Retaining Walls – vulcanhammer.net

Because of the wide variety of topics covered on this page, it has been divided into several categories:

This manual is for the guidance of designers, specification writers, and especially field personnel engaged in designing, planning, and conducting earthwork operations around major deep-seated or subsurface structures.

The greatest deficiencies in earthwork operations around deep-seated or subsurface structures occur because of improper backfilling procedures and inadequate construction control during this phase of the work. Therefore, primary emphasis in this manual is on backfilling procedures. Design and planning considerations, evaluation and selection of materials, and other phases of earthwork construction are discussed where pertinent to successful backfill operations.

Although the information in this manual is primarily applicable to backfilling around large and important deep-seated or buried structures, it is also applicable in varying degrees to backfilling operations around all structures, including conduits.

This manual is an updated version of the Geotextile Design & Construction Guidelines, used for the FHWA training course Geosynthetic Engineering Workshop. The update was performed to reflect current practices and codes for geotextile design, and has been expanded to address geogrid and geomembrane materials. The manual was prepared to enable the Highway Engineer to correctly identify and evaluate potential applications of geosynthetics as an alternative to other construction methods and as a means to solve construction problems. With the aid of this text, the Highway Engineer should be able to properly design, select, test, specify, and construct with geotextiles, geocomposite drains, geogrids and related materials in drainage, sediment control, erosion control, roadway, and embankment on soft soils applications. Steepened slope and retaining wall applications also are addressed, but designers are referred to the FHWA Demonstration Project No. 82 references on mechanically stabilized earth structures for details on design. Application of geomembranes and other barrier materials to highway works are summarized within. This manual is directed toward geotechnical, hydraulic, roadway, bridge and structures, and route layout highway engineers.

This manual outlines the state-of-the-art and recommended practice for designing and constructing Geosynthetic Reinforced Soil (GRS) technology for the application of the Integrated Bridge System (IBS). The procedures presented in this manual are based on 40 years of State and Federal research focused on GRS technology as applied to abutments and walls. This manual was developed to serve as the first in a two-part series aimed at providing engineers with the necessary background knowledge of GRS technology and its fundamental characteristics as an alternative to other construction methods. The manual presents step-by-step guidance on the design of GRS-IBS. Analytical and empirical design methodologies in both the Allowable Stress Design (ASD) and Load and Resistance Factor Design (LRFD) formats are provided. Material specifications for standard GRS-IBS are also provided. Detailed construction guidance is presented along with methods for the inspection, performance monitoring, maintenance, and repair of GRS-IBS. Quality assurance and quality control procedures are also covered in this manual.

This report is the second in a two-part series to provide engineers with the necessary background knowledge of Geosynthetic Reinforced Soil (GRS) technology and its fundamental characteristics as an alternative to other construction methods. It supplements the interim implementation manual (FHWA-HRT-11-026), which outlines the design and construction of the GRS Integrated Bridge System (IBS). The research behind the proposed design method is presented along with case histories to show the performance of in-service GRS-IBS and GRS walls.

Rockeries consist of earth retaining and/or protection structures comprised of interlocking, dry-stacked rocks without mortar or steel reinforcement. They have been used for thousands of years and rely on the weight, size, and shape of individual rocks to provide overall stability. Some of the earliest rockeries constructed by the Federal Government date back to 1918. Within the private sector, commercially built rockeries have been constructed in the Pacific Northwest for at least the last four decades and in Northern California and Nevada for at least the last 10 years. As rockery design procedures tend to vary regionally, studies were performed to determine the methods by which rockeries are designed and constructed in various regions throughout the western United States. These design methods were then compared using several typical rockery design loading conditions to determine how the resulting rockery designs differ and which methods are most appropriate for a proposed design for the FHWAs FLH Divisions. Based on the research performed, a rational design methodology, which evaluates rockery stability as a function of the rockery geometry (height, base width, and batter), rock properties and placement, and lateral pressure imposed by the backfill materials, was developed. A sample design problem is included. Recommendations for specifying and constructing rockeries that are consistent with the design methodology are also provided.

Cantilever retaining walls can respond externally to earthquake ground motions by sliding or by rotating, or internally by stem wall yielding. The type of response that will have the greatest impact on post-earthquake performance will likely depend on restraint conditions at the base of the wall. Walls founded on soil without an invert slab are most likely to dissipate the inertial energy imposed by earthquake ground motions by sliding. This may also be true for walls founded on fissured or fractured rock. Walls founded on soil or on fissured or fractured rock and prevented by an invert slab from moving laterally are more likely to tip (i.e., rotate) than to slide during a major earthquake event. Walls founded on competent rock without significant joints, faults, or bedding planes and prevented by a strong bond at the rock-footing interface from either translating or rotating are likely to dissipate energy through plastic yielding in the stem wall. All three responses can leave the retaining wall in a permanently displaced condition.

The purpose of this report is to provide methodologies for conducting a performance-based earthquake evaluation related to plastic yielding in the stem wall. The methodologies include evaluation of brittle or force-controlled actions and the evaluation of ductile or deformation-controlled actions. The later evaluation provides estimates of permanent (residual) displacement for walls dominated by a stem wall yielding response.

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Retaining Walls - vulcanhammer.net