The stem is a vertical cantilever beam, acted on by the horizontal earth pressure. Stepbystep design of a cantilevered retaining wall. Mar 07, 2017 here i had explained about the design steps for a cantilever retaining wall as per my knowledge. Reinforced concrete cantilever retaining wall analysis and design aci 318m14 reinforced concrete cantilever retaining walls consist of a relatively thin stem and a base slab. Cantilever retaining wall sheet excel civil engineering program. The safety factor against sliding minimum required f. 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 retaining wall sheet excel web share 20161018t23. Calculate the factors of sa fety with respect to overturning, sliding, and bearing capacity. The following worked example uses a simplified lrfd design procedure with load and resistance factors taken from b1vm4. Active earth pressure or earth pressure pa and passive earth pressure p p. Preface standards australia has published as 46782002 for the design of earth retaining structures, which. The stem may have constant thickness along the length or may be tapered based on economic and construction criteria. Possible modes of failure for freestanding concrete cantilever retaining walls.
It has much thinner stem and utilize the weight of the backfill soil to provide most of the resistance to sliding and overturning. Gravity wallmasonry or plain concrete cantilever retaining wallrcc inverted t and l. Retaining walls 101 an introduction to choosing the right wall. Cantilever retaining wall reinforced concrete wall with small dimensions and it is the most economical type and the most common note. Cantilever retaining walls are the most common type of retaining walls and are generally used for wall high up to 8m. Active earth pressure tends to deflect the wall away from the backfill. Suggest suitable dimensions for the rc retaining wall example 1. Earth pressure p 8 earth pressure is the pressure exerted by the retaining material on the retaining wall. Cantilever walls are walls that do not have any supports and thus have a free unsupported excavation. Cantilever retaining wall sheet excel civil engineering. Ce 537, spring 2011 retaining wall design example 3 8 3.
Classification of retaining walls cantilever retaining wallrcc inverted t and l. Cantilever concrete retaining walls are commonly used for residential purposes, often as integral basement 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 section load combinations ev 1 ev 2 dc 2 dc 3 vehicular collision load 18. This costeffective solution completely eliminates the need for the construction of a mechanically stabilized earth zone behind the wall and requires substantially less excavation than is usually necessary in a gridreinforced wall. Consider the cantilever retaining wall with the crosssection shown in the above figure a. Design and detailing of retaining walls engineering books.
In general, they are used to hold back or support soil banks and water or to maintain difference in the elevation of the ground surface on each of wall sides. Consider the cantilever retaining wall with the cross section shown in the above figure a. The base is divided into two parts, the heel and toe. Cantilever retaining wall ouestion for the retaining wall and the profile shown below, calculate. The following text provides a general discussion and design guidelines for these flexible wall. Usually the cantilever wall stem is of concrete block. Design of retaining wall with counterfort engineering. Worked example to accompany mbie guidance on the seismic design of retaining structures for residential sites in greater christchurch version 2 november 2014. 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. Wisdot regional staff determines the need for permanent retaining walls on highway projects. Assuming that the allowable bearing pressure of the soil is 120 knm 2, the.
Active earth pressure tends to variation of earth pressure deflect the wall away from the 5. Determine the factors of safety against sliding and overturning. Design and detailing of retaining walls learning outcomes. Strength limit state a limit state of collapse or loss of structural integrity of the components of the. 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. Retaining walls types details with analysis and design. Cantilever retaining wall is the most common type of earth retaining structure. 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. Rccii design steps for cantilever retaining wall youtube. Retaining walls are usually built to hold back soil mass. Cantilever rc retaining wall 10 knm2 m 500 mm h 400 0.
Some other basic concepts are also explained like, curtailment of bars development length. The details of a cantilever retaining wall are shown below, is the design of the wall satisfactory. This publication presents an example on the design of retaining structures. Worked example 2 design of concrete cantilever retaining. Ahmadi and varaee, 5 used particle swarm algorithm to optimize the cantilever reinforced retaining wall and it is indicted that there is. Norfolk and tasman retaining walls au keystone retaining wall systems. The objective of this research was to conduct a field performance study on a full scale cantilever retaining wall in order to verify or modifyu current design procedures.
Stability limit state a limit state of loss of static equilibrium of a structure or part thereof, when considered as a rigid body. For many years reinforced masonry cantilever retaining walls, relying on gravity loads to resist the overturning forces due to soil pressure, have been constructed. Geotechnical design of cantilever retaining walls to. Jun 10, 2018 numerical of cantilever retainig wall is discussed in this video in a simple manner. Some other basic concepts are also explained like, curtailment of bars development length distribution. It is considered suitable for common residential situations with competent soils. Cantilever walls cantilever wall design deep excavation. Cantilever walls restrain retained earth by the passive resistance provided by the soil below the excavation. This procedure is intended to be readily calculated by hand, although use of. Worked example 2 design of concrete cantilever retaining walls to.
Retaining walls 101 an introduction to choosing the. The design of a retaining wall must account for all applied loads. A wall number is assigned as per criteria discussed in. This is an extremely popular system offering benefits that include zero lot lines, a vertical wall face and a range of possible finishes. Loads and forces acting on retaining wall and their. 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. Retaining wall development is described in section 11555 of the.
Conventional retaining walls gravity retaining structures stability depends on the self weight of the wall not economical for design semigravity 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 with thin stem and slab base. Cantilever retaining wall functions and design considerations. Examples of this include cip cantilever, mse and modular block walls. Deflection generally governs design for cantilever walls more than 18 feet high. Design and detailing of counterfort retaining wall when the height of the retaining wall exceeds about 6 m, the thickness of the stem and heel slab works out to be sufficiently large and the design becomes uneconomical. This design example focuses on the analysis and design of a tapered cantilever retaining wall including a comparison with model results.
In the design of civil engineering structures, retaining walls are normally used to retain soil earth materials, and they are usually found on embankments, highways, basement of buildings, etc. The focus of the guideline is the geotechnical aspects of retaining wall design. Basics of retaining wall design 10 editionth a design guide for earth retaining structures contents at a glance. Assume level backfill, no surcharge or seismic loading, active earth. Cantilever retaining wall with shear keywith shear key batter drainage hole toe 2. This gl pressure tends to deflect the wall outward.
The following worked example is for a freestanding cantilever wall that is considered sufficiently flexible for active. This objective has been accomplished and the proposed. Design the reinforced concrete masonry cantilever retaining wall shown in. It derives its name from the fact that its individual parts behave.
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. Reinforced concrete cantilever retaining wall analysis and. Cantilever retaining walls figure b are made of reinforced concrete that. Numerical of cantilever retainig wall is discussed in this video in a simple manner. The following figure shows theses different types of. Cantilever walls the cantilever wall figure 1b and figure 2 is the most common type of retaining structure and generally is used for walls in the range from 10 to 25 ft in height.
Usually the cantilever wall stem is of concrete block construction rising from an insitu concrete foundation. Check against a worked example in the reference above. Cantilevered soldier pile retaining wall design methodology and example. Assuming that the allowable bearing pressure of the soil is 120 knm. It is so named because its individual parts toe, heel, and stem behave as, and design as, cantilever beams. Reinforced concrete cantilever retaining wall analysis and design. Section 9 of en 19971 applies to retaining structures supporting ground i. Design concrete shear stress in wall section for inplane bending. An example of this is the anchorplex retaining wall system developed by anchor wall systems of oldcastle apg. The cantilever retaining wall shown below is backfilled with granular material having a unit weight. When retaining wall is designed for impact loads, the stem should be checked at equally spaced points along stem length from top to the bottom as impact load spread at the greater length of the stem.
Full details of masonry wall construction are provided in reinforced concrete masonry cantilever retaining walls design and. Loads and forces acting on retaining wall and their calculations the next step is to enter the loads on the wall as defined above. However, retaining walls can also be constructed for aesthetic landscaping purposes. Cantilever retaining wall is the most common type of earthretaining structure. Gabion retaining wall design from uk supplier gabion baskets. In such a case counterforts having trapezoidal section fixed at the base slab are provided at intervals of 1. Ce 437537, spring 2011 retaining wall design example 3 8 3.
It is so named because its individual parts toe, heel, and stem. Design retaining wall for car bumper might be necessary when the wall extends above grade, and the parking area is close to it. Many engineers use the cantilever wall term to actually describe gravity walls. Design the reinforced concrete masonry cantilever retaining wall shown in figure 2. P a active earth pressure or earth pressure pa and passive earth pressure pp.
82 418 436 472 323 596 1270 659 1185 909 1148 1266 1144 1011 1088 368 434 521 74 305 738 501 137 1273 807 379 185 749 491 1460 974 75 584 757 1028 64 584 498 1284 1296 1140 188 829