The analysis and design of a gravity retaining wall: Retaining walls are structures used to provide stability for earth or other materials at their natural slopes.
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.
Also, retaining walls are often used; in the construction of buildings having basements, roads, or bridges when it is necessary to retain embankments or earth in a relatively vertical position.
Retaining walls are commonly supported by soil (or rock) underlying the base slab, or supported on piles; as in case of bridge abutments and where water may erode or undercut the base soil as in water front
structures.
The analysis and design of a gravity retaining wall involves the following steps:
- Determine the properties of the soil. This includes the soil’s unit weight, cohesion, and angle of internal friction.
- Calculate the lateral earth pressure. There are two main theories for calculating lateral earth pressure: the Rankine theory and the Coulomb theory.
- Determine the overturning moment. This is the moment that is applied to the wall by the lateral earth pressure.
- Determine the bearing capacity. This is the maximum load that the soil can support without failing.
- Design the wall. This involves determining the dimensions of the wall, such as the height, width, and thickness.
The following are some additional considerations in the analysis and design of gravity retaining walls:
- The height of the wall: Taller walls will require more structural support than shorter walls.
- The type of soil: Some soils are more prone to erosion than others. The type of soil will affect the type of retaining wall that is needed.
- The amount of water: If the area is prone to flooding, the retaining wall will need to be designed to withstand the force of the water.
- The budget: Retaining walls can range in price from a few hundred dollars to several thousand dollars. It is important to set a budget before designing a retaining wall.
It is important to consult with a qualified engineer to ensure that the gravity retaining wall is designed and constructed properly.
Here are some of the most common methods for analyzing and designing gravity retaining walls:
- Rankine theory: This theory assumes that the soil behind the wall is a rigid mass. The lateral earth pressure is calculated using the following equation:
p = kh
where:
- p is the lateral earth pressure
- k is the coefficient of active earth pressure
- h is the height of the wall
- Coulomb theory: This theory assumes that the soil behind the wall is a frictional mass. The lateral earth pressure is calculated using the following equation:
p = ka + cn
where:
- ka is the coefficient of active earth pressure
- c is the cohesion of the soil
- n is the angle of internal friction of the soil
- Finite element analysis: This is a more complex method that uses computer software to analyze the stresses and strains in the retaining wall. Finite element analysis can be used to model more complex retaining wall geometries and soil conditions.
The best method for analyzing and designing a gravity retaining wall will depend on the specific project. It is important to consult with a qualified engineer to determine the best method for your project.
Two eBook Take Note (You Can Download for Free)
1-eBook Civil-Engineers have to read for Retaining Wall Analysis: Reinforced-Concrete-Cantilever-Retaining-Wall-Analysis-and-Design-ACI-318-14
2-eBook Civil-Engineers have to read for Retaining Wall Analysis: DESIGN AND ANALYSIS OF
RETAINING WALLS