Geotechnical design dublin, 14 june, 20 support to the implementation, harmonization and further development of the eurocodes. The stones used in the wall should be of large size and roughly hammerdressed so as to ensure maximum bedding area. Results from pre vious large scale retaining wall tests and field studies are presented. We believe that a twelve degree setback maximizes the leverage achieved by a battered wall, while providing a finished retaining wall that fulfills the. Worked example 2 design of concrete cantilever retaining. This is not meant to be a final authority as each project has its own set of unique situations. Gravity walls depend upon bulk weight for stability, as opposed to a cantilevered retaining wall fixed to a foundation. A rock retaining wall is suitable in situations where the wall is up to about 10 feet and where the slope is 2h. Cantilever concrete retaining walls are commonly used for residential purposes, often as integral basement walls. 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.
Degree gravel and coarse sandy backfill soil 3336 medium to fine sandy backfill soil 2932 silty sand 2730 p max k a. 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. Gravity walls rely on their own weight and setback to hold up the soil behind them. Because of their large mass, gravity retaining walls may not. Deflection generally governs design for cantilever walls more than 18 feet high. 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. 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. Avoid slopes greater than 3 to 1 without first consulting a local engineer. Retaining walls types, design, stability the construction. The following worked examples have been prepared to illustrate the application of bs8002 to retaining wall design. Retaining walls are designed to resist earth pressures exerted by only the weight of soil retained. Lateral forces on retaining wallsence 454 assakkaf design of retaining walls the design of retaining wall must account for all applied loads.
Depending upon the site conditions, type of material to be. Worked examples of retaining wall design to bs8002. To add a retaining wall, you must first have a terrain perimeter on your plan. The safety factor against sliding minimum required f. Ce 437537, spring 2011 retaining wall design example 1 8 design a reinforced concrete retaining wall for the following conditions. It is not advisable to include the actual strength of the retaining wall. Reinforced masonry design requires that a groutreinforcement spacing be assumed.
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. Gravity retaining wall ouestion a gravity retaining wall is shown below. 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. Drainage is an important aspect of any retaining wall project. Some easytoadopt retaining wall design ideas have been listed below. Design of semi gravity retaining walls wec civilians. 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. The wall must be securely anchored to the rock base or firm subsoil. 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. Design of semi gravity retaining walls 1 a semi gravity retaining wall consisting of plain concrete weight 145 lbft. Dr andrew bond director, geocentrix ltd chairman tc250sc7.
Gravity retaining walls tek 156 structural 1995 keywords. The grout spacing affects the wall weight, which in turn affects the seismic load. The wall is assumed to be protecting a levelled dwelling platform with a steep, 20 degree hill slope above. Drainage is an important aspect of any retainingwall project. The cantilever retaining wall shown below is backfilled with granular material having a unit weight. What is the design procedure for gravity 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. They are composed of a light form of concrete that is further blended with aggregates to make the blocks sturdier. A n beal earth retaining structures worked examples 7 bs8002 bs8002 design table 1 soil saturated density 21. How to choose the right retaining wall for your project. Please note that the gravity wall chart provided has specific heights for specific site and soil conditions. Design a reinforced concrete retaining wall for the following conditions. A n beal earth retaining structures worked examples 1. 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.
Retaining blocks are among the easiest of constructional elements used for building retaining walls. Each type of retaining wall has its own particular characteristics, which make it. Example 1 retaining wall designs using retaining blocks. 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. Figure 4 is a graph showing the frictional angle used along the slip surface. The ab stones provide a nominal setback of twelve degrees from vertical. Assuming that the allowable bearing pressure of the soil is 120 knm 2, the. Worked examples presented at the workshop eurocode 7.
For design purposes, an equipment impact point load on the gravity block retaining wall face will be assumed at 30 inches 2. Gravity retaining wall depends on its weight for resisting lateral earth force because it have a large weigh 2. 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. Mcgrawhill international edition, 1997 may be referred. Retaining walls in theory and practice, a textbook for. Assume variation of water pressure below wall same as cp2 example. Retaining walls in theory and practice, a textbook for students. Ce 537, spring 2011 retaining wall design example 6 8 2.
Water must not be allowed to build up behind the wall. Worked example to accompany mbie guidance on the seismic design of retaining structures for residential sites in greater christchurch version 2 november 2014. The wall is assumed to be located in the christchurch port hills. Norfolk and tasman retaining walls au keystone retaining wall systems. The load that presents the greatest problem and its primary concern is the lateral earth pressure induced by the retained soil. Assuming that the allowable bearing pressure of the soil is 120 knm. 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. Creating a retaining wall home design software for diy.
These are much less than the hydrostatic pressure exerted by water trapped behind the wall. For details of other type the book foundation analysis and design by j. 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. Course objectives they seem to crop up everywhere, like cell phone towers. Semi gravity retaining wall reduce the dimensions of the gravity retaining wall by using some reinforcement. 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. Cantilever retaining wall ouestion for the retaining wall and the profile shown below, calculate. 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. Some of the many types of gravity retaining walls were described in chapter 1. 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. Even though the wall is founded on clay, the backfill has been assumed to.
From the menu, select terrain create terrain perimeter. 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. Basics of retaining wall design 10 editionth a design guide for earth retaining structures contents at a glance. 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. Earth pressure p 8 earth pressure is the pressure exerted by the retaining material on the retaining wall. This input is a variable that can range from 20 lbs. 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 this example, the structural design of the three retaining wall components is performed by hand.
Different types of retaining walls are used to retain soil in different places. Pdf a new design method for retaining walls in clay. The stability of such walls depends upon the arrangement of stones in the wall and the friction between the individual stones. Mechanically stabilized earth mse retaining walls are growing in popularity. Note that the slip surface is forced to slide just below the gravity wall. Type of retaining wall failure to design retaining walls, it is necessary to know how wall can fail. Retaining wall design design examples and construction. Preface standards australia has published as 46782002 for the design of earth retaining structures, which. Stability limit state a limit state of loss of static equilibrium of a structure, or part thereof, when considered as a rigid body. Project topic on analysis and design of a retaining wall.
A brief version of the results of the analysis is shown the following page. Whereas, if bracing is in front of the wall and is in compression instead of tension, the wall is called buttress retaining wall. Cantilever or restrained retaining wall calculations o r g a n iz a io n f. The example calculations are made here using mathcad. 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. Design the reinforced concrete masonry cantilever retaining wall shown in figure 2. If you design retaining walls, you know its tedious and timeconsuming. 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. Active earth pressure or earth pressure pa and passive earth pressure p p. It is commonly required in the construction of hill roads, masonry dams, abutments and wings walls of bridges and so on.
The designer must determine the reinforcement size and spacing required to resist the applied loads, listed below. Pc17 retaining walls idaho transportation department. Design and analysis of retaining walls 2 economical when the wall height exceeds 8m. Strength limit state a limit state of collapse or loss of structural integrity of the components of the retaining wall.
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. Retaining walls page 10 lateral soil pressure on retaining walls typical angle of internal friction for backfill soil soil type. Ab engineering manual retaining walls allan block wall. Ce 437537, spring 2011 retaining wall design example 28 substituting eqn. Concrete wall form design example civil engineering. Retaining wall design example revised jim richardson. Abwall here is example 1 as designed using keywall 2001. Eurocode retaining wall stem design example structural. Precast concrete retaining wall blocks shall be vertiblock units as produced by a licensed verti. A n beal earth retaining structures worked examples. Worked example 4 design of a tiedback retaining wall to. The bank of supported earth is assumed to weigh 110 lbft.
683 416 435 801 1377 1611 720 773 949 1495 358 563 40 1080 620 1188 280 93 1278 559 848 1575 1483 292 1527 716 1095 430 1271 841 166 607 279 782 1488 860 708