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 Engineering applications of new probabilistic seismic ground-motion maps of Canada

1983 ◽  
Vol 10 (4) ◽  
pp. 670-680 ◽  
Author(s):  
A. C. Heidebrecht ◽  
P. W. Basham ◽  
J. H. Rainer ◽  
M. J. Berry
Keyword(s):  
Ground Motion ◽  
Seismic Risk ◽  
Velocity Ratio ◽  
Large Population ◽  
Building Code ◽  
Base Shear ◽  
Probability Of Exceedance ◽  
Seismic Ground Motion ◽  
Short Period ◽  
Current Code

New peak horizontal acceleration and velocity zoning maps with a probability of exceedance of 10% in 50 years and seven seismic zones are developed from new probabilistic strong seismic ground-motion estimates for replacement of the 1970 seismic zoning map in the National Building Code of Canada. The adoption of a probability of exceedance of 10% in 50 years produces reference seismic ground motion appropriate to the level of protection afforded by provisions of the current code; the use of two ground-motion parameters, the relative levels of which vary considerably throughout the country, provides independent reference levels for structures having short and long fundamental periods.For calculating seismic base shear, a new seismic response factor is derived in which seismic forces for long-period structures are directly proportional to zonal velocities, and for short-period structures proportional to zonal accelerations, with an upper limit on the acceleration/velocity ratio applicable for any location. To maintain the same design standard as provided by the current code, the base shear is calibrated to remain the same, on average, in large population centres in regions of moderate to high seismic risk. The resulting changes in the base shear applicable at various locations reflect the improved estimates of seismic risk, in particular the introduction of additional zones in the higher risk regions of the country and the higher levels of short-period ground motion estimated for some regions of eastern Canada.These and associated changes in seismic design provisions have been recommended for adoption in the 1985 edition of the National Building Code of Canada.

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.

Floating Roof Influence on Seismic Response of Large Vertical Storage Tank

2013 ◽  
Vol 671-674 ◽  
pp. 1399-1402
Author(s):  
Ying Sun ◽  
Jian Gang Sun ◽  
Li Fu Cui
Keyword(s):  
Seismic Response ◽  
Storage Tank ◽  
Numerical Solutions ◽  
Fluid Pressure ◽  
Seismic Intensity ◽  
Site Conditions ◽  
Storage Tanks ◽  
Analysis Model ◽  
Base Shear ◽  
The Impact

To study the impact of floating roof on seismic response of vertical storage tank structure system subjected to seismic excitation, select 150000m3 storage tanks as research object, and the finite element analysis model of storage tanks with and without floating roof were established respectively. The seismic response of these two types of structure in different site conditions and seismic intensity were calculated and the numerical solutions were compared. The results show that floating roof has little impact on base shear and base moment in different site conditions and seismic intensity. Floating roof can effectively reduce the sloshing wave height. The influence of floating roof on dynamic fluid pressure decreases with the increase of seismic intensity, which is less affected by ground conditions.

scholarly journals The development of seismic zones and the evaluation of lateral loadings for earthquake resistant design of buildings in Papua New Guinea

1984 ◽  
Vol 17 (4) ◽  
pp. 292-296
Author(s):  
Kevin McCue
Keyword(s):  
Papua New Guinea ◽  
New Guinea ◽  
Building Code ◽  
Seismic Zoning ◽  
Seismic Zones ◽  
Earthquake Resistant Design ◽  
Earthquake Resistant

A recently published seismic zoning map of Papua New Guinea does not correlate particularly well with either presentday seismicity or tectonic models of the region. Several reasons are given and a modified version of the map is presented for discussion and as a replacement in the Building Code.

scholarly journals Seismic Performance of Multistorey RC Frame Building With The Soft Storey and Masonry Infill

2021 ◽  
pp. 650-656
Author(s):  
Kugan K ◽  
Mr. Nandha Kumar P ◽  
Premalath J
Keyword(s):  
Time History ◽  
Seismic Loading ◽  
Rc Frame ◽  
Base Shear ◽  
Maximum Displacement ◽  
Soft Storey ◽  
Masonry Infills ◽  
Frame Building ◽  
History Analysis ◽  
Rc Frame Building

In this study, four geometrically similar frames having different configurations of masonry infills, has been investigated. In this article attempts are made to explain the factors that impact the soft storey failure in a building are compared with different type of infill. That is Four models like RC bare frame, RC frame with brick mansonry infill, RC frame with brick infill in all the storeys exept the firstsoft storey, RC frame with inverted V bracing in the soft storey. Time history analysis has been carried out for a G+8 multistoried building to study the soft storey effect at different floor levels using E tabs software. The behavior of RC framed building with soft storey under seismic loading has been observed in terms of maximum displacement ,maximum storey drift, base shear and storey stiffness as considered structure.

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

1989 ◽  
Vol 16 (6) ◽  
pp. 966-966
Author(s):  
T. J. Zhu ◽  
W. K. Tso ◽  
A. C. Heidebrecht
Keyword(s):  
Building Code ◽  
Base Shear

Benchmark NBC editions for seismic risk management of existing buildings in Canada

2021 ◽  
pp. 1-11
Author(s):  
Reza Fathi-Fazl ◽  
Bessam Kadhom ◽  
Zhen Cai ◽  
Farrokh Fazileh
Keyword(s):  
Risk Management ◽  
Seismic Risk ◽  
Model Building ◽  
National Research Council ◽  
The United States ◽  
Building Code ◽  
Existing Buildings ◽  
Design Standards ◽  
Multi Level ◽  
Seismic Risk Management

The National Research Council Canada recently developed a multi-criteria and multi-level framework for seismic risk management of existing buildings in Canada. One of the key criteria in this framework is benchmark NBC edition, which refers to the applicable edition of National Building Code of Canada (NBC) in which significantly improved seismic requirements were adopted and enforced. Since post-benchmark buildings are expected to demonstrate satisfactory seismic performance, they may be exempt from structural seismic risk assessment. This paper identifies benchmark NBC editions for 17 model building types in Canada. The identification starts by tracking major seismic improvements in the United States benchmark codes and standards. These improvements are then mapped to applicable NBC editions and relevant design standards. Provincial building code editions corresponding to benchmark NBC editions are also identified. The benchmark NBC editions and corresponding provincial building code editions help building owners quickly identify and exempt post-benchmark buildings with acceptable seismic risks and thus allocate resources to the buildings with potentially unacceptable seismic risks.

Crack Growth Prediction for Cracked Dissimilar Metal Weld Joint in Pipe Under Large Seismic Cyclic Loading

2018 ◽  
Author(s):  
Yoshihito Yamaguchi ◽  
Jinya Katsuyama ◽  
Yinsheng Li
Keyword(s):  
Risk Assessment ◽  
Crack Growth ◽  
Seismic Risk ◽  
Evaluation Method ◽  
Seismic Loading ◽  
Steel Pipes ◽  
Dissimilar Metal ◽  
Growth Evaluation ◽  
Nickel Based Alloy ◽  
Metal Weld

Seismic risk assessment of nuclear power plants (NPPs) based on seismic hazard and fragility analyses of structures/components has become important since Japanese NPPs have experienced several large earthquakes beyond the design basis ground motion. In addition, cracks resulting from the long-term operation of NPPs have been detected in piping system of NPPs. For example, in the pressurized water reactor environment, crack initiation and propagation due to primary water stress corrosion cracking (PWSCC) have been observed in dissimilar metal welds made of nickel-based alloy. Therefore, fragility analyses related to seismic probabilistic risk assessment considering such PWSCC and seismic loading are important for more realistic seismic risk assessment. In our previous study, a fragility analysis method for cracked pipes that is applicable for the carbon and stainless steel pipes has been developed. The developed method consists of two functions for evaluating the crack growth due to seismic loading as well as the age-related degradation. Since the crack growth evaluation method is available for only carbon steel and stainless steel pipes, it is important to enhance the applicability of the method to dissimilar metal welds of pipes where the cracks due to PWSCC were observed. In this study, an extensive study for crack growth evaluation method is performed for the dissimilar metal welds. Here, applicability of the previously developed method to a nickel-based alloy weld is investigated. We performed crack growth tests using the center cracked plate specimens and welded pipe specimens with circumferential through-wall crack machined from dissimilar metal weld joint of pipes. It is found that the amount of crack growth predicted by our crack growth evaluation method are in good agreement with the experimental results. Therefore, we conclude that the previously developed method can be widely used for evaluating the crack growth behavior under seismic loading conditions in the nuclear piping including dissimilar metal welds of pipes.

Combined seismic base shear and torsional loading provisions in the 1990 edition of the National Building Code of Canada

1991 ◽  
Vol 18 (6) ◽  
pp. 945-953
Author(s):  
A. M. Chandler
Keyword(s):  
Ground Motions ◽  
Building Code ◽  
Soil Conditions ◽  
Building Structures ◽  
Base Shear ◽  
Ground Acceleration ◽  
Period Range ◽  
Natural Period ◽  
Short Period ◽  
Edge Response

This paper evaluates the earthquake-resistant design provisions of the 1990 edition of the National Building Code of Canada (NBCC 1990) for asymmetric building structures subjected to combined lateral shear and torsional dynamic loadings arising from earthquake base excitation. A detailed parametric study is presented, evaluating the dynamic edge displacement response in the elastic range, for the side of the building which is adversely affected by lateral–torsional coupling. A series of buildings is studied, with realistic ranges of the fundamental natural period, structural eccentricity, and uncoupled frequency ratio. These buildings are evaluated under base loadings arising from a total of 45 strong motion records taken from earthquakes in North America, Mexico, Europe, the Middle East, and Southern Pacific, categorized according to site soil conditions and the ratio a/v of peak ground acceleration to velocity. The latter parameter together with the uncoupled lateral period are found to influence strongly the combined dynamic edge response, with the greatest forces on edge members arising from earthquakes with high a/v ratio in structures with natural periods below 0.8 s. In this case the NBCC 1990 loading provisions significantly underestimate the elastic dynamic response. For buildings with periods longer than 0.8 s, the conservatism of the base shear provisions leads to overestimation of combined dynamic edge response in asymmetric systems, and this is also true in the short-period range for buildings subjected to ground motions with low a/v ratio. The NBCC 1990 provisions are reasonably conservative for short-period systems subjected to ground motions with intermediate a/v ratio. Key words: earthquakes, seismic, design, response, spectra, base, shear, torsional, provisions.

Effects of Base Uplifting on the Seismic Response of Unanchored Liquid Storage Tanks

2012 ◽  
Author(s):  
Maria Vathi ◽  
Spyros A. Karamanos
Keyword(s):  
Seismic Response ◽  
Pushover Analysis ◽  
Hydrodynamic Pressure ◽  
Base Plate ◽  
Seismic Loading ◽  
Storage Tanks ◽  
Liquid Storage ◽  
Detailed Simulation ◽  
Steel Tank ◽  
Static Pushover Analysis

Unanchored liquid storage tanks under strong earthquake loading tend to uplift. In the present study, the effects of base uplifting on the seismic response of unanchored tanks are presented with emphasis on elephant’s foot buckling, base plate strength and shell-to-base connection capacity. Towards this purpose, base uplifting mechanics is analyzed through a detailed simulation of the tank using non-linear finite elements, and a static pushover analysis is conducted that considers the hydrodynamic pressure distribution due to seismic loading on the tank wall and the base plate. The uplifting provisions from EN 1998-4 and API 650 Appendix E standards are briefly described. Numerical results for a typical 27.8-meter-diameter steel tank are compared with the above design provisions.

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