Item 4D - MemoItem 4D
M E M O R A N D U M
(November 6, 2018)
To: Shana Yelverton, City Manager
From: Rob Cohen, Director of Public Works
Subject: Ratify approval of an Engineering Services Agreement with
Halff Associates, Inc. for professional design services for the
emergency repair of the North White Chapel Road culvert
crossing of Kirkwood Branch previously authorized by the City
Manager in an amount not to exceed $59,000.
Action
Requested: Ratify approval of an Engineering Services Agreement with Halff
Associates, Inc. for professional design services for the emergency
repair of the North White Chapel Road culvert crossing of Kirkwood
Branch previously authorized by the City Manager in an amount not
to exceed $59,000.
Background
Information: The North White Chapel culvert crossing at Kirkwood Branch was
recently damaged by a significant flood event in September. The
road has remained closed since the event as the crossing has been
declared unsafe for equipment or traffic by our structural consultant.
Staff has engaged Halff Associates, Inc. to provide professional
design services, construction plans and specifications for the
interim improvements to the crossing.
The repair of this crossing is deemed an emergency requiring
assistance from a third party engineering consultant and utility and
paving contractor in order to re-open the road. The current closure
is considered an emergency due to the impact on emergency
response times to 300+ single family homes, multiple park facilities,
a private school, a number of businesses, active residential
construction sites as well as a cell tower site. Staff has consulted
with the City Attorney and determined procuring these services falls
under the Texas Local Government Code Chapter 252 Section
252.022 General Exemptions from Bidding for (a) a procurement
necessary to preserve or protect the public health or safety of the
municipality’s residents; (b) a procurement necessary because of
unforeseen damage to public machinery, equipment, or other
property; and (c) a procurement for personal, professional, or
planning services.
Item 4D
Halff will also provide project coordination services with other
interested agencies as well as the selected contractor to expedite
the delivery of this project and reopening the road.
Financial
Considerations: The North White Chapel Road culvert crossing of Kirkwood Branch
emergency repair will be funded from the current N. White Chapel,
Kirkwood Branch Bridge project via the Storm Water Utility System
Fund in the FY 2015 - 2019 Capital Improvement Program Budgets
in the amounts of $1,675,000.
Strategic Link: The North White Chapel Road culvert crossing of Kirkwood Branch
emergency repair links to the City’s strategy map relative to the
focus areas of Safety and Security, Mobility and Infrastructure. The
specific corporate objectives that are met by this construct ion
project are to (C1) Achieve the highest standards of safety &
security, (C2) Provide travel convenience within City & region, (F1)
Adhere to financial management principles & budget and (F2)
Invest to provide & maintain high quality public assets.
Citizen Input/
Board Review: The closure of North White Chapel is not only an inconvenience but
significantly impacts emergency response times to this part of the
City.
Legal Review: The proposed agreement is a standard agreement that the City
Attorney has reviewed and approved.
Alternatives: The Council may ratify approval of the engineering services
agreement or decline.
Supporting
Documents: Agreement with Halff Associates, Inc.
Concept Exhibit for Drainage Improvements
Halff Site Visit Report
Emergency Repair Memo
Staff
Recommendation: Ratify approval of an Engineering Services Agreement with Halff
Associates, Inc. for professional design services for the emergency
repair of the North White Chapel Road culvert crossing of Kirkwood
Branch previously authorized by the City Manager in an amount not
to exceed $59,000.
Staff Contact: Rob Cohen, Director of Public Works
Kyle D. Hogue, P.E., Deputy Director/City Engineer
Sheet Number
Sheet Title
Checked By:
Drawn By:
Project No.:
Issued:
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P.E. NO.
DATE
FOR INTERIM REVIEW ONLY
PRELIMINARY
SUPERVISION OF:
WERE PREPARED BY OR UNDER THE
OR CONSTRUCTION PURPOSES. THEY
REGULATORY APPROVAL, PERMIT, BIDDING
REVIEW AND NOT INTENDED FOR
THESE DOCUMENTS ARE FOR INTERIM
NAME
LEVI R. HEIN 109956
10/23/2018
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CL
1+00 1+50 2+00 2+50 3+00 3+50
PLAN AND PROFILE
CULVERT
1 OF 1
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P N WHITE CHAPEL RD
2
1
'
1
0
'
44.2'
EX.27"SS
EX. FO
EX. 24" WL EX. 12" WL
EX. FO
ROCK RIPRAP
PROPOSED
ROCK RIPRAP
PROPOSED
TO MATCH EXISTING
PROVIDE STRIPING
CONTRACTOR TO
DELINEATORS WITH EQUAL OR BETTER
REPLACE EXISTING OBJECT
CONTRACTOR TO REMOVE AND
NORTH/SOUTH CULVERT CENTERLINE
PROJECT LIMITS 150 FT
BLVD
CHAPEL
N WHITE
SGT(12S)31-18
GF(31)MS-17
GF(31)LS-17
GF(31)DAT-14
GF(31)-14
TxDOT STANDARDS,
APPLICABLE STANDARDS
REPLACE EXISTING MBGF
CONTRACTOR TO REMOVE AND
NCTCOG 803.3 DRY RIPRAP
LIMITS TO BE DETERMINED BY ENGINEER
CONTRACTOR TO INSTALL ROCK RIPRAP,
NCTCOG 702
TxDOT CH-PW-S (MOD)
APPLICABLE STANDARDS
REPLACE EXISTING HEADWALL
CONTRACTOR TO REMOVE AND
TO BE DETERMINED BY ENGINEER
PAVING PER TYPICAL SECTION
TEMPORARY SHORING AS REQUIRED
SLOPE BACK EXCAVATION
BRANCH
KIRKWOOD
REMAIN
RCP TO
EXISTING 72"
1
1
151050 20
VERT. SCALE: 1"=2.5'
HORZ. SCALE: 1"=10'
CONDITIONS.
CONSTRUCTION MUST BE RETURNED TO PRE-PROJECT GRADES AND
FOR CARE OF WATER. ANY TEMPORARY FILLS DURING
USAGE FLOWAGE EASEMENT. CONTRACTOR WILL BE RESPONSIBLE
3. CONSTRUCTION IS WITHIN FLOODPLAIN AND GRAPEVINE LAKE
CONSTRUCTION
2. CONTRACTOR TO VERIFY LOCATIONS OF ALL UTILITIES PRIOR TO
1. CONSTRUCT PER NCTCOG STANDARD SPECIFICATIONS
NOTES:
COMPLETED 10/22-10/26
GEOTECHINICAL INVESTIGATION TO BE
10/22-10/26
DESIGN SURVEYS TO BE COMPLETED
PLANS
10/17/18 AND CITY OF SOUTHLAKE AS-BUILT
BASE ON FIELD MEASUREMENTS HALFF DATE
ALL DIMENSIONS AND UTILITIES ARE SHOWN
NOTE:
TYP
2%
TO BE DETERMINED BY ENGINEER
EMBANKMENT AND DRAINAGE MATERIAL
NCTCOG 202.2, 202.4, 202.6
TOPSOIL AND SEED RIGHT-OF-WAY
EROSION CONTROL BLANKET
CONTRACTOR TO INSTALL TEMPORARY
NCTCOG 300
THE ENGINEER
HMAC PAVEMENT TO BE DETERMINED BY
FLEXIBLE PAVEMENT WITH CONCRETE OR
REMOVE AND REPLACE EXISTING HMAC WITH
APPROXIMATELY 700 SY CONTRACTOR TO
PER NCTCOG
TO CONTRACT
(203.5, 203.6) WILL BE SUBSIDIARY
PER NCTCOG 203.3,
RIGHT-OF-WAY PREPARATION
MBGF
D/S OF CULVERT CROSSING
RESTORE EXISTING U/S AND
MINOR CHANNEL GRADING TO
CONTRACTOR TO PERFORM
October 24, 2018
P35201.001
Kyle Hogue
City Engineer/Public Works Deputy Director
1400 Main Street
Southlake, Texas 76092
Subject: North White Chapel Road at Kirkwood Branch Culvert
Dear Mr. Hogue,
At your request, I visited the site of the above referenced project on September 25, 2018. The
purpose of this visit was to observe the structural condition of the culvert after it had become
overtopped after a heavy rainfall. Our evaluation of the culvert is limited to visual observations
only. No “As-built” drawings, geotechnical information or previous inspection reports have been
made available for our review. Furthermore, we have not undertaken any materials testing or
conducted any exploratory excavations.
The rain event of September 22, 2018 inundated the culvert crossing requiring a family to be
rescued from the structure when their vehicle became stranded after attempting to drive
through the flood waters. At the time of my visit, North White Chapel Road was barricaded to
prevent traffic from crossing the culvert. During this site visit I observed the following:
• The asphalt pavement had delaminated from the underlying flex base subgrade.
• One of the metal beam guard rail posts had dislodged from its foundation and was
carried downstream approximately 20 feet.
• Scour and erosion were evident along the stream embankment and at the shoulder
between the roadway and headwalls.
• Both the upstream and downstream headwalls have rotated outward.
The most pressing concern is the low elevation of the roadway above Kirkwood Branch. Without
significant upgrades to either elevate the roadway profile or expand the capacity of the culvert
opening, White Chapel Road will continue to be overtopped during similar rain events. A
secondary but still significant concern is the rotation of the headwalls. The rotation is most likely
due to surface water from the roadway draining toward the headwalls, infiltrating behind the
walls and saturating the backfill materials. These saturated soils increase the lateral driving
pressures behind the walls leading to rotation and/or translation. The headwall rotation will
become progressively worse if no measures are undertaken to prevent further water infiltration.
Temporary measures to reduce the rate of further rotation would include capping the open
surface area at the shoulder to inhibit water infiltration and strengthening the walls to withstand
Kyle Hogue
City of Southlake
October 24, 2018
Page 2
the increased lateral pressures. Possible strengthening alternatives would include the
installation of soil anchors behind the walls or buttresses in front of the walls. Replacement of
the headwalls is also a possibility however this will not address the primary cause of the flooding
and should only be considered temporary until a permanent solution is constructed. If the City
chooses not to undergo any temporary or permanent measures to address the inundation
problems at this site, the headwalls will eventually fail and will no longer be capable of retaining
the soils beneath the roadway exposing them to the stream flow. Given the turbulent flows, the
soils will eventually erode and the roadway will be undermined. Until either permanent or
temporary repairs are undertaken, we do not recommend reopening the culvert to traffic or
construction equipment.
If you should have any questions or require any further assistance with this matter, please
contact me at your earliest convenience.
Sincerely,
HALFF ASSOCIATES, INC.
Paul J. Rielly, P.E.
Vice President