Engineering Disciplines


Services

Coastal Access Stairways

Seascape Sur Beach Access Stairway, Solana Beach, CA.

Initially, NCI's services included evaluation of an existing access timber stairway which traversed a steep bluff face via three intermediate landings with a 36-inch diameter drain pipe beneath the stairway. This drain line had failed taking out a section of the steep bluff and seriously undermining and exposing the existing stairway foundation. A feasibility report was prepared which evaluated alternatives from repair of the existing stairway to design of a new stairway. Construction cost estimates and potential funding sources were also developed. NCI then performed engineering design for a new stairway, and prepared the construction drawings, specifications, and contract documents. The new stairway consisted of 8 landings from top of bluff to beach level over a 70-feet drop in elevation, with 30-inch diameter reinforced concrete piers supporting reinforced concrete landings. Stairs were constructed of timber stringers and steps with a guardrail consisting of aluminum vertical pickets and handrail, and Western Red Cedar top rail and posts. The slope was repaired by installing a sub-drain system and re-compacting the slope materials with reinforced earth geogrids. A new 24-inch diameter lined and coated storm drain pipe was installed down the reconstructed bluff slope with use of a concrete anchor block. NCI services also included providing full time resident inspection and construction management services.

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Tide Beach Park Lifeguard Platform and Stairway, Solana Beach, CA.

This project consisted of replacing a lifeguard station platform and beach access stairway/landing platforms for the Tide Beach Park coastal access. The existing lower section of stairway was in a deteriorating state, while the lifeguard station and its platform had been removed due to unsafe conditions. NCI's services consisted of performing the engineering design, and preparing the construction drawings, specifications and contract documents for a new stairway and lifeguard station platform. The stairway design consisted of drilled-in-place reinforced concrete piers supporting reinforced concrete landings with concrete ramps and stair steps poured-on-grade for the upper section, and timber framed stairs for the lower section. The guardrail consisted of aluminum vertical pickets and handrail with cedar posts and top rail.

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Repair and Rehabilitation of Malibu Beach Accessways, Malibu, CA.

NCI performed conceptual design analysis of eight beach accessways along the Malibu shoreline to assess existing conditions, recommend repairs, and prioritize replacement.  The stairs are primarily reinforced concrete designs with conventional guardrail details and structural features such as concrete masonry retaining walls.  Each access experienced varying degrees of coastal storm damage and long term deterioration.  The scope of services included detailed condition assessments of each structure, preparation of conceptual repair plans or replacement designs, and preparation of detailed designs and construction plans for the most severely deteriorated facilities.  NCI also provided assistance to staff to coordinate interaction with the regulatory agencies.

 

 

 

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Promenade Beach Stairs and Seawall Improvement Design, San Buenaventura, CA.

NCI has provided engineering services to improve 1,850 lined feet of a promenade beach access walkway, stairs and seawall which is constructed of reinforced concrete and has been experiencing advanced structural degradation.  Our work consisted of providing an aerial site survey and control, geotechnical investigation, concrete testing, engineering analysis to identify the causes of observed failures, preliminary and detailed engineering design of recommended improvements, constructability review and opinion of construction cost, landscape architectural plan to address the overall promenade reconstruction, amenities and design treatments, preparation of construction drawings and contract specifications and documents, and attendance at pre-construction and other meetings.

 

 

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Del Mar Shores Beach Access Stairway, Solana Beach, CA. 

NCI performed a detailed assessment of the Del Mar Shores Beach Access to evaluate the condition of the existing structure and determine the most feasible repair or replacement plan for the stairway.  Our responsibilities included a geohazards assessment of the site conditions, conceptual design analysis of the stairs structure, and collaboration with staff to arrive at a preferred plan recommendation.  A conceptual design report was prepared for City Council review to summarize the existing condition and outline alternative repair and replacement options.  NCI is currently is the process of overseeing the final design, construction documents and will manage the construction of the plan selected by the City.

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Dana Headlands Pedestrian Walkway, Retaining Wall and Stairway, Dana Point, CA.

As part of the Dana Headlands development, a walkway and associated retaining wall was built atop the shore protective revetment to promote public use and enhance the aesthetic scenic view. To construct the walkway, following installation of the center footing and stem wall, forms were set on the graded surface along each edge of the walkway.  The walkway was cast against grade and temporary support from the riprap along the beach side of the structure.  The cantilevered slab concept did increase thickness and reinforcement in the section; however, those additional costs were made up in reduced labor and materials costs eliminating the down-slope supports for the structure.

 

 

 

 

 

Beach access, through the riprap revetment, is provided by an ADA compliant stairway and an emergency-vehicle access ramp.   The stairway is oriented diagonal to the alongshore alignment to minimize wave uprush, with the stairs accommodating a sand elevation range of over 10-feet. The cast-in-place concrete structure is founded on spread footings keyed into bedrock at the base and bearing on competent soil near the top.

To thoroughly understand behavior of the structure under loading and settlement scenarios, a finite element model was used in the structural analysis. Stress levels in the structure, when subjected to lateral earth or seismic forces depend largely on the soil characteristics that support it. By modeling the soil as springs in the finite element analysis, and altering spring constants to cover a safe range of soil characteristics, stress envelopes reflecting the worst-case scenario for all loading and soil combinations were clearly defined. Using this approach produced a design that reliably meets its service requirements.

 

 

 

 

 

 

 

 

 

 

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