What Is Grade Beam | What Is Grade Beam Foundation | Grade Beam Construction Process |Advantages & Disadvantage of Grade Beam
What Is a Grade Beam?
A grade beam is a component of a building's foundation. It consists of a reinforced concretebeam 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.
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 150mm. The grade beams are stronger than the plinthbeams. 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.
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.
After completing the process of excavation the formwork for the construction of grade beams is installed.
The formwork for the grade beam was 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.
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.
Definition: Grade beams are reinforced concrete beams that are constructed at or below ground level to support and distribute the load of a structure.
Placement: Grade beams are typically placed at a shallow depth, near the ground surface, and they may be directly connected to column footings or isolated footings.
Purpose: Grade beams are primarily used to transfer the load from columns, walls, or other vertical members to the underlying soil or foundation.
Load Distribution: Grade beams are designed to distribute the load evenly along their length, thereby reducing the pressure exerted on the soil.
Reinforcement: Grade beams are reinforced with steel bars to enhance their strength and resistance to bending or cracking.
Definition: Spread footings, also known as pad footings, are concrete footings that are wider in plan dimensions compared to the supported column or wall they serve.
Placement: Spread footings are typically located at the base of columns or walls and are placed at a greater depth compared to grade beams.
Purpose: Spread footings are used to transmit the load from columns or walls to a larger area of soil or rock beneath. They distribute the load over a wider area to prevent excessive settlement or bearing capacity failure.
Load Distribution: Spread footings distribute the load through the bearing pressure exerted on the soil directly beneath the footing.
Reinforcement: Spread footings may or may not contain reinforcement, depending on the design requirements and the soil conditions.
Reinforcement Bars (Rebars): Grade beams are reinforced with steel rebars that provide tensile strength to resist bending and cracking. The rebars used are typically deformed bars (commonly known as rebar) and are specified by their diameter and grade (e.g., #4 rebar, Grade 60).
Bottom Reinforcement: Grade beams usually have a layer of reinforcement bars placed at the bottom. The spacing and size of these bars are determined by the design specifications and the expected loads. The bars are often placed parallel to the length of the grade beam and are supported by chairs or other means to maintain the required cover from the bottom surface.
Top Reinforcement: In some cases, additional reinforcement bars may be provided at the top of the grade beam to enhance its bending resistance. This top reinforcement can help in preventing cracking and increasing the load-carrying capacity of the grade beam.