What are the advantages of combined footing with reinforcement?

• A combined footing is required to construct two or more columns in a small area.
• Having a combined footing in the area where soil is low helps in laying a solid foundation.
• A combined footing is widely used to distribute pressure evenly under the footing.

• When the combined footing is used the reinforcement sometimes the groundwater level rises.
• One of the common disadvantages of combined footing is the size of the footing varies.

The footing is referred to as combined footing if two or more columns are supported in a row and given a common base. I am an architect by profession so I know these things. But I know many people do not really understand these concepts. The term "combined footing" refers to when a single footing must accommodate two columns, or in rare circumstances, more. Typically, reinforcement concrete is also used to create the combined footing. The combined footing is assumed to be stiff and to rest on uniform soil. I will tell you the advantages of combined footing detail.

Miss Shrishti has already explained the combined footing types. So, I will try to define combined footing so that you can understand it better.

When the soil's ability to support loads is low and extra space is needed under each individual footing, a combined footing is created. The four types of combined footing that should be used are raft combined footing, strap combined footing, and rectangle combined footing. The maximum bending moment is used as the design value for the reinforced concrete footing in this combination footing. The longitudinal steel's development length was checked. The economy is restricted by the longitudinal bars. The combined footing is frequently utilised to obtain homogeneous pressure distribution under the footing.

Advantage of Combined Footing: Why combined footing is used?

The advantage of Combined Footing is as follows.

1. The benefit of combined is that we can utilise combined footing if two or more columns need to be constructed in a short space.

2. Another benefit of combined footing is that it can be constructed in areas where the soil has a low load-bearing capacity.

3. We constructed combination footing where the soil capacity of the construction site was insufficient to transmit the weight to the subsoil uniformly. Another benefit of combined footing is this.

4. When a column closes a property line and footing is not distributed in front of the property line, combined footing assists in the construction of the column.

5. The combined footing is frequently utilised to obtain homogeneous pressure distribution under the footing.

6. The benefit of combined is that we can utilise combined footing if two or more columns need to be constructed in a short space.

7. Another benefit of combined footing is that it can be constructed in areas where the soil has a low load-bearing capacity.

8. We constructed a combination footing where the soil capacity of the construction site was insufficient to transmit the weight to the subsoil uniformly. Another benefit of combined footing is this.

9. When a column closes a property line and footing is not distributed in front of the property line, combined footing assists in the construction of the column.

10.  The combined footing is frequently utilised to obtain homogeneous pressure distribution under the footing.

I hope I was able to explain the advantages of c

ombined footing details to you.

I came to know about combined footing when I was getting my home office renovated. My builder told me that a concrete foundation that sustains two columns or load-bearing walls is known as a

combined footing foundation

. It is positioned directly beneath the walls or columns it is sustaining and is typically rectangular in shape. The footing is often built of concrete and is normally broader than the columns or wall it is supporting. When the weights on the walls or columns are similar and they are close together, combined footings are typically used. A combined footing is constructed when the foundations of two or even more columns are adjacent to one another and overlap. I will tell you all about it ahead.

Combined footing definition

The engineer or architect develops the fundamental designs of combined footing depending on several types of footing after carefully examining the site circumstances and the width of the ground cover.

When building a combined footing, numerous elements must be taken into account, including the soil characteristics, the loads placed on the foundation, and the footing's size and shape. The size, form, and foundation type of the footing will all be impacted by the soil conditions. The shape and size of the footing will also be impacted by the stresses on it. The sort of foundation utilised will also rely on the size and structure of the footing.

• Area of the Footing: Based on the soil's permitted bearing capacity and the column's axial load, the footing's area is chosen. Due to the combination of two columns, it is possible to increase the footing area beyond what is necessary, which would result in a decrease in the pressure on the footing. Therefore, special care must be taken when choosing a footing area, particularly when the soil has a low bearing capacity and is more likely to settle.

• Ground ImprovementsFor the soil to have the necessary bearing capacity, it must be improved as suggested in the geotechnical inquiry. Low-rise constructions may benefit from soil stabilisation or ground improvement techniques carried out under the structural engineer's strict supervision. Any weak ground failure that is incorrectly improved could result in a structure failing, the foundation failing, the foundation settling, etc.

• Consolidation Settlement: If we do not recognise it at the beginning of the project, well before design of the foundations, it will become a persistent problem. Greater consideration must be given to the soil type because the construction has several types of foundations, including combined footing and isolated footing. To prevent foundation settlement after construction, the essential steps must be followed.

This is what is

combined footing foundation.

Hey,

Living during an age where natural disasters like an earthquake can occur anytime. It is necessary to have a house with strong construction to ensure safety of residents. In an attempt to build a house like that, I have done some research on how many types of combined footing are possible. Take a look below to know more.  

When individual footing has to accommodate two or in exceptional cases more than Two columns is known as the combined footing. or. When two or three columns are located very near to each other, we provide a single substructure for them and the footing is known as a combined footing.

When two or more columns are located near each other, common footing is provided for them. This is deemed as combined footing. 

• Combined footing is to be used in the following cases :

• When the load-bearing capacity of the soil is low a

• When individual footing required more area 

• When two or more columns are located near each other

• When uniform pressure distribution is needed under the footing

• When the heavily loaded column is near the property line 

• When there is a restriction on the total length of the footing

• When one column carries a heavy load compared to others. 

• When there is a need for a rigid and resting structure.

• Rectangular combined footing

• Trapezoidal combined footing 

• Raft combined footing.

• Slab Type Combined Footing

• Strap Beam Type Combined Footing 

• Slab Beam Type Combined Footing

Now, you know how many types of combined footing are possible.

Both longitudinal and transverse detailing steel is used in a combined footing. It is the same as a conventional beam-SP-34. Overall, both beams and slabs have the same design requirement. 

This is all from my end on how many types of combined footing are possible.

A Combined footing supports 2 or more columns in a row. It can be trapezoidal in case there are space limitations and they carry unequal loads or can be rectangular in case both the cumin carry equal loads. Usually, they are made of reinforced concrete. Read below to know about the advantages and disadvantages of combined footing reinforcement:

• Combined footing can be used in case there are 2 or more columns construed in a small space.

• It helps maintain the column’s center of gravity.

• You can use combined footing in the difficult construction sides.

• You can use combined footing to equally distribute the load to the super-structure to the sub-soil.

• You can construe combined footing where soil’s load-bearing capacity is low.

• Sometimes the ground-water level rises that causes the loss of contact of soil with the foundation.

• The issue may arise due to the heat difference, in case the foundation raft thickness is high.

• Since a common footing is used for many columns, the footing area is reduced.

• It is hard to maintain the columns’ center of gravity in combined footing.

• Mark the point of column loads’ application on the footing.

• Proportion the footing in a way that the loads pass through the footing’s center.

• Calculate the footing area in a way that it is more than the allowable soil pressure.

• Compute the bending moments and shear forces at the salient points and draw BMD and SFD.

• Fix the footing’s depth from the max. bending moment.

• Design the transverse section for reinforcement and depth after calculating the transverse bending moment. Also, check for shear and anchorage.

• Design the longitudinal steel after checking the footing for longitudinal shear

• Design and place the reinforcement for the longitudinal moment in a proper way.

• prepare the bar bending schedule, draw the reinforcement, curtail the longitudinal bars for the economy, check the development length for longitudinal steel.

I hope now you know about the combined footing advantages and disadvantages.