GEOTECHNICAL DESIGN PROCEDURE FOR FLEXIBLE WALL SYSTEMS GDP-11 Revision 4 STATE OF NEW YORK geotechnical design of flexible cantilevered or anchored retaining walls to be constructed on New B The sloping backfill may be assumed to be equivalent to a horizontal surcharge loading, located an offset of one-half the distance from the wall
A uniform vertical pressure applied to the ground surface in the vicinity of a retaining wall is called a surcharge load. This surcharge load will result in an additional horizontal pressure on the wall. Calculations Like the pressure caused by soil, the surcharge lateral earth pressure is related to the vertical
General Design Requirements: Retaining walls designed using code tabulated values shall meet the conditions cited below: 1. Fill materials behind retaining walls shall be fully drained of water and other fluids by means of sub-drain, weep holes and/or other approved method at least equivalent to the attached detail.
Retaining walls. free to move and rotate at the top are permitted to be designed for active pressure. Design lateral pressure from surcharge loads shall be added to the lateral earth. pressure load. Design lateral pressure shall be increased if soils with expansion. potential are present at the site.
SECTION 5 - RETAINING WALLS Part A . General Requirements and Materials . 5.1 GENERAL . Retaining walls shall be designed to withstand lateral earth and water pressures, the effects of surcharge loads, the self-weight of the wall and in special cases, earth quake loads in accordance with the general principles specified in this section.
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. Any wall that sustains significant lateral soil pressure is a retaining wall. However, the term is usually used with
Given: Active equivalent fluid pressure is 30 pcf Surcharge location is 0 feet from shoring/retaining wall Height of retaining wall/shoring is 10 feet Traffic Surcharge = × = 30 pcf Given in this example x 3.5 ft From Table 1 = 105 psf.
timber. Each of these walls must be designed to resist the external forces applied to the wall from earth pressure, surcharge load, water, earthquake etc. Prior to completing any retaining wall design, it is first necessary to calculate the forces acting on the wall. Retaining Wall to Support a Fill. Retaining Wall to Support a Cut. Cut Fill
Definition: Equivalent fluid pressure is a simplification of backfill earth pressure against retaining structures. If the backfill behind a cantilever retaining wall or restrained basement wall is level, we can use the equivalent pressure. For a cantilever retaining wall, level and drained condition subdrain , the equivalent fluid pressure is simply the product of Ka *
Equivalent Surcharge and shows a 2 foot scaled; not specified fill on top of a retaining wall backfill. Elsewhere .. Question Where was the 250 psf Uniform Surcharge originated from? Question Practically, in reality, there is no such a Uniform, Infinite Long Strip Load of 250 psf. 6 Common Cases Conventional Construction Equipment
Retaining Wall: A landscaping technique intended to change the contour or grading of the lot. Construction of any Retaining Wall with exposed height greater than 2-0 two feet requires a permit. Retaining Walls with exposed heights of 24 twenty-four inches or greater with surcharge or problem soil shall be engineered.
In the analysis of retaining walls subjected to earth pressure, it is very common to observe trapezoidal load distribution on the walls. Normally, earth pressure on a retaining wall is assumed to adopt a triangular load distribution, but due to surcharge which is usually assumed to act on the ground surface, the top of the wall experiences some degree of lateral pressure.
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. It is so named because its individual parts toe, heel, and stem behave as, and design as, cantilever beams.
Wall to Footing Centerline Distance: : This is the distance from the center of the adjacent footing to the back face of the stem at the retained height. The nearest edge of the footing should be at least a foot away from the wall face otherwise suggest using an equivalent heel surcharge instead.
Assumed additional height of backfill Assumed equivalent uniformly distributed surcharge. \i Tl 1111 Ml I. Retaining wall Pressure due to equivalent surcharge Pressure due to backfill only. Figure 1. Traditional method of estimating lateral pressure due to surcharge load.
When a recommendation is made for an Equivalent Fluid Pressure, it is always accompanied by a statement about the expected movement of the retaining wall. If the wall is assumed to be stationary, the EFP is derived from the Ko condition at rest .
Traffic live load surcharges on retaining walls 2. Generally if you can keep the edge of road at least 5 feet from the face of the wall, the pressure will be managable. To analyize the pressure fast and dirty: assme a 250 psf strip surcharge at edge of road to edge of road. At top of ground the pressure equals 0.
In the conventional design of retaining walls and bridge abutments, the lateral earth pressure due to live load surcharge is estimated by replacing the actual highway loads with a 600 mm layer of backfill. This original recommendation was made several decades ago when the highway truck loads were much lighter.
structural strength. Methods for evaluating earth pressures on retaining walls and design procedures are summarized herein for cohesionless backfill materials, which should be used whenever practicable. 1.2 FORCES ACTING ON RETAINING WALLS. Forces include earth pressures, seepage and uplift pressures, surcharge loads, and weight of the wall
All other retaining wall conditions such as taller walls, tiered walls, and/or walls supporting sloping backfill or other surcharges will generally require a building permit. When a Building Permit is Required A building permit can usually be issued over the counter when two copies of the following are
The actual load imposed on a semi-vertical retaining wall is dependent on eight aspects of its construction: 1. The degree of saturation of the wall backfill in the zone of active or at-rest earth pressure. 2. The degree of relative compaction of the wall backfill within the active or at-rest envelopes. 3.
If heavy equipment will be operated near the wall, an additional surcharge equivalent to two feet of soil shall be applied in the wall analysis.. Machinery on Soil Cont. The two feet additional soil as machinery loading will increase lateral pressure on wall by :
In the retaining wall, vertical backfill or soil mass acts along with surcharge for retaining wall. Assume that term H is the height of the back fill, q is the intensity of surcharge and is the unit weight of the back fill soil. Calculate the effective height in terms of the lateral stress exerted by the surcharge over the wall in terms of
This is where geogrid comes in - Allan Blocks Reinforcement Grid provides a simple solution by creating a solid structure with more resistance to soil pressure and surcharges for retaining walls under 6 ft. 1.8 m tall. Learn more about reinforced retaining wall construction. Conditions Above and Behind the Retaining Wall
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