Control of wind-induced motion of mid-rise buildings using smart facade systems

To date the engineering community has seen structural facade systems as non-structural elements with high aesthetic value and a barrier between the outdoor and indoor environments. The role of facades in energy use in a building has also been recognized and the industry is also witnessing the emergence of many energy efficient facade systems. It has also been recognized that facade systems add some stiffness and damping to the overall building despite the new and modern systems, eg., curtain walls, which add a relatively small amount of stiffness and damping to the overall building. Despite these advancements, the facade has been rarely considered or designed as a potential wind-induced vibration absorber for tall buildings. In this paper the potential of utilizing a moveable exterior facade in a double-skin facade is investigated and shown that with optimal choices of materials for stiffness and damping of brackets connecting the two skins, a substantial portion of wind-induced vibration energy can be dissipated which leads to avoiding expensive lateral stiffening systems and/or space consuming large damper systems such as tuned mass or liquid dampers. The initial works have demonstrated that up to 50% of accelerations and displacements caused by winds can be absorbed by a smart and efficient facade design, including purely passive systems with constant stiffness and damping or better, by a smart system possessing variable stiffness for different phases of facade movement.