scholarly journals Proposal of A Non Linear Static Analysis Procedure for Bridges: The Incremental Modal Pushover Analysis for Bridges (IMPAβ)

2020 ◽  
Author(s):  
Alessandro Vittorio Bergami ◽  
Camillo Nuti ◽  
Davide Lavorato ◽  
Gabriele Fiorentino ◽  
Bruno Briseghella
Keyword(s):  
Seismic Response ◽  
Good Accuracy ◽  
Pushover Analysis ◽  
Higher Modes ◽  
Modal Pushover Analysis ◽  
Dynamic Analyses ◽  
Non Linear ◽  
Modal Mass ◽  
Existing Bridges ◽  
Modal Pushover

A large number of bridges are designed and built without considering seismic actions and, differently from buildings, there are currently no comprehensive guidelines to evaluate existing bridges without performing, as in the well known incremental dynamic analysis (IDA), complex non linear dynamic analyses (RHA). Bridges are structurally very different from building but, at the same time, are sensitive to higher modes as well as many multi-storey buildings that inspired innovative pushover procedures such as the well known modal pushover analysis (MPA). In the present study the incremental modal pushover analysis (IMPA), a pushover based approach already proposed and applied on buildings by the same authors, is revised and proposed for bridges (IMPAβ). IMPAβ accounts for the effects of higher modes in order to accurately estimate the seismic response of bridges; the effect of higher modes is considered by introducing a suitable number of modes to ensure the participation of a predefined total effective modal mass. The efficiency of the proposed method is demonstrated by conducting a study on two bridges, one regular and one irregular, and the IDA analysis is employed as reference solution. Numerical results indicate good accuracy of the proposed method in assessing the seismic response and a very good accuracy if compared to other available pushover procedures available in the literature.

Studies and Improvements on Modal Pushover Analysis and Application on Bridge

2010 ◽  
Vol 163-167 ◽  
pp. 4076-4082
Author(s):  
Ying Na Mu ◽  
Lei Shi ◽  
Zhe Zhang
Keyword(s):  
Seismic Response ◽  
Pushover Analysis ◽  
High Accuracy ◽  
Analysis Procedure ◽  
Bridge Structure ◽  
Higher Modes ◽  
Modal Pushover Analysis ◽  
Multi Mode ◽  
Inertia Forces ◽  
Modal Pushover

Because the traditional pushover analysis can not take the contributions of higher modes into account, To overcome this limitation, a modal pushover analysis procedure (MPA) is proposed by some researchers, which can involve the combination of multi-mode contributions to response. In this paper, much improvement on MPA procedure is made with consideration of the changes of seismic response after structural yielding and anew distribution of inertia forces. The method is verified by one example of bridge structure. It is concluded that the improvement part-sectionalized MPA presented in this paper has high accuracy.

scholarly journals IMPAβ: Incremental Modal Pushover Analysis for Bridges

2020 ◽  
Vol 10 (12) ◽  
pp. 4287 ◽  
Author(s):  
Alessandro Vittorio Bergami ◽  
Camillo Nuti ◽  
Davide Lavorato ◽  
Gabriele Fiorentino ◽  
Bruno Briseghella
Keyword(s):  
Pushover Analysis ◽  
Structural Response ◽  
Small Contribution ◽  
Base Shear ◽  
Higher Modes ◽  
Modal Pushover Analysis ◽  
Complementary Method ◽  
Incremental Methods ◽  
Total Base ◽  
Modal Pushover

In the present study, the incremental modal pushover analysis (IMPA), a pushover-based approach already proposed and applied to buildings by the same authors, was revised and proposed for bridges (IMPAβ). Pushover analysis considers the effects of higher modes on the structural response. Bridges are structurally very different from multi-story buildings, where multimodal pushover (MPA) has been developed and is currently used. In bridges, consideration for higher modes is often necessary: The responses of some structural elements of the bridge (e.g., piers) influence the overall bridge response. Therefore, the failure of these elements can determine the failure of the whole structure, even if they give a small contribution total base shear. Incremental dynamic analysis (IDA) requires input accelerograms for high intensities, which are rare in the databases, while scaling of generated accelerograms with a simple increment of the scaling acceleration is not appropriate. This fact renders IDA, which is by its nature time-consuming, not straightforward. On the contrary, the change of input spectrum required by IMPA is simple. IMPAβ also utilizes a simple complementary method coupled to MPA, to obtain bounds at very high seismic intensities. Finally, the two incremental methods based on static nonlinear and dynamic nonlinear analyses are compared.

Applicability of Modal Pushover Analysis on Bridges

2011 ◽  
Vol 255-260 ◽  
pp. 806-810
Author(s):  
Biao Wei ◽  
Qing Yuan Zeng ◽  
Wei An Liu
Keyword(s):  
Seismic Analysis ◽  
Pushover Analysis ◽  
Time History ◽  
Seismic Demand ◽  
Seismic Demands ◽  
Modal Pushover Analysis ◽  
History Analysis ◽  
Bridge Structures ◽  
Scope Of Application ◽  
Modal Pushover

Taking one irregular continuous bridge as an example, modal pushover analysis (MPA) has been conducted to judge whether it would be applicable for seismic analysis of irregular bridge structures. The bridge’s seismic demand in the transverse direction has been determined through two different methods, inelastic time history analysis (ITHA) and MPA respectively. The comparison between those two results indicates that MPA would be suitable only for bridges under elastic or slightly damaged state. Finally, some modifications are used to improve the MPA’s scope of application, and the results illustrate that the adapted MPA will be able to estimate bridges’ seismic demands to some extent.

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

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.

scholarly journals A Multimode Adaptive Pushover Procedure for Seismic Assessment of Integral Bridges

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Ehsan Mohtashami ◽  
Ahmad Shooshtari
Keyword(s):  
Seismic Response ◽  
Demand Curve ◽  
Inelastic Response ◽  
Higher Modes ◽  
Seismic Performance Evaluation ◽  
History Analysis ◽  
Integral Bridges ◽  
Response History Analysis ◽  
Modal Mass ◽  
Adaptive Pushover

This paper presents a new adaptive pushover procedure to account for the effect of higher modes in order to accurately estimate the seismic response of bridges. The effect of higher modes is considered by introducing a minimum value for the total effective modal mass. The proposed method employs enough number of modes to ensure that the defined total effective modal mass participates in all increments of the pushover loading. An adaptive demand curve is also developed for assessment of the seismic demand. The efficiency and robustness of the proposed method are demonstrated by conducting a parametric study. The analysis includes 18 four-span integral bridges with various heights of piers. The inelastic response history analysis is employed as reference solution in this study. Numerical results indicate excellent accuracy of the proposed method in assessment of the seismic response. For most bridges investigated in this study, the difference between the estimated response of the proposed method and the inelastic response history analysis is less than 25% for displacements and 10% for internal forces. This indicates a very good accuracy compared to available pushover procedures in the literature. The proposed method is therefore recommended to be applied to the seismic performance evaluation of integral bridges for engineering applications.

Extension of the Modal Pushover Analysis to Assess Structures Exposed to Blast Load

2018 ◽  
Vol 144 (3) ◽  
pp. 04018006
Author(s):  
Amir Saedi-Daryan ◽  
Sahman Soleimani ◽  
Masoud Hasanzadeh
Keyword(s):  
Pushover Analysis ◽  
Blast Load ◽  
Modal Pushover Analysis ◽  
Modal Pushover
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