A PROCEDURE FOR ESTIMATING INPUT ENERGY SPECTRA FOR SEISMIC DESIGN

This study investigates the input energy spectra for inelastic single-degree-of-freedom (SDOF) systems under main shock–aftershock sequences. The input energy spectra quantitatively reveal the effects of aftershocks on input energy, which verifies the necessity of incorporating aftershocks in energy-based seismic design. The investigation selects the sequences including one aftershock or two aftershocks respectively, according to the proposed criteria for selecting earthquake records. Then, the input energy for sequences is normalized by mass, m, and expressed in terms of the equivalent velocity, V E, seq. Next, the variation of V E, seq is studied in consideration of the hysteretic models, ductility values, periods of vibration, site conditions, relative intensities of aftershocks and number of aftershocks. The results indicate that the effects of aftershocks on input energy are significant in almost the whole period region. Finally, a simplified expression of input energy is proposed for incorporating aftershocks in energy-based seismic design.

Download Full-text

Design elastic input energy spectra based on Iranian earthquakes

Canadian Journal of Civil Engineering ◽

10.1139/l08-013 ◽

2008 ◽

Vol 35 (6) ◽

pp. 635-646 ◽

Cited By ~ 21

Author(s):

Gholamreza Ghodrati Amiri ◽

Gholamreza Abdollahzadeh Darzi ◽

Javad Vaseghi Amiri

Keyword(s):

Dynamic Response ◽

Seismic Design ◽

Strong Earthquake ◽

Energy Spectra ◽

Input Energy ◽

Code Of Practice ◽

Earthquake Records ◽

Load Effects ◽

Ground Types ◽

Seismic Design Of Structures

The goal of this paper is to propose input energy spectra applicable to seismic design of structures based on Iranian earthquakes. In terms of input energy, these spectra represent the load effects of a strong earthquake that a structure may encounter during its lifetime. For this purpose, from among 1800 existing earthquake records in Iran, 110 records were selected. By using these records and through dynamic response analyses, the design input energy spectra for four ground types, defined by the Iranian earthquake code of practice, have been derived.

Download Full-text

Analysis of the Effects of Soil on the Seismic Energy Responses of an Equipment-Structure System via Substructure Shaking Table Testing

Shock and Vibration ◽

10.1155/2019/4351329 ◽

2019 ◽

Vol 2019 ◽

pp. 1-11 ◽

Cited By ~ 2

Author(s):

Lanfang Luo ◽

Nan Jiang ◽

Jihong Bi

Keyword(s):

Seismic Design ◽

Seismic Energy ◽

Shaking Table ◽

Input Energy ◽

Test Results ◽

Element Analysis ◽

Testing Method ◽

Shaking Table Testing ◽

Soil Effects ◽

Substructure Approach

This study investigated the real-time substructure shaking table testing (RTSSTT) of an equipment-structure-soil (ESS) system and the effects of soil on the seismic energy responses of the equipment-structure (ES) subsystem. First, the branch modal substructure approach was employed to derive the formulas needed for the RTSSTT of the ESS system. Then, individual equations for calculating the energy responses of the equipment and the structure were provided. The ES subsystem was adopted as the experimental substructure, whereas the reduced soil model was treated as the numerical substructure when the RTSSTT was performed on the ESS system. The effectiveness of the proposed testing method was demonstrated by comparing the test results with those of the integrated finite element analysis. The energy responses of the ES subsystem in the case of rigid ground (i.e., the ES system) were compared with those considering the effects of soil (i.e., the ESS system). The input energy responses of the ES subsystem were found to decrease significantly after taking the effects of soil into account. Differences due to the soil effects should be considered in the seismic design for the ES system.

Download Full-text

Ground-motion prediction equations for constant-strength and constant-ductility input energy spectra

Bulletin of Earthquake Engineering ◽

10.1007/s10518-019-00725-x ◽

2019 ◽

Vol 18 (1) ◽

pp. 37-55 ◽

Cited By ~ 4

Author(s):

Yin Cheng ◽

Andrea Lucchini ◽

Fabrizio Mollaioli

Keyword(s):

Ground Motion ◽

Energy Spectra ◽

Motion Prediction ◽

Input Energy ◽

Ground Motion Prediction Equations ◽

Prediction Equations ◽

Ground Motion Prediction ◽

Constant Strength

Download Full-text

Energy-Based Seismic Design Method for EBFs Based on Hysteretic Energy Spectra and Accumulated Ductility Ratio Spectra

Advances in Civil Engineering ◽

10.1155/2019/3180596 ◽

2019 ◽

Vol 2019 ◽

pp. 1-11 ◽

Cited By ~ 1

Author(s):

Cuiling Ma

Keyword(s):

Seismic Design ◽

Design Method ◽

Time History ◽

Soil Classification ◽

Nonlinear Static Analysis ◽

Energy Spectra ◽

Hysteretic Energy ◽

Shear Links ◽

Seismic Design Method ◽

Ductility Ratio

In the case of far field earthquakes, structural failure often results from accumulated damage caused by cyclic effects and gradual accumulation of energy. This paper proposes an energy-based seismic design method for steel eccentrically braced frames (EBFs) with two shear links at every story according to the energy balance concept. The proposed method is theoretically supported by hysteretic energy spectra and accumulated ductility ratio spectra according to the Chinese soil classification. Furthermore, the method can be used to clarify the relationship between cumulative hysteretic energy and one-way pushover energy. For developing the method, it is assumed that all the hysteretic energy is dissipated by the shear links, column bases, and beam ends of the frames at both sides. Therefore, the parts outside the links, including beam segments, braces, and columns, are specially designed to perform elastically during an earthquake. Furthermore, a V-scheme steel EBF with ten stories and three spans is designed. The seismic performances of the designed structure, such as story drift and energy dissipation, are evaluated by nonlinear static analysis and time-history analysis. Finally, the reliability and accuracy of the proposed seismic design method are validated.

Download Full-text