Design and detailing of retaining walls learning outcomes. Types of gravity retaining walls classification of retaining walls. Retaining walls in theory and practice, a textbook for. Infill material the soil material placed behind the retaining wall facing. The safety factor against sliding minimum required f. Retaining wall design design examples and construction. The retaining wall as a whole must satisfy two basic conditions.
Retaining walls also may be used at bridge abutments to support the structure. These are much less than the hydrostatic pressure exerted by water trapped behind the wall. There are another type of retaining wall called counterfort rw and is a. P a active earth pressure or earth pressure pa and passive earth pressure pp.
Calculations per aci 31811, aci 53011, ibc 2012, cbc 20, asce 710. Mse retaining wall design considerations by marcus galvan. The design and planning phase of retaining walls is critical and must address the actual site conditions, including soil and loading, that the wall will be subjected to. Drainage material the crushed rock, gravel or similar material placed behind a retaining wall to convey ground water away from the wall and foundations. Excavation support overview trench excavation protection temporary special shoring 7. The following worked examples have been prepared to illustrate the application of bs8002 to retaining wall design. Worked examples of retaining wall design to bs8002. The wall is braced top and bottom against lateral translation. Lateral forces on retaining wallsence 454 assakkaf design of retaining walls the design of retaining wall must account for all applied loads. Cantilever concrete retaining walls are commonly used for residential purposes, often as integral basement walls. A n beal earth retaining structures worked examples. Moreover, find out characteristics of both insitu and back fill soil which includes density and. Cantilever concrete retaining walls are commonly used for residential.
W wheel wfill wsur k ft klf ft u u klf ft ft ft w l m w plf. The basic design precepts employed in cantilever walls include considerations of dead man tiebacks, taking active pressures to the bottom of the wall and considering any reductions in passive resistance for inclined slopes. Cantilever timber pole walls are probably the most commonly used form of. A brief version of the results of the analysis is shown the following page. Type of retaining wall failure to design retaining walls, it is necessary to know how wall can fail. Seismic design of retaining wall is considerably complicated problem in which assumptions have to be considered in order to make indeterminable issue solvable employing theory of statics and differential calculus. 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. Retaining walls are structure used to retain soil, rock or other materials in a vertical condition.
Retaining wall layouts general content layout plans for specific wall types 3. Active earth pressure tends to deflect the wall away from the backfill. The stem may have constant thickness along the length or may be tapered based on economic and construction criteria. Worked example 1 design of cantilever pol retaining. Ce 437537, spring 2011 retaining wall design example 1 8 design a reinforced concrete retaining wall for the following conditions. Underpinning to be formed in continuous reinforced concrete. Retaining walls are designed to resist earth pressures exerted by only the weight of soil retained. Suggest suitable dimensions for the rc retaining wall example 1. Design the reinforced concrete masonry cantilever retaining wall shown in. The design guidelines and values recommended for tensar geogrids are not applicable for, and. 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. In order to promote public education and public safety, equal justice for all, a better informed citizenry, the rule of law, world trade and world peace, this legal document is hereby made available on a noncommercial basis, as it is the right of all humans to know and speak the laws that govern them. Hence they provide a lateral support to vertical slopes of soil that would otherwise collapse into a more natural shape.
The computation of each static and dynamic pressure acting on retaining wall need more research and site selection is becoming codified. Reinforced concrete cantilever retaining wall analysis and. Review of ncma segmental retaining wall design manual for. Component quality is important due diligence when a designer issues a design certificate a form 15 in queensland, the design is being certified against a specified criteria, for example as 4678, earth retaining structures code. The load that presents the greatest problem and its primary concern is the lateral earth pressure induced by the retained soil. Design of retaining wall with counterfort engineering.
However, retaining walls can also be constructed for aesthetic landscaping purposes. Reinforced concrete cantilever retaining wall analysis and design aci 31814 reinforced concrete cantilever retaining walls consist of a relatively thin stem and a base slab. Ab engineering manual retaining walls allan block wall. Drainage is an important aspect of any retaining wall project. Some easytoadopt retaining wall design ideas have been listed below. The ab stones provide a nominal setback of twelve degrees from vertical. Geogrid segmental retaining wall design with calculations.
A retaining wall forms a vertical or nearvertical face through confinement andor. Creating a retaining wall home design software for diy. Mechanically stabilized earth mse retaining walls are growing in popularity. Example 1 retaining wall designs using retaining blocks. Assuming that the allowable bearing pressure of the soil is 120 knm 2, the. Deflection generally governs design for cantilever walls more than 18 feet high. Worked example 2 design of concrete cantilever retaining. This gl pressure tends to deflect the wall outward. Structural design of cantilever retaining wall is depend on separating each part of wall and design it as a cantilever, so its called cantilever r.
Drainage is an important aspect of any retainingwall project. A n beal earth retaining structures worked examples 7 bs8002 bs8002 design table 1 soil saturated density 21. A n beal earth retaining structures worked examples 1. Geotechnical design dublin, 14 june, 20 support to the implementation, harmonization and further development of the eurocodes. Ce 537, spring 2011 retaining wall design example 6 8 2. The design of all retaining walls needs to consider, the soil profile, soil type, clay, gravel or sand, the final height of the wall and any loadings from driveways and nearby buildings, that will increase the design forces that the wall has to withstand. An example of a completed project is illustrated in figure 1.
What is the design procedure for gravity retaining wall. The example calculations are made here using mathcad. Most common materials used for retaining walls are. In minutes you can design or analyze nearly any configuration or loading condition for cantilevered, restrained, gravity, gabion, soldier pile, or segmental retaining walls. For details of other type the book foundation analysis and design by j. Whereas, if bracing is in front of the wall and is in compression instead of tension, the wall is called buttress retaining wall. Worked example 4 design of a tiedback retaining wall to. Earth pressure p 8 earth pressure is the pressure exerted by the retaining material on the retaining wall. Example 5 design a reinforced concrete bearing wall to support a series of steel wideflange beams at 8 ft0 in. Abarac current retaining wall design procedures are summarized with emphasis on the prediction of lateral earth pressures using the coulomb and rankine earth pressure theories, and the equivalent fluid pressure method. To add a retaining wall, you must first have a terrain perimeter on your plan. Mse retaining wall design considerations by marcus galvan, p. Worked examples of retaining wall design to bs8002 the following worked examples have been prepared to illustrate the application of bs8002 to retaining wall design.
Geotechnical design dublin, 14 june, 20 support to the implementation, harmonization and. Assume variation of water pressure below wall same as cp2 example. Mcgrawhill international edition, 1997 may be referred. Cantilever rc retaining wall 10 knm2 m 500 mm h 400 0. Design of semi gravity retaining walls wec civilians. The stability of retaining wall structures designed with these guidelines and using tensar geogrids has been verified through the monitoring of instrumented wall structures since 1985. They are composed of a light form of concrete that is further blended with aggregates to make the blocks sturdier.
Design of cantilever pole retaining walls to resist earthquake loading for residential sites. Active earth pressure tends to variation of earth pressure deflect the wall away from the 5. Design and analysis of retaining walls 2 economical when the wall height exceeds 8m. Following are the different types of retaining walls, which is based on the shape and the mode of resisting the pressure.
Slope stability for each design example, please state. Retained height ft wall height above soil ft slope behind wall. Basics of retaining wall design 10 editionth a design guide for earth retaining structures contents at a glance. Some of the many types of gravity retaining walls were described in chapter 1. Retaining blocks are among the easiest of constructional elements used for building retaining walls. Results from pre vious large scale retaining wall tests and field studies are presented. Abwall here is example 1 as designed using keywall 2001. From the menu, select terrain create terrain perimeter. Design example the following design example briefly illustrates some of the basic steps used in the allowable stress design of a reinforced concrete masonry cantilever retaining wall. They are not full detailed calculations such as might be prepared for a real wall design but are limited to the calculation of earth pressure and bearing capacity, showing how the. If you design retaining walls, you know its tedious and timeconsuming. To change the height of a retaining wall in home designer pro open the plan in which you would like to add a retaining wall, or create a new plan by selecting file new plan. Gravity walls depend upon bulk weight for stability, as opposed to a cantilevered retaining wall fixed to a foundation. The base is divided into two parts, the heel and toe.
Water must not be allowed to build up behind the wall. Retaining walls in theory and practice, a textbook for students. Active earth pressure or earth pressure pa and passive earth pressure p p. The wall is assumed to be protecting a levelled dwelling platform with a steep, 20 degree hill slope above. 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.
Terms used in retaining wall design are shown below f. 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. You should also be aware of the difference in assumed skin friction, depending on whether the wall stem was poured inplace against the roughened earth, or poured against smooth concrete forms. Moreover, find out characteristics of both insitu and back fill soil which includes density and internal friction value. Worked example to accompany mbie guidance on the seismic design of retaining structures for residential sites in greater christchurch version 2 november 2014. Design considerations general design design criteria for specific wall types 4. Course objectives they seem to crop up everywhere, like cell phone towers. Worked examples presented at the workshop eurocode 7. In this example, the structural design of the three retaining wall components is performed by hand. The following figure shows theses different types of retaining walls. Cantilever retaining wall ouestion for the retaining wall and the profile shown below, calculate.
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