Abstract
A methodology is developed in this paper for the design and proportioning of interventions for seismic upgrading of substandard reinforced-concrete (RC) buildings. The retrofit approach is presented in the form of a simple design tool that aims toward both demand reduction and enhancement of force and deformation supply through controlled modification of stiffness along the height of the building. This objective is achieved by engineering the translational mode-shape of the structure, so as to optimize the distribution of interstory drift. Results from the proposed approach are summarized in a spectrum format in which demand, expressed in terms of interstory drift, is related to stiffness. Design charts, which relate the characteristics of commonly used global intervention procedures to influence drift demands, are developed to facilitate the retrofit design. The intervention procedures considered in this paper are reinforced-concrete jacketing, the addition of reinforced-concrete walls, and the addition of masonry infills. The proposed methodology is also amenable to adaptation to other strengthening methods, such as the addition of cross-bracing.
Highlights
Earthquakes have repeatedly illustrated the deficiencies of older reinforced concrete construction built prior to the proliferation of contemporary earthquake design principles
Deformation supply refers to the individual elements of the structure; it is controlled by availability of confinement, shear reinforcement, lap and anchorage conditions, ratio of compression to tension reinforcement and amount of axial compression
Considering that nonlinear behavior of the retrofit is often limited by the existing reinforcement anchorages, which may remain a weak zone of behavior even after rehabilitation, it is generally advisable that the ductility demand targeted for through the choice of the design Yield Point Spectra (YPS) should not exceed the value of 3 (EC8-I 2004, KANEPE 2010); this limit refers to the structural system
Summary
Earthquakes have repeatedly illustrated the deficiencies of older reinforced concrete construction built prior to the proliferation of contemporary earthquake design principles. To calculate the work equivalent stiffness contribution of the j-th element (beam, column, or wall) of the i-th floor, consider the chord rotations θj1, θj2 developing in the ends of that member when the structure deflects laterally following the applied deflection shape, Φ (Fig. 5(a)); end moments of each member are obtained from the deformational member stiffness matrix:
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
