Design and construction manual gravity retaining walls. No analysis of global stability, total or differential settlement, or seismic effects has been performed. An information series from the national authority on concrete masonry technology ncma tek 155b 1 segmental retaining wall design introduction segmental retaining walls srws function as gravity structures by relying on selfweight to resist the destabilizing forces due to retained soil backfill and surcharge loads. Terraforce retaining blocks can be used either as part of a gravity system or as the fascia of a geosynthetic reinforced segmental retaining wall structure, or as a fascia for a cement stabilized backfill.
An example of a completed project is illustrated in figure 1. Variations on the basic design, including curves, tiers, railings, stairs, walkways and the like are making them more and more attractive to designers and architects. Belgard commercial offers retaining wall materials in a wide variety of colors, sizes, and textures and can be used to create straight or curved lines, steps, and. Design manual for segmental retaining walls, second edition. Worked example 2 design of concrete cantilever retaining. Segmental retaining wall types, design and advantages segmental retaining wall is constructed of large number of collected dry masonry blocks. Cross section of typical segmental concrete masonry gravity retaining wall. Our retaining walls are manufactured from high strength concrete. The blocks are drystacked no mortar and either hand or machine laid. After evaluating the location, soil, design, and drainage, you can begin thinking about the type of retaining wall your project will need. Versalok segmental retaining walls are made from highstrength concrete units, drystacked, interlocked with pins, and set on granular leveling pads.
The design of a recon segmental retaining wall may be straightforward or it may be quite complex and involve a high degree of geotechnical andor civil engineering expertise. Procedure for design of geogrid segmental retaining wall design criteria for geogrid segmental retaining wall. Sketches of the retaining wall forces should be considered to properly distinguish the different forces acting on our retaining wall as tackled in the previous article, retaining wall. An example of this is the anchorplex retaining wall system developed by anchor wall systems of oldcastle apg. Mar 04, 2019 sketches of the retaining wall forces should be considered to properly distinguish the different forces acting on our retaining wall as tackled in the previous article, retaining wall. Segmental retaining wall design page 4 the town of clayton manual of specifications, standards, and design july 2010 2. The design steps for gravity segmental retaining walls are as follow. The term, owner refers to the property owner or their designated representative. Th is design only provided to illu strate the general arrangement of srw ructure for preliminary co ing and feasibility purposes only.
Select blocks with specified texture, size, and configuration. Standard, accent, cobble, harmony, mosaic, square foot, ultra, nexus, brute, bronco 30h, bronco 18h and versagreen, a plantable retaining wall system that becomes a living part of your landscape. Design life the time over which the structure is required to fulfil its function and remain serviceable. The active pressure increases on the retaining wall proportionally from zero at the. Types of retaining walls keystone wall made up of segmental block units, made to last based around a system with. In this example, the structural design of the three retaining wall components is performed by hand. This method creates walls that are easy and economical to install. Whether the recon application focuses on the scale and aesthetics of the recon block, the durability of the wetcast, airentrained concrete retaining wall blocks. Ncmas srwall design software is the valuable resource for onestop design of segmental retaining walls. The an alysis was perfor d as outlined in the nation concrete masonry association design manual for segmental retaining walls, second edition. At recon, we are proud of our tradition of offering a big block retaining wall product line that adds value for our customers, and for our retaining wall design and retaining wall contractor partners.
Design criteria for geogrid segmental retaining wall determine retaining wall height along its length, plan view alignment, and contouring that sloped backfill may be needed. Design manual for segmental retaining walls 3rd edition. They can be constructed with either a single depth of unit or with. Retaining wall design per the latest ibc, aci 318 specifications.
Concrete retaining walls retaining solutions sydney. This costeffective solution completely eliminates the need for the construction of a mechanically stabilized earth zone behind the wall and. Geogrid segmental retaining wall design with calculations. The perfect retaining wall system versalok retaining wall systems are costeffective, easytoinstall, and give you endless design options. The wall design shall be performed by a professional engineer licensed in the state of north carolina that prepares and seals the design drawings and submittals as required herein. Belgard commercials wall blocks for segmental retaining wall projects are designed to fulfill the needs of a variety of projects, from both an aesthetic and a functional standpoint. Fhwa has mandated all retaining walls be designed using lrfd after october 1, 2010. This latest version of software generates structural designs utilizing srws according to the ncma design manual for segmental retaining walls. The ab stones provide a nominal setback of twelve degrees from vertical. For information into the basic concepts behind an allan block retaining wall design see page 18 of the ab spec book and best. The national concrete masonry as sociation ncma recently adopted the term soil reinforced. In 1990 the concrete masonry association of australia cmaa published masonry walling guide no 4 design for earth loads retaining walls, which set out a design methodology for earth retaining structures.
The selfweight of the srw system is either the weight of the srw. Cantilever concrete retaining walls are commonly used for residential purposes, often as integral basement walls. Instead, the retaining wall units are simply stacked on a shallow, granular leveling pad. A segmental retaining wall is a network of masonry units that rely largely upon their own mass for strength and stability. Segmental concrete reinforced soils segmental concrete gravity retaining walls reinforced concrete masonry cantilever retaining walls scope this manual applies to the use of the microsoft excel spreadsheet to analyse and check the. The keyestimator spreadsheet ms excel allows the user to quickly estimate the square feet of wall and caps, soil reinforcement, draining fill, reinforced fill and base leveling pad material that you would need to build a wall. Assuming that the allowable bearing pressure of the soil is 120 knm 2, the. Geosynthetic reinforced segmental retaining walls srws. A gravity wall depends on the weight of their mass stone, concrete or other heavy material to resist pressures from behind and will often have a slight batter setback, to improve stability by leaning back into the retained soil. Each of these retaining wall systems has its advantages, and the choice may depend on a number of factors including. Segmental retaining walls are generally installed with a small horizontal setback between units, creating a wall batter into the retained soil.
Worked example to accompany mbie guidance on the seismic design of retaining structures for residential sites in greater christchurch version 2 november 2014. Segmental retaining wall srw units typically have a smaller face area 1 square foot or less with a unit depth of less than 24inches most are 12 inchesin depth, and are generally hand installed and drycast by astm definition. This guide, segmental retaining walls best practices guide for the specification, design, construction, and inspection of srw systems, is published and maintained by the national concrete masonry association ncma since segmental retaining wall systems were first introduced in the 1980s, there has been a continuous evolution and. Segmental retaining walls best practices guide 3 segmental retaining walls best practices guide for the speci. About the instructor about the sponsor ask an expert. Choose from a large selection of colors, textures and patterns to create your own unique look. In minutes you can design or analyze nearly any configuration or loading condition for cantilevered, restrained, gravity, gabion, soldier pile, or segmental retaining walls. The wall batter compensates for any slight lateral movement of the srw face due to earth pressure and complements the aesthetic attributes of. Specify embedment depth below grade is equal to either 30 cm or block depth and the wall height. Basics of retaining wall design 10 editionth a design guide for earth retaining structures contents at a glance. Download the recommended specifications on the downloads page. At first glance, the steps involved in construction of a recon retaining wall appear relatively simple. Versatile modular components make smooth inside and outside radii, as well as 90.
The design methodologies contained within allow the engineer to analyze the influence of all components of the srw system on wall performance. Table 1gravity srw design heights for various unit, soil and wall properties. It is our opinion that the ncma design manual represents a comprehensive approach to segmental retaining wall srw design but tends to con. K instructions geogrid keywall appedix keystone r e t a i n i. Segmental retaining walls the concrete network the. These concrete units are placed together without the use of mortar and typically employ some type of interlocking mechanism. The wall batter compensates for any slight lateral movement of the srw face due to earth pressure and complements the aesthetic attributes of the srw system. Local concrete masonry suppliers should be contacted for specific system details. There are three types of modular units used for retaining wall systems. Segmental retaining wall design page 1 the town of clayton manual of specifications, standards, and design july 2010 segmental block retaining wall design section 1 introduction srw last revised 61810 the following division has been established to assist engineers with the design of segmental retaining walls. Ce 437537, spring 2011 retaining wall design example 1 8 design a reinforced concrete retaining wall for the following conditions. Retainpro turns this specialized design task into a 5 minute optimization session.
We believe that a twelve degree setback maximizes the leverage achieved by a battered wall, while providing a finished retaining wall that fulfills the goal of more useable flat land. L4 length of geogrid in feet at 4 high level off base. Segmental retaining walls srws are constructed of manufactured concrete modular blocks that are uniform in weight and dimensional tolerances. Moreover, find out characteristics of both insitu and back fill soil which includes density and internal friction value. Design manual for segmental retaining walls, second edition, 1997. Review of ncma segmental retaining wall design manual for. The national concrete masonry as sociation ncma recently adopted the term soilreinforced. Construction of concrete segmental retaining walls. The objective of this guideline is to provide information on retaining wall design in accordance with the city of nanaimo the city and the british columbia building code bcbc requirements. Design aid resources by keystone retaining wall systems. Retainpro offers extensive design capability for all of the most common wall types. Mechanically stabilized earth mse retaining walls are growing in popularity.
The example problems in this manual are based on walls constructed with allan block retaining. Resources design aids keystone retaining wall systems. Ab engineering manual retaining walls allan block wall. Suggest suitable dimensions for the rc retaining wall example 1. Details and design of geogrid segmental retaining wall with calculations is. They are the only integrated srw systems available to incorporate these three critical elements. The other two forms of construction are covered in separate guides. This tek addresses the unreinforced gravity retaining walls only.
Specification for segmental retaining wall system part 1. Gravity segmental retaining wall stability depends on weight of the wall and overturning safety factor is 1. Table of contents segmental retaining walls best practices guide. Geotechnical engineers should be hired to evaluate the overall stability of the site. Example e2 shows a segmental precast panel mse wall with steel reinforcement. Best practices for segmental retaining wall design the intent of this material is to communicate the best practices for design of segmental retaining walls srw as determined by allan block corporation based on 25 plus years of research, design and field experience. Section 32 32 23 gravity segmental retaining wall guide specification gravity srw page 4 of 12 january 2016. Determine retaining wall height along its length, plan view alignment, and contouring that sloped backfill may be needed. Table 1 gravity srw design heights for various unit, soil and wall properties. Most block manufacturers offer assistance in determining the maximum height a retaining wall can be built to before reinforcement is required.
Design examples which demonstrates the use of the australian standard and analysis method. The wall design shall be performed by a professional engineer licensed in the state of north carolinathat prepares and seals the desig n drawings and submittals as required herein. When a wall is built and soil is placed behind it and compacted, the soil is in the atrest state. These masonry blocks are significantly economical and effective for segmental retaining wall construction and it is also broadly accepted. Design manual for segmental retaining walls second edition. From design assistance to installation information, our partnership will ensure your retaining wall project is a success. The representation will address the history of reinforced earth structures and summarize the site conditions that impact srw performance and design. Asdip retain is a suite of modules specifically dedicated to the design of retaining walls, based on the latest ibc aci 318 specifications, that greatly simplifies the timeconsuming calculations in any structural engineering office. The national concrete masonry as sociation ncma recently adopted the term soilreinforced segmental retaining wall to identify this type of retaining wall system 4,p. Title date vdot special provision for mechanically stabilized earth walls segmental block facing contd 10.
Reinforced srw systems are compositefacing, mechanically stabilized earth mse retaining wall structures that have unique features and design requirements that are addressed in detail in this guideline. If the pressure on the wall due to the soil is too great, the wall will move forward. The design process for a segmental retaining wall typically has a wall design engineer or site civil engineer responsible for the wall design envelope. Segmental retaining wall types, design and its advantages. Segmental retaining wall design introduction segmental retaining walls srws function as gravity structures by relying on selfweight to resist the destabilizing forces due to retained soil backfill and surcharge loads. Mass segmental retaining wall msrw units have a larger face area. This guide covers the design of segmental concrete gravity retaining walls. In this course you will find examples of the design of these walls and the principles which underlie those designs. Segmental retaining walls are constructed without mortar or concrete footings. Tek 24a specification for segmental retaining wall units 2.
Because every anchor system is backed up with the support of a highly qualified team of manufacturing, design and engineering specialists. Segmental retaining walls srws or modular block retaining walls have gained popularity over the years as a soil retention technique because of their economy and speed of installation, the flexibility of geometric configuration, and the variety of blocks available in the market to suit a projects architectural and aesthetic requirements figure 1. The selfweight of the srw system is either the weight continue reading. A retaining wall is a structure designed and constructed to resist the lateral pressure of soil when there is a desired change in ground elevation that exceeds the angle of repose of the soil.
Click on the topics below to view more information on the best practices for allan block segmental retaining wall design for residental and commercial applications. Some manufacturers offer segmental retaining wall systems for when excavation is limited. If you design retaining walls, you know its tedious and timeconsuming. Course objectives they seem to crop up everywhere, like cell phone towers. It also features updated bulging calculation methodology, offset surcharges, rectangular distribution of dynamic loads, variable deflection of. Retaining walls 101 an introduction to choosing the.
Design and construction manual recon gravity retaining walls. Refer to the ncma segmental retaining walls best practices guide for a checklist of these considerations and more. The wall height includes below grade depth and the wall above the grade. The focus of the guideline is the geotechnical aspects of retaining wall design. The soil behind a retaining wall exists in one of three states. Retaining walls 101 an introduction to choosing the right wall. The general mass movement of a segmental retaining wall srw structure and the adjacent soil is called global stability failure. Segmental retaining wall blocks may be solid or hollow with a gravel fill material. Versalok offers attractive segmental retaining wall systems equally suited for residential, commercial and public works applications. Installation details, the proper constructions sequence, and specifications are also addressed. This program will address the basic concepts about segmental retaining wall srw systems.
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