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 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.

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.

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