BSCE 2020, cum laude, Undergraduate Research Project Title: Evaluation of the Base Shear Contribution of Moment-Resisting Frames in High-Rise Reinforced Concrete Non-Regular Dual Systems

Abstract:

Dual systems are one of the most used lateral load resisting structural systems utilized in mid-to-high rise structures. The lateral load resistance of a dual system combining reinforced concrete (RC) shear walls and slab-column moment resisting frame (MRF) is studied. Past studies show that shear walls reduce the effects (e.g. stress concentration and torsion) of plan non-regularities in buildings. Currently, NSCP (2015) specifies the design requirements for dual systems to the following: MRFs should be capable of independently resisting at least 25% of the seismic forces while the MRFs and shear walls must be capable of resisting the entire seismic forces in proportion to their relative rigidities at all levels. Results show that the models followed the NSCP provision for dual systems as the moment-resisting frames (columns) took over at least 25% of the base shear in both X and Y directions, except for models with a large percentage of re-entrant corner non-regularity. The shear walls in these models are found to carry greater lateral load, provide the strength and stiffness, and control the horizontal displacements and inter-story drifts. Also, as the percentage of re-entrant corner non-regularity increases along a horizontal direction, the base shear contribution of columns along the perpendicular horizontal direction decreases.

Keywords: base shear distribution, dual systems, RC buildings, re-entrant corner, linear static analysis