Anchors are used in civil engineering practice to provide resistance against uplift and overturning forces for structures such as transmission line towers, aircraft mooring, pipelines, offshore structures, mobile homes, and so forth. Although there are a wide variety of anchor types available, helical screw anchors, consisting of a steel shaft to which one or more helices are attached by welding, are finding wider usage particularly for the support of transmission line towers. Because these anchors are installed by truck mounted power augurs they can be used immediately after installation. Although there exists in the geotechnical engineering literature a variety of techniques for evaluating lateral-load capacity of piles, there are no published methods for analyzing helical anchor lateral stability when used as piling. The present study was undertaken to develop suitable mathematical models based upon the current state of the art for determination of lateral-load capacity of helical-type anchor piles. The model selected was patterned after Matlock and Reese's elastic theory model. The model was modified to take into account the influence of the method of installation and other unique characteristics of this type of foundation. Based on the results of this study it was found that helical anchor piles can develop significant resistance to lateral loads, and this resistance is almost exclusively controlled by the extension shaft diameter.
Model test results for the ultimate bearing capacity of rectangular surface foundations supported by geogrid-reinforced sand are presented. The tests were conducted using one type of sand at one relative density of compaction with only one type of geogrid. The length-to-width ratios of the model foundations were varied as 1, 2, 3, and ∞. Based on the model test results, the maximum required depths of reinforcement and the sizes of the geogrid layers to obtain maximum-bearing-capacity ratios have been presented.
Laboratory tensile and unconfined compression test results on lightly cemented sand specimens are reported. Type I portland cement was mixed with sand in proportions of 4, 6, and 8% by weight to prepare the specimens. Tensile strength was determined by indirect tensile strength testing and direct tension testing. The variation of tensile strain with stress in indirect tensile strength tests was measured by a computer-aided image analysis method. Based on the test results, tensile and compressive strengths and strain levels at failure have been determined and compared. Nondimensional tensile stress-strain relationships in the form of a rectangular hyperbola as obtained from the indirect tensile strength tests and direct tension tests have been developed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.