It develops building strengthening methods in order to prevent structural damage during accidents such as storms, earthquakes, floods, etc., and they play an important role in increasing safety and creating a feeling of peace for the residents of buildings.
It is necessary to use the best strengthening methods for the building, especially in areas prone to earthquakes and buildings with sensitive uses that must be constantly maintained. In this article, we will learn about some common solutions for strengthening buildings.
How do you choose the most effective way to strengthen a building?
Some building strengthening methods are done by installing equipment at the structure construction stage, others are designed to strengthen structural elements in existing buildings. To choose the most effective method of strengthening, you must first check the structure and identify its weak points, including connections, columns, beams, slab, etc.
Because column strengthening solutions may be different from slab strengthening methods. Factors such as age of the building, number of floors, budget, importance of the building, presence of specialized staff, available equipment and facilities, time limit, ease of implementation, etc. are important factors to pay attention to when choosing the most effective method of strengthening.
What are the types of strengthening methods for a building?
Reinforcing the building with FRP fibers
The use of FRP materials is one of the latest methods of strengthening the building. FRP stands for fiber reinforcement polymer and refers to a group of layered materials obtained by placing glass, carbon, aramid and basalt fibers into a covering material.
FRP reinforcement can be used to strengthen weak structural members such as columns, slab, beams, connection areas, etc. For example, by wrapping weak columns in old and damaged structures with FRP strips, buckling and spreading of damage can be prevented.
Advantages:
- Light weight compared to high resistance
- High tensile strength compared to steel
- Low thickness (Does not create restrictions in architecture.)
- Speed of implementation
- High insulation and corrosion resistance • No restrictions on use during implementation
Defects:
- Weakness against fire and the need for a fire-resistant cover
- Low ductility and brittleness
- Low resistance to stress
- Sensitivity to corrosion
Strengthening the building with a shear wall
Shear wall is one of the most effective ways to strengthen a building to increase the seismic resistance of a building, which deals with destructive lateral forces through energy consumption. These types of walls are usually placed on the outside of the structure and attached directly to the building’s foundation.
Shear walls are available in various types of concrete, steel, composites and building materials, and by absorbing the bulk of the shear generated by lateral forces, they are a suitable choice for strengthening concrete and steel structures.
Advantages:
- Increase the solidity and resistance of the building against earthquakes
- High ductility
- Increase safety and prevent damage to non-structural members due to reduced fluctuations
- Reduce floor deflection
- Increased gravity and lateral load
Defects:
- Reducing the building geometry
- Increased building weight
- Intricate details of the reinforcement
Strengthening the building with clips
Wind braces are the most common structural strengthening elements that control lateral loads on a building. The braces are constructed from several diagonal members that are placed at fixed angles to each other and are positioned symmetrically within the building frames in order to increase the stability of the structure.
Angle sections, nails and steel bars are usually used in the construction of wind trusses. These members resist external forces such as earthquakes, strong winds, floods etc. and prevent the transmission of destructive forces to the foundation of the structure. There are different types of clamps called cross, converging, oblique, K-shaped, V-shaped, etc.
Advantages:
• Increased structural rigidity
• Increased lateral load
- Deviation control
- Increased degree of uncertainty and stability of the structure
Defects:
- Establishing constraints in the architecture and creating openings
- Low malleability (low ductility)
- Complex details related to communications
Strengthening the building with seismic insulation
Seismic isolators are equipment that replace the rigid connections of a structure to the foundation, and by isolating the building from the ground, they prevent ground movements from reaching the structure. Seismic isolators are flexible and concentrate movement at the building level. In this case, the building vibrates as a solid body without significant deformation.
In this way, less force reaches the upper parts and injuries and damage to the equipment are reduced. Slip isolators, elastomeric rubbers, lead-core rubber seats, pendulum systems, etc., are different types of seismic isolators.
Advantages:
- Prevent seismic energy from reaching the building
- Reduce lateral movement
- Ensure continued performance in high-criticality structures
- Reducing the amount of materials required
Defects:
• Expensive (al-Maklaf)
- Complex modeling
Strengthen the building with a damper
Installing a damper is one of the latest solutions to deal with destructive lateral forces in the structure. The damper or damper is a German that absorbs earthquake and wind energy, and reduces the vibration amplitude of the structure so that the damage to structural and non-structural members due to vibrations is reduced.
The damper does this by creating a restraining force against the direction of the lateral loads. The mechanism of action of dampers can be based on velocity or displacement. Elastic, viscous, friction, mass, yield, etc. dampers. Among the available types of dampers.
Advantages:
- Reducing vibrations during an earthquake and the resulting damage
- Reduce floor deflection
- Reducing the weight of the structure
- Reducing the volume of consumables
- Ease and speed of installation
Defects:
- Expensive (al-Maklafa)
- The need for reform
Reinforcing the building with a metal and concrete jacket
The use of concrete and metal jackets is one way to strengthen structural members, especially columns. The concrete jacket is a layer of concrete with longitudinal forces and closed sound silencers. When columns are damaged and do not have sufficient capacity against lateral forces, concrete caps are used.
The concrete jacket can be placed on one side only or around the column. Steel jacket is also implemented as a continuous shelf or shelf and can be effective in reducing destructive deformations of structural members.
Advantages:
- Improve resistance to bending, shear and gravity load
- Improving connections in tires
- Increased ductility
- Prevent column bending
- No need for a fire-resistant cover (concrete jacket)
- Ease of creating connections between members
- No need for molding (steel jacket) • Low thickness (steel jacket
Defects:
- Increasing the weight of the structure (concrete jacket)
- Increase column dimensions and reduce architectural space (concrete jacket)
- Need for fire resistant cover and increased cost (steel jacket)
- The large volume of reinforcement implants, welding and injection operations
conclusion
It is clear that each of the listed building strengthening methods imposes an additional cost on the building. But given the current economic conditions, the destruction and construction of structures leads to much higher costs, the use of strengthening methods is considered the ideal way to increase safety and prevent loss of life and finances resulting from accidents.