Force Balance Analysis

Wind Force on Buildings
Models constructed from high density ridged foam can be used to predict the dynamic response of structures to wind. Knowledge of modal forces acting upon tall buildings, irregularly shaped buildings, or buildings in close proximity, is useful when engineering building structural systems.

High Frequency Force Balance Analysis
Ultra light, ridged foam models mounted on a sensitive high-frequency balance and subject to an appropriately structured wind environment provide an excellent description of the full scale structure’s modal forces acting on a building, as they are a function of the aerodynamic shape of the building.

Site Model:
High Frequency Force Balance analysis requires construction of a detailed scale model of the proposed building and other significant structures within the vicinity. The principal building is mounted on the balance: a rigid frame with force links and miniature load cells capable of measuring six components.

Testing:
The model is tested in a wind tunnel under appropriate boundary layer conditions for the site. Force readings are taken with a high speed computerized data acquisition system for the approximate equivalent of one hour full scale. The system is capable of measuring six channels at high frequencies.

Analysis:
Force Balance data provides linear elastic responses for peak, mean, and rms for 36 wind directions. These are combined with the statistical wind climate for the area to provide predictions of wind induced loading and their effects. The results are based on estimates of dynamic properties provided and often presented as predictions of full scale responses to wind effects. These are wind induced base bending moments and torque, accelerations, deflections, effective loads, and joint loading of members. The results are used to design structural systems, removing the guess work from strucural design.