Retaining walls and chapter 730 steep reinforced slopes. Gravity wall design considerations all retaining walls need to be designed to withstand various imposing forces. The focus of the guideline is the geotechnical aspects of retaining wall design. The main forces acting on the wall are lateral earth pressure at the back face and vertical forces which is the weight of the wall as shown in figure 4, the latter force is employed to resist the. Seismic analysis and design of retaining walls, buried structures, slopes, and embankments explores analytical and design methods for the seismic design of retaining walls, buried structures, slopes, and embankments. Gravity walls are the earliest known retaining structures. However, the term is usually used with reference to a cantilever retaining wall, which. Ce 437537, spring 2011 retaining wall design example 1 8 design a reinforced concrete retaining wall for the following conditions. Retaining walls in theory and practice, a textbook for.
Principles of retaining wall design the constructor. They depend for stability on their own weight and any soil resting on the masonry. C69 neuniversi,y l brary rejajningwallsintheoryandpractice,a 31924004084780 allbooksaresubjecttorecallaftertwoweeks. Design principles for gravity retaining walls soil. A total of ten designs were considered, of which three were retaining walls. Gabion wall design materials and applications of gabion wall. The ssr is sent to the wall designer structures design section or wisdots consultant for wall selection, design andcontract plan preparation. Overturning is caused by the horizontal component of the resultant active earth pressure, p a, in the form of an overturning moment. Read seismic analysis and design of retaining walls. Different types of retaining walls are used to retain soil in different places. Example 11 castinplace concrete cantilever retaining wall 4 2020 summary of unfactored loads and moments resolve moments about point a see figure 1 typical section load combinations ev 1 ev 2 dc 2 dc 3 vehicular collision load 18. The bank of supported earth is assumed to weigh 110 lbft.
The cantilever retaining wall shown below is backfilled with granular material having a unit weight. Worked examples of retaining wall design to bs8002. Types of retaining walls gravity wall depends entirely on its own weight to provide necessary stability usually constructed of plain concrete or stone masonry plain concrete gravity wall height 3 m in designing this wall. Retaining walls also may be used at bridge abutments to support the structure. Pre sented in tabular form, the designs are for wall heights up to 10 feet, and for walls with ve rtical backs or with nearly ve rtical faces. The procedure is more of a general summary and an appreciation of the role of subsurface exploration in geotechnical design. Design of earth retaining structures for dynamic loads, prof h. In this example, the structural design of the three retaining wall components is performed by hand. Design of slopped gravity retaining wall in excel design of vertical gravity retaining wall. Assuming that the allowable bearing pressure of the soil is 120 knm. Naturally, the biggest concern is the force imposed 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 semigravity wall is a modification of the gravity wall. Under static conditions, retaining walls are acted upon by body forces related to the mass of the wall.
This material is presented for the use of a qualified. Figure 4 is a graph showing the frictional angle used along the slip surface. Magnumstone gravity retaining wall extenders also reduce the amount of concrete required compared to competitive solid gravity wall. Retaining walls in theory and practice, a textbook for students. Retaining structures i d i f it design of gravity walls eurocodes.
Assuming that the allowable bearing pressure of the soil is 120 knm 2, the. This guide describes the design and construction of gravity earth retaining. In this course you will find examples of the design of these walls. Cantilever concrete retaining walls are commonly used for residential. Some manufacturers offer technical support, in the form of brochures showing engineer designed details, for their particular wall type. Presented in tabular form, the designs are for wall heights up to 10 feet, and for walls with ve r tical backs or with nearly ve r tical faces. This type of construction is not economical for high walls. Gravity retaining wall ouestion a gravity retaining wall is shown below.
Gravity retaining walls gravity retaining walls are a basic design and rely on the mass of the wall to retain the earth behind. Ab engineering manual retaining walls allan block wall. The use of horizontal layers of wire mesh as a horizontal tieback or soil reinforcement is discussed separately. Small gravity retaining walls concrete construction. Norfolk and tasman retaining walls au keystone retaining wall systems. Gravity walls the gravity wall figure 1a depends mostly on its own weight for stability. 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. The report discusses the seismic design of gravity walls retaining granular backfill without pore water. Chance company and its agents assume no responsibility for the design, construction or performance of soil nail structures, even if the design and construction of the walls were performed using a.
Cantilever retaining wall reinforced concrete wall with small dimensions and it is the most economical type and the most common note. Gravity retaining wall design, gravity walls magnumstone. The design parameters for design of these ers are based on the aashto design specifications, 4 th edition, 2007, and the 2010 california amendments california amendments. This is a cross section of a gravity wall composed of srw facing units and drainage aggregate. Usually the cantilever wall stem is of concrete block. Any wall that sustains significant lateral soil pressure is a retaining wall. Very broadly, retaining walls are cut walls, in which the wall is cut into the existing slope, and fill walls in which the retaining wall is built in front of the slope, and then the space behind it is filled. Whereas, if bracing is in front of the wall and is in compression instead of tension, the wall is called buttress retaining wall.
Cantilever timber pole walls are probably the most commonly used form of retaining wall for residential purposes. They are not full detailed calculations such as might be prepared for a real wall design. 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. Semi gravity retaining wall reduce the dimensions of the gravity retaining wall. Design of concrete cantilever retaining walls to resist earthquake loading for residential sites. Presented in tabular form, the designs are for wall heights. Adstir act s ss reverse as if necessary and fdeitfy by bl ock bor. Retaining walls design and construction lc richardselms retaining wall design method wes.
Design calculations alone cannot ensure that designs will yield a safe and properly functioning structure. The other two forms of construction are covered in separate guides. To design retaining walls, it is necessary to define failure and to know how walls can fail. Design of gravity retaining walls in excel sloped and. Presented in tabular form, the designs are for wall heights up to 10 feet, and for walls. 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. Semi gravity retaining wall reduce the dimensions of the gravity retaining wall by using some reinforcement. A very simple method to design a gravity retaining wall is to use the base width x 2 to calculate the height. The use of horizontal layers of welded wire mesh anchor mesh as horizontal tiebacks for soil reinforcement mse walls. Preface standards australia has published as 46782002 for the design of earth retaining structures, which. Ers that appear as 2010 standard plans or revised standard plans are.
Design of semi gravity retaining walls wec civilians. It is usually made of plain concrete and is used for walls up to approximately 10 ft in height. Deflection generally governs design for cantilever walls. Example 11 castinplace concrete cantilever retaining wall 4 2020 summary of unfactored loads and moments resolve moments about point a see figure 1 typical. Structural design of cantilever retaining wall is depend on separating each part of wall and. The lateral forces from backfill is resisted by the weight of wall itself, and due to their massive nature, they develop little or no tension. Cantilever concrete retaining walls are commonly used for residential purposes, often as integral basement walls. Review current design procedures to use as a format for the. 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. Design of semi gravity retaining walls 1 a semi gravity retaining wall consisting of plain concrete weight 145 lbft. Hollow or solid concrete masonry units used in gravity retaining walls should meet the requirements of astm c 90 ref. 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. This guide describes the design and construction of gravity earth retaining structures, consisting of a reinforced concrete footing and a reinforced concrete masonry cantilever stem.
Allan block combines the basic engineering principles of setback, leverage and total unit mass with simple mechanics to make highly stable gravity walls. Units of gabion wall are considered as one cohesive mass for design purposes. The paper covers a theoretical approach in data acquisition needed for design of a 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. A retaining wall that relies solely on its own weight to stand up is called a gravity wall. Note that the slip surface is forced to slide just below the gravity wall. Design principles for gravity retaining walls soil engineering. Mechanically stabilized earth mse retaining walls are growing in popularity. Gravity retaining wall design can be greatly simplified t h r ough the use of a series of sample designs deve l o p e d recently by the po r tland cement association pca. The following worked examples have been prepared to illustrate the application of bs8002 to retaining wall design. However, retaining wallscanalsobeconstructed for aesthetic landscaping. There various parts of a retaining wall and design principles of these retaining wall components based on different factors and material and methods of construction are discussed. The design principles of gravity retaining walls are discussed below.
Conventional retaining walls gravity retaining structures stability depends on the self weight of the wall not economical for design semi gravity retaining structures minimum amount of reinforcement may be used in the wall to reduce the size of wall cantilever retaining walls reinforced concrete is used in wall design. Weight of the concrete in a gravity wall provides stability against overturning. Design and analysis of retaining walls 2 economical when the wall height exceeds 8m. The report discusses the seismic design of gravity walls retaining. Worked example 1 design of cantilever pol retaining walls to resist. 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. It is commonly required in the construction of hill roads, masonry dams, abutments and wings walls. Course objectives they seem to crop up everywhere, like cell phone towers.
Reinforced concrete cantilever retaining wall analysis and design. Therefore, they are usually not reinforced with steel. Gravity retaining wall design can be greatly simplified through the use of a series of sample designs developed recently by the portland cement association pca. Flexural and shear stresses in gravity retaining walls will almost always be of minor importance. Gravity retaining wall depends on its weight for resisting lateral earth force because it have a large weigh 2. 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. It is not intended as a textbook of soil mechanics or geotechnical engineering. A design example which demonstrates the use of the australian.
Chapter 7 retaining walls seismic analysis and design of. They are built from solid concrete or rock rubble mortared together. Flexural and shear stresses are checked in the second design example, and it is seen that the magnitudes are very low. Gabion wall is designed in the same way as gravity retaining wall. Reinforced concrete cantilever retaining walls consist of a relatively thin stem and a base slab. The semigravity wall is a modification of the gravity wall in which small amounts of reinforcing steel are introduced. 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. Deflection generally governs design for cantilever walls more than 18 feet high. Gabion walls design guide gravity wall design gabion walls are generally analyzed as gravity retaining walls, that is, walls which use their own weight to resist the lateral earth pressures.
This manual presents the techniques used by allan block in our engineering practice to design retaining walls. However, retaining wallscanalsobeconstructed for aesthetic landscaping purposes. Retaining walls are structures used to retain earth or water or other materials. Design of gravity retaining walls in excel sloped and stepped. Basics of retaining wall design 10 editionth a design guide for earth retaining structures contents at a glance. As you can see, the weight of the soil or soil pressure. 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. Worked example 2 design of concrete cantilever retaining. Trbs national cooperative highway research program nchrp report 611.
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