Design of torsionally unbalanced structural systems based on code provisions I: Ductility demand

1992 ◽  
Vol 21 (7) ◽  
pp. 609-627 ◽  
Author(s):  
W. K. Tso ◽  
T. J. Zhu
Keyword(s):  
Structural Systems ◽  
Ductility Demand ◽  
Code Provisions

Predicted Ductility Demands for Steel Moment Resisting Frames

1989 ◽  
Vol 5 (2) ◽  
pp. 409-427 ◽  
Author(s):  
Charles W. Roeder ◽  
James E. Carpenter ◽  
Hidetake Taniguchi
Keyword(s):  
United States ◽  
Seismic Design ◽  
The United States ◽  
Structural Systems ◽  
Ductility Demand ◽  
Steel Moment Resisting Frames ◽  
The Past ◽  
Moment Resisting Frames ◽  
Column System ◽  
Moment Resisting

Recent changes to the United States seismic design provisions permit the use of weak column-strong beam steel moment resisting frames. This design concept has not been used in the past, because it results in plastic hinges in the columns during moderate or extreme earthquakes. This paper shows the results of inelastic dynamic response calculations on a weak column frame and a comparable strong column system. The results show that the ductility demand is much greater for the weak column strong beam framing system with some acceleration records. The required ductility is then compared for the different structural systems and both are compared to the results of experiments. The comparison suggests that the weak column system may not be able to develop the required ductility. The results of this paper should help define the viability and limits in applicability of the weak column system.

Period-dependent seismic force reduction factors for short-period structures

1991 ◽  
Vol 18 (4) ◽  
pp. 568-574 ◽  
Author(s):  
W. K. Tso ◽  
N. Naumoski
Keyword(s):  
Reduction Factor ◽  
Structural Systems ◽  
High Ductility ◽  
Base Shear ◽  
Ductility Demand ◽  
Seismic Design Code ◽  
Short Period ◽  
Seismic Force ◽  
Force Reduction ◽  
Reduction Factors

The seismic force reduction factors proposed in the seismic provisions of the National Building Code of Canada 1990 (NBCC 1990) are examined using ground motion records from two recent Canadian earthquakes. The displacement ductility demands are analyzed for structural systems with different ductility capacity. It is found that the NBCC 1990 force reduction factors, which are period independent, lead to a very high ductility demand for short-period structural systems. To avoid this, two types of period-dependent force reduction factors for short-period structures are investigated. The results show that the linearly varying period-dependent reduction factor represents a viable means to resolve the high ductility problems associated with short-period structural systems. Key words: earthquake, seismic, design, code, response, spectra, ductility, reduction factor, base shear.

scholarly journals A modal seismic design procedure based on a selected level of ductility demand

2019 ◽  
Vol 52 (2) ◽  
pp. 78-94 ◽  
Author(s):  
Milad Farahanchi Baradaran ◽  
Farhad Behnamfar
Keyword(s):  
Seismic Design ◽  
Design Procedure ◽  
Structural Systems ◽  
Code Design ◽  
Vibration Modes ◽  
Ductility Demand ◽  
Final Design ◽  
Ductility Capacity ◽  
Different Levels

Determination of seismic design forces of structures is performed by the building codes usually using response reduction (or behaviour) factors that incorporate indeterminacy and ductility capacity of lateral bearing systems. In this procedure story drifts are checked as a final design step approximately preventing stories from assuming excessive ductility demands, or seismic damage. If this procedure is reversed, a more logical seismic design approach may be developed by starting with a ductility-controlled procedure. It is the incentive of this research in which by using a large number of earthquakes, first nonlinear acceleration spectra are developed for different levels of ductility demand. Then an energy-based modal procedure is developed in which the system ductility demand is distributed between the important vibration modes based on their contribution. Finally, the developed method is applied to seismic design of several buildings selected from both regular and irregular structural systems. Comparison with a sample code design establishes success of the method in developing a more rational seismic design.

scholarly journals On the Seismic Design of Structures with Tilting Located within a Seismic Region

2017 ◽  
Author(s):  
Federico Valenzuela-Beltrán ◽  
Sonia E. Ruiz ◽  
Alfredo Reyes-Salazar ◽  
J. Ramón Gaxiola-Camacho
Keyword(s):  
Annual Rate ◽  
Soil Conditions ◽  
Structural Systems ◽  
Fundamental Vibration ◽  
Seismic Region ◽  
Vibration Period ◽  
Ductility Demand ◽  
Mathematical Expressions ◽  
Engineering Demand Parameter ◽  
Dominant Period

A reliability-based criterion to estimate strength amplification factors for buildings with asymmetric yielding located within a seismic region presenting different soil conditions is proposed and applied. The approach involves the calculation of the mean annual rate of exceedance of structural demands of systems with different levels of asymmetric yielding. Two simplified mathematical expressions are developed considering different soil conditions of the valley of Mexico. The mathematical expressions depend on the ductility of the structural systems, their level of asymmetric yielding, their fundamental vibration period and the dominant period of the soil. In addition, the proposed expressions are compared with that recommended by the current Mexico City Building Code (MCBC). Since the expressions are developed with the help of simplified structural systems, the validity of such expressions is corroborated by comparing the expected ductility demand of multi-degree of freedom (MDOF) structural systems with respect to that of their equivalent simplified systems. Both structural representations are associated with a given annual rate of exceedance value of an engineering demand parameter. The expressions proposed in this study will be incorporated in the new version of the MCBC.

POST-TENSIONED STRUCTURAL SYSTEMS - DALLAS-FT. WORTH AIRPORT

PCI Journal ◽  
1973 ◽  
Vol 18 (6) ◽  
pp. 72-91
Author(s):  
Eugene A. Lamberson
Keyword(s):  
Structural Systems ◽  
Post Tensioned

Redesigning the dynamics of structural systems

AIAA Journal ◽  
2000 ◽  
Vol 38 ◽  
pp. 147-154 ◽  
Author(s):  
John B. Ferris ◽  
Michael M. Bernitsas ◽  
Jeffrey L. Stein
Keyword(s):  
Structural Systems
Sign in / Sign up

Export Citation Format

Share Document