STRUCTURAL DYNAMIC PROPERTIES OF A REINFORCED-CONCRETE HIGH-RISE BUILDING DURING CONSTRUCTION

This paper presents the results of a study on the variability of the d ynamic properties of an irregular high-rise building during its constr uction. Most of the knowledge about structural dynamics of high-rise r einforced concrete buildings is based on uniform structures. Hence, th ere is concern about extrapolating this knowledge to the behaviour of nonuniform building that emerge from current architectural trends. A c lear example of these trends is the building selected for this study. This 30-storey reinforced concrete building is representative of the t ype of current construction in Vancouver, British Columbia. The latera l force resisting system in this structure is uniform in plan and elev ation, while the distribution of storey mass is asymmetrical owing to its geometry as well as a major setback at one corner. Dynamic charact eristics were determined by analyzing ambient vibrations of the struct ure. The objectives of this study included determining natural frequen cies and corresponding mode shapes, determining the effect of architec tural components, assessing base motion, and assessing the manner of t he core's deformation. In addition, a three-dimensional dynamic analys is was performed to assess the accuracy of modeling techniques. Finall y, base shears and overturning moments during different stages of cons truction were assessed in accordance with current building codes.