Walls, windows, doors and a roof are the components that make up the "envelope" of a building. Damage to the building increases dramatically as the envelope of the building breaks down. When one component fails, the pressure inside the building increases. This pressure, when combined with other forces, can cause the roof to lift away from the building. When this happens, rain and wind can get inside the building, and structural failure of the building frame can result.
Computer models have been developed to better understand, and even predict, the failure of different types of buildings. For each type of building, the specific components of the building envelope (roof sheathing, rafters, walls, windows, etc) are connected together to provide a solid structure. The connections between each of these components are critical, and identifying the weakest connections is the key to predicting damage and failure.
All components of the building envelope are analyzed. Doors, windows, types of roofing, etc. Also analyzed is each type of connection. Strength ratings are assigned to each connection and component. This process is an effort to identify the weakest connections and components.
After the data is input into the model, simulations can be created for every type of building under a wide variety of wind and environmental conditions. As a result, researchers begin to understand how one failure can lead to others, and how a cascade of component or connection failures can lead to the failure of the envelope or even the structural failure of the building itself.
Another critical factor in building damage is wind born debris. Larger, heavier objects like tree branches and aluminum siding usually tumble near the ground, while other smaller objects like shingles or gravel travel at higher speeds and greater heights. High winds, combined with debris can shatter some envelope surfaces such as roof tiles, siding or glass.
Research on the effects of wind born debris led to a growing realization of the importance of postimpact strength of components. Previous to this research, only the preimpact strength of components has been considered. Of all surface cladding materials, glass, even fully tempered glass, is the most susceptible to small wind born debris.
Wind born debris can also have a devastating effect on external insulation and finish systems. Hard cladding materials such as vinyl siding or asbestos cement may shatter from impacts. Soft external insulation may be pulled from the building envelope. Building officials have recognized the need for improved impact resistance in the newer building codes created after Hurricane Andrew. Testing standards for research and wind resistant products have also changed to reflect the reality of an impact followed by cycles of higher and lower pressures.
Many years of research into high wind damage and wind born debris have revealed the importance of the building envelope. This research has led to several important changes in building design. First, that the design and components of the building envelope must be given the same importance as the structural frame. Second is that the critical effect of wind born debris must be addressed in the building design process. Third is the idea that the postimpact performance of building envelope components be considered equally with preimpact performance. Together, these changes will help preserve the building envelope,and help reduce building damage and failure. - 15437
Computer models have been developed to better understand, and even predict, the failure of different types of buildings. For each type of building, the specific components of the building envelope (roof sheathing, rafters, walls, windows, etc) are connected together to provide a solid structure. The connections between each of these components are critical, and identifying the weakest connections is the key to predicting damage and failure.
All components of the building envelope are analyzed. Doors, windows, types of roofing, etc. Also analyzed is each type of connection. Strength ratings are assigned to each connection and component. This process is an effort to identify the weakest connections and components.
After the data is input into the model, simulations can be created for every type of building under a wide variety of wind and environmental conditions. As a result, researchers begin to understand how one failure can lead to others, and how a cascade of component or connection failures can lead to the failure of the envelope or even the structural failure of the building itself.
Another critical factor in building damage is wind born debris. Larger, heavier objects like tree branches and aluminum siding usually tumble near the ground, while other smaller objects like shingles or gravel travel at higher speeds and greater heights. High winds, combined with debris can shatter some envelope surfaces such as roof tiles, siding or glass.
Research on the effects of wind born debris led to a growing realization of the importance of postimpact strength of components. Previous to this research, only the preimpact strength of components has been considered. Of all surface cladding materials, glass, even fully tempered glass, is the most susceptible to small wind born debris.
Wind born debris can also have a devastating effect on external insulation and finish systems. Hard cladding materials such as vinyl siding or asbestos cement may shatter from impacts. Soft external insulation may be pulled from the building envelope. Building officials have recognized the need for improved impact resistance in the newer building codes created after Hurricane Andrew. Testing standards for research and wind resistant products have also changed to reflect the reality of an impact followed by cycles of higher and lower pressures.
Many years of research into high wind damage and wind born debris have revealed the importance of the building envelope. This research has led to several important changes in building design. First, that the design and components of the building envelope must be given the same importance as the structural frame. Second is that the critical effect of wind born debris must be addressed in the building design process. Third is the idea that the postimpact performance of building envelope components be considered equally with preimpact performance. Together, these changes will help preserve the building envelope,and help reduce building damage and failure. - 15437
About the Author:
Florida Engineering Solutions has an experienced structural engineering team. They can create safer building designs that minimize the risk of wind damage and wind born debris.
