HomeMy WebLinkAboutWRSA-EvaluationReport(1-31-17)Wesley R. Segawa and Associates, Inc.
Committed to Quality Performance & Value
January 31, 2017
Mr. Frank DeMarco P.E.
Director of Public Works
County of Hawaii
Department of Public Works
101 Pauahi Street, Suite 7
Hilo, HI 96720
Subject: Hakalau Stream Bridge (#29-3)
Structural Condition Survey Report
Hilo Office
101 Silva Street, Suite 201
Hilo, Hawaii 96720
Honolulu O 808-5364495
736 South Street Suite 203
Hmmlulu, Howd 96813
Ell 808-935-4611 ® HbCaNw moluiions.mm
O 8BUBO-6307 8 www.wwsolulimcom
Keihin 8mm ® 808-329-8249
73-5577 Kouh* %cot #4
Koiluo-Km Hawe6 96740
Wesley R. Segawa & Associates (WRSA), conducted a field visit on January 13, 2017 to observe
the condition of observable portions of the Hakalau Stream Bridge for the purpose of rendering a
professional opinion regarding the structural condition of the bridge at the time of our visit.
This field visit was conducted after review of the following documents provided by the County
of Hawaii (COH):
1. Original construction drawings, specifications and miscellaneous contract documents
(circa 1929).
2. Biennial Bridge Inspection Report, dated June 3, 2015.
3. Underwater Inspection Report by Hawaii Engineering Group (BEG), dated March 2016.
4. FHWA e-mail by Mr. Domingo Galiciano, P.E. (FWHA), dated August 4, 2016.
5. Draft Preliminary Geotechnical Consultation Letter by Yogi Kwong Engineers (YKE),
dated November 15, 2016.
General Descriotion
1. The Hakalau Stream Bridge is a reinforced concrete arch bridge spanning over Hakalau
Stream.
2. The project specifications indicate the bridge was designed and constructed as an arched
structure based on prescribed construction sequencing and monitoring while placing
concrete for the Arch Ring Abutments and Arch Ring.
3. A recent underwater inspection of the bridge's Arch Ring Abutments discovered severe
scouring beneath the full width of the North Arch Ring Abutment (North Abutment) that
measured 17 to 25 feet in horizontal depth measured from the face of the Sub -Ledge and
vertical opening measuring 5.5 to 8 feet from the stream bed, as identified in the BEG
report.
County of Hawaii
Department of Public Works
Mr. Frank DeMarco, P.E., Director of Public Works
Hakalau Stream Bridge (#29-3)
Structural Condition Survey Report
January 31, 2017
Field Visit Observations
General:
1. The purpose for this field visit was to familiarize ourselves with existing conditions and
to identify evidence of structural irregularities.
2. This field visit was conducted on January 13, 2016 around 2:30 p.m. during clear/calm
skies and sunshine.
3. The stream flow was below the rock/concrete ledge that was installed at the base of a
rockwall that protects the roadway embankment and North Abutment.
4. Rock outcroppings and small boulders were visible above and just beneath the water
surface.
5. Views of the bridge superstructure was mostly unobstructed from the West side of the
bridge while views of the East side of the bridge were limited due to overgrown
vegetation and poor lighting.
Roadway Level:
1. The roadway asphalt pavement, adjoining rock walls, sign posts, guardrails and concrete
bridge railings had no visible signs of structural irregularities.
2. Existing cracks on the concrete bridge railings were patched with an unknown patching
material and there were no signs of patch separations or new cracks. In addition, there
was no visible joint separation at locations where construction joints might have been
installed.
Stream Level:
1. Access to the North Abutment was gained from an access point located on the West side
of the roadway by climbing down a rock embankment to a concrete ledge that continued
toward and beneath the North Abutment.
2. Access on the East side of the North Abutment was gained by climbing down a dirt path
adjacent to the North Abutment.
3. No attempt was made to access the South Abutment.
4. Evidence of scour was visible on the underside of the concrete ledge running parallel
with the roadway and beneath the bridge however no attempt was made to determine the
extent of the scour.
5. The visible portions of the arched concrete bridge soffit and abutment did not show signs
of structural irregularities such as cracks, fractures or settlement.
6. The silhouetted shape of the Arch Ring Abutment and Arch Ring were visible from the
East side of the bridge.
Field Visit Summary
1. Based on our field visit, we concluded that observable portions of the Hakalau Stream
Bridge are constructed in accordance with the design intent presented on the drawings.
County of Hawaii
Department of Public Works
Mr. Frank DeMarco, P.E., Director of Public Works
Hakalau Stream Bridge (#29-3)
Structural Condition Survey Report
January 31, 2017
2. Other than the cracks observed on the concrete bridge railings we did not observe any
structural irregularities including cracks, fractures or differential settlement that would
indicate adverse movement or manifestations of structural distress requiring immediate
attention.
Conclusions and Recommendations
Structural Opinion: We believe the arched design and construction of this bridge causes
the majority of the foundation's resultant forces to be applied at an angle that is more
tangent with the arch and not directly over the scoured cavity. Based on this assumption,
it is our professional opinion that the structural integrity of this bridge will remain intact
provided the bridge foundation bears upon stable and structurally sound subgrade
material. Notwithstanding the risks associated with the scouring beneath the North
Abutment, it is WRSA's considered opinion that the subject bridge is capable of
supporting a single passenger vehicle not exceeding 6 Tons at any given time. WRSA's
opinion that the bridge is safe for limited usage is influenced somewhat by its projected
low ADT, lightweight vehicles and YKE's opinion that a significant portion of the
foundation loads placed upon the subgrade are beyond the surveyed scoured zone.
2. If adverse physical changes in the bridge are reported in the immediate future or if the
COH discovers or acquires new information about this bridge, the COH shall be solely
responsible for delivering this information to WRSA for review and appropriate response,
including rescinding our Structural Opinion. In any event, we recommend conducting
another condition survey within the next 6 months to give WRSA an opportunity to
determine whether our Structural Opinion should be revised.
To insure public safety, WRSA recommends continued monitoring and frequent
inspections of the bridge by qualified and experienced bridge inspectors employed by or
hired by the COH. Any changes in the physical condition of the bridge should then be
brought to the COH's attention for appropriate action. In addition, WRSA should be
notified if movement is observed or suspected. For example, monitoring of the patched
cracks on the bridge rails should be check regularly for any signs of movement such as
separation of the patching material from the cracked surfaces.
4. WRSA concurs with FWHA's concerns, recommendations and urgency for the COH to
take immediate action to reduce or eliminate the risk to the traveling public.
County of Hawaii
Department of Public Works
Mr. Frank DeMarco, P.E., Director of Public Works
Hakalau Stream Bridge (#29-3)
Structural Condition Survey Report
January 31, 2017
5. WRSA supports YKE's recommendation to conduct site specific in -water reconnaissance
and geotechnical investigations as necessary for preparing recommendations to
reestablish and protect the subgrade integrity beneath the North Abutment.
Limitations
This report was prepared for the sole use by the COH, Department of Public Works, and
the opinions stated in this report are based on limited visual observations on the date of
this field visit. No warranty is expressed or implied, no physical testing was performed
and no calculations have been made to determine the adequacy of the bridge, its
structural system/elements or its compliance with applicable codes and standards of
practice.
2. In the event of a claim, as defined by our professional insurance policy, and/or lawsuit
filed against WRSA related to the Hakalau Bridge, the COH shall defend, indemnify and
hold harmless WRSA, and their officers, employees, and agents from and against all
liability, loss, damage, cost, and expense, including attorneys' fees, and all claims, suits,
and demands therefore, arising out of or resulting from the acts or omissions of WRSA or
WRSA's employees, officers, agents, or subcontractors under the services provided for
this Hakalau Stream Bridge project. These provisions shall remain in full force and
effect notwithstanding the expiration or early termination of WRSA's services.
3. WRSA reserves the right to revise or change its opinion at any time when new
information or data is discovered or revealed and/or physical changes occur in the bridge
structure such as cracks, fractures and/or settlement, including rescinding our Structural
Opinion.
Thank you for giving us this opportunity to assist and serve the County of Hawaii and its
residents. Should there be any questions regarding this report, please feel free to contact the
undersigned at (808) 935-4677.
Respectfully submitted,
We ley R. Segawa &Associates, Inc.
ZWeslee.gaw .
Managing Principal