Influence of P – Delta effects on seismic design

1981 ◽  
Vol 8 (1) ◽  
pp. 31-43 ◽  
Author(s):  
C. James Montgomery

The influence of P – Delta effects on the response of buildings subjected to earthquake ground motion is illustrated using time – history studies. It is shown that the influence of P – Delta effects is of great importance for buildings responding in a highly inelastic manner. However, for buildings responding in an elastic or slightly inelastic manner, the influence of P – Delta effects is relatively small. The stability factor approach for estimating the influence of P – Delta effects is reviewed. It appears that this approach gives reasonable results only for systems responding in an elastic or slightly inelastic manner. The strength and drift characteristics of buildings are briefly described. The results presented suggest that the response of certain types of well-designed buildings will not be significantly influenced by P – Delta effects. Finally, recommendations are made for assessing the significance of P – Delta effects for a given building design.

1991 ◽  
Vol 18 (1) ◽  
pp. 130-139 ◽  
Author(s):  
W. K. Tso ◽  
T. J. Zhu

The November 25, 1988, Saguenay earthquake was the most significant seismic event in eastern North America over the last 50 years. Based on strong ground motion records from this earthquake, an analytical study was undertaken to evaluate the seismic design base shear provisions of the National Building Code of Canada for buildings located in the eastern regions of Canada. In light of the observed damage to masonry structures in the epicentral region, emphasis was placed on the evaluation of the codified minimum seismic strength for masonry structural systems. Key words: earthquake, ground motion, seismic design strength, code, masonry, buildings, damage, ductility.


2015 ◽  
Vol 31 (2) ◽  
pp. 617-635 ◽  
Author(s):  
Gang Wang ◽  
Robert Youngs ◽  
Maurice Power ◽  
Zhihua Li

The Design Ground Motion Library (DGML) is an interactive tool for selecting earthquake ground motion time histories based on contemporary knowledge and engineering practice. It was created from a ground motion database that consists of 3,182 records from shallow crustal earthquakes in active tectonic regions rotated to fault-normal and fault-parallel directions. The DGML enables users to construct design response spectra based on Next-Generation Attenuation (NGA) relationships, including conditional mean spectra, code spectra, and user-specified spectra. It has the broad capability of searching for time history record sets in the database on the basis of the similarity of a record's response spectral shape to a design response spectrum over a user-defined period range. Selection criteria considering other ground motion characteristics and user needs are also provided. The DGML has been adapted for online application by the Pacific Earthquake Engineering Research Center (PEER) and incorporated as a beta version on the PEER database website.


1989 ◽  
Vol 16 (5) ◽  
pp. 753-766 ◽  
Author(s):  
A. Filiatrault ◽  
S. Cherry

This paper is concerned with a study of the parameters influencing the seismic design of structures fitted with friction dampers. For the efficient design of such systems, the slip load distribution which minimizes structural response during a major earthquake must be determined for the dampers; this distribution is referred to herein as the optimum slip load distribution. A simple procedure is presented for establishing this basic design parameter. An analogy is first made between a single-storey friction damped structure and a simple nonlinear mechanical system. The response of this system to sinusoidal base excitation is then computed using an existing analytical solution. The solution clearly shows that the optimum slip load of the analogous friction damped structure depends on the amplitude and frequency of the ground motion and is not strictly a structural property. By extension, the optimum slip load distribution of a multistorey friction damped structure will be influenced by the characteristics of the earthquake ground motion anticipated at the construction site. Using this information, numerical sensitivity and parametric studies are performed on multistorey friction damped structures excited by a large number of artificial accelerograms generated from an existing stochastic earthquake model. The results of the study lead to the construction of a design slip load spectrum for the rapid evaluation of the optimum slip load distribution in a multistorey friction damped structure. The spectrum takes into account the properties of the structure and of the ground motion anticipated at the construction site and greatly simplifies the seismic design of this new structural system. Key words: braced frames, brake lining, design, damping, dynamics, earthquakes, energy, friction, slip load spectrum.


2021 ◽  
Vol 9 (3A) ◽  
Author(s):  
Hongmei Hou ◽  

It is of great importance to select appropriate ground motion records for time-history dynamic analysis of structures. The consistency between record response spectral shape and seismic design response spectral shape is the basic principle for records selection. A sectionalized-dual-band (SDB) method considering influence of higher modes was proposed to select ground motion records according to the seismic fortification intensity requirements and the site characteristic. Furthermore, the newly proposed method has been employed to construct record sets within the whole response spectrum period. As compared with other traditional methods, the records obtained from the SDB method are more effective in predicting base shear derived from time-history dynamic analysis. When the period of a structure is determined, the records in the matched period range of the records set can be directly used to conduct time-history dynamic analysis. This method can avoid tedious work for reselecting ground motion records for different structures in the same seismic design intensity and site conditions.


2011 ◽  
Vol 261-263 ◽  
pp. 1182-1190 ◽  
Author(s):  
Shi Guo Xiao ◽  
Wen Kai Feng

Near-field ground shock features are analyzed according to the seismological record of the May 12 Wenchuan earthquake made at the Wolong observation station. A numerical analysis model is established by taking the record as the input seismic load and a real high and steep rock slope on the bank of the Zipingpu Reservoir. The acceleration response and shear strain increment distribution features at different locations of the slope under horizontal seismic force are analyzed using Plaxis software. The moment when the widest plastic zone occurs for the slope is obtained by time history analysis. The corresponding stability factor of the slope at that moment is calculated using the strength reduction method (including shear strength and tensile strength). The above is the Time History Analysis–Strength Reduction Method presented in this article. In addition, the stability factor of the slope can be calculated using the pseudostatic method by taking the seismic force as the external load. This is the Time History Analysis–Pseudostatic method put forward in this paper. Analysis results demonstrate that, as far as the studied high and steep slope is concerned, at 31.89 s, the stability factor calculated with the Time History Analysis–Strength Reduction Method is 1.004, which is slightly larger than the 0.833 obtained using the Time History Analysis–Pseudostatic Method (Spencer method). Both results demonstrate that there is collapse and sliding failure of the localized rock mass at the top of the slope at that moment because of joint fracture. Field investigation after the earthquake further verified the calculation result, proving to a certain degree the rationality of the analysis method presented.


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