Seismic Evaluation and Retrofitting Existing Strutures

Retrofitting of masonry structures

Retrofitting of masonry structures

Retrofitting of steel structures

Retrofitting of steel structures

Retrofitting of concrete structures

Retrofitting of concrete structures

Adding Coaxial Megabrace Braces

Facade implementation and completion of retrofitting

Execution of hard work

Reinforcement of the foundation section

Excavation and exposure of existing foundation

Installing a shear connector to connect the new foundation to the old foundation

Joining the new foundation with the old one

Adding new gusset plates

Concreting the reinforced foundation

Forced execution

Increasing the moment of inertia of some beams

The resistance of buildings to incoming loads is so important that there are different regulations for designing and implementing building retrofitting methods. Each part of the building must be retrofitted with an appropriate method so that it does not suffer damage when various loads are applied. Especially in the current situation when buildings are no longer single-story like a villa house, but are designed as large, multi-story residential towers. There are different methods for retrofitting, and choosing the best method depends on the opinions of experts. In the rest of this article, we intend to use the experiences of the retrofitting experts of Technopole Company to fully discuss the details of building retrofitting and the reasons why a building needs retrofitting.

Why does a building need retrofitting?

When talking about building retrofitting, we mean using methods that allow each part of the building to have high resistance to incoming loads. Under normal circumstances, if the construction process is carried out in accordance with the regulations and laws announced by the National Engineering System Organization, the building does not require secondary reinforcement and the same building construction process that has been carried out safely is sufficient.

In some cases, due to design or execution errors or changes in the use of buildings, the likelihood that buildings will need to be retrofitted increases significantly. In fact, the following reasons can increase the need for buildings to be retrofitted with appropriate methods.

1. Errors in building construction

Sometimes buildings are not constructed in accordance with the construction plans. For example, the reinforcement of beams and columns may not match the structure or the concrete forms may be opened earlier than the required time for concrete to set. In these cases, engineers or construction teams cause such errors. Therefore, construction errors in buildings are also called human errors. In the event of such errors, the likelihood of damage to buildings increases significantly and buildings must be retrofitted by choosing the appropriate method so that they can perform properly against gravity and seismic loads.

2. Errors in building design

Building design is done by a structural engineer. In order to design a building, it is essential to pay attention to the safety of each part of the building. But sometimes, errors occur during design that, even if they are small, have a very negative impact on the load-bearing capacity of buildings. In this case, even though the construction teams implement the building in accordance with the provided plan; but still, the existence of errors in the design of the building causes many problems, including the building's weakness against the incoming loads.

3.  Change of use of the building

The use of the building determines the amount of loads applied to the building. If the use of the building changes, the load-bearing capacity also changes. For example, a residential building has a different load-bearing pattern than a commercial building. Therefore, if the use of a residential building changes to commercial, the building must be reinforced according to certain principles to prevent possible damage.

4.  Building wear and tear

Buildings undergo changes and wear and tear over time, which affects the performance of the building. The deterioration of buildings is the main reason for retrofitting buildings, and it is recommended that old buildings that have been built for more than 20 years be renovated in accordance with the rules recommended by the relevant authorities.

What are the three main methods of building reinforcement?

Building reinforcement is a process that ultimately leads to increasing the resistance of buildings to incoming loads and forces. There are many methods for increasing the resistance of buildings; but among all these methods, the following three methods are more practical and their effectiveness for reinforcing buildings is much greater.

1. Reinforcing a building with a concrete jacket method

2. Reinforcing a building with a FRP composite method

3. Reinforcing a building with a steel jacket method

What is reinforcing a building with a concrete jacket method?

Another method of reinforcing structures and buildings that has a great impact on the resistance of various buildings is the concrete jacket method. In this method, longitudinal or transverse rebars are planted in the concrete cross-section by means of rebar planting, and then the concrete member is reinforced by forming and re-concreting. Reinforcement using the concrete jacket method can be used to increase the load-bearing capacity of various types of concrete beams, concrete columns, concrete slabs, concrete foundations, and concrete shear walls.

In order to implement the reinforcement of a building using the concrete jacket method, it is first necessary to place the rebars according to the reinforcement design using rebar planting adhesive inside the beams, columns, building foundation, and shear walls. Then, concreting operations will be performed on all these rebars to create a resistant concrete layer around the desired element and increase the element's resistance to incoming loads.

What is FRP fiber reinforcement of a building?

One of the building reinforcement methods that has attracted the attention of many civil engineers in recent years is FRP reinforcement. This new reinforcement method can be implemented to strengthen old structures or with operational and calculation errors. The most important materials used in this reinforcement method are carbon fibers and epoxy resin. The FRP composite reinforcement method is actually a fiber-reinforced polymer that has a relatively low weight and very high tensile strength. Two parts, fibers and resin, are used to make FRP composite.

For example, if the load on the column increases, a concrete column can be wrapped with FRP composite. In this case, layers of carbon fibers can be used with epoxy resin to increase the resistance of the columns to the applied loads. If FRP fibers are implemented safely and correctly, the column resistance will increase significantly.

Today, new methods of structural repair and reinforcement, such as FRP reinforcement, are gradually replacing conventional structural reinforcement methods. Some of the advantages of building reinforcement using FRP composites are:

1. Very low weight of FRP fibers in contrast to its very high tensile strength

2. Due to the low thickness of FRP fiber layers (in the range of millimeters), it has been very noticeable to architects

3. Very high implementation speed of FRP reinforcement compared to other methods

4. High resistance to corrosion

Applications of FRP reinforcement include:

1.     Column reinforcement with FRP

2.     Beam reinforcement with FRP

3.     Slab reinforcement with FRP

4.     Foundation reinforcement with FRP

5.     Shear wall reinforcement with FRP

6.      Reinforcement of masonry and non-load-bearing walls with FRP

What is steel jacket reinforcement of a building?

The steel jacket method is one of the other methods of reinforcing concrete and steel buildings that has had a great impact on increasing the load-bearing capacity of buildings. This method uses steel parts that are placed around the required element, such as a column, and increase the ductility and strength of that element. This method of reinforcing buildings increases the bearing capacity of the building without significantly increasing the weight of the building.

Which method is suitable for reinforcing the building?

In the event of an execution and calculation error or a change in the use of the building, using the reinforcement method is not only useful; it is also necessary. However, one of the common questions asked by people for reinforcing the building is which method is the best method for reinforcing the building?

Choosing the best method for reinforcing the building depends on the project conditions, the cost of the reinforcement plan, the speed of work, the reason why the building needs reinforcement, etc. Therefore, it is necessary to proceed in an expert and engineered manner to choose the best method for reinforcement. Otherwise, the desired result may not be achieved even despite spending a lot of money on reinforcing the building. Therefore, you can contact the reinforcement experts of Technopole Company before taking any action to reinforce various types of buildings.

What factors does the price of building retrofitting depend on?

One of the reasons why some employers unfortunately prefer not to retrofit buildings or to replace this process is the price of building retrofitting. However, it should be noted that if retrofitting in buildings is not done in a systematic manner and reducing the safety of the building causes unfortunate incidents, the supervising engineers and other engineers who have been involved in this matter must be held accountable.

Therefore, even despite the increase in the price of retrofitting, it is necessary that this work be done in a systematic manner and in accordance with the opinions of experts. In addition, there are many factors that can affect the price of building retrofitting, and the cost paid for each building will be different.

1. The cost of specialized building retrofitting tests

One of the factors that affects the cost of retrofitting in a building

2. Design and calculation price of building retrofitting

After conducting the tests and in accordance with the results obtained, the design and calculations of the buildings will be carried out. The cost of design and calculations made for the use of steel, concrete or FRP composite will affect the total cost of retrofitting. Obviously, the more complex the design and calculations, the higher the cost received.

3. Price of materials and implementation of the building retrofitting plan

The materials prepared for retrofitting buildings must be purchased at current prices and it is obvious that the greater the amount of these materials, the higher the price of retrofitting. In addition, depending on the chosen method, the materials used can also be different. The cost of implementing the retrofitting plan for various types of buildings, the cost received from the execution teams and the complexity of the work affect the price of retrofitting.

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