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Claudio Modena – 1st expert on this subject based on the ideXlab platform
simplified seismic assessment of railway masonry Arch Bridges by limit analysisStructure and Infrastructure Engineering, 2016Co-Authors: Francesca Da Porto, Paolo Zampieri, Claudio Modena, Giovanni Tecchio, Andrea ProtaAbstract:
In this work, the seismic capacity of single and multi-span masonry Arch Bridges was assessed by limit analysis. A preliminary statistical survey was carried out on a stock of about 750 railway Bridges in Italy, classified according to characteristics and expected collapse mechanisms under seismic excitation. A comprehensive parametric study was carried out on identified homogeneous classes, to calculate limit horizontal accelerations triggering the collapse mechanism in longitudinal and transverse directions. Iso-acceleration envelope curves, representing limit horizontal acceleration of the bridge as a function of geometric parameters, were then derived. These graphs can be used for preliminary seismic safety checking of existing masonry Bridges, once the main geometric parameters are available by simple visual inspections and geometric surveys, and can easily be implemented in a Bridge Management System to prioritise seismic retrofitting interventions.
simplified seismic assessment of multi span masonry Arch BridgesBulletin of Earthquake Engineering, 2015Co-Authors: Paolo Zampieri, Mariano Angelo Zanini, Claudio ModenaAbstract:
The paper describes a simplified methodology for the evaluation of the seismic retrofit intervention types to be performed on clusters of multi-span masonry Arch Bridges, on the basis of the main Bridges geometrical characteristics. The structural behaviour of the analysed sample Bridges has been evaluated in their principal directions highlighting the potential local and global vulnerabilities and the related retrofit intervention typologies that need to be selected. The main aim of this study is to take the form of an useful tool for identify the best retrofit strategies for each masonry bridge structure in function of its geometrical characteristics and thus planning rationally the management of Bridges belonging to rail and road networks.
performance evaluation of short span reinforced concrete Arch BridgesJournal of Bridge Engineering, 2004Co-Authors: Giovanna Zanardo, Carlo Pellegrino, Carlo Bobisut, Claudio ModenaAbstract:
In this paper, the static and seismic performance of some short span reinforced concrete Arch Bridges, before and after strengthening interventions, are evaluated. To verify whether retrofit strategies for the considered Arch Bridges, which were designed for resisting under permanent and service actions, were adequate for earthquake resistance, seismic analyses of the as-built model of the structures have been undertaken. To account for multiple input effects on Arches, induced by out-of-phase motions at foundation levels as well as different boundary conditions at structural supports, the seismic response of the structures under correlated horizontal and vertical multiple excitations is calculated. The effects on Arch Bridges of conventionally used uniform input and partially correlated multiple inputs with phase shifts are compared. In all cases, the results are discussed with particular reference to the influence of structural configuration, secondary systems, cross-section thickness of the Arch, and retrofit interventions.
Hanbin Ge – 2nd expert on this subject based on the ideXlab platform
a seismic upgrading method for steel Arch Bridges using buckling restrained bracesEarthquake Engineering & Structural Dynamics, 2005Co-Authors: Tsutomu Usami, Zhihao Lu, Hanbin GeAbstract:
In this study the employment of buckling-restrained braces (BRBs) as energy dissipation dampers is attempted for seismic performance upgrading of steel Arch Bridges and the effectiveness of BRBs to protect structures against strong earthquakes is numerically studied. With buckling restrained, BRB members can provide stable energy dissipation capacity and thus damage of the whole structure under major earthquakes can be mitigated. Cyclic behaviour of such members is addressed with a numerical simulation model, and a strength design method for BRBs is proposed. BRBs are then placed at certain locations on the example steel Arch bridge to replace some normal members with two schemes, and the effect of the two installation schemes of BRBs for seismic upgrading is investigated by non-linear time-history analyses under various ground motions representing major earthquake events. Compared with the seismic behaviour of the original structure without BRBs, satisfactory seismic performance is seen in the upgraded models, which clarifies the effectiveness of the proposed upgrading method and it can serve as an efficient solution for earthquake-resistant new designs and retrofit of existing steel Arch Bridges. Copyright © 2005 John Wiley & Sons, Ltd.
seismic performance evaluation of steel Arch Bridges against major earthquakes part 2 simplified verification procedureEarthquake Engineering & Structural Dynamics, 2004Co-Authors: Zhihao Lu, Tsutomu Usami, Hanbin GeAbstract:
The performance-based philosophy has been accepted as a more reasonable design concept for engineering structures. For this purpose, capacity evaluation and demand prediction procedures for civil engineering structures under earthquake excitations are of great significance. This work presents a displacement-based seismic performance verification procedure including capacity and seismic demand predictions for steel Arch Bridges and investigates its applicability. Pushover analyses is employed as a basis in this method to investigate the structure’s behaviors. A failure criterion for steel members accounting for the effect of local buckling is involved and an equivalent single-degree-of-freedom (ESDOF) system with a simplified bilinear hysteretic model formulated using pushover analyses results is introduced to estimate the displacement capacity and maximum demand of steel Arch Bridges under major earthquakes. To check the accuracy of the proposed method, seismic capacities and demands from multi-degree-of-freedom (MDOF) time-history analyses with Level-II design earthquake record inputs modeling major earthquakes are used as benchmarks for comparison. By a case study, it is clarified that the proposed prediction procedure can give accurate estimations of displacement capacities and demands of the steel Arch bridge in the transverse direction, while insufficient for the longitudinal direction, which confirms the conclusion drawn in other structure types about the applicability of pushover analyses.
applicability of pushover analysis based seismic performance evaluation procedure for steel Arch BridgesEngineering Structures, 2004Co-Authors: Zhihao Lu, Hanbin Ge, Tsutomu UsamiAbstract:
An investigation on the application of a capacity and demand prediction procedure based on a nonlinear pushover analysis and an equivalent single-degree-of-freedom (ESDOF) system approximation for seismic performance evaluation of steel Arch Bridges, as well as limitations of the pushover analysis is presented here. The procedure is applied to the transverse direction of two representative Arch Bridges with different spans for capacity and demand estimation. Displacement capacities are obtained by conducting pushover analysis until the ultimate state of the structure is reached, determined by a failure criterion proposed for thin-walled steel members governed by the local buckling-induced failure. Displacement demands under major earthquakes are estimated by ESDOF systems formulated using pushover analysis results. Capacities and demands are then compared with those from rigorous nonlinear time–history analyses on multi-degree-of-freedom (MDOF) models for verification and acceptable accuracy of the pushover analysis-based procedure is evidenced. Furthermore, applicability of the pushover analysis involving the fundamental mode only for seismic performance evaluation is extensively investigated considering the higher mode effect. A factor to account for higher mode contribution to seismic response is proposed and an applicable range of using the pushover analysis is quantitatively specified.
Mohammad S Marefat – 3rd expert on this subject based on the ideXlab platform
seismic performance assessment of plain concrete Arch Bridges under near field earthquakes using incremental dynamic analysisEngineering Failure Analysis, 2019Co-Authors: Mahdi Yazdani, V Jahdngiri, Mohammad S MarefatAbstract:
Abstract In the railway network of Iran, a large number of masonry Arch Bridges exist which most of them was constructed 80 years ago. Despite these types of Bridges have shown an appropriate behavior under the influence of gravity (vertical) loads, they have not been designed seismically. Concerning to the seismic hazard zoning map of Iran, most of these railway infrastructures are placed in the very high seismicity zones and constructed near the major faults. So the seismic assessment of these types of Bridges has become a significant subject for the engineers to explain the failure and seismic performance levels of these structures. Thus, they can be rehabilitated or removed if it is found required. Among various methods for seismic estimation of the capacity of the structures under seismic loading, the non-linear dynamic method or the incremental dynamic analysis (IDA) may be mentioned as the most precise and complete method for near-field excitations. For this purpose, by selecting 28 near-field earthquake records, this study has seismically surveyed two railway masonry Arch Bridges, which are respectively placed in the kilometers 23 (2L20 bridge) and 24 (5L06 bridge) of the old railway of Tehran-Qom. The macro-modeling approach was used in the finite element method. In total, 316 non-linear dynamic analyses have been carried out for the seismic assessment of the masonry Arch Bridges under near-field ground motion. The results found from the IDA analysis specified that the near-field seismic performance of the masonry Arch bridge with lower span length (i.e., 5L06 bridge) is safer than the bridge with longer span length (i.e., 2L20 bridge). Mostly, it has to decide to retrofit the masonry bridge with longer span length to improve their performance since the seismic behavior of those has been found inappropriate under near-field earthquakes.
intensity measures for the seismic response assessment of plain concrete Arch BridgesBulletin of Earthquake Engineering, 2018Co-Authors: Vahid Jahangiri, Mahdi Yazdani, Mohammad S MarefatAbstract:
Intensity measures (IMs) are used as a link between seismic hazard and seismic demand analysis and therefore have a key role in performance-based earthquake engineering. To the best of our knowledge, no study has been carried out on the determination of suitable IMs to evaluate the seismic demand of plain concrete Arch Bridges. In the present study, the efficiency, sufficiency, scaling robustness and practicality of 34 potential IMs for evaluating the seismic response of two old railway plain concrete Arch Bridges in km-23 and km-24 of Tehran–Qom railway are investigated. The considered Bridges are simulated using finite-element method and subjected to incremental dynamic analysis (IDA) using 22 far-field earthquake ground motion records. Complete response of the models is obtained through IDA method in terms of engineering demand parameter measured by the maximum displacement of the Bridges. The optimal IMs among the considered intensity measures for evaluating seismic demand of the investigated plain concrete Arch Bridges are recognized using the concepts of efficiency, sufficiency, scaling robustness and practicality. Using the results of the regression analysis, it is concluded that root mean square acceleration is the optimal IM based on efficiency, sufficiency, scaling robustness and practicality for seismic response evaluation of plain concrete Arch Bridges under far-field ground motions.