Seismic load distribution in buildings with eccentric setback

1994 ◽  
Vol 21 (1) ◽  
pp. 50-62 ◽  
Author(s):  
W. K. Tso ◽  
Shu Yao
Keyword(s):  
Dynamic Analysis ◽  
Key Words ◽  
Wide Class ◽  
Load Distribution ◽  
Lateral Loading ◽  
Building Code ◽  
Seismic Load ◽  
Load Distributions ◽  
Static Approach ◽  
Code Procedure

A study is carried out to evaluate the seismic load distribution in buildings with eccentric setback subjected to lateral loading in a direction perpendicular to the setback. Such loading causes both translational and torsional deformations. Since buildings with eccentric setback possess significant irregularities both height-wise and plan-wise, both the static and the dynamic approaches are used in this study to examine the limitations of the static approach when applied to this class of structures. It is shown that the static approach cannot simulate the higher modal contribution, nor can it simulate the inertial floor torques caused by the first mode of vibration. Consequently, the static approach leads to an underestimation of edge frame shears. However, by modifying the static approach as is done in the Canadian code (National Building Code of Canada, 1990) one can obtain load distributions in eccentric buildings that are similar to that using dynamic analysis. Based on the work of Goel and Chopra, it is further shown that implementation of the Canadian code procedure for seismic load distribution involving torsion can be simplified greatly. As a result, this procedure can be implemented efficiently in design offices to cover a wide class of buildings, including buildings with eccentric setbacks. Key words: seismic, buildings, torsion, setback, irregularity, code.

Eccentricity in irregular multistory buildings

1986 ◽  
Vol 13 (1) ◽  
pp. 46-52 ◽  
Author(s):  
V. W.-T. Cheung ◽  
W. K. Tso
Keyword(s):  
Dynamic Analysis ◽  
Necessary Conditions ◽  
Vertical Axis ◽  
Building Code ◽  
Necessary Condition ◽  
Practical Procedure ◽  
Multistory Buildings ◽  
Plane Frame ◽  
Code Procedure ◽  
Code Provisions

To evaluate the seismic torsional effect on multistory buildings, the concept of eccentricity is extended from single-story buildings to multistory buildings by defining the locations of the centers of rigidity at each floor. A practical procedure to locate the centers of rigidity and hence floor eccentricity is introduced. This procedure depends on the use of plane frame computer programs only and is suitable for use in design offices. The seismic torsional provisions in the National Building Code of Canada 1985 (NBCC 1985) explicitly emphasize that the code provisions apply to buildings where the centres of rigidity lie on a vertical axis only. By means of examples, it verifies the claim of NBCC 1985. Also, it shows that, for buildings with centers of rigidity scattered from a vertical axis, the code procedure may or may not apply. Therefore, one should interpret the condition of centers of rigidity located along a vertical axis to be a sufficient, but not a necessary, condition for the NBCC 85 code provisions to be applicable. Until the necessary conditions are known, dynamic analysis remains the most reliable method to assign the torsional effects to various portions of the building. Key words: building code, center of rigidity, dynamic analysis, eccentricity, irregular, multistory, seismic, torsion.

Seismic storey drift estimation

1994 ◽  
Vol 21 (6) ◽  
pp. 1081-1083 ◽  
Author(s):  
T. J. Zhu
Keyword(s):  
Dynamic Analysis ◽  
Key Words ◽  
Estimation Procedure ◽  
Building Design ◽  
High Rise ◽  
Moment Resisting Frame ◽  
Drift Estimation ◽  
Frame Buildings ◽  
Moment Resisting ◽  
Code Procedure

The seismic storey drift estimation procedure in the 1990 edition of the National Building Code of Canada is evaluated for ductile moment-resisting frame buildings located in different seismic regions. The evaluation is based on a comparison of the storey drifts estimated from the code procedure with those obtained from the inelastic dynamic analysis of the buildings. The results indicate that the code procedure underestimates storey drift for low-rise ductile moment-resisting frame buildings. It provides good estimates of storey drift for medium- and high-rise ductile moment-resisting frame buildings. The code estimation tends to become conservative as the number of storeys increases. Key words: building, design, drift, seismic, storey.

Seismic loading for buildings with setbacks

1994 ◽  
Vol 21 (5) ◽  
pp. 863-871 ◽  
Author(s):  
C. M. Wong ◽  
W. K. Tso
Keyword(s):  
Dynamic Analysis ◽  
Fundamental Mode ◽  
Load Distribution ◽  
Static Load ◽  
Seismic Loading ◽  
Seismic Load ◽  
Base Shear ◽  
Reasonable Estimate ◽  
Equivalent Static Load ◽  
Irregular Buildings

Dynamic analysis is in general accepted as the best method to obtain the seismic load distribution for buildings with a setback. However, most building codes require the base shear obtained by dynamic analysis to be calibrated by the static base shear obtained using the code's equivalent static load procedure. In obtaining the code static base shear, two issues often arise among the design professionals. First, it is unclear whether the code static base shear is applicable for buildings with setbacks because the period prescribed by the code to be used in the base shear formula is in general not pertinent to buildings with setbacks. Second, it is uncertain whether the higher mode period should be used in computing the base shear when the modal weight of a higher mode is larger than that of the fundamental mode — a case often encountered in designing buildings with setbacks. This paper is an attempt to resolve the above issues. For the first issue, modification factors were derived for adjusting the code period formula so that it can provide a more reasonable estimate for the period of a building with a setback. For the second issue, it was demonstrated in this paper that for cases where the modal weight of a higher mode is larger than that of the fundamental mode, using the higher mode period for base shear calculation will result in unnecessarily conservative design. Key words: earthquake, seismic, irregular buildings, setback, dynamic analysis.

The Force Analysis of Anchor Anti-Slide Pile in Slope Reinforcement under Seismic Load

2015 ◽  
Vol 777 ◽  
pp. 148-153
Author(s):  
Hui Ding ◽  
Jie Chen ◽  
Li Song
Keyword(s):  
Dynamic Analysis ◽  
Seismic Wave ◽  
Contact Stress ◽  
Dynamic Performance ◽  
Bending Moment ◽  
Dynamic Contact ◽  
Design Parameters ◽  
Seismic Load ◽  
Slope Reinforcement ◽  
Earthquake Action

The force affect factors of anchor anti-slide pile in slope reinforcement under seismic load are studied in this paper. First of all, the method of dynamic analysis is introduced in FLAC3D. At the same time, seismic wave is selected in seismic dynamic analysis. Then, the sensitivity influence of anti-slide pile design parameters on dynamic contact stress, shear force and dynamic bending moment is analyzed by applying the seismic wave, giving the most significant effect factors of the dynamic contact stress and dynamic moment. In the end, the distribution regular of the contact force and the pile body stress under earthquake action is analyzed by selecting a case, laying a theoretical foundation for the further study of the dynamic performance of the reinforced slope.

Case Study of Seismic Response for Shell Key Gasification Equipment Based on Transient Dynamic Analysis

2016 ◽  
Author(s):  
Jun Shen ◽  
Yunlong Wu ◽  
Heng Peng ◽  
Yinghua Liu
Keyword(s):  
Dynamic Analysis ◽  
Cross Sections ◽  
Coal Gasification ◽  
High Efficiency ◽  
Seismic Analysis ◽  
Seismic Load ◽  
Fe Model ◽  
Transient Dynamic Analysis ◽  
Transient Dynamic ◽  
Gasification Process

Coal gasification is a key technology for clean coal conversion with high efficiency. During the past decade, more than twenty Shell Key Gasification Equipments (SKGE) used in the Shell Coal Gasification Process (SCGP) have been built in coal-to-chemicals industry in China. SKGE is composed of Gasifier and Syngas cooler which are connected by Transfer duct. The support skirt of the Gasifier base is fixed, while the Syngas cooler side is supported by a constant hanger (floating support). In this paper, a FE model of the largest 2000-ton SKGE system in China is established by using ANSYS. The global dynamic response under the seismic load is simulated. In order to verify the correction of the calculation, the results are also compared with that by using ABAQUS. Compared to the traditional static analysis, it can be found that the deformation and stress distribution, the force and moment on several specified cross sections of SKGE change over time under seismic load based on the transient dynamic analysis. As the result of the seismic analysis is the prerequisite and foundation for accurate calculation of each key part (e.g. connection between Transfer duct and Gas reversal chamber), the seismic analysis is one of the most important analyses in the Gasification design, which will ensure the essential safety of SKGE system.

scholarly journals Floor vibrations from aerobics

1990 ◽  
Vol 17 (5) ◽  
pp. 771-787 ◽  
Author(s):  
D. E. Allen
Keyword(s):  
Key Words ◽  
Structural Design ◽  
Building Code ◽  
Design Criteria ◽  
Recent Experience ◽  
Loading Function ◽  
Floor Vibrations ◽  
Floor Vibration ◽  
Vibration Problems ◽  
First Time

Recent vibration problems with floors used for aerobics have shown the need for better guidelines for structural design and evaluation. Such guidelines were introduced for the first time in the Supplement to the 1985 National Building Code (NBC), but more recent experience with one particular floor has shown the need for some improvements to these guidelines. The paper describes the investigation of the floor and the use of the floor to estimate the loading function for aerobics, and recommends changes to the NBC design criteria. The paper provides guidance on estimating parameters used in the criteria and discusses repair alternatives related to the floor problem. Key words: floor vibration, aerobics, design criteria, repair.

Wind resistance of a narrow partially built house

1986 ◽  
Vol 13 (3) ◽  
pp. 375-381
Author(s):  
Ronald A. Macnaughton
Keyword(s):  
Key Words ◽  
Wind Load ◽  
Building Code ◽  
Wind Loads ◽  
Wind Loading ◽  
Critical Component ◽  
Wind Resistance ◽  
Early Stages ◽  
Resistance Analysis

This paper contains a wind load and resistance analysis for a type of structure that has frequently failed: partially built houses. The critical component of such structures is identified to be the first-storey shearwalls running across the house. The calculated racking strength of that storey is compared to the wind loading the structure would be expected to resist if it were engineered. Various methods are proposed for builders to provide these structures with more wind resistance during the early stages of construction. Differences between Canadian codes and codes in other jurisdictions with respect to this are pointed out. Key words: wind loads, houses, failure, wind bracing, temporary bracing, shearwalls, fibreboard, sheathing, permanent bracing, racking strength, construction procedures, nailing, building code.

A Variational Method for Evaluating Thrust Bearing Element Load Distribution

1989 ◽  
Vol 111 (1) ◽  
pp. 79-86
Author(s):  
R. J. Stango ◽  
R. H. Jungmann
Keyword(s):  
Variational Method ◽  
Load Distribution ◽  
Variational Formulation ◽  
Thrust Bearing ◽  
Computational Procedure ◽  
Superior Performance ◽  
Thrust Bearings ◽  
Bearing Element ◽  
Numerical Studies ◽  
Load Distributions

A variational method is outlined for computing thrust bearing element loads on the basis of minimizing the potential energy of the system. The problem is formulated in terms of a polynomial displacement assumption for bearing elements. To illustrate the computational procedure, numerical studies are presented for a thrust bearing subjected to a range of load eccentricities. The variational approach is demonstrated to result in an accurate and efficient solution for bearing element load distributions. Excellent agreement is achieved when comparison is made to conventional methods of classical bearing theory for nominal load eccentricities, while superior performance is obtained when load eccentricities are considerably larger. Basic advantages of the variational formulation are discussed and an illustrative problem is presented which demonstrates extended capability of the variational method for examining the load distribution in thrust bearings.

Axle Load Distribution Characterization for Mechanistic Pavement Design

1998 ◽  
Vol 1629 (1) ◽  
pp. 13-23 ◽  
Author(s):  
Jong R. Kim ◽  
Leslie Titus-Glover ◽  
Michael I. Darter ◽  
Robert K. Kumapley
Keyword(s):  
Load Distribution ◽  
Pavement Design ◽  
Performance Study ◽  
Traffic Loading ◽  
Design Procedures ◽  
Motion Data ◽  
The North ◽  
Load Distributions ◽  
Weigh In Motion ◽  
The 1960S

Proper consideration of traffic loading in pavement design requires knowledge of the full axle load distribution by the main axle types, including single, tandem, and tridem axles. Although the equivalent single axle load (ESAL) concept has been used since the 1960s for empirical pavement design, the new mechanistic-based pavement design procedures under development by various agencies most likely will require the use of the axle load distribution. Procedures and models for converting average daily traffic into ESALs and axle load distribution are presented, as are the relevant issues on the characterization of the full axle load distributions for single, tandem, and tridem axles for use in mechanistic-based pavement design. Weigh-in-motion data from the North Central Region of the Long-Term Pavement Performance study database were used to develop the models for predicting axle load distribution.

Sign in / Sign up

Export Citation Format

Share Document