Development of Acceleration Factors to Evaluate the Across-Wind and Torsional Accelerations for Wind-Sensitive Buildings

Wind-induced acceleration represents one of the main challenges in the dynamic behavior of tall buildings. Its estimation can be carried out through experimental wind tunnel tests or using the analytical expressions proposed in various international codes and standards. However, the explicit consideration of uncertainty in structural dynamic properties, wind characteristics, and human-perceived response is limited or nonexistent in most standards. Slender structures like tall buildings can experience excessive acceleration due to wind loading, which can impact the activities of the buildings’ users. To prevent excessive wind-induced vibration, some international codes require that the serviceability limit state, in terms of acceleration, is satisfied. These serviceability limit states require that the wind-induced acceleration is less than or equal to a predefined value, which is taken from perception curves that are developed based on perceived vibration alone. The main objective of this work is to develop acceleration factors for across-wind and torsional acceleration that are calibrated for the selected targeted probability of perception levels by considering the uncertainty in the structural dynamic characteristics and wind characteristics, as well as in the human perception of motion. The acceleration factors are incorporated in a simple-to-use procedure to evaluate the wind-induced acceleration in tall buildings. A numerical example is provided to illustrate the use of the proposed acceleration factors.