Implications of the 1994 northridge earthquake ground motions for the seismic design of tall buildings

1994 ◽  
Vol 3 (4) ◽  
pp. 247-267 ◽  
Author(s):  
Farzad Naeim
Keyword(s):  
Seismic Design ◽  
Ground Motions ◽  
Tall Buildings ◽  
Northridge Earthquake ◽  
Earthquake Ground Motions ◽  
1994 Northridge Earthquake

DAMAGE EVOLUTION SPECTRA FOR SEISMIC ANALYSIS OF HIGH-RISE BUILDINGS

2012 ◽  
Vol 06 (03) ◽  
pp. 1250021
Author(s):  
Y. B. HO ◽  
J. S. KUANG
Keyword(s):  
Damage Evolution ◽  
Seismic Analysis ◽  
Ground Motions ◽  
Time History ◽  
Tall Buildings ◽  
Response Spectra ◽  
Seismic Damage ◽  
Analysis And Design ◽  
High Rise ◽  
Earthquake Ground Motions

Seismic response spectra are amongst one of the most important tools for characterizing earthquake ground motions. In design practice, the response spectra are presented without including any load history, hence the nonlinear analysis of structures based solely on conventional earthquake response spectra is theoretically unsound, particularly for long-period or vertically irregular high-rise buildings. In this paper, a concept of seismic damage evolution is introduced and the method of analysis for characterizing the process of seismic damage to structures under earthquakes is presented. Seismic damage evolution spectra for analysis and design of high-rise buildings are then developed as an effective means of describing and simplifying earthquake ground motions. These spectra are shown to be very useful in selecting the ground motion-time history and, particularly, validating the equivalent static-load analysis and design of high-rise buildings under near-fault pulse-like ground motions. Case studies of the seismic inelastic performance of two vertically irregular, tall buildings are presented considering the seismic damage evolution spectra.

Damage to concrete structures due to the 1994 Northridge earthquake

1995 ◽  
Vol 22 (2) ◽  
pp. 361-377 ◽  
Author(s):  
Denis Mitchell ◽  
Ronald H. DeVall ◽  
Murat Saatcioglu ◽  
Robert Simpson ◽  
René Tinawi ◽  
...  
Keyword(s):  
Seismic Design ◽  
Precast Concrete ◽  
Concrete Structures ◽  
Shear Walls ◽  
Northridge Earthquake ◽  
Short Columns ◽  
Gravity Load ◽  
Current Design ◽  
Design Earthquake ◽  
1994 Northridge Earthquake

Observations on damage to concrete structures, due to the 1994 Northridge earthquake, are reported from a Canadian code perspective. Most of the damaged structures were older, nonductile, structures that do not conform to current design and detailing requirements. Concern is expressed about the seismic hazard of older Canadian structures having similar deficiencies. A significant number of parking structures suffered extensive damage and a number of precast concrete parking structures collapsed. Deficiencies in these structures include lack of proper diaphragm connections, a mix of gravity load columns with ductile framing, inappropriate number and distribution of shear walls, torsional effects caused by ramps, and the creation of short columns due to geometric features. This earthquake also demonstrated the deficiencies in connections of pre-1973 tilt-up structures. Key words: seismic design, earthquake, Northridge, structures, codes, concrete, precast concrete.

Seismic weaknesses of some residential wood framed buildings: confirmations from the 1994 Northridge earthquake

1995 ◽  
Vol 22 (2) ◽  
pp. 403-414 ◽  
Author(s):  
André Filiatrault ◽  
Chris K. A. Stieda
Keyword(s):  
Seismic Design ◽  
Earthquake Engineering ◽  
Residential Construction ◽  
Northridge Earthquake ◽  
Wood Structures ◽  
Canadian Association ◽  
Epicentral Region ◽  
The U.S ◽  
Construction Practice ◽  
1994 Northridge Earthquake

As part of the reconnaissance team of the Canadian Association for Earthquake Engineering (CAEE), the authors visited the epicentral region of the January 17, 1994, Northridge earthquake. This paper reviews the various potential weaknesses of some residential timber framed buildings. The damage observed during the Northridge earthquake as a result of these weaknesses is used to illustrate the need to introduce engineering concepts in the seismic design and retrofit of residential wood structures. Typical mitigation procedures to strengthen and increase the earthquake safety of wood buildings are discussed. Recognizing the close similarity between residential construction practice in Canada and the U.S., the information presented is topical for Canadian engineers, architects and owners. Key words: earthquake, seismic, timber, wood framed buildings.

Energy Criterion for Seismic Design under Earthquake Ground Motions

2017 ◽  
Author(s):  
Prahlad Prasad ◽  
◽  
A.K.L Srivastava ◽  
Gopinat h C. ◽  
◽  
...  
Keyword(s):  
Seismic Design ◽  
Ground Motions ◽  
Energy Criterion ◽  
Earthquake Ground Motions

scholarly journals Response of seismically isolated buildings with buffers subjected to near-source ground motions and possible alternative isolation systems

2004 ◽  
Vol 37 (3) ◽  
pp. 111-133 ◽  
Author(s):  
J. X. Zhao
Keyword(s):  
Inelastic Deformation ◽  
Ground Motions ◽  
Damping Ratio ◽  
Structural Response ◽  
Deformation Capacity ◽  
Northridge Earthquake ◽  
Period Range ◽  
Isolation System ◽  
Seismically Isolated ◽  
1994 Northridge Earthquake

The response of a seismically isolated building with lead rubber bearings (LRB) to near source ground motions from large earthquakes was investigated. The building was assumed to have a buffer to limit the maximum bearing displacement in a rare event of large magnitude and the buffer gap was assumed to be only 150mm (the level of maximum isolator displacement used in the 1980s). The structure was assumed to be designed for 1.5 times the NS component of the 1940 El Centro record. The 15% damped (an amount of damping which is close to the equivalent damping ratio for an seismically isolated building at its isolator design displacement) displacement spectrum of the design motion is only 40% that of the Sylmar County Hospital Parking Lot record from the 1994 Northridge earthquake (Mw= 6.7) in the period range around the first modal periods of both isolated and un-isolated structure used in the present study. Among the near-source records that are available, the near-source Sylmar record from the 1994 Northridge earthquake was found to have a very large displacement demand in a period range of 2.0 - 3.0s and this record is thought to be a better representation of the expected near-source motions than the 1.5 times the 1940 El Centro record. Structure-buffer impact was found to impose very large inter-storey drifts and produce very large storey accelerations, when the building was subjected to the excitation of the Sylmar record. The structure-buffer impact was found to be detrimental to the structural response if the structure was not designed to provide inelastic deformation capacity, and the structural response did not improve when the gap was increased to 200-250 mm, the expected maximum displacement capacity of the LRBs used in the building. An alternative isolation system of LRBs and hysteretic dampers was investigated and found to be adequate for resisting near-source motions. A large initial damper stiffness and relatively small buffer stiffness (compared with the total initial stiffness of LRBs) were found to be effective in reducing inter-storey drifts and storey accelerations at floors except for the base and roof of the structure. A disadvantage of such a system is the relatively large base and roof accelerations. The system has relatively large inter-storey drifts and storey accelerations compared with an isolated structure using LRBs only when the structure was subjected to either the 1940 El Centro type ground motions or the Joshua Tree type ground motions with backward directivity effect. Such an isolation system would still enable the structure to respond essentially elastically under the excitation of the Sylmar record even though the isolated structure was designed for a much lower level of ground shaking. As the upper structure of a seismically isolated building is usually designed to respond essentially elastically, the detailing used in the design of a reinforced concrete structure to provide inelastic deformation capacity was generally uncommon and was not fully accounted for in the present study.

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