Abstract
The paper describes the dynamic and static analyses and design of a four storey ductile reinforced concrete frame structure isolated from the foundations by elastomeric bearings incorporating lead energy dampers. Results from inelastic, time-history analyses for the isolated and non-isolated structure are compared for several input earthquake motions. The benefits of energy dampers in reducing the isolated building's response (shears, plastic hinge demands and interstorey drifts) are detailed. Differences from conventional ductile design and detailing as well as design recommendations are included.
Highlights
The proposed building is a four storey reinforced concrete frame structure (97 x 40 m plan dimensions), including a basement, with column grid lines at 7 . 2 m centres
The structure is the first building known to be designed with baseisolation using elastomeric rubber bearings with lead energy dampers included to reduce the structure * s seismic response
Had the structure been designed as non-isolated a torsional increase of up to 54% over the basic base shear would have been required for the exterior transverse frames
Summary
The proposed building is a four storey reinforced concrete frame structure (97 x 40 m plan dimensions), including a basement, with column grid lines at 7 . 2 m centres. Note that the basement and ground floor beams reach only about 50% of the yield capacity available while the second floor beams nearly yield This was due mainly to the triangular seismic load distribution used for the member design, see section 4, whereas the dynamic lateral forces follow a distribution up the structure in the isolated response which closely follows the lateral mass distribution. A deflection ductility factor of 7.6 was recorded at roof level (maximum roof deflection divided by roof deflection when first hinge forms) This compares well with Skinner's^10) non-isolated structure assuming hinging first occurs at a base shear of about 0.34 Wt. A ductility demand of 1.6 was required for the isolated frame above the energy dampers, again showing good agreement
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 callMore From: Bulletin of the New Zealand Society for Earthquake Engineering
Disclaimer: 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.
