Specification for segmental retaining wall system part 1. 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. Segmental retaining walls best practices guide ncma. About the instructor about the sponsor ask an expert. Tek 24a specification for segmental retaining wall units 2. 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. 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. The national concrete masonry as sociation ncma recently adopted the term soil reinforced. This method creates walls that are easy and economical to install. 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. Whether the recon application focuses on the scale and aesthetics of the recon block, the durability of the wetcast, airentrained concrete retaining wall blocks. There are three types of modular units used for retaining wall systems.
Design examples which demonstrates the use of the australian standard and analysis method. After evaluating the location, soil, design, and drainage, you can begin thinking about the type of retaining wall your project will need. This guide covers the design of segmental concrete gravity retaining walls. 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. Review of ncma segmental retaining wall design manual for. Geosynthetic reinforced segmental retaining walls srws. The design methodologies contained within allow the engineer to analyze the influence of all components of the srw system on wall performance. Installation details, the proper constructions sequence, and specifications are also addressed. Construction of concrete segmental retaining walls. Th is design only provided to illu strate the general arrangement of srw ructure for preliminary co ing and feasibility purposes only.
Because every anchor system is backed up with the support of a highly qualified team of manufacturing, design and engineering specialists. Section 32 32 23 gravity segmental retaining wall guide specification gravity srw page 4 of 12 january 2016. Segmental retaining wall blocks may be solid or hollow with a gravel fill material. 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. Design guidelines for tensar geogrid reinforced soil walls with mesa segmental concrete.
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. The other two forms of construction are covered in separate guides. Most block manufacturers offer assistance in determining the maximum height a retaining wall can be built to before reinforcement is required. 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. Versalok segmental retaining walls are made from highstrength concrete units, drystacked, interlocked with pins, and set on granular leveling pads. This latest version of software generates structural designs utilizing srws according to the ncma design manual for segmental retaining walls.
The example problems in this manual are based on walls constructed with allan block retaining. 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. Segmental retaining wall types, design and advantages segmental retaining wall is constructed of large number of collected dry masonry blocks. Types of retaining walls keystone wall made up of segmental block units, made to last based around a system with. Segmental retaining walls are generally installed with a small horizontal setback between units, creating a wall batter into the retained soil. Design manual for segmental retaining walls second edition.
Design and construction manual recon gravity retaining walls. For information into the basic concepts behind an allan block retaining wall design see page 18 of the ab spec book and best. Segmental retaining wall design page 4 the town of clayton manual of specifications, standards, and design july 2010 2. 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. 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. The wall batter compensates for any slight lateral movement of the srw face due to earth pressure and complements the aesthetic attributes of. 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, second edition. Assuming that the allowable bearing pressure of the soil is 120 knm 2, the. The perfect retaining wall system versalok retaining wall systems are costeffective, easytoinstall, and give you endless design options. From design assistance to installation information, our partnership will ensure your retaining wall project is a success. Our retaining walls are manufactured from high strength concrete.
Global stability analysis is an important component of srw design, particularly under the following conditions. In this course you will find examples of the design of these walls and the principles which underlie those designs. In this example, the structural design of the three retaining wall components is performed by hand. This costeffective solution completely eliminates the need for the construction of a mechanically stabilized earth zone behind the wall and. Ce 437537, spring 2011 retaining wall design example 1 8 design a reinforced concrete retaining wall for the following conditions. Cross section of typical segmental concrete masonry gravity retaining wall. Design and construction manual gravity retaining walls.
Srwall design software for segmental retaining walls ncma. At first glance, the steps involved in construction of a recon retaining wall appear relatively simple. 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. Worked example 2 design of concrete cantilever retaining. Ncmas srwall design software is the valuable resource for onestop design of segmental retaining walls. The term, owner refers to the property owner or their designated representative. An example of a completed project is illustrated in figure 1. Retainpro offers extensive design capability for all of the most common wall types. This tek addresses the unreinforced gravity retaining walls only. Specify embedment depth below grade is equal to either 30 cm or block depth and the wall height. 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. If the pressure on the wall due to the soil is too great, the wall will move forward. Moreover, find out characteristics of both insitu and back fill soil which includes density and internal friction value.
Apr 05, 2020 a segmental retaining wall is a network of masonry units that rely largely upon their own mass for strength and stability. Each of these retaining wall systems has its advantages, and the choice may depend on a number of factors including. Title date vdot special provision for mechanically stabilized earth walls segmental block facing contd 10. 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. The ab stones provide a nominal setback of twelve degrees from vertical. Some manufacturers offer segmental retaining wall systems for when excavation is limited. 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. 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.
Versalok offers attractive segmental retaining wall systems equally suited for residential, commercial and public works applications. The an alysis was perfor d as outlined in the nation concrete masonry association design manual for segmental retaining walls, second edition. Choose from a large selection of colors, textures and patterns to create your own unique look. 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. An example of this is the anchorplex retaining wall system developed by anchor wall systems of oldcastle apg. Example e2 shows a segmental precast panel mse wall with steel reinforcement. Select blocks with specified texture, size, and configuration. A segmental retaining wall is a network of masonry units that rely largely upon their own mass for strength and stability.
The wall height includes below grade depth and the wall above the grade. Basics of retaining wall design 10 editionth a design guide for earth retaining structures contents at a glance. These concrete units are placed together without the use of mortar and typically employ some type of interlocking mechanism. No analysis of global stability, total or differential settlement, or seismic effects has been performed. Retaining wall design per the latest ibc, aci 318 specifications. The design steps for gravity segmental retaining walls are as follow.
The selfweight of the srw system is either the weight continue reading. The representation will address the history of reinforced earth structures and summarize the site conditions that impact srw performance and design. They are the only integrated srw systems available to incorporate these three critical elements. Procedure for design of geogrid segmental retaining wall design criteria for geogrid segmental retaining wall. Segmental retaining walls best practices guide 3 segmental retaining walls best practices guide for the speci. Local concrete masonry suppliers should be contacted for specific system details. Concrete retaining walls retaining solutions sydney. Retaining walls 101 an introduction to choosing the. It also features updated bulging calculation methodology, offset surcharges, rectangular distribution of dynamic loads, variable deflection of.
If you design retaining walls, you know its tedious and timeconsuming. Retainpro turns this specialized design task into a 5 minute optimization session. Download the recommended specifications on the downloads page. Design manual for segmental retaining walls 3rd edition. 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. Details and design of geogrid segmental retaining wall with calculations is. The selfweight of the srw system is either the weight of the srw. Design life the time over which the structure is required to fulfil its function and remain serviceable. In minutes you can design or analyze nearly any configuration or loading condition for cantilevered, restrained, gravity, gabion, soldier pile, or segmental retaining walls. K instructions geogrid keywall appedix keystone r e t a i n i. 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. Design manual for segmental retaining walls, second edition, 1997.
The design process for a segmental retaining wall typically has a wall design engineer or site civil engineer responsible for the wall design envelope. Mechanically stabilized earth mse retaining walls are growing in popularity. The blocks are drystacked no mortar and either hand or machine laid. Table 1gravity srw design heights for various unit, soil and wall properties. The mesa units, combined with tensar geogrids and mesa connectors, form the mesa retaining wall systems. Versatile modular components make smooth inside and outside radii, as well as 90. Worked example to accompany mbie guidance on the seismic design of retaining structures for residential sites in greater christchurch version 2 november 2014. They can be constructed with either a single depth of unit or with.
Segmental retaining walls are constructed without mortar or concrete footings. 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. The active pressure increases on the retaining wall proportionally from zero at the. L4 length of geogrid in feet at 4 high level off base. Geogrid segmental retaining wall design with calculations. Fhwa has mandated all retaining walls be designed using lrfd after october 1, 2010. 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. Instead, the retaining wall units are simply stacked on a shallow, granular leveling pad.
When a wall is built and soil is placed behind it and compacted, the soil is in the atrest state. Refer to the ncma segmental retaining walls best practices guide for a checklist of these considerations and more. 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. Resources design aids keystone retaining wall systems. The focus of the guideline is the geotechnical aspects of retaining wall design. Gravity segmental retaining wall stability depends on weight of the wall and overturning safety factor is 1. This program will address the basic concepts about segmental retaining wall srw systems. 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. Determine retaining wall height along its length, plan view alignment, and contouring that sloped backfill may be needed. Suggest suitable dimensions for the rc retaining wall example 1. 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. Segmental retaining walls the concrete network the.
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. Design aid resources by keystone retaining wall systems. 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. 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. It is our opinion that the ncma design manual represents a comprehensive approach to segmental retaining wall srw design but tends to con.
Table of contents segmental retaining walls best practices guide. The national concrete masonry as sociation ncma recently adopted the term soilreinforced. Course objectives they seem to crop up everywhere, like cell phone towers. 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. Table 1 gravity srw design heights for various unit, soil and wall properties. 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.
Examples of live load surcharges are vehicular traffic and bulk material. Mass segmental retaining wall msrw units have a larger face area. Geotechnical engineers should be hired to evaluate the overall stability of the site. The soil behind a retaining wall exists in one of three states. These masonry blocks are significantly economical and effective for segmental retaining wall construction and it is also broadly accepted. 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. Segmental retaining wall types, design and its advantages. 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. Cantilever concrete retaining walls are commonly used for residential purposes, often as integral basement walls. Ab engineering manual retaining walls allan block wall.