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From page 75... ... 75 4.1 Overview This chapter presents a summary of information, observations, and recommended guidance for the installation of filters underwater. Guidance for selecting filter types and placement techniques are presented in flowchart fashion. Read the entire page →
From page 76... ... 76 Guidance for Underwater Installation of Filter Systems • Self-sinking mat (machine-placed) • Self-sinking mat (diver-placed) Read the entire page →
From page 77... ... Legend: = Well suited P = Possible use = Unsuitable Figure 4.1. Selection based on access and clearance. Read the entire page →
From page 78... ... Figure 4.2. Selection based on velocity and depth. Read the entire page →
From page 79... ... Guidance for Installation of Filter Systems 79 4.3.3 Additional Considerations There are additional issues to consider when selecting a filter to be placed underwater. For granular filters, issues to consider are the following: • Availability of filter material of the required size and gradation • Haul distance For all filter types, issues to consider are the following: • Site access • Equipment requirements, including barge if necessary • Environmental and water quality issues and permitting requirements • Habitat and/or migration issues for threatened and endangered species • Traffic control during construction activities Lastly, materials and installation costs will be a factor in the selection of a filter when more than one filter type and/or construction technique is viable at a particular site: 1. Read the entire page →
From page 80... ... 80 Guidance for Underwater Installation of Filter Systems A successful demonstration of the flexible tremie hose technique is summarized in Section 3.3.2. That demonstration used a standard contractor solids-handling pump ("trash pump") Read the entire page →
From page 81... ... Guidance for Installation of Filter Systems 81 Cu = d60/d10 ranging from 1.5 to 2.5. Table 4.2 is from ASTM C33/C33M, which identifies the particle size limits for each of the 15 standard classes. Read the entire page →
From page 82... ... Table 4.2. Standard coarse aggregate gradations from ASTM C33. Read the entire page →
From page 83... ... Guidance for Installation of Filter Systems 83 4.4.6 Quality Assurance/Quality Control In construction, the quality assurance program focuses on the procedures used to ensure that the design meets quality standards. This includes design calculations, construction plans and detail drawings, and specifications for required material properties. Read the entire page →
From page 84... ... 84 Guidance for Underwater Installation of Filter Systems under water in a stream, the only likely change in the physical habitat would be to the bed material factor. The design and installation of an erosion protection countermeasure might require placing a granular filter component prior to placing much larger material, such as riprap, as an armor layer. Read the entire page →
From page 85... ... Guidance for Installation of Filter Systems 85 subgrade. Individual sheets should be overlapped a minimum of 12 inches and temporarily weighed down before the armor is placed (see Figure 2.32) Read the entire page →
From page 86... ... 86 Guidance for Underwater Installation of Filter Systems Example specification language for geotextiles used in permanent erosion control applications is provided in Holtz et al. Read the entire page →
From page 87... ... Guidance for Installation of Filter Systems 87 Quality Assurance Quality assurance measures for the design and installation of geotextile filters under water include the following checklist items: 1. Filter design per methods identified in Section 4.5.1. Read the entire page →
From page 88... ... 88 Guidance for Underwater Installation of Filter Systems If water quality is a primary concern with the use of geotextiles in the aquatic environment, a closer look at the chemical and biological characteristics of these materials is justified. Geotextile producers and suppliers indicate that geotextiles are manufactured from fibers, filaments, and yarns, formed by the extrusion of polypropylene or polyethylene, individually or in combination (see Section 2.2.6) Read the entire page →
From page 89... ... Guidance for Installation of Filter Systems 89 Reese, State Hydraulic Engineer, Idaho DOT. Installation of the A-Jacks® system took place on two bridges -- the Ferry Butte Bridge and the West Shelley Bridge on the Snake River between Idaho Falls and Pocatello, Idaho. Read the entire page →
From page 90... ... 90 Guidance for Underwater Installation of Filter Systems Idaho DOT required that the contractor: • Fit modules as close as possible to each other and to the pier structure. • Meet the manufacturer's recommendation of ± 6 inches except that one fit-up in four placements could exceed the 6-inch fit-up tolerance by 3 inches. Read the entire page →
From page 91... ... Guidance for Installation of Filter Systems 91 Figure 4.6. Applying the geotextile filter to an A-Jacks® module (courtesy Idaho DOT) Read the entire page →
From page 92... ... 92 Guidance for Underwater Installation of Filter Systems Figure 4.8. Installation at the bridge started downstream and proceeded upstream (courtesy Idaho DOT) Read the entire page →
From page 93... ... Guidance for Installation of Filter Systems 93 Shelley Bridge. In 2013, site inspection at the Ferry Butte Bridge indicated that the streambed had aggraded to approximately 1.5 ft above the top of the A-Jacks® modules (Lotwick Reese, personal communication) Read the entire page →
From page 94... ... 94 Guidance for Underwater Installation of Filter Systems Countermeasure Strategy The weather forecast added an additional factor of urgency to the situation. High winds, heavy seas and extreme tidal exchange from a three day nor'easter is always a concern for Oregon Inlet and the coastal highway, which parallels the shoreline along most of the Outer Banks. Read the entire page →
From page 95... ... Guidance for Installation of Filter Systems 95 containers to periods of slack tide twice a day (Figures 4.13, 4.14, 4.15, and 4.16) Read the entire page →
From page 96... ... 96 Guidance for Underwater Installation of Filter Systems (a) Assembly area (b) Read the entire page →
From page 97... ... Guidance for Installation of Filter Systems 97 Summary Observations The Emergency Declaration by the Governor of North Carolina minimized many potential obstacles in immediate contract negotiation and established a dialogue with a host of state agencies including Marine Fisheries, Division of Water Quality, and Coastal Area Management Commission. Collaboration with USACE, U.S. Read the entire page →
From page 98... ... 98 Guidance for Underwater Installation of Filter Systems of communication, which created a positive climate for managing internal roles and external influences of social, media, and political pressures. 4.7 Description of Stand-Alone Training Document A training manual for implementation of research results was developed as a stand-alone document (see NCHRP Web-Only Document 254, Volume 2) Read the entire page →
From page 99... ... Guidance for Installation of Filter Systems 99 could be incorporated into several NHI course offerings as additional or optional workshops. Moreover, the underwater filter workshop provides the basic instructional components for the development of a distance learning (web-based) Read the entire page →

From page 75...

... 75 4.1 Overview This chapter presents a summary of information, observations, and recommended guidance for the installation of filters underwater. Guidance for selecting filter types and placement techniques are presented in flowchart fashion.