HomeMy WebLinkAboutPA2022-0314_20230207_Bulkhead Condition Report_dated 12-03-2018
3 December 2018
Mr. Randy Beers
W.T. Durant, Inc.
2706 St. Louis Avenue
Signal Hill, CA 90755
Re: Bulkhead Conditions Report for 944 Via Lido Nord, Newport Beach, CA
Dear Mr. Beers:
Simpson Gumpertz & Heger Inc. (SGH) is retained by W.T. Durant, Inc. (Durant) to provide a
Bulkhead Conditions Report for the property of 944 Via Lido Nord, Newport Beach, CA. The
objective of the report is to evaluate the current condition of the bulkhead and make
recommendations regarding the need for repair, augmentation, or replacement of the bulkhead
or any parts thereof as it relates to proposed use and associated loadings as well as the relevant
findings of the Coastal Hazards Report. This report has been developed in accordance with City
of Newport Beach Municipal Code Section 21.30.015(E)(3).
1. BACKGROUND
The owner of the property is exploring potential modifications including the possibility of
demolishing the existing residential structure and landscaping the lot. The property is located on
Lido Island in Newport Bay. The property is bounded by residential lots on either side, Via Lido
Nord, and the bay. On the bayside, an approximately 6 ft high precast concrete bulkhead retains
site soils. SGH was tasked with visually assessing the current condition of the bulkhead,
assessing the bulkhead for the proposed change, and recommending repairs, augmentations, or
replacement as necessary.
2. DOCUMENT REVIEW
As part of the assessment, we have conducted a site visit as well as reviewed relevant information
in the following documents:
• Bulkhead Upgrade at Richard Steele Residence 944 Via Lido Nord by Richard K.
Shogren, 10 December 1987.
• Simpson Gumpertz & Heger, Coastal Hazards Report for 944 Via Lido Nord,
3 December 2018.
3. CONDITION ASSESSMENT
Michael Perkins, P.E. of SGH, visited the site on 21 August 2018 and made a Level 1 inspection
of the visual portions of the bulkhead in accordance with the recommendations provided in
American Society of Civil Engineers (ASCE) Manual of Practice (MOP) 130, Waterfront Facilities
Mr. Randy Beers – Project 187550 - 2 - 3 December 2018
Inspection and Assessment (ASCE MOP 130). The site visit was timed to coincide with low tide,
so the current silt line at the base of the bulkhead was exposed and above the water line. The
inspection was performed without any soil excavation or marine growth removal.
The bulkhead is 46 ft long and consists of precast concrete sheet piles that are 5 ft wide, 10 in.
thick, and 24 ft tall. SGH observed that the silt line generally slopes downward from south to north
along the bulkhead face. The exposed height of the piles varies due to the sloped silt line but
was about 6 ft on average. The piles are connected by tongue-in-groove joints and capped by a
cast-in-place 26 in. x 20 in. reinforced concrete cap beam.
SGH made the following observations during the visual assessment of the bulkhead:
• The concrete sheet piles appeared to be in generally good condition in accordance with
ASCE MOP 130. No significant spalls, cracks, or corrosion were observed.
• Most of the sheet piles were leaning slightly offshore. Rotations between 0.5 and 2
degrees off vertical were measured.
• The joints between the sheet piles appeared to be well-sealed and did not exhibit signs
of water or debris movement between piles.
• The cap beam is generally in good condition in accordance with ASCE MOP 130. Only
some minor pitting and surface level cracks approximately 1/64 in. wide were observed.
• SGH did not observe any evidence of the tieback anchor rod shown at the east end of
the bulkhead in the structural drawings. However, SGH did observe potential evidence
of a similar anchor rod at the west end of the bulkhead.
• SGH did not observe the condition of the concrete patio slab (clad with brick masonry)
or the steel bars embedded within the slab.
• SGH did not observe the connection between the patio slab and the residential structure
foundation.
4. DISCUSSION
According to the bulkhead structural drawings from 1987, the sheet piles are tied back to the
foundation of the house by #8 steel reinforcing bars embedded in the patio slab that terminal into
the house foundation. The existing house is behaving as a deadman for the tieback system. Our
analysis confirms that the rebar tiebacks are an essential component of the structural load path
for the bulkhead. The bulkhead cannot adequately behave as a cantilever for the lateral loads
considered. The tiebacks function together with the weight of the residential building to provide
lateral restraint. If the building was to be demolished, an alternative support or tieback system for
the bulkhead would need to be designed and installed prior to demolition.
5. CONCLUSION AND RECOMMENDATIONS
Based on our inspection and analysis, we conclude the following:
Mr. Randy Beers – Project 187550 - 3 - 3 December 2018
• The sheet piles and cap beam are generally in good structural condition.
• The bulkhead is structurally adequate to support the coastal hazards scenarios detailed
in the 3 December 2018 Coastal Hazards Report in its present condition. No
strengthening is required for current use.
• Overtopping of the bulkhead is likely subject to the combined effects of long-term sea
level rise (75-yr) and a 100-yr storm or flood event. However, overtopping would not
impact structural performance of the bulkhead structure. No strengthening is required
to accommodate overtopping associated with 75-yr sea level rise.
• Neither the existing residential structure nor the patio slab should be removed until a
more detailed assessment of the tieback system is done. SGH recommends further
analysis be conducted to determine more precisely how much dead load is required to
safely restrain the existing bulkhead structure for the load conditions considered. An
alternative tie-back system could be installed to allow complete removal of these existing
structures. Other combinations of existing structure and new may also provide adequate
restraint for the bulkhead structure.
If there are any questions regarding this, please do not hesitate to contact me at (510) 457-4449
or by e-mail at WMBruin@SGH.com.
Sincerely yours,
William M. Bruin, P.E. Michael J. Perkins, P.E.
Senior Principal Staff II – Structures
CA License No. C57867 CA License No. C88664
I:\OAK\Projects\2018\187550.00-LIDO\WP\001WMBruin-L-187550.00.els_2018-12-03 Bulkhead Conditions Report.docx
12/3/2018