CC 2016-04-12_09g Resolution Specs and Engineering StandardsMEMORANDUM
TO: CITY COUNCIL
FROM: TERESA MCCLISH, DIRECTOR OF COMMUNITY DEVELOPMENT
GEOFF ENGLISH, DIRECTOR OF PUBLIC WORKS
BY: MATT HORN, CITY ENGINEER
SUBJECT: CONSIDERATION OF ADOPTING A RESOLUTION APPROVING THE
STANDARD SPECIFICATIONS AND ENGINEERING STANDARDS FOR
CONSTRUCTION
DATE: APRIL 12, 2016
RECOMMENDATION:
It is recommended that the City Council adopt a Resolution approving the updated
Standard Specifications and Engineering Standards for Construction.
IMPACT ON FINANCIAL AND PERSONNEL RESOURCES:
The updated Standard Specifications and Engineering Standards will have an
insignificant impact on the cost of City or private development projects.
BACKGROUND:
The City maintains a set of Standard Specifications and Engineering Standards,
historically using the American Public Works Association Greenbook Standard
Specifications. The Standard Specifications and Engineering Standards set forth the
general guidelines and requirements for design and construction for City projects,
including private development work within existing and future public right-of-way. The
purpose of these standards is to set a level of quality and consistency in construction.
These two things, combined with active inspections, increase the longevity and function
of public improvements and reduce long term maintenance costs. In addition, the
Standard Specifications provide contractual language to guide the behavior and
relationship between contractors and the City during construction activities. Adoption of
these standards by the City Council assists in protecting the City from litigation through
laws relating to design immunity.
The Standard Specifications and Engineering Standards should be periodically updated
to reflect changes in construction practices, materials, and to add clarifications. The
City’s existing Engineering Standards were last comprehensively updated on July 1,
2004.
The Standard Specifications and Engineering Standards were placed on the March 22,
2016 City Council Meeting agenda, but deferred until a later meeting in order to provide
the City Council the necessary time to review the document. Additional changes to the
document have been made since that time. A modification to the trenching standard
Item 9.g. - Page 1
CITY COUNCIL
CONSIDERATION OF ADOPTING A RESOLUTION APPROVING STANDARD
SPECIFICATIONS AND ENGINEERING STANDARDS FOR CONSTRUCTION
APRIL 12, 2016
PAGE 2
that will allow contractors to remove only portions of an asphalt concrete street were
made to recognize that some streets have very thick asphalt concrete section and
replacement of this entire section in not necessary. Additional clarification was provided
concerning the Regional Water Quality Control Board’s Post Construction Water Quality
requirements to better guide project designers. Finally, minor edits to the document’s
pagination and list numbering were completed.
ANAL YSIS OF ISSUES:
Unlike past updates, the revisions for the 2016 Standard Specifications and
Engineering Standards updates are significant. In the past, the City has used the
American Public Works Association’s Greenbook Standard Specifications wholly
without any changes. The updated Standard Specifications have incorporated the
Caltrans 2015 Standard Specifications ("Caltrans Specifications") rather than the
American Public Works Association's Greenbook Standard Specifications.
Incorporating the Caltrans Specifications has many benefits such as:
1. Caltrans Standard Specifications are readily available and free to download.
2. Caltrans Standard Specifications are used and known by our local contractors.
3. Allows for better integration between the City and Caltrans when completing
Caltrans Oversight Projects such as bridge replacement or interchange work.
4. Provides a standard set of construction claims tools and processes to follow.
5. Complies with Government Code Section 6219 and Presidential Executive Order
of 1998 requiring the use of plain language.
Example of Plain Language
The City Standard Specifications work in conjunction with the Caltrans Specifications.
The City references Caltrans Specifications with modifications where appropriate to
meet City needs. The Caltrans Specifications cover many standard contract issues and
legal requirements such as labor laws, payment and liability. The City Specifications
focus on construction specifications for work the State does not typically handle such as
water, wastewater, and park facilities.
The Engineering Standards include pictorial construction details showing how facilities
are put together. These are largely specific to City construction with only a few
references to using typical State construction details.
The Engineering Standards have been revised and augmented. Uniform Design
requirements have been added that include:
1. Plan Requirements
Item 9.g. - Page 2
CITY COUNCIL
CONSIDERATION OF ADOPTING A RESOLUTION APPROVING STANDARD
SPECIFICATIONS AND ENGINEERING STANDARDS FOR CONSTRUCTION
APRIL 12, 2016
PAGE 3
2. Hydraulics and Hydrology Report Requirements
3. Post Construction Stormwater Requirements
4. Roadway Design Requirements
5. Storm Drain Requirements
6. Waterline Requirements
7. Sewerline Requirements
8. Marked crosswalk design requirements
These design requirements are either standards of the industry, included in the City’s
Municipal Code, or included in a City Master Plan or some other City document. The
intent is to compile the most used Engineering and Construction requirements into one
document making it easier for designers, private project applicants, and staff to follow.
Additional new or revised Engineering Standards include:
1. New driveway details with required Americans with Disabilities Act (ADA) path of
travel
2. New cross-gutter detail with ADA curb ramps
3. New sidewalk underdrain details
4. New ADA curb ramp details
5. New water and sewer separation guidelines
6. New roadway details including guidance for speed humps and speed tables
7. New standard traffic handling details
8. New tree wells
9. New Quality Assurance Program
10. Emergency vehicle turning template details
11. Stormwater Zones map
12. Bioretention and Bioswales details and planting information
The Standard Specifications and Engineering Standards will be compiled into one
bound book available for sale at City Hall or free to download from the City’s web site.
ALTERNATIVES:
The following alternatives are provided for the Council’s consideration:
• Adopt a Resolution approving the updated Standard Specifications and
Engineering Standards;
• Do adopt a Resolution; or
• Provide direction to staff.
ADVANTAGES:
Approval of the Standard Specifications and Engineering Standards will provide a
standard document for engineers, contractors, and staff to follow during design and
construction of public improvements. Additionally, it will allow staff managing Capital
Improvement Plan projects the ability to use Caltrans process for project
documentation and construction claims avoidance.
Item 9.g. - Page 3
CITY COUNCIL
CONSIDERATION OF ADOPTING A RESOLUTION APPROVING STANDARD
SPECIFICATIONS AND ENGINEERING STANDARDS FOR CONSTRUCTION
APRIL 12, 2016
PAGE 4
DISADVANTAGES:
No disadvantages have been identified.
ENVIRONMENTAL REVIEW:
In compliance with California Environmental Quality Act (CEQA) the project is
categorically exempt per section 15061(b)(3) of the CEQA Guidelines.
PUBLIC NOTIFICATION AND COMMENTS:
The Agenda was posted in front of City Hall on Thursday, April 7, 2016. The Agenda
and staff report were posted on the City’s website on Friday, April 8, 2016.
Attachments:
1. Standard Specifications and Engineering Standards (available for public
review at City Hall and on the City's website at
www.arroyogrande.org/AgendaCenter)
2. Excerpts from the Standard Specifications and Engineering Standards
showing latest revisions.
Item 9.g. - Page 4
RESOLUTION NO.
A RESOLUTION OF THE CITY COUNCIL OF THE CITY
OF ARROYO GRANDE APPROVING REVISED
STANDARD SPECIFICATIONS AND ENGINEERING
STANDARDS FOR CONSTRUCTION
WHEREAS, the Public Works and Community Development Departments are
responsible for maintaining Standard Specifications and Engineering Standards
establishing quality requirements and contract conditions for construction; and
WHEREAS, the Standard Specifications and Engineering Standards must be
periodically updated to allow for changes in construction practices and contract law.
NOW, THEREFORE BE IT RESOLVED that the City Council of the City of Arroyo
Grande does as follows:
1. The 2016 Standard Specifications and Engineering Standards dated and
effective April 13, 2016, copies of which are on file in the Office of the City Clerk,
are hereby approved.
2. Previous editions of the Standard Specifications and Engineering Standards are
hereby superseded and the 2016 Standard Specifications and Engineering
Specifications approved herein shall be applicable to all projects advertised and
approved following the approval of these standards, except as expressly
provided below.
3. The Director of Public Works is authorized to release for advertising under the
previous Standard Specifications, currently pending projects that are deemed by
the Director of Public Works substantially complete with design at the time of this
adoption. The Council expressly affirms its prior approval of the Standard
Specifications as applicable to those projects.
On motion of Council Member , seconded by Council Member ,
and on the following roll call vote, to wit:
AYES:
NOES:
ABSENT:
the foregoing Resolution was passed and adopted this 13th day of April, 2016.
Item 9.g. - Page 5
RESOLUTION NO.
PAGE 2
JIM HILL, MAYOR
ATTEST:
KELLY WETMORE, CITY CLERK
APPROVED AS TO CONTENT:
DIANNE THOMPSON, CITY MANAGER
APPROVED AS TO FORM:
HEATHER WHITHAM, CITY ATTORNEY
Item 9.g. - Page 6
ATTACHMENT 1
(FULL DOCUMENT AVAILABLE FOR PUBLIC REVIEW AT CITY HALL AND ON THE
CITY WEBSITE AT WWW.ARROYOGRANDE.ORG/AGENDA CENTER)
STANDARD SPECIFICATIONS
&
ENGINEERING STANDARDS
APRIL 2016
COMMUNITY DEVELOPMENT DEPARTMENT
ENGINEERING DIVISION
300 East Branch Street
Arroyo Grande, CA 93420
(805) 4 73-5420
Item 9.g. - Page 7
CITY OF ARROYO GRANDE – ENGINEERING STANDARD PLAN 1010
Issue Date: March 2016 UNIFORM DESIGN CRITERIA Sheet 51 of 66
3.Dissipater trench dimensions
4.Rock placement method
5.RSP fabric type
Culvert energy dissipaters must be designed for the flow from the Design Storm. Rock slope
protection gradation shall conform to Section 72 of the State Standard Specifications.
5.2 Post Construction Stormwater Compliance
5.2.1 Performance Requirements
A. Performance Requirement No. 1: Site Design and Runoff Reduction
Projects that create and/or replace 2,500 square feet or more of impervious surface must:
1.Limit disturbance of creeks and natural drainage features
2.Minimize compaction of highly permeable soils
3.Limit clearing and grading of native vegetation at the site to the minimum area needed to
build the project, allow access, and provide fire protection
4.Minimize impervious surfaces by concentrating improvements on the least-sensitive portions
of the site, while leaving the remaining land in a natural undisturbed state
5.Minimize stormwater runoff by implementing one or more of the following site design
measures:
a.Direct roof runoff into cisterns or rain barrels for reuse
b.Direct roof runoff onto vegetated areas safely away from building foundations and
footings, consistent with California building code
c.Direct runoff from sidewalks, walkways, and/or patios onto vegetated areas safely away
from building foundations and footings, consistent with California building code
d.Direct runoff from driveways and/or uncovered parking lots onto vegetated areas safely
away from building foundations and footings, consistent with California building code
e.Construct bike lanes, driveways, uncovered parking lots, sidewalks, walkways, and patios
with permeable surfaces
6.Define the development envelope and protected areas, identifying areas that are most
suitable for development and areas to be left undisturbed
7.Conserve natural areas, including existing trees, other vegetation, and soils
8.Limit the overall impervious footprint of the project
9.Set back development from creeks, wetlands, and riparian habitats
10. Conform the site layout along natural landforms
11. Avoid excessive grading and disturbance of vegetation and soils
B. Performance Requirement No. 2: Water Quality Treatment
Projects that create and/or replace 5,000 square feet or more of impervious surface must treat
stormwater runoff from existing, new, and replaced impervious surfaces on sites where runoff from
existing impervious surfaces cannot be separated from runoff from new and replaced impervious
surfaces. Water Quality Treatment must be treated onsite and designed to treat stormwater runoff
equal to the volume of runoff generated by the 85th percentile 24-hour storm event, of 1 inch.
Water Quality Treatment may implement a treatment system that use multiple systems to complete
Water Quality Treatment. The Water Quality Treatment system must first implement Low Impact
Development Treatment Systems, then may implement Biofiltration Systems, and then finally may
ATTACHMENT 2
Item 9.g. - Page 8
CITY OF ARROYO GRANDE – ENGINEERING STANDARD PLAN
1010
Issue Date: March 2016 UNIFORM DESIGN CRITERIA Sheet 52 of 66
implement Non-Retention Based Treatment Systems. Projects subject to Performance
Requirement No. 2 must also include design strategies required by Performance Requirement No.
1.
1. Low Impact Development Treatment System – Design details may be found in Appendix K of
the Engineering Standards.
2. Biofiltration treatment systems with the following design parameters:
a. Prevent erosion, scour and channeling within the biofiltration treatment system based on
the flow of runoff produced from a rain event equal to 0.2 inches per hour intensity.
b. Minimum surface reservoir volume equal to the biofiltration treatment system surface
area times a depth of 6 inches
c. Minimum planting medium depth of 24 inches. The planting medium must sustain a
minimum infiltration rate of 5 inches per hour throughout the life of the project and must
maximize runoff retention and pollutant removal. A mixture of:
i. Sand - 60% to 70% meeting ASTM C33
ii. Compost - 30% to 40% may be used
d. Proper plant selection
e. Subsurface drainage/storage (gravel) layer with an area equal to the biofiltration
treatment system surface area and having a minimum depth of 12 inches
f. Underdrain with discharge elevation at top of gravel layer
g. No compaction of soils beneath the biofiltration facility (ripping/loosening of soils required
if compacted)
h. No liners or other barriers interfering with infiltration, except for situations where lateral
infiltration is not technically feasible.
3. Non-Retention Based Treatment Systems must collectively achieve at least one of the following
hydraulic sizing criteria:
a. Hydraulic Sizing Criteria for Non-Retention Based Treatment Systems:
i. Volume Hydraulic Design Basis must be based on the 85th percentile 24-hour
storm event of 1 inch.
ii. Flow Hydraulic Design Basis must be based on the flow of runoff resulting from a
rain event equal to at least 0.2 inches per hour intensity.
iii. See Performance Requirement No. 3: Runoff Retention for information to calculate
the required water quality volume.
C. Performance Requirement No. 3: Runoff Retention
Projects that create and/or replace 1 5,000 square feet or more of impervious surface must retain
runoff for optimal management of watershed processes. Projects subject to Performance
Requirement No. 3 must also include design strategies required by Performance Requirement No.
2 and 1.
1. Adjustments for Redevelopment – Replaced impervious surface, shall be multiplied by 0.5
when calculating the volume of runoff subject to Runoff Retention Performance
Requirements.
2. Retention must meet the following performance requirements:
a. Prevent offsite discharge from events up to the 95th percentile 24-hour rainfall event, 1.8
inches.
b. Achieve retention by:
i. optimizing soil infiltration
Item 9.g. - Page 9
See Sheet 2 of 2 for paving llmlts
6" ·.
·~~~-::o···. · .... .-.·:>=·.: 6• Min. -s• Max.
·: .. ~-._·· .......... · .. ·~--------
.... :. ~.. .. . . .: .. = .... .;: . l
•:. . . . ~~--:-i~---~
·• ... ·". · · ··: · ·: · 6• below baffel
· :.~. ·· . ~ :·· · .. ~ ··.. and 3• below bell ---~ Greatest O.D. pip0
dimension at all pipe
joints.
NOTE:S:
1. See Standard Specification Section 26-1 and 77-1 for backfill material and bedding requirements.
2. Prior to any beginning any trench cut, Contractors shall mNt with the Pub/le Works Department
to determine If pavement cuts are restricted by the City of AffO)O Grande Pavement Cut Polley
(Resolution No. 3819) •
.J. It is the responsib17ity of the Contractor or Premittee to contact ·underground Service Alert•
{USA) to determine locations for existing Power, Telephone, 017, Natural Gos, Coble rv. Sewer,
Storm Drainage, and any other underground facHltles.
4. Initial trench width may be only as wide as necessary to complete utility installation.
5. Pipe bedding shall be clean sand compacted to a 95X Minimum.
6. Number 12 insulated THW copper wire shall be placed continuously Ollflf' all pi;r: pipe and shall be
brought to the surface In valve wells, meter boxes, ct similar structures.
7. Trench backfill shall be 1-Sock (sand/cement -94 lbs cement per cubic yard) sluffy.
8. Temporary trench paving shall be 3• Min. of Cold Mix Asphalt. (Steel Traffic Plates may be used
in lieu of temporary paving upon approval of the City Engineer).
9. Provide vertical surfaces and square corners. Overlapping cuts shall not be permitted
10. ~en edge of trench cut Is with 3' of on existing trench or gutter, pavement cut shall extend to
existing trench or curb.
11. All pavements markings and markers which ore disturbed during trenching and asphalt
replocemen t shall be replaced
12. ~en the existing roadway asphalt concrete section depth is s• thick or greater, the Contractor
may grind and replace to a depth of 4• within paving limits of work that Is not directly over
trench area. Alternatively, the Contractor may remove and replace the entire asphalt concrete
section depth plus 1".
CITY OF ARROYO GRANDE -ENGINEERING STANDARD PLAN 6020
ISSUE DATE: MARCH 2016 TRENCH DETAIL SHEET10F2
Item 9.g. - Page 10