One widely used method to increase the resistance of buildings in areas with high earthquake potential is the use of braces. On the other hand , With growing concerns about the safety of old buildings, As well as changes in the use of buildings (for example, increase floors), Discussion was raised about increasing the safety and strengthening of buildings.
It takes into account many new and innovative methods to improve the strength of buildings, One of these methods is to use BRB or swing torsion clamps.
Expert design and selection of strengthening methods
After the detailed experts decide that the building has problems in terms of resistance, Or that the geographical area is one of the areas with a high probability of earthquakes, He suggests different methods of strengthening.
According to the building shape, foundation dimensions, and construction area, type of materials used, Determines the appropriate method of strengthening. previously , The traditional methods of using clamps were, In the face of earthquake pressures and shocks, not effective. You have shown imperfection. for this reason , Uses newer methods.
What is BRB?
When structures encounter shocks and earthquakes, They experience the spread of a large amount of kinetic energy in their structure, In fact, In fact, the amount of damage to which a building is exposed depends largely on the type of spread of this movement in the building.
for this reason , Building engineers have long sought to design a system that is resistant to vibrations and movements, It is a system that can analyze the aforementioned energy as it enters the building.
In reality , The main function of the energy analysis element is to reduce the amount of damage to the main structures of the structure. for this purpose , Restraints are used for a long period to stabilize the structure against incoming loads caused by wind or earthquakes. But the main disadvantage of traditional braces is the deterioration of the strength of the braces due to the pressure exerted on the supports. The solution to this problem is swing torsion clamps.
Swing torsion braces are an earthquake-resistant system that has proven to work better than traditional braces. In this method , A level of flexibility has been attempted to be achieved in a special way, So that under pressure, it is able to repel or withstand pressure due to flexibility.
History of oscillating torsion clamps
BRBs can be considered a new development and advancement in the field of building resistance. Its first samples appeared in the 1980s and testing began in the middle of this decade. The concept of oscillating torsion clamps was first proposed by a Japanese engineer named Biyashi.
During the 1990s, It is used on an experimental basis in Japan, And because he was successful, It was also used in the United States in 1998, وینتهی من مراحل الاختبار والمحاكاة في الولايات المتحدة في عام 1999. In 2000, It is used in many construction projects and has practically demonstrated its safety.
BRB format
The main structure of the swing torsion clamp consists of a steel core embedded in concrete. Our space between the main core and the belt is filled with a concrete-like material, A special coating is applied to the belt to prevent it from bending under pressure. This innovative shape makes the BRB more flexible when subjected to stress.
Benefits of BRB
1. Possibility of easy connection to the structural frame of the structure.
2. High ability to distribute applied pressure and work stability in times of stress.
3. Lack of influence and sensitivity in the face of changes in different environmental conditions.
4. Flexibility in design.
5. In most cases, There is no need to reinforce the chassis and frame to install the BRB.
Disadvantages of BRB
1. Impossibility of fully investigating damage to gratings after possible earthquakes.
2. There are no sufficient studies related to the precise strength of the support or the clips attached to the frame.
3. Non-self-centering of BRB which affects its resistance to some extent.
Uses
Swing torsion clamps may be used in many different structures, In offices, hospitals, parking lots, multi-storey buildings, schools, mosques and stadiums. But other than that, The use of BRB has been successful in non-residential structures such as bridges.
Mechanism of Action
When encountering a lateral load, BRB shows consistency in load bearing, In fact, The load on the device is balanced and symmetrical. BRB design type does not experience bending during the compression cycle.
Swing torsion clamps have high resistance to bending under pressure. Bending or bending the brace during pressure will weaken its strength and can cause the braces to fall out. Poor resilience means lower propagation of seismic energy, This was the problem with previous clips.
BRB is used in bridges as a compression transfer structure to capture vibration energy and has shown its effectiveness in large projects.
conclusion
Various studies have shown the effectiveness of oscillating torsion clamps. Of all the clamps, BRB showed the highest resistance to seismic stresses. The structural features of BRB and stable energy release without bending make it resistant to lateral loads.
A few decades ago, When these clamps were first used in buildings in Japan, Even today, The effectiveness of these clamps has been proven in practice. This appears to be the case for Iran. Taking into account that the cases of earthquakes compared to earthquake-prone countries like Japan are not many, Its use is actually effective, And of course, This problem has been proven in practice, It also showed one case of using RRB in buildings damaged by the Kermanshah earthquake.