A Reliability-Based Dual Level Seismic Design Procedure for Building Structures

1995 ◽  
Vol 11 (3) ◽  
pp. 417-429 ◽  
Author(s):  
Kevin R. Collins
Keyword(s):  
Seismic Design ◽  
Design Procedure ◽  
Response Spectra ◽  
The United States ◽  
Complex Problem ◽  
Building Structures ◽  
Inelastic Behavior ◽  
Earthquake Excitation ◽  
Final Design ◽  
Hazard Response

structural design, Limit design, Spectra The seismic design provisions of most building codes in the United States specify ground motion parameters for various regions of the country and provide simple formulas to determine a distribution of lateral forces for which the structure should be designed. The simple formulas typically involve the use of one or more “factors” to account for anticipated inelastic behavior of the structure, relative importance of the structure, and site soil effects. Although these code provisions are very simple to use, they oversimplify a complex problem and are based on many implicit assumptions which many designers may not appreciate. Furthermore, the reliability of the final design is not known. This paper describes the key features of an alternative seismic design procedure in which the underlying assumptions are more clearly defined and which provides a more uniform level of reliability in the final design. The procedure requires the designer to consider two levels of earthquake excitation. An “equivalent” single-degree-of-freedom model and uniform hazard response spectra are used to predict structural performance. The alternative procedure should enable designers to achieve code-specified target performance objectives for moderate and severe levels of earthquake excitation.

SEISMIC DESIGN OF FRAME STRUCTURES EQUIPPED WITH INNOVATIVE HYSTERETIC DISSIPATIVE DEVICES

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Michele Palermo ◽  
Vittoria Laghi ◽  
Stefano Silvestri ◽  
Giada Gasparini ◽  
Tomaso Trombetti
Keyword(s):  
Seismic Design ◽  
Design Procedure ◽  
Structural Instability ◽  
Hysteretic Behavior ◽  
Frame Structure ◽  
Frame Structures ◽  
Order Effects ◽  
Final Design ◽  
Structural Engineer ◽  
Performance Based Seismic Design

In the present work, a Performance-Based Seismic Design procedure applied to multi-storey frame structures with innovative hysteretic diagonal steel devices (called Crescent Shaped Braces or CSB) is introduced. CSBs are steel elements of peculiar geometrical shapes that can be adopted in frame buildings as enhanced hysteretic diagonal braces. Based on their "boomerang" configuration and placement inside the frame structure, they are characterized by a lateral stiffness uncoupled from the yield strength and, if properly inserted, by an overall symmetric hysteretic behavior with hardening response at large drifts, thus preventing from global structural instability due to second-order effects. The procedure here presented is intended to guide the structural engineer through all the steps of the design process, from the selection of the performance objectives to the preliminary sizing of the CSB devices, up to the final design configuration. The steps are described in detail through the development of an applicative example.

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.

Performance-Based Seismic Design of Pallet-Type Steel Storage Racks

2006 ◽  
Vol 22 (1) ◽  
pp. 47-64 ◽  
Author(s):  
André Filiatrault ◽  
Robert E. Bachman ◽  
Michael G. Mahoney
Keyword(s):  
Seismic Design ◽  
Ground Motions ◽  
Design Procedure ◽  
The United States ◽  
Moment Frames ◽  
Type Steel ◽  
Collapse Prevention ◽  
Moment Resisting ◽  
Performance Based Seismic Design ◽  
Storage Racks

This paper develops a performance-based seismic design procedure for pallet-type steel storage racks located in areas accessible to the public. Performance objectives for racks consistent with current building code procedures in the United States are defined. The paper focuses on collapse prevention of racks in their down-aisle direction under the Maximum Considered Earthquake (MCE) ground motions at the site. The down-aisle lateral load-resisting systems of racks are typically moment frames utilizing special proprietary beam-to-column moment-resisting connections that may result in large lateral displacements when subjected to MCE ground motions. A simple analytical model that captures the seismic behavior of racks in their down-aisle direction is proposed. The model assumes that the beams and columns remain elastic in the down-aisle direction and that all nonlinear behavior occurs in the beam-to-column connections and the moment-resisting connections between the base columns and support concrete slab. Therefore the behavior is based on the effective rotational stiffnesses developed by the beam-to-column connectors and column-to-slab connections that vary significantly with connection rotation. The model is validated against the results of shake-table tests conducted on full-scale racks under several ground-motion intensities. Finally, the model is incorporated in a displacement-based procedure to verify collapse prevention of racks in their down-aisle direction under the MCE.

Response Modification Factor for Y-Eccentric-Braced Steel Frame Structures

2011 ◽  
Vol 250-253 ◽  
pp. 2285-2290
Author(s):  
Wen Xia Yang ◽  
Qiang Gu ◽  
Zhen Sen Song
Keyword(s):  
Seismic Design ◽  
Pushover Analysis ◽  
Steel Frames ◽  
Design Procedure ◽  
Response Spectra ◽  
Elastic Response ◽  
Base Shear ◽  
Response Modification Factor ◽  
Elastic Response Spectra ◽  
Modification Factor

In current seismic design procedure, structural base shear is calculated according to the linear elastic response spectra divided by response modification factorR. The response modification factor is important to the reliability and economy of building seismic design. In this paper, the response modification factors of Twelve Y-eccentric braced steel frames with various stories and spans lengths were evaluated by capacity spectrum method based on the global capacity envelops obtained from an improved pushover analysis and incremental dynamic analysis. According to the results, an appropriate formula of the response modification factor for the Y-eccentric braced steel frames was suggested.

Systematic Seismic Design for Manageable Loss in Wood-Framed Buildings

2009 ◽  
Vol 25 (4) ◽  
pp. 851-868 ◽  
Author(s):  
Shiling Pei ◽  
John W. van de Lindt
Keyword(s):  
Seismic Design ◽  
Design Procedure ◽  
Residential Building ◽  
The United States ◽  
Single Family ◽  
Financial Loss ◽  
End User ◽  
Building Stock ◽  
Framed Structures ◽  
Performance Based Seismic Design

Light frame wood structures make up the vast majority of the residential building stock in the United States. Because of this, earthquake-induced losses for this category of building from a significant earthquake would have a substantial financial impact on the regional economy, as well as on the building owner. Current wood-framed structural design philosophy focuses only on life safety and only limits damage through implicit assumptions. The concept of loss-based seismic design is introduced in this paper with typical loss-based design statements explicitly formulated with the intent of addressing the concerns, e.g., financial loss, of the building end-user. The loss-based design procedure was established based on a loss estimation framework that relied on the existing concept of assembly-based vulnerability (ABV). With the help of an automated dynamic and loss analysis package developed for wood-framed structures (SAPWood™) at Colorado State University, loss-based seismic design for a typical North American single family residential building was conducted for several different explicitly stated loss targets. The results from the numerical examples showed that loss-based seismic design for wood-framed structures is a viable concept that can serve as an important step in the evolution of end-user oriented, performance-based seismic design (PBSD).

Nonlinear Seismic Design of Multistory Frames

1975 ◽  
Vol 2 (4) ◽  
pp. 494-516 ◽  
Author(s):  
V. V. Bertero ◽  
H. Kamil
Keyword(s):  
Optimum Design ◽  
Seismic Design ◽  
Computer Aided Design ◽  
Linear Optimization ◽  
Design Procedure ◽  
Optimization Procedure ◽  
Preliminary Design ◽  
Displacement Ductility ◽  
Final Design ◽  
Design Earthquake

A five-step, computer-aided design procedure representing a significant change from current seismic design practices is proposed.In the first step, the ‘design earthquake’ and the safety and serviceability criteria are established, and appropriate values of a damping coefficient and displacement ductility factor are assumed. An iterative preliminary analysis procedure, centered around specified values of a seismic coefficient and a drift index, is used to determine the design story shears using modal analysis.Then, a preliminary design is carried out using a simplified story-wise optimization procedure. This is followed by inelastic static and dynamic analyses of the design. The maximum values of story shears and ductilities and their overall pattern, so obtained, are compared against those used initially. The procedure is repeated until a satisfactory agreement is obtained and the final design story shears are determined. In the fourth step, these shears are used to attain the final optimum design through a procedure similar to that used in the preliminary design, but using an improved story subassemblage and a more formal linear optimization technique.Finally, the reliability of the optimum design is evaluated by determining its nonlinear response to severe earthquakes and its serviceability. The design procedure is demonstrated on a 10-story 3-bay frame.

Pushover Analysis of Buildings Considering Soil-Structure Interaction

2016 ◽  
Vol 857 ◽  
pp. 189-194 ◽  
Author(s):  
P.V. Joy ◽  
Bennet Kuriakose ◽  
Mini Mathew
Keyword(s):  
Seismic Design ◽  
Soil Structure ◽  
Pushover Analysis ◽  
Design Procedure ◽  
Structural Response ◽  
Soil Structure Interaction ◽  
Seismic Behaviour ◽  
Earthquake Excitation ◽  
Structure Interaction ◽  
Performance Based Seismic Design

Structural vulnerability of buildings to damage needs to be identified during the time of earthquake for reliable seismic design. Conventional linear elastic design methods cease to predict seismic damages in buildings. Pushover analysis is a popular displacement-based nonlinear structural analysis procedure employed to predict the seismic behaviour of structures. Generally, buildings are designed based on the assumption that they are fixed at their base, without considering the foundation as well as soil. But in reality, when a structure is subjected to an earthquake excitation, it interacts with the soil, influencing the structural response. In this study, a multi-bay building with different heights are modelled and analysed, duly considering Soil-Structure Interaction (SSI). The study can form foundation for rigorous performance-based seismic design procedure, considering the effect of soil beneath the structure.

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