Simplified Analysis Of High-Rise Buildings

Abstract

The development and continued utilization of taller, more slender building structures has brought about an increasing need for accurate analysis techniques. These analysis techniques require the understanding of a variety of areas that range from the continuity of joints within the structure to the nature of the forces that act upon it. Architects must consider the design of a building as a total system and cannot consider the structure as an addition that will be plugged in later by an engineer. This approach is especially essential when considering high-rise structures which require complex support systems. The safety and stability of these systems depends to a high degree on the continuity of joints which enable the building to act as a rigid, cantilevered tube. This continuity results in forms that are highly statically indeterminate. These are structures in which the number of reactions and/or stresses exceeds the number of statical equations that are available for their determination. For such structures an indefinite number of combinations of unknowns will satisfy the laws of equilibrium, however, only one set of values will result in the distortions that are compatible with the continuity and special conditions that are unique to the structure. Statically indeterminate structures may be analyzed by many different methods. Many approximate methods exist and often times may provide results as accurate as more time consuming exact methods. While these approximate methods also serve as areas in estimating individual member sizes, they usually require the use of certain assumptions that may restrict their use in high-rise analysis. Exact methods are often very lengthy and extensive; the method of moment distribution is a method that has been especially noted for its speed and accuracy. It is a method that will be extensively studied and applied throughout the research. The magnitude of stresses and deformations in the structures are dependent on the imposed loads and many other effects. High-rise buildings, more than low buildings are affected by the instability of forces as well as secondary effects that range from changes in temperature, settlement of foundations, to the dynamic effect of lateral loads due to wind or seismic disturbances. Another factor that must be considered in the analysis of high-rise structures is the effect that the structural geometry may have in the determination of stresses and probable deformations. The determination of the structure's shape may be a prime consideration when designing for a specific loading condition. The objective of this research is to investigate the analysis methods of statically indeterminate frames and apply these techniques to high-rise structures. An analysis of loading conditions and structural geometry are factors that also must be considered in this investigation. I intend to approach this objective with extensive research in engineering journals and publications along with a constant working relationship with my faculty advisor. I believe this research and program will greatly aid me in any graduate studies I may choose to endeavor in the future.