Reply: Evaluation of the seismic response factor introduced in the 1985 edition of the National Building Code of Canada

1989 ◽  
Vol 16 (6) ◽  
pp. 961-961
Author(s):  
A. C. Heidebrecht ◽  
C. Y. Lu
Keyword(s):  
Seismic Response ◽  
Building Code ◽  
Response Factor

Evaluation of the seismic response factor introduced in the 1985 edition of the National Building Code of Canada

1988 ◽  
Vol 15 (3) ◽  
pp. 382-388 ◽  
Author(s):  
A. C. Heidebrecht ◽  
Chee Yuen Lu
Keyword(s):  
Seismic Response ◽  
Strong Motion ◽  
Building Code ◽  
Response Factor ◽  
Seismic Zone ◽  
Response Factors ◽  
Dynamic Factors ◽  
Wall Structures ◽  
Time Histories ◽  
Velocity Spectra

The seismic loading provisions included in the 1985 edition of the National Building Code of Canada simulate the dynamic response of structures using a seismic response factor, which has three branches depending upon the relationship between the velocity-related seismic zone Zv and the acceleration-related zone Za. This paper utilizes three ensembles of actual seismic strong motion records to evaluate the seismic response factor; each ensemble has acceleration/velocity ratios corresponding to one of the three branches of the seismic response factor. These strong motion time histories are used as input to relatively simple elastic models of frame and wall structures in order to obtain dynamic seismic response factors. The comparison of these dynamic factors with those specified in the NBCC 1985 indicates that the code factors are generally quite satisfactory, with the exception of the case of frame structures with low fundamental periods located such that Za is two zones higher than Zv. The paper references several other investigations that produce similar results. In that instance, it is recommended that the seismic response factor should be increased, particularly if the structure is located on stiff soil rather than on rock. Key words: structures, loading, seismic, code, earthquake, dynamic, elastic, acceleration, velocity, spectra.

Confirmation of Reduction Effect Due to Tank’s Rocking Behavior and Proposal for a Simplified Evaluation Method of Nonlinear Seismic Response

2003 ◽  
Author(s):  
Satoru Yamaguchi ◽  
Hideyuki Tazuke ◽  
Kazuo Ishida
Keyword(s):  
Nonlinear Analysis ◽  
Seismic Response ◽  
Evaluation Method ◽  
Time History ◽  
Bottom Plate ◽  
Response Factor ◽  
Mass System ◽  
Nonlinear Seismic Response ◽  
Reduction Effect ◽  
Rocking Behavior

Aboveground LNG storage tank consists of inner and outer cylindrical containers. LNG is stored in the inner container made by 9%Ni steel. Anchorages are attached to some tanks in order to prevent bottom plate from excessive uplifting by seismic overturning moment. However tanks without anchorages have some probability that the seismic response factor decreases since the resonance period of tank is lengthened by nonlinear behaviors, for example uplifting of bottom plate (rocking behavior). In this paper, the reduction effect of response factor due to rocking behavior was quantitatively confirmed by 3-dimensional FEM nonlinear analysis and time-history nonlinear analysis that was modeled with single-degree-of-freedom spring-mass system. And a simplified evaluation method that allows easily calculating the reduction effect was proposed. As the result of study, it was proved that this method gave valid and conservative results.

Seismic loading provision changes in National Building Code of Canada 1985

1985 ◽  
Vol 12 (3) ◽  
pp. 653-660 ◽  
Author(s):  
A. C. Heidebrecht ◽  
W. K. Tso
Keyword(s):  
Seismic Response ◽  
Seismic Risk ◽  
Seismic Loading ◽  
Building Code ◽  
Seismic Zoning ◽  
Probability Level ◽  
Base Shear ◽  
Response Parameter ◽  
Most Significant Change ◽  
Risk Methodology

This paper describes the process by which Canadian seismic loading provisions are developed and then details the primary changes being introduced in the 1985 edition of the National Building Code of Canada. The most significant change is the inclusion of new seismic zoning maps, based on a new seismic risk methodology, a new probability level, and additional seismic zones, and incorporating both horizontal ground velocity and acceleration as zoning parameters. The format of base shear calculation is revised to incorporate these changes, including the specification of a new seismic response parameter. The base shear formula is calibrated to ensure that, on a cumulative basis throughout the country, the level of seismic loading remains unchanged. Additional changes discussed in the paper include the removal of dynamic analysis as a specific option in the base shear calculation and some significant changes in the calculation of torsional effects.

scholarly journals Performance Based Assessment of Seismic Response Factor for SMRF Staging Elevated Water Tank

10.29007/n83t ◽  
2018 ◽  
Author(s):  
Kashyap Patel ◽  
Jignesh Amin
Keyword(s):  
Seismic Response ◽  
Pushover Analysis ◽  
Nonlinear Behavior ◽  
Response Factor ◽  
Water Tank ◽  
Performance Based Assessment ◽  
Soil Flexibility ◽  
Elevated Water ◽  
The Impact ◽  
R Factors

RC staging water tanks are essential facilities that are expected to remain operational even after sever earthquakes. The seismic design codes/standards of most countries incorporate the nonlinear response of a structure through a ‘seismic response factor’ (R). This factor permits a designer to use a linear elastic force based design while accounting for nonlinear behavior and deformation limits. In this paper orderly approach is deputed to determine the seismic response factor of elevated water tank having different soil flexibility. For nonlinear static pushover analysis finite element method is used. The capacity curve of each model is generated and the ‘R’ factors are obtained such wise. The impact of soil flexibility on seismic response factor of RC framing tank is evaluated. ‘R’ factors are determined for existing tanks at two performance level.

On the dynamic foundation factor for the National Building Code of Canada: low to medium rise buildings

1994 ◽  
Vol 21 (2) ◽  
pp. 353-356
Author(s):  
A. C. Heidebrecht ◽  
A. Rutenberg
Keyword(s):  
Engineering Design ◽  
Seismic Response ◽  
Earthquake Engineering ◽  
Building Codes ◽  
Building Code ◽  
Building Structures ◽  
Response Factors ◽  
Vibration Period ◽  
Site Specific ◽  
Site Investigations

Site-specific seismic response factors for low-period building structures are presented as an alternative to the recently proposed foundation factor F* for inclusion in the seismic provision of the National Building Code of Canada. These factors are not explicit functions of the site vibration period, and, therefore, are more suitable for the design of small to medium rise buildings for which only limited site investigations are routinely carried out. Key words: earthquake engineering, design spectra, site-specific, building codes.

Free-Field Seismic Response Analysis

2018 ◽  
Vol 9 (1) ◽  
pp. 1-21 ◽  
Author(s):  
Andrea Angina ◽  
Andrea Steri ◽  
Stefano Stacul ◽  
Diego Lo Presti
Keyword(s):  
Seismic Response ◽  
Free Field ◽  
Ground Level ◽  
Response Spectra ◽  
Site Investigation ◽  
Building Code ◽  
Elastic Response ◽  
Response Analysis ◽  
Elastic Response Spectra ◽  
The Time Domain

This paper shows the results of free-field seismic response analyses (SRA), that were performed for the subsoil conditions of Piazza dei Miracoli in Pisa. The site investigation and in particular the shear wave velocity profile is extended down to 120 m below the ground level. One-dimensional SRA were carried out by using three computer codes, EERA, STRATA and ONDA. The first two codes perform the analyses in the frequency domain considering a linear-equivalent soil model. ONDA analyses the problem in the time domain assuming a true non-linear soil behaviour. In particular, the Ramberg-Osgood constitutive model, coupled with a modified Masing criterion was assumed. The computed elastic response spectra were compared to those prescribed by the Italian Building Code, which represents the Italian implementation of Eurocodes. Some details concerning the response spectra prescribed by Italian Building Code are also given.

Evaluation of base shear provisions in the 1985 edition of the National Building Code of Canada

1989 ◽  
Vol 16 (1) ◽  
pp. 22-35 ◽  
Author(s):  
T. J. Zhu ◽  
W. K. Tso ◽  
A. C. Heidebrecht
Keyword(s):  
Yield Strength ◽  
Seismic Response ◽  
Structural Damage ◽  
Ground Motions ◽  
Response Spectra ◽  
Building Code ◽  
Base Shear ◽  
Response Factors ◽  
Period Range ◽  
Short Period

A statistical analysis is performed to evaluate the base shear provisions in the 1985 edition of the National Building Code of Canada (NBCC 1985). Three sets of real earthquake records are selected to represent seismic ground motions with low, normal, and high peak acceleration to velocity (a/v) ratios. Single degree of freedom stiffness degrading systems are used as structural models; three damage indicators are employed to measure structural damage. The yield strength of the systems is specified in two different ways: (a) a single seismic response factor is used, irrespective of the a/v ratios of the input ground motions; (b) three different seismic response factors are used in the short-period range, depending upon the a/v ratios of the input ground motions, as suggested in NBCC 1985. A comparison of the statistical results of the three damage parameters for the systems designed with these two methods of strength specification indicates that the NBCC 1985 base shear provisions provide consistent control over structural damage when the structural systems are subjected to ground motions with different a/v ratios. Key words: earthquakes, ground motions, response spectra, stiffness degrading systems, seismic design, base shear, yield strength, inelastic response, damage parameters.

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