Seismic response of multi-span continuous irregular bridges using displacement-based and conventional force-based methods

The seismic responses of continuous multi-span reinforced concrete (RC) bridges were predicted using inelastic time history analyses (ITHA) and incremental dynamic analysis (IDA). Some important issues in ITHA were studied in this research, including: the effects of using artificial and natural records on predictions of the mean seismic demands, effects of displacement directions on predictions of the mean seismic response, the use of 2D analysis with combination rules for prediction of the response obtained using 3D analysis, and prediction of the maximum radial displacement demands compared to the displacements obtained along the principal axes of the bridges. In addition, IDA was conducted and predictions were obtained at different damage states. These issues were investigated for the case of regular and irregular bridges using three different sets of natural and artificial records. The results indicated that the use of natural and artificial records typically resulted in similar predictions for the cases studied. The effect of displacement direction was important in predicting the mean seismic response. It was shown that 2D analyses with the combination rules resulted in good predictions of the radial displacement demands obtained from 3D analyses. The use of artificial records in IDA resulted in good prediction of the median collapse capacity.

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Seismic Assessment and Retrofitting of an Under-Designed RC Frame Through a Displacement-Based Approach

Advances in Civil and Industrial Engineering - Performance-Based Seismic Design of Concrete Structures and Infrastructures ◽

10.4018/978-1-5225-2089-4.ch002 ◽

2017 ◽

pp. 36-58

Author(s):

Marco Valente ◽

Gabriele Milani

Keyword(s):

Seismic Response ◽

Numerical Models ◽

Seismic Assessment ◽

Original Structure ◽

Rc Frame ◽

Existing Structures ◽

Dynamic Analyses ◽

Non Linear ◽

Displacement Based ◽

Southern European Countries

Many existing reinforced concrete buildings were designed in Southern European countries before the introduction of modern seismic codes and thus they are potentially vulnerable to earthquakes. Consequently, simplified methodologies for the seismic assessment and retrofitting of existing structures are required. In this study, a displacement based procedure using non-linear static analyses is applied to a four-storey RC frame in order to obtain an initial estimation of the overall inadequacy of the original structure as well as the extent of different retrofitting interventions. Accurate numerical models are developed to reproduce the seismic response of the RC frame in the original configuration. The effectiveness of three different retrofitting solutions countering structural deficiencies of the RC frame is examined through the displacement based approach. Non-linear dynamic analyses are performed to assess and compare the seismic response of the frame in the original and retrofitted configurations.

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Displacement – based parametric study on the seismic response of gravity earth-retaining walls

Soil Dynamics and Earthquake Engineering ◽

10.1016/j.soildyn.2015.10.012 ◽

2016 ◽

Vol 80 ◽

pp. 210-224 ◽

Cited By ~ 10

Author(s):

Manya Deyanova ◽

Carlo G. Lai ◽

Mario Martinelli

Keyword(s):

Seismic Response ◽

Parametric Study ◽

Retaining Walls ◽

Displacement Based

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An Analytical Mechanical Model for the Seismic Assessment of Bell Towers

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.624.97 ◽

2014 ◽

Vol 624 ◽

pp. 97-105

Author(s):

Sergio Lagomarsino ◽

Daria Ottonelli ◽

Serena Cattari

Keyword(s):

Seismic Response ◽

Mechanical Model ◽

Main Body ◽

Seismic Action ◽

3D Fem ◽

Fem Model ◽

Bell Tower ◽

Preliminary Validation ◽

Proposed Model ◽

Displacement Based

The paper describes the analytical model, recently proposed in the Perpetuate Project, aimed to assess the seismic response of the shaft of bell towers, of which the vulnerability to the seismic action has been dramatically testified also by the recent events (as that which hit L’Emilia region in 2012). As main novelties, the model follows the Displacement Based Approach (DBA) for the seismic verification and catches both the shear and combined bending and compression response of the main body of bell towers. In order to clarify the application and to provide a preliminary validation of the proposed model, the seismic response of the bell tower of the San Carlo Church in Castellazzo Bormida (Al, Italy) has been studied. It includes also a detailed analysis on a 3D FEM model aimed to support the calibration of some parameters which the model is founded on in case of quite irregular bell towers characterized by non symmetric boundary conditions that can significantly affect their dynamic behavior, as the case analyzed.

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Seismic Strengthening of Non-Ductile R/C Structures Using Infill Wall or Ductile Steel Bracing

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.602-604.1583 ◽

2012 ◽

Vol 602-604 ◽

pp. 1583-1587 ◽

Cited By ~ 3

Author(s):

Marco Valente

Keyword(s):

Seismic Response ◽

Numerical Models ◽

Original Structure ◽

Structural Members ◽

Infill Wall ◽

Steel Bracing ◽

Earthquake Resistant ◽

Ductile Steel ◽

Displacement Based ◽

Nonlinear Dynamic Analyses

This study deals with the seismic assessment and retrofitting of existing non-ductile R/C structures and the issue of selecting effective strengthening solutions is addressed. A displacement based procedure using nonlinear static pushover analyses is adopted in order to assess the main characteristics of the original structure and to select valuable retrofitting strategies. The procedure is applied to a four-storey R/C frame tested at the JRC ELSA Laboratory some years ago. The R/C frame was designed for gravity loads without specific earthquake-resistant provisions. Accurate numerical models are developed to reproduce the seismic response of the R/C frame in both the original and retrofitted configurations. The effectiveness of two strengthening techniques is examined. First, a retrofitting intervention is carried out by adding a concrete shear wall to the short bay of the frame. This solution is efficient in controlling global lateral drift and thus reducing damage in structural members. Then, a retrofitting solution involving the introduction of eccentric steel bracing is investigated in order to reduce the displacement demand and to increase the energy dissipation capacity of the frame. Nonlinear dynamic analyses are performed to assess and compare the seismic response of the frame in the original and retrofitted configurations.

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Direct Displacement Based Seismic Design of High Rise Structures with Strengthened Stories (I) - Theory

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.250-253.2176 ◽

2011 ◽

Vol 250-253 ◽

pp. 2176-2185

Author(s):

Ke Jia Yang ◽

Xing Wen Liang ◽

Lin Zhu Sun

Keyword(s):

Seismic Response ◽

Seismic Design ◽

Design Procedure ◽

Single Degree Of Freedom ◽

Mode Theory ◽

High Rise ◽

Single Degree ◽

Actual Design ◽

Displacement Based ◽

Displacement Based Seismic Design

High rise structures with strengthened stories are widely used nowadays. A rational seismic design procedure for this kind of structure is thus necessary. Based on mode theory and direct displacement based seismic design of multi-story buildings, this paper proposed a new direct displacement based seismic design procedure. In the proposed method, each mode of the high rise structure is equivalent to a single degree of freedom (SDOF) system. Seismic response of each mode is calculated and adds up to consider the contributions of higher modes. Considering the characteristic of strengthened stories, two stories above the strengthened stories are taken as the “key stories”, whose performance indicates the performance of the building. The proposed procedure is logical, simple and can serve for reference of actual design.

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