Active earth pressure or earth pressure pa and passive earth pressure p p. Eurocode retaining wall stem design example structural. 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. Geotechnical design ith k d lgeotechnical design with worked examples 14 j d bli14 june, dublin contents of en 19971 section 9 retaining structures section 9 applies to retaining structures supporting ground i. The wall is assumed to be protecting a levelled dwelling platform with a steep, 20 degree hill slope above. Abwall here is example 1 as designed using keywall 2001. Design and analysis of retaining walls 2 economical when the wall height exceeds 8m. Please note that the gravity wall chart provided has specific heights for specific site and soil conditions. The safety factor against sliding minimum required f.
Pdf a new design method for retaining walls in clay. How to choose the right retaining wall for your project. A brief version of the results of the analysis is shown the following page. E 1982 forces on gravity retaining wall the active earth pressure is computed by using either the rackine or coulomb methods if the coulombs method is used it is assured that there is incipient sliding on the back face of the wall, and the earth pressure acts at the angle of wall frication to a normal with. If you are not sure of your site conditions we recommend being conservative with your retaining wall heights or use geogrid in your retaining wall. 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. The load that presents the greatest problem and its primary concern is the lateral earth pressure induced by the retained soil. 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. The stability of such walls depends upon the arrangement of stones in the wall and the friction between the individual stones. Cantilever concrete retaining walls are commonly used for residential purposes, often as integral basement walls.
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. The following worked examples have been prepared to illustrate the application of bs8002 to retaining wall design. Example 1 retaining wall designs using retaining blocks. We believe that a twelve degree setback maximizes the leverage achieved by a battered wall, while providing a finished retaining wall that fulfills the.
Whereas, if bracing is in front of the wall and is in compression instead of tension, the wall is called buttress retaining wall. Exposed faces of precast concrete retaining wall blocks shall be reasonably free of large chips, cracks, or stains when viewed from a distance of 10 feet. Different types of retaining walls are used to retain soil in different places. Because of their large mass, gravity retaining walls may not. Retaining walls may be defined as a wall built to resist the pressure of liquid, earth filling, sand, or other granular material filled behind it after it is built. Retaining wall design design examples and construction. Semi gravity retaining wall reduce the dimensions of the gravity retaining wall by using some reinforcement. Retaining walls are designed to resist earth pressures exerted by only the weight of soil retained. 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.
Drainage is an important aspect of any retaining wall project. Dr andrew bond director, geocentrix ltd chairman tc250sc7. What is the design procedure for gravity retaining wall. Some of the many types of gravity retaining walls were described in chapter 1. Design the reinforced concrete masonry cantilever retaining wall shown in figure 2.
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. For design purposes, an equipment impact point load on the gravity block retaining wall face will be assumed at 30 inches 2. Design of semi gravity retaining walls wec civilians. Oct 23, 2012 ce 437537, spring 2011 retaining wall design example 18design a reinforced concrete retaining wall for slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. The designer must determine the reinforcement size and spacing required to resist the applied loads, listed below. 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. Basics of retaining wall design 10 editionth a design guide for earth retaining structures contents at a glance.
Figure 4 is a graph showing the frictional angle used along the slip surface. These are much less than the hydrostatic pressure exerted by water trapped behind the wall. Spacings are chosen based on closest multiple of 3 for illustrative purposes, more appropriate choices are typically multiples of 12 or 16 as was discussed in class. Design of semi gravity retaining walls 1 a semi gravity retaining wall consisting of plain concrete weight 145 lbft. This input is a variable that can range from 20 lbs. Gravity walls depend upon bulk weight for stability, as opposed to a cantilevered retaining wall fixed to a foundation. Ce 437537, spring 2011 retaining wall design example 1 8 design a reinforced concrete retaining wall for the following conditions.
Norfolk and tasman retaining walls au keystone retaining wall systems. Gravity walls rely on their own weight and setback to hold up the soil behind them. This is not meant to be a final authority as each project has its own set of unique situations. Preface standards australia has published as 46782002 for the design of earth retaining structures, which. Semigravity retaining wall reduce the dimensions of the gravity retaining wall by using some reinforcement. For example, chose the top deflection as the representative quantity for the design of a cantilever wall and evaluated the model uncertainty of the mobilized strength design msd proposed by. The cantilever retaining wall shown below is backfilled with granular material having a unit weight. Retaining blocks are among the easiest of constructional elements used for building retaining walls. Note that the slip surface is forced to slide just below the gravity wall. Cantilever retaining wall ouestion for the retaining wall and the profile shown below, calculate. Gravity retaining wall depends on its weight for resisting lateral earth force because it have a large weigh 2. Pc17 retaining walls idaho transportation department. Geotechnical design dublin, 14 june, 20 support to the implementation, harmonization and further development of the eurocodes. Ce 437537, spring 2011 retaining wall design example 28 substituting eqn.
Worked example 4 design of a tiedback retaining wall to. From the menu, select terrain create terrain perimeter. Type of retaining wall failure to design retaining walls, it is necessary to know how wall can fail. In this example, the structural design of the three retaining wall components is performed by hand. Assuming that the allowable bearing pressure of the soil is 120 knm.
Mechanically stabilized earth mse retaining walls are growing in popularity. Worked example 2 design of concrete cantilever retaining. Degree gravel and coarse sandy backfill soil 3336 medium to fine sandy backfill soil 2932 silty sand 2730 p max k a. Project topic on analysis and design of a retaining wall. Assume variation of water pressure below wall same as cp2 example. Each type of retaining wall has its own particular characteristics, which make it. Course objectives they seem to crop up everywhere, like cell phone towers. To add a retaining wall, you must first have a terrain perimeter on your plan. Concrete wall form design example civil engineering. Ce 537, spring 2011 retaining wall design example 6 8 2. Worked examples of retaining wall design to bs8002. The grout spacing affects the wall weight, which in turn affects the seismic load. Water must not be allowed to build up behind the wall.
Ab engineering manual retaining walls allan block wall. Cantilever or restrained retaining wall calculations o r g a n iz a io n f. Gravity retaining walls tek 156 structural 1995 keywords. Creating a retaining wall home design software for diy. Retaining wall design example revised jim richardson. Design a reinforced concrete retaining wall for the following conditions. 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. Some easytoadopt retaining wall design ideas have been listed below. Precast concrete retaining wall blocks shall be vertiblock units as produced by a licensed verti. Worked examples presented at the workshop eurocode 7. 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. Lateral forces on retaining wallsence 454 assakkaf design of retaining walls the design of retaining wall must account for all applied loads. The wall is assumed to be located in the christchurch port hills.
In minutes you can design or analyze nearly any configuration or loading condition for cantilevered, restrained, gravity, gabion, soldier pile, or segmental retaining walls. Retaining walls in theory and practice, a textbook for. Results from pre vious large scale retaining wall tests and field studies are presented. A n beal earth retaining structures worked examples 1. The ab stones provide a nominal setback of twelve degrees from vertical. The stones used in the wall should be of large size and roughly hammerdressed so as to ensure maximum bedding area. Retaining walls such as mse walls with precast concrete panel facing that are susceptible to damage from vehicular impact shall be protected by a roadway barrier. A slope above a retaining wall will add more pressure and weight, while slopes below the retaining wall may make the wall unstable due to sliding or erosion. Retaining walls in theory and practice, a textbook for students. They are composed of a light form of concrete that is further blended with aggregates to make the blocks sturdier. Retaining walls types, design, stability the construction. Gravity retaining wall ouestion a gravity retaining wall is shown below. Deflection generally governs design for cantilever walls more than 18 feet high.
If you design retaining walls, you know its tedious and timeconsuming. The example calculations are made here using mathcad. Depending upon the site conditions, type of material to be. Avoid slopes greater than 3 to 1 without first consulting a local engineer. It is not advisable to include the actual strength of the retaining wall. 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. Assuming that the allowable bearing pressure of the soil is 120 knm 2, the.
Reinforced masonry design requires that a groutreinforcement spacing be assumed. The bank of supported earth is assumed to weigh 110 lbft. Earth pressure p 8 earth pressure is the pressure exerted by the retaining material on the retaining wall. A rock retaining wall is suitable in situations where the wall is up to about 10 feet and where the slope is 2h. Mcgrawhill international edition, 1997 may be referred. 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 type of retaining wall retaining walls can be broadly divided into four main categories namely, gravity walls, cantilever walls, anchored walls, and reinforced soil or nailed walls. Even though the wall is founded on clay, the backfill has been assumed to be granular which would be typical for this type of wall. Strength limit state a limit state of collapse or loss of structural integrity of the components of the retaining wall. It is commonly required in the construction of hill roads, masonry dams, abutments and wings walls of bridges and so on. 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.
For details of other type the book foundation analysis and design by j. Worked example to accompany mbie guidance on the seismic design of retaining structures for residential sites in greater christchurch version 2 november 2014. Even though the wall is founded on clay, the backfill has been assumed to. The wall must be securely anchored to the rock base or firm subsoil.
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