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This report provides procedures for determining allowable design loads for embedment anchors under all types of dynamic loads, including impact (as from a ship driving into a mooring), cyclic (as from a buoy or ship riding in a mooring system during a storm), and earthquake loading. The design procedures are simplified in the form of guidelines applicable to most site conditions and are complete to the point of including the following: (1) site survey requirements; (2) detailed static design procedures; (3) description and definition of dynamic loads; (4) design procedures for impact, cyclic, and earthquake loading; (5) selection and use of appropriate factors of safety; and (6) description of available existing CEL embedment anchor hardware. While the procedures are designed specifically for the NCEL-developed family of propellant (often termed explosive) embedded anchors, they are applicable to other types of embedment anchors and screw anchors.

The report presents a systematic analysis of foundation systems for seafloor installations. Current and foreseeable Navy needs for seafloor installations are summarized, and the foundation requirements for such installations are defined in terms of four foundation requirement parameters. Environmental conditions and technological capabilities, major influences in the process of selecting a foundation system, are defined in terms of design constraints. These include seafloor type, which ranges from weak and compressible cohesive soil to sound rock; maximum topographic slope, which ranges from less than 1 degree to 20 degrees; and required emplacement capability, which can range from simply setting a single module on the seafloor to in-situ assembly or fabrication of a multimodule installation.

The report summarizes interim procedures for designing seafloor footing foundations. Methods for determining foundation loads including the estimation of drag forces and seismic loadings are summarized. General requirements for site surveys and evaluation of the engineering properties of the soil profile are outlined. Detailed procedures for predicting bearing capacity, resistance to lateral loads and footing settlement are included along with an example design problem. These procedures are considered adquate for designing all but manned installations. (Author)

The report describes the development and evaluation of two devices for monitoring long-term seafloor foundation settlement and tilting. The LOBSTER(Long-Term Ocean Bottom Settlement Test for Engineering Research) is an instrumented foundation used as a test device, whereas the FMS(Foundation Monitor System) is an instrument that can be attached to any seafloor foundation to be monitored. Data and preliminary analysis are presented from successful foundation deployments for periods of up to 1 year at water depths of 4,120,600, and 1,200 feet in the Santa Barbara Channel area of the Pacific Ocean. The analysis presented includes data from an extensive laboratory program of core analysis and consolidation testing. (Author)

The characteristics, basic foundation design parameters, and foundation performance of a number of seafloor installations are summarized. These installations include offshore towers, habitats, acoustic arrays, and numerous other objects located in water depths from 20 to 12,000 feet. A number of case histories are analyzed. Some findings indicate behavioral problems not normally considered during foundation design. Several unique foundation configurations are documented which have been devised and utilized by a few to overcome the conditions imposed by the unique seafloor environment. The value of foundation performance monitoring, both to the operation of an installation and to the field of seafloor foundation design, and the value and need for continued cooperation in the sharing of such information and experience are discussed. (Author)

Experimental results and empirical relations are given which define the behavior of reinforced-concrete model cylinders that are buried in dry sand with their longitudinal axis parallel to the surface. The model cylinders were 9 inches in outside diameter and had a single layer of reinforcement at midsection. Thickness, percent reinforcement, and depth of cover were varied. The 12 test cylinders cracked at uniform surface pressures of less than 60 psi and subsequently deformed in such a way that the ratio of the effective stiffness of the cylindrical inclusion to the stiffness of the soil in the vertical direction remained constant. Significant moments were induced that would preclude the design of buried cylindrical shelters on the basis of the pure compression mode. The magnitude of the induced moments increased with increasing wall thickness and increased at a decreasing rate with increasing load. Empirical relations which agree reasonably well with the test data are given for permitting estimates of horizontal expansion, arching, thrust, moment, and interface pressure. (Author)

The report is concerned with the laboratory determination of the residual shear strength of weak shales such as might be encountered in construction within the Canal Zone. This laboratory measurement is proposed mainly as in index property to estimate the potential for shales or deeply weathered rocks to lose substantial strength with time. In addition to the residual strength parameter, five other index properties are outlined to form a comprehensive means for expediently evaluating potential loss of strength. By definition, the residual shear strength is a constant for any given soil regardless of stress history, and is the lowest 'ultimate' strength. In practice, however, the laboratory measurements of residual strength can vary simply because of failure to reach this lowest strength. The main effort in this present research is to develop the equipment and testing procedures to reliably measure residual strength. It was found that the repeated direct shear test, with about 30 repetitions of loading, on mechanically disintegrated and resedimented samples resulted in an adequate index property test. The results of comprehensive testing of two Canal Zone shales (from the Cucaracha and the Culebra formations), Pierre shale from the Oahe damsite in South Dakota and a kaolinite clay are contained in the report. (Author), Sponsored by Army Engineer Nuclear Cratering Group, Livermore, Calif., See also AD-626 899.