Near Shore and on Shore: Materials of Construction
Contents
Primary Guidance
Concrete
- Marine Mix Design
- Certify using independent commercial testing laboratory with testing conducted within last six months.
- Applicability: All in-water concrete including but not limited to piles, pile and sheet caps, precast deck panels, fascia beams, and outfalls.
- SCC: All precast members, closure pours between precast elements.
- RCC: RCC or asphalt overlaid RCC in travel lanes and stern ramp landing pads on roll on/roll off berths where tracked vehicles are transferred.
Reinforcement
- Corrosion Resistant: Investigate cost, local availability, contractor experience and utilize where feasible, especially alloys that do not corrode for in-water structural elements.
Structural steel
- Passive Cathodic Protection (CP) system for all structural steel in contact with water with minimum 25 year design life.
- Passive or active system as required to mitigate stray currents from CP systems of layberthed vessels.
- Stray current investigation for all submerged structural steel within 500 feet of layberthing terminal for vessels with CP systems.
Timber
- Non-commercial, non-industrial facilities only.
Pavement Surface Course
- Highway Trucks: No special requirements.
- Superload Trailers/Mafis: Solid tire vehicles require durable surface course and low speeds.
- Forklifts: Concrete for axle loads > 27,000lbs.
- Outriggers: RCC prohibited in the absence of matting.
- Track Vehicles: RCC, asphalt overlaid RCC or concrete pavers.
Discussion
Concrete
Waterfront facilities composed of conventional highway concrete mix designs demonstrate materials-related service levels below half the service life expectation. Adequately performing marine concretes are both highly impermeable to water-born chlorides and sulfates and immune to expansive deterioration due to the formation of ettringite, whether that formation is the result of aggregate reactivity or high temperature curing of precast concrete. Ion transfer analyses are one method of estimating the service life of a given mix while empirical data is developed.
Reinforcement
Waterfront facilities deteriorating due to concrete reinforcement corrosion can be deferred or avoided by selecting corrosion-resistant reinforcement. The onset of corrosion is not necessarily a late-term effect, but can occur at any time an incident causes cracking damage, whether due to environmental storms, accidents involving equipment, or vessel berthing.
Structural Steel
Placing carbon steel members in water should be avoided where possible. Protective coatings have a finite service life and are prone to holidays. Existing steel piles and new sheeting require a passive CP system to prevent rapid corrosion and section loss, especially where vessels are layberthed.
Timber
Timber structures are not appropriate in industrial settings due to their inherent weak material strengths and susceptibility to soft rot.
Surface Course of Pavement
Durable surface courses are required in travel lanes for tracked vehicles to resist aggressive surface stripping in turning maneuvers.
