A Direct Displacement-Based Design Method Based on Chinese Code of Base Isolated Structures

2011 ◽  
Vol 255-260 ◽  
pp. 2555-2559
Author(s):  
Zhen Sun ◽  
Wei Qing Liu ◽  
Shu Guang Wang ◽  
Ding Zhou ◽  
Dong Sheng Du
Keyword(s):  
Seismic Isolation ◽  
Design Method ◽  
Response Spectrum ◽  
Base Shear ◽  
Direct Displacement Based Design ◽  
High Intensity Zone ◽  
Lead Rubber Bearings ◽  
Displacement Based ◽  
Rubber Bearings ◽  
Relationship Of

A simple and efficient direct displacement-based design (DDBD) method is introduced to base isolated (BI) structures. Assuming the vibration mode of superstructure to be the shear type and considering the BI structure to be an equivalent single degree of freedom (ESDOF) system with spring and damper at the seismic isolation layer. The acceleration response spectrum in Chinese code is converted to displacement response spectrum. Corresponding to the design displacement, the equivalent period is obtained. The relationship of the deign displacement, equivalent period, equivalent stiffness and base shear of the system can be derived from the given formulations. Then, the distribution of the base shear along the floors is obtained. This method has been applied to the design of a 12-story BI structure with lead rubber bearings in high intensity zone in Suqian city, Jiangsu province. The results show that the method is feasible for the design of BI structures.

scholarly journals Comparative Study of Direct Displacement Based and Forced Based Design Method for RC- Frame with Shear Wall

10.29007/lft5 ◽  
2018 ◽  
Author(s):  
Bijal Chaudhri ◽  
Dipali Patel
Keyword(s):  
Seismic Design ◽  
Design Method ◽  
Shear Wall ◽  
Performance Based Design ◽  
Rc Frame ◽  
Base Shear ◽  
Global Parameter ◽  
Direct Displacement Based Design ◽  
Moment Resisting ◽  
Displacement Based

The Seismic design of structure has conventionally been force based. Displacement is the major factor for the damage rather than force. The alternative procedure for seismic design, which becomes more popular, is performance based design method. Displacement is global parameter of performance based design method. Direct displacement based design method has been used for seismic design of structure. The paper attempts to design moment resisting RC-frame using Displacement based design method and Forced based design method. 15-storey building with shear wall has been taken for parametric study. The parameter like base shear and lateral load distribution are taken for the study. It is observed that base shear of RC building calculated by DDBD is less compared to FBD.

Seismic Isolation Design for Approach Spans of Suiwei Bridge in Wenchuan

2011 ◽  
Vol 71-78 ◽  
pp. 1444-1450
Author(s):  
Wen Zheng Zhu ◽  
Zhong Gen Xu
Keyword(s):  
Energy Dissipation ◽  
Seismic Isolation ◽  
Design Method ◽  
Response Spectrum ◽  
Damping Ratio ◽  
Time History ◽  
Large Earthquake ◽  
Bridge Design ◽  
Dynamic Time ◽  
Rubber Bearings

The process and thought for the approach bridge of Suiwei bridge design using the method of isolation and energy dissipation were proposed in this paper. The concept of protecting a bridge from the damaging effects of an earthquake by introducing isolating bearings to isolate it from the moving ground is an attractive one. Firstly, the sizes of the laminated rubber bearings and the dia- meters of lead plugs are calculated with static analysis. Then the internal forces of the piers and the damping ratio of the isolated bridge needed to restrict the seismic deformation to 8cm during earth- quakes with seldom intensity were calculated using the Response Spectrum Method, and the result verified with dynamic time history method demonstrates that the Response Spectrum Design Method can restrict the girder displacement to 8cm during large earthquake and reach the goal of 25 percent shock reduction. The design process can be of reference to the bridge design with isolation and energy dissipation.

A Displacement-Based Optimal Design Method of RC Frames Subjected to Minor Earthquakes

2012 ◽  
Vol 594-597 ◽  
pp. 795-799
Author(s):  
Gui Tao Chen ◽  
De Min Wei
Keyword(s):  
Optimal Design ◽  
Optimization Design ◽  
Virtual Work ◽  
Design Method ◽  
Horizontal Displacement ◽  
Target Displacement ◽  
Programming Technique ◽  
Direct Displacement Based Design ◽  
Rc Frames ◽  
Displacement Based

A displacement-based optimization design method of RC structure was proposed by combining direct displacement-based design method with nonlinear programming technique. To avert the influence of target displacement, the stationary constraint displacement was presented, and the target displacement can be updated during the optimal design process. Principle of virtual work and Gaussian integral method was employed to simplify the explicit relationship between horizontal displacement and the section dimension. Comparison analysis of the local optimal results corresponding to different displacement shapes was conducted to achieve global optimal design. The numerical tests presented demonstrate the computational advantages of the discussed methods and suggesting that the proposed method is a reliably and efficiently tool for displacement-based optimal design.

Impact of Damping Scaling Factors on Direct Displacement-Based Design

2016 ◽  
Vol 32 (2) ◽  
pp. 843-859 ◽  
Author(s):  
Cuiyan Kong ◽  
Mervyn J. Kowalsky
Keyword(s):  
Response Spectra ◽  
Equivalent Linearization ◽  
Base Shear ◽  
Limit States ◽  
Scaling Factors ◽  
Equivalent Viscous Damping ◽  
Direct Displacement Based Design ◽  
Displacement Response Spectra ◽  
Performance Limit States ◽  
Displacement Based

Damping scaling factors (DSFs) play an important role in direct displacement-based design (DDBD) as they provide a means to establish displacement response spectra for damping values beyond 5%. Response spectra for multiple damping values are needed for DDBD as the approach relies on equivalent linearization, expressed in the form of effective stiffness and equivalent viscous damping, to establish design forces for prescribed performance limit states. In the past, DSFs based on the Eurocode have been employed for DDBD; however, recent research has resulted in more robust DSF models. This paper examines the accuracy of the current DSF equation used in DDBD across the parameters that are important for structural design. A nonlinear regression analysis is performed based on the data obtained by the Rezaeian et al. (2014) model, and a base shear adjustment factor (SAF) is proposed for application to the DDBD base shear equation.

scholarly journals Implementation of the structural performance factor (Sp) within a displacement-based design framework

2018 ◽  
Vol 51 (3) ◽  
pp. 159-165 ◽  
Author(s):  
Dion Marriott
Keyword(s):  
Response Spectrum ◽  
Time History ◽  
Structural Performance ◽  
Integration Time ◽  
Design Framework ◽  
Base Shear ◽  
Structural Behaviour ◽  
Performance Factor ◽  
Design Response Spectrum ◽  
Displacement Based

This paper discusses the application of the Structural Performance factor (SP) within a Direct Displacement-Based Design framework (Direct-DBD). As stated within the New Zealand loadings standard, NZS1170.5:2004 [1], the SP factor is a base shear multiplier (reduction factor) for ductile structures, i.e. as the design ductility increases, the SP factor reduces. The SP factor is intended to acknowledge the better-than-expected structural behaviour of ductile systems (both strength, and ductility capacity) by accounting for attributes of response that designers are unable to reliably estimate. The SP factor also recognizes the less dependable seismic performance of non-ductile structures, by permitting less of a reduction (a larger SP factor) for non-ductile structures. Within a traditional force-based design framework the SP factor can be applied to either the design response spectrum (a seismic hazard/demand multiplier), or as a base shear multiplier at the end of design (structural capacity multiplier) – either of these two approaches will yield an identical design in terms of the required design base shear and computed ULS displacement/drift demands. However, these two approaches yield very different outcomes within a Direct-DBD framework – in particular, if SP is applied to the seismic demand, the design base shear is effectively multiplied by (SP)2 (i.e. a two-fold reduction). This paper presents a “DBD-corrected” SP factor to be applied to the design response spectrum in Direct-DBD in order to achieve the intent of the SP factor as it applies to force-based design. The proposed DBD-corrected SP factor is attractive in that it is identical to the SP relationship applied to the elastic site hazard spectrum C(T) for numerical integration time history method of analysis within NZS 1170.5:2004 [1], SP,DDBD = (1+SP)/2.

scholarly journals Application of Modal-Displacement Based Design Method to Multi-Story Timber Blockhaus Structures

2020 ◽  
Vol 10 (11) ◽  
pp. 3889
Author(s):  
Martina Sciomenta ◽  
Vincenzo Rinaldi ◽  
Chiara Bedon ◽  
Massimo Fragiacomo
Keyword(s):  
Design Method ◽  
Fe Model ◽  
Structural Elements ◽  
Base Shear ◽  
Shear Loads ◽  
Story Drift ◽  
Displacement Based ◽  
Technical Interest ◽  
Wooden Structures

Structures under seismic excitation undergo different inter-story drift levels that can be associated to damage of both structural and non-structural elements, and thus to the expected losses. The Modal-Displacement Based Design (DBD) procedure, in this regard, has been developed to fix major issues of Force Based Design (FBD) approaches, thus to design multi-story buildings in which the inter-story drift can allow one to control damage mechanisms. In this paper, the conventional Modal-DBD methodology is applied to multi-story timber buildings constructed using the Blockhaus technology. Given their intrinsic geometrical and mechanical features (i.e., stacking of logs, door/window openings, gaps and friction mechanisms, etc.), dedicated methods of analysis are required for them, compared to other wooden structures. A three-story case-study Blockhaus system of technical interest is thus presented for the assessment of Modal-DBD calculation steps. As shown, special care must be spent for the selection of convenient inter-story drift limits that in general should reflect the characteristics of the examined structural typology. The backbone parameters are thus collected for each shear-wall composing the 3D Blockhaus building, based on refined Finite Element (FE) analyses of separate log-walls. The overall results of the Modal-DBD process are thus finally assessed by means of a Push-Over (PO) analysis, carried out on a simplified 3D FE model of the examined multi-story structure. The comparison of FE predictions, as shown, demonstrates that reliable estimates can be obtained when the Modal-DBD procedure is applied to timber Blockhaus systems. In particular, base shear loads can be estimated with good accuracy, while the corresponding top displacements are slightly overestimated (with up to +10%–14% the expected values, for the collapse prevention performance level).

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