What Is a Grade Beam?
- A grade beam is a component of a building’s foundation. It consists of a reinforced concrete beam that transmits the load from a bearing wall into spaced foundations such as pile caps or caissons.
- The grade beam is a component of the foundation of the structure. The construction of the grade beam is done with the reinforced cement concrete.
- The Grade Beam is generally constructed on the Grade level or earth level. These beams are constructed to act as a horizontal bond between footings for pile caps.
- The main function of the grade beam is to transfer the load coming from the superstructure to the foundation. The Grade beam helps to control the differential settlement.
- The grade beam also supports the wall loads at the ground floor which tend to be heavy and cannot be supported by the slab only. In this article, you will get to know what is a Grade Beam, its Advantages and disadvantages and the Grade beam Construction Process
- Grade Beams are Constructed and designed with concrete and mainly acts as horizontal ties between the two footings.
- The grade beam is generally used in the areas where the surface bearing capacity of the soil is less. Grade beam connects the column with each other.
- The Grade Beam generally rests on the soil or above the soil which spans between piles.
- Grade beams are reinforced with the reinforcement in a continuous manner. The grade beams are generally used to connect the column foundations with each other.
- Grade beam should be reinforced with the continuous reinforcement which is developed within the supported column.
What Is Grade Beam Foundation?
- The main purpose of using a grade beam Foundation is to transfer all load coming from structure to the underground soil Strata.
- The size and the depth of the grade beam depend upon the type and the intensity of the load coming on the beam and the bearing capacity of the soil on the construction site.
- The minimum depth of the grade beam should be 150 mm. The grade beams are stronger than the plinth beams. Grade beam also carries the load of the walls.
- Grade beam Foundation uses less amount of concrete as compared to the conventional Foundation. One of the disadvantages of the construction of the grade beam foundation is that it cannot be used for the basement.
- The minimum reinforcement which is required in the grade beam at the top and the bottom side is 3 bars of 10 mm diameter.
Grade Beam Construction Process
The steps which are involved in the construction process of the grade beams are as follows. Here we are listed step by step procedure for the construction of the grade Beams.
- Preparation and excavation for grade beam.
- Installation of formwork for grade beam.
- Reinforcement placement for grade beam.
- Pouring concrete for grade beam.
#1. Preparation and Excavation for Grade Beam
- The first step on the excavation is done for the construction of the grade beams. The excavation for the grade beam is done based on its level.
- The construction of the grade beam is done on the prepared base surface. The ground surface should be levelled and prepared with plain cement concrete to rest grade beam.
- If the grade beam is used to connect between two piles then the Construction of the grade beam will begin after the Construction of pile foundation.
#2. Installation of Formwork for Grade Beam
- After completing the process of excavation the formwork for the construction of grade beams is installed.
- The formwork for the grade beam installed as per the measurements for the construction of the grade beam which is provided in the drawing.
- If the construction of the grade beam is done on the surface of the ground then the bottom of the formwork should be replaced prior on both sides.
- The cage of the reinforcement should be placed on the flat soling brick before the shuttering is fixed.
- If the grade beam is constructed above the ground level then the formwork should be similar to that conventional beam. In this condition, the shutter should be placed for the bottom and both sides of the grade beam.
- After the installation of the formwork for the construction of the grade beam ensure that all dimensions which are provided are according to the drawing.
- Check that whether sufficient reinforcement cover is provided or not. It is also necessary to check the shuttering strength, waterproof and verticality of the shutters.
#3. Reinforcement Placement for the Grade Beam
- After the completion of the formwork, the reinforcement placement for the grade beam is done. The Reinforcement of the Grade Beam should be properly placed.
- The reinforcement detailing is provided in the structural drawings. The details which structural drawings consists are size and number of the longitudinal reinforcement bar
- After the placement of reinforcement, the number of bars and the size of the top and bottom bar should be checked properly as per the Structural drawing.
#4. Pouring of Concrete for Grade Beam
- The casting of the grade beam is done with the help of ready mix concrete for onsite machine mixed concrete.
- While casting the care should be taken that concrete should be properly compacted. The top surface of the grade beam should be properly finished.
- Finally, the side of the grade beam should be removed after the 24 hours. The bottom shutter cannot be removed until the concrete can the strength.
Advantages of Grade Beam
- Grade beam can be easily formed in different shapes and sizes.
- Grade beam provides excellent support for both concrete as well as soil. They can support the soil.
- The installation of the grade required less excavation.
- The construction of the grade beam required less amount of concrete as compared to conventional Foundation.
- This will help to reduce the cost of the project.
- The Grade beam will save time and money and required less amount of money.
- The grade beams allow the entry of other materials such as rebar, conduit pipes and dowels etc
Disadvantages of Grade Beam
- To construct the foundation of the grade beam it required a levelled construction site.
- Grade beam Foundation does not work with the basement.
- The construction of the grade beam Foundation cannot be done on the hilly areas.
- The construction of the grade beam on the slope areas required a larger amount of excavation which will increase the cost of the project.