Earthquake resistant structures

About: Earthquake resistant structures is a research topic. Over the lifetime, 1126 publications have been published within this topic receiving 27467 citations.

Quantitative Comparison of Optimization Approaches for the Design of Supplemental Damping in Earthquake Engineering Practice

Abstract: One approach to the optimal design of passive controllers in linear structures for earthquake engineering applications makes use of active control tools. Usually, when this approach is adopted, the actual objective function is a time integral of a functional of given mathematical structure of response quantities and control forces. This approach has been used for the design of added dampers and is appealing due to its simplicity and the minor computational effort it requires. In adapting the active control approach to passive control, it has often been assumed that an objective function of this kind is suitable. It has been a widespread opinion in the passive control community, however, that minimization of such a smeared quantity that has a predetermined mathematical structure cannot lead to truly optimal added damper schemes. This paper formally addresses this issue and shows that what has been suspected for some time is indeed the case. The optimal location and size of each of the added dampers and, thus, the total added damping for given structures are attained here by directly solving the practical optimization problem as a reference. For the same total added damping, an active control approach is then used to find its own optimal location and size of each of the added dampers. A time history analysis is finally carried out for an a priori chosen ensemble of earthquakes to yield the envelope of maximal interstory drifts. It is shown that the active control approach is not satisfactory, in the practical sense, since it leads to much larger maximal interstory drifts.

Seismic Response of Eccentrically Braced Tall Building

Abstract: Spectral analyses and system identification techniques are used to analyze a set of acceleration response records obtained during the October 17, 1989, Loma Prieta earthquake (\IM\ds\N = 71) from the 47-story, moment-resisting framed and eccentrically braced Embarcadero Building (EMB), located in San Francisco The EMB was constructed in 1979 based on the 1976 Uniform Building Code requirements and a design response spectra defined by two levels of earthquake performances The EMB is in the Lower Market area of San Frandicso, which is of great interest to the engineering community because of the area’s soft-soil characteristics that amplify ground motions originating at long distances, and because the Embarcadero Freeway (within 100 m of the building) suffered extensive damage during the earthquake and was razed in 1991 The first modal frequencies of the building at approximately 019 Hz (north-south) and 016 Hz (east-west) are identified The torsional response and rocking motions of the building are insignificant Discontinuity of stiffness and mass at the 40th-floor level causes significant response issues above that floor such as excessive drift ratios

Seismic Design Enhancements and the Reduced Beam Section Detail for Steel Moment Frames

Abstract: An area of heightened interest after the 1994 Northridge earthquake damage was the seismic ductility of steel moment frame connections. Work conducted by the Federal Emergency Management Agency ~FEMA! and the SAC Joint Venture, National Institute of Standards and Technology ~NIST!, the American Institute of Steel Construction Inc. ~AISC!, and many others in academia, industry, and the profession over the last few years has greatly expanded the knowledge base in a number of relevant areas. This resulting information has led to a set of new and modified steel moment connection details and accompanying design criteria for improved seismic performance. One of the more popular seismic connection types that has been prequalified in FEMA 350-353 is the new reduced beam section detail.