Seismic performance of the facade

In this article, we would like to specify the effect of building facade covering in earthquake and facade covering, earthquake in building, elements of building facade, seismic performance of facade, facade parts, facade in earthquake, stiffness of building facade in earthquake, application of stiffness in building facade Let's explain in detail and according to the trend of earthquakes in our country's cities and the use of suitable facades for the conditions of natural crises, stay with us until the end of the article.

 

The effect of building facade cover in earthquakes

 

Observations from past earthquakes and studies conducted by various researchers show the effect of the facade on the seismic performance of the structure. The fact is that even if facade walls are considered as non-structural members, they will interact with the main structure of the building during strong earthquakes, and this interaction will change the seismic performance of the structure; This becomes more important especially in the case of concrete frames, because in these frames, the characteristics of the materials and the arrangement of the facade in the height of the structure, in the type and the mechanism of breaking the enclosing frame are very important.

 

facade cover

 

The failure of the extension system such as the facade or its components can cause more injuries and death even more than the structural failure. Examples of the failure of the extension elements in the earthquakes that occurred in Iran are not few. But the research done in Iran related to the influence of facade behavior and their connections under moderate to severe earthquakes on the seismic behavior of structures and their effect on the overall response of the building and how the facade interacts with the structure, it can be said that there is no development. not found

 

Earthquake in the building

 

  Due to the seismicity of most areas in Iran and the many human and financial losses related to the elements, additional reports and articles have been written about the causes of damage to facades in various earthquakes in Iran, but the numerical and experimental researches that the facades carried out in has evaluated Iran and provided solutions to improve its performance and information about effective methods in reducing the potential risk of damage to the facade, unfortunately, it cannot be mentioned.

 

Building facade elements

 

Considering that facades have a significant effect on changing the behavior of the frame, the type of facade and the weight and hardness it imposes on the structure, it can cause significant changes in the overall behavior of the structure, in fact, based on the amount of mass and the type of facade connections. The supporting structure of facade walls can affect the dynamic response of the entire building in an earthquake. In earthquake-prone countries, this group has the most different characteristics among the corresponding groups, and they are the most problematic group among the additional non-structural elements in Iran. The main characteristics of this group are:

o High weight

o Low intrinsic coherence and integrity

o Poor connection to the supporting structure

Exterior walls and interior partition walls made of heavy brick materials or large and heavy slab stones, especially 3 cm brick facades, are examples of additional architectural elements that have all the mentioned characteristics.

 

Seismic performance of the facade

 

Facade components are prone to deformations in the plane and accelerations perpendicular to the plane. Facades that are connected to the outside of the structural frame should be checked for both of the aforementioned effects. It is worth mentioning that if the supplementary elements are not allowed to act as a part of the lateral resistant system in bearing part of the lateral seismic load, the amount of seismic load received by the entire building system will be much less because the stiffness of the building skeleton alone It is less than the stiffness of the combined structure with the extension system. This means that the building has a lower natural period and therefore receives more seismic force.

For many years, there was a common misconception that facades were meant as non-structural components. Although the research conducted in the past two or three decades has shown that facades actually contribute to the lateral stiffness of the building. Today, there are enough analytical and experimental results in a way that can verify the capacity of the facade effect index in the response and behavior of the building during the earthquake.

 

facade parts

 

Façade parts were considered as non-structural elements, and therefore no action was taken to contribute them to the resistance against the loads on the building. As a result, when the designers analyzed the building, they did not consider the facade parts in the building modeling. The reason that these parts cause serious risks to human life during an earthquake and their falling in an earthquake is the result of not understanding their behavior in seismic design. It is necessary to examine and evaluate these parts as a secondary system in the building structure. .

 

Facade in an earthquake

 

In general, structural engineers consider the weight of the facade in the supports in the structure analysis, and again the hardness and resistance applied by the facade are ignored. For them, it is assumed that the connections are designed in such a way that the skeleton and facade are It also has free movement and the stiffness imposed by the facade is close to zero, but the examination of the damage to the facade in the 1994 Northridge earthquake by Cohen showed that the seismic performance of the buildings was affected by the heavy facade parts and these additional parts, the facade performance It has significantly affected several buildings. Anyway, facade systems are basically designed in such a way that they only transfer their own weight and the lateral forces outside the plane of wind and earthquake to the supporting structure. The participation of the facade system in the lateral stiffness and relative displacement of the building is often ignored in the design of the structure.

 

Hardness of the facade of the building in an earthquake

 

Numerical and experimental studies have shown that external facade parts have many effects on structural behavior. They have anyway in seismic analysis and design b In the conventional way, engineers ignore the additional stiffness and damping that the facade system provides, while it can be effective in the beneficial or destructive seismic performance of the building, depending on the arrangement of the facade parts and the type of connections, the facade can provide To make the lateral stiffness and higher strength to bear the frame.

 

Applying hardness to the facade of the building

 

McCue studied the effect of facade stiffness in a structural frame under earthquake and found out that the effect of increasing the stiffness caused by the facade leads to a change in the direction of building vibration frequencies to the frequency range of critical earthquake impulses. This can cause a larger seismic response. Smith and Gayotti studied the analytical interaction of building frames with and without facade.

Their study showed that the building frame with the facade has 35 times more stiffness than the building frame without the facade, and also the reduction in elastic deformation from 126 mm to 36 mm in the frame with the facade. De Mattis analyzed the effect of facade parts on the overall response of the building with metal frame. The results of his research showed that the facade increases the stiffness of the building compared to the skeleton alone. Hunt and Stojadinovic also performed a wear analysis for both models with and without facades. They showed that in the cladding analysis, the presence of the facade has significantly changed the response of the building.

 

Pulping set:

 

If you decide to implement building facade coverings, taking into account the conditions and possible risks to prevent future damages; You can ask for guidance from Pulping Group, which has a brilliant experience in the field of implementing the best and highest quality building facade coatings in Iran and the top manufacturer of building facades. We hope that the information we have provided about the effect of building facade coatings in an earthquake has been useful to you. For more questions, you can contact our experts to answer as soon as possible. Thank you for staying with us until the end of the content.