Implementation of Inelastic Displacement Patterns in Direct Displacement-Based Design of Continuous Bridge Structures

2006 ◽  
Vol 22 (3) ◽  
pp. 631-662 ◽  
Author(s):  
Hazim Dwairi ◽  
Mervyn Kowalsky
Keyword(s):  
Rigid Body ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Stiffness Index ◽  
Earthquake Ground Motion ◽  
Inelastic Displacement ◽  
Direct Displacement Based Design ◽  
Displacement Pattern ◽  
Displacement Based ◽  
Displacement Patterns

Through the use of nonlinear time-history analysis, the displacement patterns of bridges subjected to transverse seismic attack are investigated. The variables considered in the study consist of bridge geometry, superstructure stiffness, substructure strength and stiffness, abutment support conditions, and earthquake ground motion. A series of three inelastic displacement pattern scenarios were identified: (1) rigid body translation (2) rigid body translation with rotation, and (3) flexible pattern. A relative stiffness index that is a function of the superstructure and substructure stiffness was shown to be a key variable in determining the type of displacement pattern a bridge is likely to follow. The results described in this paper have significant implications for performance-based seismic design procedures such as direct displacement-based design (DDBD). If the displacement pattern for a bridge can be identified with significant confidence at the start of the design process, application of approaches such as DDBD can be simplified. However, if the characteristics of the bridge are such that prescribing a pattern at the start of the process is not feasible, then an alternative approach must be employed for DDBD to proceed. Of the three displacement pattern scenarios defined in this paper, the first two require minimal effort in the design. For the third scenario, an iterative algorithm is proposed. Lastly, as a means for verification and demonstration, a series of bridges with various configurations was designed using DDBD for rigid body translation and flexible pattern scenarios. The designs for the flexible scenario showed good agreement with selected target profiles for bridges with up to five spans.

scholarly journals Application of Direct Displacement Based Design of Reinforced Concrete Frames Subjected to Earthquake Loads

2020 ◽  
Vol 8 (5) ◽  
pp. 5153-5160
Keyword(s):  
Response Spectrum ◽  
Design Procedure ◽  
Time History ◽  
Building Design ◽  
Life Safety ◽  
Nonlinear Time History Analysis ◽  
Performance Levels ◽  
Collapse Prevention ◽  
Direct Displacement Based Design ◽  
Displacement Based

Numerous studies are reported in literature on performance evaluation and rehabilitation of building however, limited studies are reported on performance based design of new buildings. Displacement based design procedure is a new method which is not available in Indian building design codes. An effort has been done to investigate the Direct Displacement Based Design (DDBD) for four, eight and twelve story regular RC frame buildings proposed by Priestley et al, using Indian code Response Spectrum for Zone V which is considered as a very high intensity seismic risk zone for life safety and collapse prevention performance levels. Nonlinear time history analysis is carried out for available ground motion and compared with the performance levels (in terms of drift, displacement). Observations show that design displacement reduction factor should be different for life safety and collapse prevention levels. The effective damping increases as the height of the building increases and is higher for collapse prevention.

Direct Displacement-Based Design of a Novel Hybrid Structure: Steel Moment-Resisting Frames with Cross-Laminated Timber Infill Walls

2016 ◽  
Vol 32 (3) ◽  
pp. 1565-1585 ◽  
Author(s):  
Matiyas A. Bezabeh ◽  
Solomon Tesfamariam ◽  
Siegfried F. Stiemer ◽  
Marjan Popovski ◽  
Erol Karacabeyli
Keyword(s):  
Design Method ◽  
Hybrid Structure ◽  
Nonlinear Time History Analysis ◽  
Earthquake Ground Motion ◽  
Cross Laminated Timber ◽  
Steel Moment Resisting Frames ◽  
Moment Resisting Frames ◽  
Direct Displacement Based Design ◽  
Moment Resisting ◽  
Displacement Based

This study proposes an iterative direct displacement based design method for a novel steel-timber hybrid structure. The hybrid structure incorporates cross-laminated timber (CLT) shear panels as an infill in steel moment-resisting frames. The proposed design method is applied to design three-, six-, and nine-story hybrid buildings, each with three bays and a CLT-infilled middle bay. Nonlinear time history analysis, using 20 earthquake ground motion records, is carried out to validate the performance of the design method. The results indicate that the proposed method effectively controls the displacements due to seismic excitation of the hybrid structure.

scholarly journals Comparison of Force-Based and Displacement-Based Design approaches for RC coupled walls in New Zealand

2014 ◽  
Vol 47 (3) ◽  
pp. 190-205 ◽  
Author(s):  
Matthew J. Fox ◽  
Timothy J. Sullivan ◽  
Katrin Beyer
Keyword(s):  
Linear Time ◽  
Numerical Models ◽  
Design Procedure ◽  
Time History ◽  
Good Representation ◽  
Coupling Beam ◽  
Coupling Beams ◽  
Direct Displacement Based Design ◽  
Coupled Walls ◽  
Displacement Based

Reinforced concrete coupled walls are a common lateral load resisting system used in multi-storey buildings. The effect of the coupling beams can improve seismic performance, but at the same time adds complexity to the design procedure. A case study coupled wall building is designed using Force-Based Design (FBD) and Direct Displacement-Based Design (DDBD) and in the case of the latter a step by step design example is provided. Distributed plasticity fibre-section beam element numerical models of the coupled walls are developed in which coupling beams are represented by diagonal truss elements and experimental results are used to confirm that this approach can provide a good representation of hysteretic behaviour. The accuracy of the two different design methods is then assessed by comparing the design predictions to the results of non-linear time-history analyses. It is shown that the DDBD approach gives an accurate prediction of inter-storey drift response. The FBD approach, in accordance with NZS1170.5 and NZS3101, is shown to include an impractical procedure for the assignment of coupling beam strengths and code equations for the calculation of coupling beam characteristics appear to include errors. Finally, the work highlights differences between the P-delta considerations that are made in FBD and DDBD, and shows that the code results are very sensitive to the way in which P-delta effects are accounted for.

scholarly journals Inelastic Displacement Ratios for Evaluation of Degrading Peak – Oriented SDOF Systems

2017 ◽  
Vol 62 (1) ◽  
pp. 33-47 ◽  
Author(s):  
Muzaffer Borekci ◽  
Murat S. Kirçil ◽  
Ibrahim Ekiz
Keyword(s):  
Dynamic Instability ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Elastic Displacement ◽  
Hysteretic Model ◽  
Collapse Potential ◽  
Inelastic Displacement ◽  
The Mean ◽  
Displacement Demand ◽  
Inelastic Displacement Ratio

Estimation of the inelastic displacement demand (IDD) is an important part of the performance-based design. Coefficient method is one of the methods for the estimation of IDD and in this method, IDD is determined by multiplying elastic displacement demand with inelastic displacement ratio (CR ). Previous researches showed that structures deteriorate and also exhibit dynamic instability under severe earthquakes and these behaviors should be considered in the estimation of CR to estimate a reliable IDD. In this study, CR of the non-degrading bilinear hysteretic model and the degrading peak-oriented hysteretic model with collapse potential were determined and effects of degradation on IDD were investigated. Nonlinear time history analysis of SDOF systems were performed using considered hysteretic models. Furthermore a new equation is proposed for the mean CR of degrading SDOF systems. Also, effect of local site conditions and post-yield stiffness on the mean CR of degrading SDOF systems were investigated.

Development of improved inelastic displacement prediction equations for the seismic design of hybrid systems

2012 ◽  
Vol 45 (1) ◽  
pp. 1-14 ◽  
Author(s):  
J.L. Ceballos C. ◽  
T.J. Sullivan
Keyword(s):  
New Zealand ◽  
Hybrid Systems ◽  
Linear Time ◽  
Time History ◽  
Systems Design ◽  
Viscous Damping ◽  
Equivalent Viscous Damping ◽  
Seismic Displacement ◽  
Inelastic Displacement ◽  
Displacement Based

The use of hybrid joints to provide pre-cast concrete and timber structures with ductile response and self-centering capability is becoming increasingly popular in New Zealand, as is evident by the increasing number of building solutions that incorporate the technology as well as the design provisions for hybrid systems currently included in the New Zealand Concrete standard. This paper raises some issues with the current code approach to estimate the inelastic seismic displacement demand on hybrid systems. The work then presents the results of a series of non-linear time history analyses of single degree of freedom (SDOF) systems characterised by the flag-shaped hysteretic rule, in order to identify a general, improved expression for the equivalent viscous damping of hybrid systems. The new equivalent viscous damping expression is expected to provide more reliable control of inelastic displacement demands for hybrid systems design used Displacement-Based Design (DBD) procedures. In addition, the last part of the paper also discusses how the findings in the paper could be utilised to provide improved control of displacement demands when hybrid systems are designed using force-based procedures.

A Drift Pushover Analysis Procedure for Estimating the Seismic Demands of Buildings

2014 ◽  
Vol 30 (4) ◽  
pp. 1601-1618 ◽  
Author(s):  
Arash Sahraei ◽  
Farhad Behnamfar
Keyword(s):  
Lateral Displacement ◽  
Plastic Hinge ◽  
Pushover Analysis ◽  
Time History ◽  
Relative Displacement ◽  
Analysis Procedure ◽  
New Method ◽  
Nonlinear Time History Analysis ◽  
Displacement Based ◽  
Nonlinear Time History

Relative displacement is a parameter that has a very high correlation with damage. The objective of this article is to develop an analysis procedure founded on the displacement-based seismic design methodology. Generalized interstory drift spectrum is applied as an essential tool in this new method called drift pushover analysis. In order to evaluate the behavior of structures, three demand parameters—lateral displacement, story shear, and plastic hinge rotation—are computed with conventional pushover analysis (CPA), modal pushover analysis (MPA), and drift pushover analysis (DPA), and are compared with those of the nonlinear time history analysis (NTA). It is observed that the new method, DPA, predicts the peak response measures more precisely and with less effort than the other nonlinear pushover procedures investigated in this study.

Study on normalization of residual displacements for single-degree-of-freedom systems

2021 ◽  
pp. 875529302098801
Author(s):  
Zhibin Feng ◽  
Jinxin Gong
Keyword(s):  
Structural Characteristics ◽  
Permanent Deformation ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Intermediate Step ◽  
Residual Displacement ◽  
Inelastic Displacement ◽  
Residual Displacements ◽  
Constant Strength ◽  
Nonlinear Time History

Residual displacement spectrum is one of the most important means to predict the permanent deformation of structures after the earthquake, and various normalizations of residual displacements have generally been used for construction of the spectrum. However, the issue regarding the merits and drawbacks of each normalization has not yet been investigated thoroughly. A comparison between two normalizations that relate the residual displacements to the elastic and inelastic displacements is made in terms of the effect of ground motion and structural characteristics by means of the results of nonlinear time history analysis. The statistical results reveal that the residual-to-peak-inelastic displacement ratios have the advantages of small dispersion, samples without any outliers, and relatively symmetric distribution, which benefits from the strong correlation between residual and peak inelastic displacements. Moreover, the residual-to-peak-inelastic displacement ratios are almost independent of site conditions, significant duration, and natural periods. Consequently, the peak inelastic displacements are superior to the elastic ones as an intermediate step for residual displacements estimation, provided that the peak inelastic displacements are estimated with a low uncertainty. For providing alternatives to estimate residual displacement demands, the constant-strength residual displacement spectra are developed for both normalizations.

scholarly journals Nonlinear Time-History Analysis for Validation of the Displacement-Based Seismic Assessment of the RC Upper Bridge of a Dam

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
P. Lestuzzi ◽  
H. Charif ◽  
S. Rossier ◽  
M. Ferrière ◽  
J.-P. Person
Keyword(s):  
Structural Characteristics ◽  
Time History ◽  
Seismic Assessment ◽  
Nonlinear Time History Analysis ◽  
Soil Conditions ◽  
Acceleration Time Histories ◽  
Nonlinear Time History Analyses ◽  
Displacement Demand ◽  
Displacement Based ◽  
Nonlinear Time History

The seismic assessment of a secondary structure of the Chancy-Pougny dam, namely, the upper bridge, is discussed in this paper. A first seismic assessment, performed according to classical force-based methodology, concluded the necessity of an extensive retrofitting for the upper bridge. By contrast, the application of the displacement-based approach showed that the current situation is already satisfactory, and therefore, practically no retrofitting is needed. The paper focuses on the nonlinear time-history analyses which were achieved in order to check the accuracy of the results obtained using the displacement-based method. The structural characteristics of the reinforced concrete upper bridge are similar to those of conventional bridges. However, the piers were built with very little reinforcement and consequently they will exhibit a rocking behavior in case of earthquake loading. Rocking is rather a favorable failure mechanism and is related to a certain amount of displacement capacity. However, this behavior is not linked to plastic energy dissipation which may significantly increase the related displacement demand. In order to determine the real displacement demand, nonlinear time-history analyses were achieved with SDOF systems defined by an “S” shape hysteretic model. Spectrum compatible stationary synthetic accelerograms and slightly modified recorded earthquakes were both used for acceleration time-histories. The results showed that the displacement demand corresponds well with the one determined by usual push-over analysis. The results show a very favorable seismic situation, related to a relatively stiff structure associated to rock soil conditions with an A class soil. The seismic safety of the upper bridge is already satisfactory for the current state (without retrofitting). Consequently, the proposed costly reinforcement for the upper bridge could be significantly reduced.

scholarly journals Incorporation of Torsional & Higher-Mode Responses in Displacement-Based Seismic Design of Asymmetric RC Frame Buildings

2019 ◽  
Vol 9 (6) ◽  
pp. 1095
Author(s):  
Beka Abebe ◽  
Jong Lee
Keyword(s):  
Seismic Design ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Rc Frame ◽  
Performance Objective ◽  
Frame Buildings ◽  
Displacement Based ◽  
Rc Frame Buildings ◽  
Plan Configuration ◽  
Displacement Based Seismic Design

Direct displacement-based design (DDBD) is currently a widely used displacement-based seismic design method. DDBD accounts for the torsional response of reinforced concrete (RC) frame buildings by using semi-empirical equations formulated for wall-type buildings. Higher-mode responses are incorporated by using equations obtained from only a few parametric studies of regular planar frames. In this paper, there is an attempt to eliminate torsional responses by proportioning frames’ secant stiffnesses so that the centers of rigidity and supported mass (the mass on and above each story) coincide. Once the torsional rotations are significantly reduced and only translational motions are achieved, higher-mode responses are included using a technique developed by the authors in their recent paper. The efficiency of the proposed design procedure in fulfilling the intended performance objective is checked by two plan-asymmetric 20-story RC frame building cases. Case-I has the same-plan configuration while Case-II has a different-plan configuration along the height. Both cases have different bay widths in orthogonal directions. Verification of the case studies by nonlinear time history analysis (NTHA) has shown that the proposed method results in designs that satisfy the performance objective with reasonable accuracy without redesigning members. It is believed that a step forward is undertaken toward rendering design verification by NTHA less necessary, thereby saving computational resources and effort.

Direct Displacement-Based Design of a RC wall-steel EBF dual system with added dampers

2009 ◽  
Vol 42 (3) ◽  
pp. 167-178 ◽  
Author(s):  
Timothy J. Sullivan
Keyword(s):  
Linear Time ◽  
Design Method ◽  
Design Procedure ◽  
Time History ◽  
Dual System ◽  
System Structure ◽  
Design Solution ◽  
Equivalent Viscous Damping ◽  
Direct Displacement Based Design ◽  
Displacement Based

An innovative application of Direct Displacement-Based Design (DBD) is presented for a modern 8-storey dual system structure consisting of interior concrete walls in parallel to a number of large steel eccentrically braced frames, fitted with visco-elastic dampers at link positions. The innovative DBD methodology lets the designer directly control the forces in the structure by choosing strength proportions at the start of the design procedure. The strength proportions are used to establish the displaced shape at peak response and thereby establish the equivalent single-degree-of-freedom system design displacement, mass and effective height. A new simplified formulation for the equivalent viscous damping of systems possessing viscous dampers is proposed which also utilises the strength proportions chosen by the designer at the start of the process. The DBD approach developed is relatively quick to use, enabling the seismic design of the 8-storey case study structure to be undertaken without the development of a computer model. To verify the ability of the design method, non-linear time-history analyses are undertaken using a suite of spectrum-compatible accelerograms. These analyses demonstrate that the design solution successfully achieves the design objectives to limit building deformations, and therefore damage.

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