Concrete Frame Construction

Concrete frame construction types, key components, advantages and Disadvantages

Concrete frame construction is a construction method that consists of a network of columns and beams to successfully transfer the load coming into the structure to the foundation. Overall, it creates a structural skeleton for the building that is used to support other members such as floors, roofs, walls and claddings.

Type of framed structure

1. Rigid frame structure

These frames are built on site and cannot be poured continuously. They provide more stability and effectively resist rotation. The advantage of rigid frames is that due to the interaction of walls, beams and slabs, they represent positive and negative bending moments throughout the structure.

2. Braided frame structure

This frame structure resists the lateral forces through the bracing action of the auditory members used to resist the lateral forces. Structures are braced by inserting diagonal structural members in the rectangular part of the structural frame. Braided structural frames are more efficient than rigid structural frames.

Large parts of concrete frame construction

1. Columns in a framed structure

The columns are important structural members of the frame building. They are vertical members that carry loads through beams and upper columns and transfer them to the base.

The loads carried can be axial or eccentric. The design of the columns is more important than the structure of the beams and slabs. This is because if a beam fails, it will be a local failure of a floor, but if a column fails, it can destroy the entire structure.

2. Beams in a framed structure

The beams are horizontal load-bearing members of the framed structure. They are the direct load of the weight of the slab and the masonry walls and their own weight.

The beams can be supported on other beams or supported by columns that form an integral part of the frame. These are primarily flexible members. They are classified into 2 types:

Main beam - transmitting floor and secondary beam loads on columns.

Secondary beam - The floor load is transmitted to the main beam.

3. Slabs in frames structure

A slab is a flat horizontal space that is used to cover a building from above and to shelter residents. These are plate elements and mainly carry elastic loads. They usually carry vertical loads.

Under the action of horizontal loads, due to the large moment of inertia, they can be carried by large wind and earthquake forces and then transferred to the beam.

4. Foundation in framemade structure

The sole function of the foundation is to transmit the load coming from the upper column and beam to the solid ground.

5. Scissor walls in framed structure

These are important structural elements in tall buildings. Scissor walls are actually very large columns that make them look like walls instead of columns. They take care of horizontal loads like wind and earthquake loads.

Shear walls also carry vertical loads. It is important to understand that they only work for horizontal loads in one direction, which is the axis of the elongated dimensions of the wall.

6. Lift shaft in framed structure

The lift shaft is a vertical concrete box in which the elevator is fed to go up and down. These shafts help to resist horizontal loads and also keep vertical loads.

Advantages of framed concrete structures

It is better in compression than other materials used for construction. Apart from this, the structure is also good in tension.
Its fire resistance is better than steel so it is able to withstand fire longer.
It has a long service life with low maintenance costs.
It is the most economical structural material in some structures such as piers, dams and bases.
It can be cast into any size required by making the most economical structural material.

This produces rigid members with minimal deflection.

The production capacity of steel is more than 15% of the compressive strength of structural concrete and 100 times of its tensile strength.

Using steel in concrete will reduce cross-sectional dimensions.

Less skilled workers are required compared to other structural systems.

Disadvantages of framed concrete structure

This requires careful mixing, casting and curing, all of which affect a member's ultimate strength.

The cost of formwork used for pouring concrete is relatively high.

It has lower compressive strength than steel, which results in larger sections of columns / beams in multistory buildings, shrinkage leads to crack development in concrete and higher direct load consumption.

If the contracting is not done properly, the steel starts to deteriorate and so the strength decreases and eventually the life is reduced. Also, later repairs are very expensive and difficult.

Code for designing framework structures

IS (Indian Standard) 456-2000

ACI (American Concrete Institute) 318-89

ICC (International Building Code) 2009

NZS (New Zealand Standard) 3101

Euro 2

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