Lateral Load Issues for Buildings

Overview

Buildings are complex physical systems. Structural Engineers deal with this complexity by creating idealized structural models that define the key structural components, the overall makeup of the building structure, and the loadings that it needs to withstand. The information provided by the idealized model allows one to apply analysis and design methods directly to the model and then extrapolate the results to the actual building.

We begin the chapter with a description of the various types of building systems and the associated structural components. In general, a building consists of plane frame structures which are interconnected by floor systems. We describe approaches for establishing the lateral loads due to wind and earthquake excitation. These loads are evaluated at each floor level and then distributed to the individual plane frames using the concepts of center of mass and center of twist. At this point, one has the appropriate lateral loading to analyze the plane frames. The topic of loading on building frames is discussed further in the next chapter where we also consider gravity loads acting on the floor systems.