivity values more

Approved: 05/31/2024 SHEET 4 of 16 Kevin Keating

MS 7210

than 3 times higher than crushed granite. In SVP substations, the default surface covering shall be 6 inches of hot mix asphalt concrete.

This document describes the general asphalt requirements utilized for SVP Substations.

Project drawings and/or specifications should be consulted for specific project requirements for asphalt concrete. In the event of a conflict between documents, the more stringent shall apply.

Submittals

Submittals shall be in accordance with the most recent revision of SVP Standard document MS-7020, “Material Submittal Requirements”, or the project documents.

Submit material certificates signed by the material producer and the Contractor, certifying that each material item complies with, or exceeds the specified requirements.

The following items shall be submitted:

1. Certificates: Submit manufacturer's notarized certificate of compliance for the bituminous materials.

2. Mix Design: Submit mix design prior to placing of the bituminous mixture. The design shall be prepared by the Contractor's laboratory and shall conform to the requirements of these specifications.

Aggregates

The grading and proportioning of aggregates shall be such that the combined mineral aggregate conforms to the specified requirements.

Aggregate for asphaltic concrete shall be ½-inch maximum size gradation, medium, Type A as described in Table 1 below.

Aggregates shall be virgin material that is clean and free from decomposed materials, organic material and other deleterious substances. Coarse aggregate is material retained on the No. 4 sieve; fine aggregate is material passing the No. 4 sieve; and supplemental fine aggregate is added fine material passing the No. 30 sieve, including, but not limited to, cement and stored fines from dust collectors.

The combined aggregate, prior to the addition of asphalt binder, shall conform to the requirements of this section. Conformance with the grading requirements will be determined by California Test 202, modified by California Test 105 when there is a difference in specific gravity of 0.2 or more between the coarse and fine portions of the aggregate or between blends of different aggregates.

The proposed gradation shall meet the gradation shown in Table 1. Changes from one mix design to another shall not be made during the progress of the work unless permitted by

Approved: 05/31/2024 SHEET 5 of 16 Kevin Keating

MS 7210

the Engineer. However, changes in proportions to conform to the approved mix design shall not be considered changes in mix design.

Sieve Sizes TV Limits (%) Allowable

Tolerances

¾” 100 -

½” 95-99 TV ± 6

⅜” 75-95 TV ± 6

No. 4 55-66 TV ± 7

No. 8 38-49 TV ± 5

No. 30 15-27 TV ± 4

No. 200 2.0-8.0 TV ± 2

Table 1: Type A Asphalt Concrete Aggregate Grading Requirements

The combined aggregate shall conform to the quality requirements of Table 2, prior to the addition of the asphalt:

Tests California Test Asphalt Concrete Type A

Percentage of Crushed Particles: 205 Coarse Aggregate (% min., one fractured face)

90%

Coarse Aggregate (% min., two fractured faces)

75%

Fine Aggregate Passing No. 4, Retained on No. 8 (min.)

70%

Los Angelas Rattler: 211 Loss (max.) at 100 Rev. 12% Loss (max.) at 500 Rev. 45% Sand Equivalent: 217 Contract Compliance (min.) 47 Fine Aggregate Angularity (% min.) 234 45 Flat and Elongated Particles (% max by weight @5:1)

235 10

Film Stripping (max.) 302 -

Table 2: Aggregate Quality Requirements

Approved: 05/31/2024 SHEET 6 of 16 Kevin Keating

MS 7210

If the results of either, or both, the aggregate grading and Sand Equivalent tests do not fall within the test value (TV) limits but meet the allowable tolerance requirements (Table 1), placement of the hot mix asphalt may be continued for the remainder of that day. However, another day's work may not be started until tests, or other information, indicate to the satisfaction of the Engineer that the next material to be used in the work will comply with the requirements specified in Tables 1 and 2.

If the results of either or both the aggregate grading and Sand Equivalent tests do not meet the requirements specified for Aggregate Quality, (Table 2), the asphalt concrete or asphalt concrete base which is represented by these tests shall be removed.

No single aggregate grading or Sand Equivalent test shall represent more than 500 tons or one day's production, whichever is smaller.

The asphalt concrete mixture, composed of the aggregate proposed for use and the optimum amount of asphalt, as determined by California Test 367, shall conform to the quality requirements described in Table 3.

Tests California Test Asphalt Concrete

Type A Swell (max.) (inch) 305 0.03 Moisture Vapor Susceptibility (min.) 307 30 Stabilometer Value (min.):

(⅜" & No. 4 Max. AC) 366 30 All Others 366 37

Table 3: Asphalt Concrete Mixture Quality Requirements

Asphalt

Asphalt binder to be mixed with aggregate shall be a steam-refined paving asphalt and shall be of the grade PG 64-10 or as determined by the Engineer.

The amount of asphalt binder to be mixed with the aggregate for asphalt concrete will be determined by the Engineer in conformance with the requirements in California Test 367 using the samples of aggregates furnished by the Contractor. Asphalt mixtures must comply with the requirements shown in Table 4.

Approved: 05/31/2024 SHEET 7 of 16 Kevin Keating

MS 7210

Quality Characteristic Test Method Requirement Air void content (%) CA Test 367 4.0 Voids in mineral aggregate (% min.) CA Test 367 -

No. 4 grading 17.0 ⅜” grading 15.0 ½” grading 14.0 ¾” grading 13.0

Voids filled with asphalt (%) CA Test 367 - No. 4 grading 76.0 – 80.0 ⅜” grading 73.0 – 76.0 ½” grading 65.0 – 75.0 ¾” grading 65.0 – 75.0

Dust Proportion CA Test 367 - No. 4 & ⅜” gradings 0.9 – 2.0 ½” & ¾” gradings 0.6 – 1.3

Stabilometer value (min.) CA Test 366 No. 4 & ⅜” gradings 30 ½” & ¾” gradings 37

Table 4: Hot Mix Asphalt Design Requirements

Asphalt shall be:

a. Homogeneous.

b. Free from water.

c. Free from residues caused by the artificial distillation of coal, coal tar, or paraffin.

Performance graded (PG) asphalt binder shall conform to the values shown in Table 5.

Approved: 05/31/2024 SHEET 8 of 16 Kevin Keating

MS 7210

Specification Grade

Property

AASHTO

Test Method

PG 64-

Original Binder

Flash Point, Min. °C T48 230 Solubility, Min. % T44 99 Viscosity at 135°C, Max., Pa·s

T316 3.0

Dynamic Shear, Test Temp. at

10 rad/s, °C Min. G*/sin(delta), kPa

T315

1.00

RTFO Test, Mass Loss, Max., %

T240 1.00

RTFO Test Aged Binder Dynamic Shear, Test Temp. at

10 rad/s, °C Min. G*/sin(delta), kPa

T315

2.20

Ductility at 25°C Min., cm

T51

PAV Aging, Temperature, °C

R28

RTFO Test and PAV Aged Binder Dynamic Shear, Test Temp. at

10 rad/s, °C Min. G*sin(delta), kPa

T315

Creep Stiffness, Test Temperature, °C Max. S-value, MPa Min. M-value

T313

0.300

Table 5: Performance Graded Asphalt Binder Requirements

Liquid asphalt for prime coats shall conform to grade PG64-10 as specified in Table 5.

Approved: 05/31/2024 SHEET 9 of 16 Kevin Keating

MS 7210

Asphaltic Emulsion

Asphaltic emulsion for paint binder (tack coat) shall be type RS-1. The asphaltic emulsion shall be composed of a bituminous material uniformly emulsified with water and an emulsifying, or stabilizing, agent. A polymer modified asphaltic emulsion shall also contain a polymer.

The asphaltic emulsion shall be homogeneous. Within 30 days after delivery, and provided separation has not been caused by freezing, the asphaltic emulsion shall be homogeneous after thorough mixing. The polymer used in the manufacture of a polymer modified asphaltic emulsion shall be, at the option of the Contractor, either neoprene, ethylene vinyl acetate or a blend of butadiene and styrene. The asphaltic emulsion shall conform to the provisions of Table 6.

Type: Rapid-Setting Grade: RS1

Properties min max Tests on Emulsions:

Viscosity, SSF @ 25°C, sec 20 100 Viscosity, SSF @ 50°C, sec — —

Settlement, 5 days, % a

— 5

Storage stability test, 1 day, % b

— 1

Demulsibility, 35 ml, 0.02 N CaCl2, % c 60 —

Coating ability and water resistance:

Coating, dry aggregate — Coating, after spraying — Coating, wet aggregate — Coating, after spraying —

Cement mixing test, % — — Sieve test, % — 0.10 Residue by distillation, % 55 —

Tests on Residue from Distillation Test:

Penetration, 25°C 100 d

Ductility, 25°C, 50 mm/min, mm 400 — Solubility in trichloroethylene, % 97.5 —

Table 6: Anionic Asphaltic Emulsion Requirements

Table 6 notes:

a) The test requirement for settlement may be waived when the asphaltic emulsion is used in less than 5 days' time; or the Engineer may require that the settlement test be run from the time the sample is received until the asphaltic emulsion is used, if the elapsed time is less than 5-days.

b) The 24-hour (1 day) storage stability test may be used instead of the 5-day settlement test.

c) The demulsibility test shall be made within 30 days from the date of shipment.

d) A harder base asphalt meeting current asphalt specifications may be specified with the provisions that the test requirements on the Residue from Distillation be waived.

Approved: 05/31/2024 SHEET 10 of 16 Kevin Keating

MS 7210

Properties of the asphaltic emulsion shown in Table 6 shall be determined in conformance with the requirements in AASHTO Designation: T 59, “Testing Emulsified Asphalt,” unless otherwise noted.

The asphaltic emulsion supplier shall make available for review a certified copy of tests representing any shipment. If asphaltic emulsion is used prior to sampling and testing, a Certificate of Compliance shall accompany each shipment of asphaltic emulsion to the worksite. The certificate shall include the shipment number, type of material, specific gravity of the material, refinery, consignee, destination, quantity, contract or purchase order number and date of shipment. The certificate shall state that the material complies with the specifications detailed in this document and shall be signed by the supplier, or supplier’s authorized representative.

Asphaltic emulsion furnished without a Certificate of Compliance shall not be used in the work until the Engineer has had sufficient time to make appropriate tests and has approved the asphaltic emulsion for use.

Asphaltic emulsion shall be reheated, if necessary, but at no time after loading into a tank car or truck for transporting to the site of the work shall the temperature of the emulsion be raised above 160° F, unless permitted by the Engineer. During all reheating operations the asphaltic emulsion shall be agitated to prevent localized overheating. Asphaltic emulsion shall be applied in conformance with the provisions above for, "Liquid Asphalt," and the following additional requirements:

a. Setting Grade 1 asphaltic emulsions, except when used for fog seal coats, shall be applied at a temperature between 75° F and 130° F, and Setting Grade 2 asphaltic emulsions shall be applied at a temperature between 110° F and 185° F, unless otherwise directed by the Engineer.

b. Asphaltic emulsions shall not be permitted to cool to a temperature of less than 40°F prior to application on the worksite.

Approved: 05/31/2024 SHEET 11 of 16 Kevin Keating

MS 7210

Aggregate Base Course Installation

Maintain the aggregate base course, in accordance with appropriate SVP substation project documents, until the asphaltic pavement is in place. Maintenance shall include drainage, rolling, compacting, shaping, and water as necessary to maintain the course in proper condition. Maintain sufficient moisture at the surface to prevent a dusty condition by light sprinkling with water. Areas of completed base course that are damaged by freezing shall be conditioned, reshaped, and recompacted in accordance with the requirements of this specification without additional cost to the City.

Figure 1: Aggregate Base Installed in a Substation

The finished surface of the base course, when tested for uniformity and smoothness of slope, shall not deviate at any point more than ⅜ inch from bottom of a 10-foot straightedge laid in any direction. When base course is constructed in more than one layer, specified smoothness requirements shall apply only to top surface. Slopes shall be as indicated on the specific project drawings and specifications.

Approved: 05/31/2024 SHEET 12 of 16 Kevin Keating

MS 7210

Asphalt Emulsion Installation

Prior to the application of the asphalt concrete, apply a bituminous prime coat of liquid asphalt on the prepared compacted base. Apply liquid asphalt by pressure distributors.

Allow sufficient time before placing the asphalt concrete to permit the prime coat asphalt to penetrate the prepared compacted base.

Prime coat shall be applied at the approximate total rate of 0.25 gallon per square yard of surface covered. The exact rate and number of applications will be determined by the Engineer.

Figure 2: Asphalt Emulsion Applied in a Substation

Prime coat shall be applied at a temperature as recommended by the manufacturer.

Liquid asphalt shall be prevented from spraying upon adjacent pavements, that portion of the traveled way being used by traffic, structures, railings and barriers, markers, trees and shrubbery that are not to be removed, adjacent property and improvements, and any other substation improvements or facilities not mentioned herein.

Approved: 05/31/2024 SHEET 13 of 16 Kevin Keating

MS 7210

Figure 3: Applying Liquid Primer Coat

Liquid asphalt shall be heated by a retort or by steam coils in such a manner that steam will not be introduced directly into the liquid asphalt during heating. The Contractor shall furnish and keep available at all times, an accurate thermometer suitable for determining the temperature of the liquid asphalt being applied.

Distributor trucks shall be of the pressure type with insulated tanks. The use of gravity distributors will not be permitted. Spray bars shall have a minimum length of 9 feet and shall be of the full circulating type. The spray bar shall be adjustable to permit positioning at various heights above the surface to be treated. The valves shall be operated by levers so that one or all valves may be quickly opened or closed in one operation.

Spreading by means of cab-controlled valves will be permitted in the application of seals.

The valves which control the flow from nozzles shall act positively so as to provide a uniform unbroken spread of bituminous material on the surface. The distributor shall be equipped with devices and charts to provide for accurate and rapid determination and control of the amount of bituminous material being applied and with a bitumeter of the auxiliary wheel type registering speed in feet per minute, and trip and total distance in feet. The spreading equipment shall be designed so that uniform application of bituminous material, in controlled amounts, may be made ranging from 0.02 gallon to one gallon per square yard of surface and with a range of pressure from 25 psi to 75 psi. If a spray bar extension is used to cover a greater width, it shall be of the full circulating type.

The distributor shall be equipped with a hose and nozzle to be used for spraying areas which are inaccessible to the distributor. The distributor shall also be equipped with pressure gages and an accurate thermometer for determination of temperatures of the

Approved: 05/31/2024 SHEET 14 of 16 Kevin Keating

MS 7210

bituminous material. Distributor and booster tanks shall be maintained at all times as to prevent the dripping of bituminous material from any part of the equipment.

In order to secure uniform distribution at the junction of 2 applications, the distribution shall be promptly stopped when the uniform flow decreases, indicating the tank is about empty.

The City reserves the right to order the use of any equipment discontinued which, in the opinion of the Engineer, fails to produce a satisfactory distribution of asphalt in accordance with the specifications.

Spreading liquid asphalt will not be permitted when the surface to be treated is appreciably damp, or when weather conditions are unsuitable, or when the atmospheric temperature is below the minimum temperature, as specified in project documents, for the particular type of work.

Disposing of excess liquid asphalt onsite will not be permitted. Distributors shall stop spreading asphalt while traffic is passing, if directed by the Engineer.

Liquid asphalt delivered to the work shall not be used for any purpose other than that provided for in the specifications.

Apply asphaltic emulsion, unless otherwise directed, at a rate of 0.05 gallons per square yard to the exposed edges of vertical surfaces against which asphalt concrete is to be placed.

Prime coat (tack coat) shall be applied only so far in advance of placing the surfacing as may be permitted by the Engineer. When asphalt emulsion is used as a prime coat (tack coat), asphalt concrete shall not be placed until the asphalt emulsion has cured.

Immediately in advance of placing asphalt concrete, additional prime coat (tack coat) shall be applied as directed by the Engineer to areas where the prime coat (tack coat) has been damaged, and loose or extraneous material shall be removed, and no additional compensation will be allowed therefor.

Asphalt Concrete Installation

Place hot mixed asphalt mixture on prepared surface, spread, and strike off. Spread mixture at minimum temperature of 225 deg F (107 deg C). Place areas inaccessible to equipment by hand. Place each course to required grade, cross section, and compacted thickness.

Immediately correct surface irregularities in finish course behind paver. Remove excess material forming high spots with shovel or lute.

Approved: 05/31/2024 SHEET 15 of 16 Kevin Keating

MS 7210

Make joints between old and new pavements, or between successive days' work, to ensure continuous bond between adjoining work. Construct joints to have same texture, density, and smoothness as other sections of hot mixed asphalt course. Clean contact surfaces and apply a tack coat.

Begin rolling when mixture will bear roller weight without excessive displacement.

Compact mixture with hot hand tampers or vibrating plate compactors in areas inaccessible to rollers.

Breakdown Rolling: Accomplish breakdown or initial rolling immediately following rolling of joints and outside edge. Check surface after breakdown rolling and repair displaced areas by loosening and filling, if required, with hot material.

Second Rolling: Follow breakdown rolling as soon as possible, while mixture is hot.

Continue second rolling until mixture has been evenly compacted.

Finish Rolling: Perform finish rolling while mixture is still warm enough for removal of roller marks. Continue rolling until roller marks are eliminated and the course has attained 95 percent compaction.

Figure 4: Installing Hot Mix Asphalt in a Substation

Approved: 05/31/2024 SHEET 16 of 16 Kevin Keating

MS 7210

Patching: Remove and replace paving areas mixed with foreign materials and defective areas. Cut out such areas, down to the aggregate base or as directed by SVP’s Inspector, and fill with fresh, hot mixed asphalt. Compact by rolling to specified surface density and smoothness.

Protection: After final rolling, do not permit vehicular traffic on pavement until it has cooled and hardened.

Erect barricades to protect paving from traffic until…