A wall for holding in place a mass of earth or the like, as at the edge of a terrace or excavation. Basics of retaining wall design 10 editionth a design guide for earth retaining structures contents at a glance. Small gravity retaining walls concrete construction. Precast concrete retaining wall blocks shall be vertiblock units as produced by a licensed verti.
Semigravity retaining wall reduce the dimensions of the gravity retaining wall by using some reinforcement. This input is a variable that can range from 20 lbs. In order to do this, place blocks on top of the base course. Nov 3, 2014 information about monolithic concrete retaining walls. Design optimization for symmetrical gravity retaining walls. Gravity walls are built with massive blocks that use a. The main forces acting on gravity retaining walls are the vertical forces from the weight of the wall, the lateral earth pressure acting on the back face and the seismic loads. Four types of concrete retaining walls the concrete network. A gravity retaining wall is a retaining wall that can be built in a tight area where there isnt a lot of room to excavate. Ab engineering manual retaining walls allan block wall. One is the check for an overturning moment and the other one is the check for sliding. For segmental gravity retaining wall s, the details must clea rly identify the block manufacturer, block type, drainage requirements, and maximum wall height.
For design purposes, an equipment impact point load on the gravity block retaining wall face will be assumed at 30 inches 2. Gravity wall design using staad pro structural engineering. The wedge is defined as the soil which extends beyond the failure. Redirock standard retaining wall blocks started the large block retaining wall revolution back in 2000. Retaining wall design charts recon gravity retaining walls. Semi gravity retaining wall reduce the dimensions of the gravity retaining wall by using some reinforcement. 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. A gravity wall is a retaining wall that can be built in a tight area where there isnt a lot of room to excavate. Rock walls rockeries are required to be designed by a kentucky design professional. Retaining walls applied and interdisciplinary physics.
Retaining walls in theory and practice, a textbook for students. A very simple method to design a gravity retaining wall is to use the base width x 2 to calculate the height. This tek addresses the unreinforced gravity retaining walls only. The principal characteristic of a retaining wall is being able to withstand the. A retaining wall that relies solely on its own weight to stand up is called a gravity wall. There are two checks to consider the stability of the retaining wall. Standard gravity wall analysis considers sliding, bearing and overturning forces. An lshaped gravity and a piled wall options were considered during the detailed. Design of gravity retaining wall gravity retaining wall. The bank of supported earth is assumed to weigh 110 lbft.
The surcharge from the dwelling was assumed to be 5 knm 2 averaged across the active soil wedge for the gravity case and 4 knm 2 for the earthquake case. Design and analysis of retaining walls 2 economical when the wall height exceeds 8m. These retaining wall structures comprise many different wall types ranging from soil. It is usually made of plain concrete and is used for walls up to approximately 10 ft in height.
Retaining walls are structure used to retain soil, rock or other materials in a vertical condition. Allan block combines the basic engineering principles of setback, leverage and total unit mass with simple mechanics to make highly stable gravity walls. Design of semi gravity retaining walls 1 a semi gravity retaining wall consisting of plain concrete weight 145 lbft. It also works well in situations where you need to access utilities behind the area after the wall has been built. These have some tension reinforcing steel included so as to minimize the thickness of the wall without requiring extensive reinforcement. Retaining walls are vertical or nearvertical structures designed to retain material on one side, preventing it from collapsing or slipping or preventing erosion. However, the term is usually used with reference to a cantilever retaining wall, which. Gravity retaining wall depends on its weight for resisting lateral earth force because it have a large weigh 2.
These forces are used herein to illustrate the design principles. Gravity walls are built with massive blocks that use a tongueandgroove system to lock together. Design of semi gravity retaining walls wec civilians. 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. Active earth pressure tends to deflect the wall away from the backfill. The main forces acting on gravity retaining walls are the vertical forces from the weight of the wall, the lateral earth pressure acting on the back. Optimum design of gravity retaining walls using charged system. They are a blend of the gravity wall and the cantilever wall designs. Sliding them into place removes any present debris.
I m referring is1893 and sp22 for this design which gives the details about the behavior of static and dynamic increment pressure during earthquake. This wall was designed to repair a roadside slipout. A specialized form of gravity walls is a semigravity retaining wall. Each of these retaining wall systems has its advantages, and the choice may depend on a number of factors including. Worked example to accompany mbie guidance on the seismic design of retaining structures for residential sites in greater christchurch version 2 november 2014.
Some of the many types of gravity retaining walls were described in chapter 1. Degree gravel and coarse sandy backfill soil 3336 medium to fine sandy backfill soil 2932 silty sand 2730 p max k a. Figure 4 is a graph showing the frictional angle used along the slip surface. 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. 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. The ab stones provide a nominal setback of twelve degrees from vertical. Different types of retaining walls are used to retain soil in different places. Global stability analysis has not been addressed in the charts. As a rule of thumb this method works and will give a. Types of retaining walls gravity walls precast crib walls gabion walls reinforced concrete walls sheet pile walls ms walls mechanically stabilized slurry and secant walls soil nailing l.
This video shows us how to build a gravity wall with allen blocks. Some manufacturers offer technical support, in the form of brochures showing engineer designed details, for their particular wall type. Rigid gravity walls consist of a solid mass of concrete or mortared rubble. Get answers fast from autodesk support staff and product experts in the forums. We believe that a twelve degree setback maximizes the leverage achieved by a battered wall, while providing a finished retaining wall that fulfills the. Gravity retaining wall ouestion a gravity retaining wall is shown below. It is not advisable to include the actual strength of the retaining wall. These large wetcast blocks are like oneton lego blocks that interlock to create tall gravity retaining walls. The weight of the retaining wall including the gravity loads within it plays a vital role in performing the stability check. Q1b calculate the soil pressure under the footing of the retaining wall of q1a. Concrete block gravity retaining wall design guide the design table above presents for the reinforced block retaining walls are indicative designs based upon a base material with allowable bearing pressure of 200kpa. Every retaining wall must be engineered to withstand the pressure from the soils and other loads behind and above them.
Four types of concrete retaining walls with images. Good piped drainage that disposes of water away from behind the wall to limit this buildup of figure 1. Gravity retaining walls retaining wall solutions gabion. To lay out and design a retaining wall or reinforced slope, consider. Integrate redirock standard blocks with the entire family of redirock products to create a seamless, structurally sound solution.
Gravity retaining walls are the walls which use their own weight to resist the lateral earth pressures. What is the design procedure for gravity retaining wall. 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 a basement wall is thus one kind of retaining wall. Masterkey retaining walls design provides the most extensive program that can be used for creating the design of both reinforced and unreinforced concrete and masonry gravity retaining walls as per eurocode 7, bs 8002, bs 8110, cp2 is 325 and bs 5628 part1 and part2. 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. Recon has the industry leading gravity retaining wall system. Gravity walls depend upon bulk weight for stability, as opposed to a cantilevered retaining wall fixed to a foundation. A buildup of water behind the wall is the principal cause of retaining wall failure. Infill material the soil material placed immediately behind the retaining wall facing. A gravity wall constructed of rock materials to provide an aesthetically attractive method of supporting a soil mass. Retaining structures i d i f it design of gravity walls eurocodes. Recons large retaining wall block can be engineered for unreinforced gravity retaining walls reaching heights in excess of 20. C69 neuniversi,y l brary rejajningwallsintheoryandpractice,a 31924004084780 allbooksaresubjecttorecallaftertwoweeks.
Principles of retaining wall design the constructor. Determine the resultant vertical force, w total intersects the bottom of the footing. The fact is, currently, engineers employ the classical theories of rankine and coulomb with certain modifications such as the ones made by caquot and kerisel 1948, shields and tolunay 1973, and zhu and qian 2000 to the coulombs theory. Retaining wall downslope and supporting dwelling foundations surcharge. Any wall that sustains significant lateral soil pressure is a retaining wall. 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, must keep the thrust line within the middle third of the base width no tensile stress to be developed. Retaining walls page 10 lateral soil pressure on retaining walls typical angle of internal friction for backfill soil soil type. You want to make sure that the bottom notch is tight against the front lip of the blocks underneath. However, retaining wallscanalsobeconstructed for aesthetic landscaping. Gravity retaining wall design, gravity walls magnumstone. Drainage material the crushed rock, gravel or similar material placed behind a retaining wall to convey ground water away from the wall and foundations.
Cantilever concrete retaining walls are commonly used for residential purposes, often as integral basement walls. Design of the retaining wall structures on the m4 smart motorway. The user is responsible for the final design and use of the cornerstone products. I m about to design gravity retaining wall of 16 m high using staad pro v8i. Worked example 2 design of concrete cantilever retaining. They provide support to terrain where the soils angle of repose is exceeded and it would otherwise collapse into a more natural form. A rock retaining wall is suitable in situations where the wall is up to about 10 feet and where the slope is 2h. How to model a gravityretaining wall using sweep in wall structure. It utilized a slope correction factor for passive resistance, but ignored the possibility of the downslope moving away from the caissons, which it did sometime later. Optimum design of gravity retaining walls using charged. The design of the above retaining wall structures must consider all the. Please practice handwashing and social distancing, and check out our resources for adapting to these times.
Note that the slip surface is forced to slide just below the gravity wall. Before you analyze any retaining wall make sure you have an accurate picture of the jobsite conditions. 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. Gravity walls the gravity wall figure 1a depends mostly on its own weight for stability. Structural calculations stamped and signed by a kentucky design professional engineer. Pc17 retaining walls idaho transportation department. 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. Complete construction details of the retaining wall, stamped and signed by a kentucky design professional.
Whereas, if bracing is in front of the wall and is in compression instead of tension, the wall is called buttress retaining wall. Usually the cantilever wall stem is of concrete block. Active earth pressure or earth pressure pa and passive earth pressure p p. Foundation material the natural soil or rock material under a retaining wall. For many years reinforced masonry cantilever retaining walls, relying on gravity loads to resist the overturning forces due to soil pressure, have been constructed. Design optimization for symmetrical gravity retaining walls erol sadoglu about the author. The wall in figure 1 is 800mm wide and 1600mm high. The semigravity wall is a modification of the gravity wall in which small. Retaining walls in theory and practice, a textbook for. Gravity retaining walls gravity retaining walls are a basic design and rely on the mass of the wall to retain the earth behind. Presented in tabular form, the designs are for wall heights up to 10 feet, and for walls with ve r tical backs or with. Very little reinforcing steel is needed because the walls dont have to resist bending and shear stresses like those developed in thinner cant i l e v er walls. Small gravity retaining walls are re l a t i v ely simple structures that can be built with unskilled labor and locally available materials.
868 132 617 94 1297 1258 1225 347 574 835 101 857 1152 940 694 226 1340 867 1386 590 908 605 754 539 123 1026 1207 1466 423 1114 1192 1222 107 1094 614 104 92 2 522