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    <title>Transport Research International Documentation (TRID)</title>
    <link>https://trid.trb.org/</link>
    <atom:link href="https://trid.trb.org/Record/RSS?s=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" rel="self" type="application/rss+xml" />
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    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
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      <title>Transport Research International Documentation (TRID)</title>
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      <link>https://trid.trb.org/</link>
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    <item>
      <title>Seismic Performance Upgrade of Double-Column Multistory Pier Bents by Integrating Sequentially Sacrificial Shear Dampers and Buckling-Restrained Braces</title>
      <link>https://trid.trb.org/View/2714179</link>
      <description><![CDATA[Reinforced concrete (RC) double-column multistory pier bents in mountainous highway bridges often employ multiple link beams to enhance lateral stiffness, but this design can amplify seismic demands and cause severe beam–column joint damage. This study proposes a seismic-resisting system that integrates shear dampers (SDs) within link beams and buckling-restrained braces (BRBs) between columns. Acting as sequentially sacrificial components, SDs and BRBs dissipate energy and fail in a controlled manner, thereby protecting columns and link beams while enhancing deformation capacity of the whole pier bents. Following an overview of the proposed system, three systems are utilized to unveil the mechanisms and validate the effectiveness, including a typical double-column pier bent in engineering practice as the prototype, the prototype without link beams used for comparison, and the prototype retrofitted with the proposed resisting system. Nonlinear pushover and incremental dynamic analyses show that the proposed system prevents premature failure of link beams and reduces the lateral displacement demands of columns under strong earthquakes without imposing additional base reaction. Additionally, the ultimate displacement capacity of the pier bent is increased by 43%, which substantially improves the seismic performance and reliability accompanied with the reduction in demands. Furthermore, results of fragility analysis confirm the lowest seismic vulnerability of the proposed system in probabilistic perspective, reducing the likelihood of suffering extensive damage at the design earthquake of the prototype with and without link beams from 33% and 26%, respectively, to 10% in the proposed system. The findings highlight the effectiveness of the proposed system as a potential seismic resilient design strategy for RC pier bents.]]></description>
      <pubDate>Mon, 27 Jul 2026 11:16:33 GMT</pubDate>
      <guid>https://trid.trb.org/View/2714179</guid>
    </item>
    <item>
      <title>Dual Mitigation of Wind-Induced and Seismic Responses in Long-Span Bridges Achieved by Damped Outriggers with Nonlinear Viscous Dampers</title>
      <link>https://trid.trb.org/View/2727436</link>
      <description><![CDATA[Long-span bridges are highly susceptible to excessive vibrations in multiple directions induced by wind and earthquakes. Conventionally, vibration control systems are designed separately to addressing wind-induced and seismic responses. This study explores the dual mitigation of these dynamic responses in long-span bridges using damped outriggers (DOs) with nonlinear viscous dampers (NVDs). The DO system consists of outriggers installed on the bridge girder and longitudinal dampers connecting the lower end of the outrigger and a bridge tower or pier. This configuration provides rotational damping to mitigate vertical vibrations and longitudinal damping to suppress the longitudinal response of the girder simultaneously. A comprehensive study has been conducted to design the parameters for DOs of long-span bridges, including the evaluation of external excitations [vortex-induced forces (VIFs) and seismic loads], a corrected modal truncation method for dynamic modeling, and a multiobjective genetic algorithm (MOGA) for optimal parameter design. The framework is validated through numerical application to the Xihoumen Bridge, serving as a representative case. The results demonstrate that DOs installed on the two towers can completely mitigate VIVs across seven modes. In addition, single DO arrangement with independently designed parameters can reduce the longitudinal displacement of the bridge under earthquakes from 18 to 5 cm. Furthermore, MOGA is adopted for optimal design of DOs for dual mitigation, resulting in an optimal system comprising three DOs located at the towers and the north end of the girder. The NVDs in the DOs are designed with an exponent of 0.7 and a viscous coefficient of approximately 10,000  kN·(s/m)0.7, while the outrigger length is kept no larger than 18 m. The performance of the optimized DOs is found to be comparable to that of systems designed separately for wind-induced or seismic responses. The proposed methodology provides a generalized and transferable design framework for integrated wind and seismic vibration mitigation in long-span suspension or cable-stayed bridges.]]></description>
      <pubDate>Mon, 27 Jul 2026 11:16:33 GMT</pubDate>
      <guid>https://trid.trb.org/View/2727436</guid>
    </item>
    <item>
      <title>Steel Pipe-Pile Experiments and Analyses: In-Ground Flexural Deformation Capacity in the Presence of Axial Load</title>
      <link>https://trid.trb.org/View/2727356</link>
      <description><![CDATA[The ASCE/COPRI 61-14 seismic design standard for pier and wharves prescribes an in-ground life safety (LS) strain limit for steel pipe-piles. The adequacy of this limit has been the topic of much discussion within the marine structural engineering community. It has been argued that steel pipes cannot achieve the LS strain limit before undergoing local buckling. In response, researchers have proposed critical strain (εcr) equations for replacement of the standing LS strain limit. The critical strain has been obtained by curve fitting data from numerous pipe flexure tests. Although these studies have provided valuable insights into pipe flexural behavior, most were conducted using three- or four- point in-air bending tests and in the absence of axial load; conditions that differ from those encountered in the field. This paper presents two 1:3-scale experiments on axially loaded soil-embedded steel pipe-piles: one subject to quasi-static monotonic and another to reversed cyclic lateral loading. The test data were used to calibrate a detailed nonlinear finite-element model (FEM) for soil-embedded steel pipe-piles. The model was employed to perform a numerical study on pile deformation capacity within the context of critical strain εcr. Practical ranges for select variables that steer pier-wharf design were considered in the numerical study. Results show that εcr is overly conservative, inconsistent, and fails to capture the influence of axial load; an undesirable attribute for capacity-driving metrics. Furthermore, in practice, the use of strain as a damage-indicating engineering parameter requires the use of an equivalent plastic hinge length, a parameter which adds uncertainty. The paper proposes the use of a strength-targeted plastic rotation capacity (θpc) which is shown to be an intuitive capacity indicator and makes use of a regression analysis on a subset of numerical results to postulate analytical θpc expressions for displacement-based design of steel pipe-piles.]]></description>
      <pubDate>Mon, 27 Jul 2026 11:16:33 GMT</pubDate>
      <guid>https://trid.trb.org/View/2727356</guid>
    </item>
    <item>
      <title>Seismic fragility of bridge systems in relation to vine copula-based series–parallel configuration of components</title>
      <link>https://trid.trb.org/View/2731016</link>
      <description><![CDATA[To accurately evaluate the fragility of bridge systems while accounting for correlations in the seismic demands of individual component, this study employs system reliability theory. The bridge is modeled as series–parallel system, and a system fragility assessment method based on a Vine Copula is proposed. In this approach, each component of the bridge system is treated as a variable within the Vine Copula, and the interdependence of seismic demands among each components is explicitly considered. Furthermore, the Copula function is used to establish a joint probability density function for assessing system fragility. A segment of the isolated continuous beam bridge of the Hong Kong–Zhuhai–Macao Bridge was selected as the case study. The proposed method was applied to analyze the correlations among 14 key components, including piers and bearings. The Akaike information criterion was employed to optimize the Copula function and determined an appropriate vine structure, after which system fragility is evaluated. Finally, the results were compared with those obtained using the conventional first-order boundary estimation method and the Monte Carlo method to validate the effectiveness and accuracy of the proposed approach.]]></description>
      <pubDate>Mon, 27 Jul 2026 09:06:56 GMT</pubDate>
      <guid>https://trid.trb.org/View/2731016</guid>
    </item>
    <item>
      <title>Probabilistic seismic demand of typical highway bridges in moderate-intensity zones</title>
      <link>https://trid.trb.org/View/2720338</link>
      <description><![CDATA[The probabilistic seismic demand for typical highway bridges in moderate-intensity zones is investigated. The seismic demands and infrastructure destructions are severe on critical bridge components during and after seismic activity in moderate-intensity zones. This article aims to determine seismic demand, predict the probabilistic seismic demand model (PSDM), and identify the interdependence of bridge components. Based on bin-ground motion, 154 analytical bridge-ground motion samples are prepared to record output data using nonlinear time history analysis (NLTHA). High-level ground motion duration and peak ground acceleration are used to measure the seismic demand and intensity of the bridge. The best-fitting lognormal distribution and correlation coefficient between demand in the transformation states are analysed to indicate the interaction between the two at dissimilar levels of interdependence. As a result, bearing pads on all abutments, the bearing pad on pier-1, and the shear key on pier-2 are best fitted with a high level of interdependence to design the seismic performance of highway bridges. Therefore, the ground motion characteristics play a vital role in the infrastructure collapse of the highway bridges in the moderate-intensity zone and should be held in high regard.]]></description>
      <pubDate>Thu, 16 Jul 2026 09:08:41 GMT</pubDate>
      <guid>https://trid.trb.org/View/2720338</guid>
    </item>
    <item>
      <title>Experimental Study and Finite Element Analysis of Seismic Performance of Light Steel Stud Walls Clad with Different Composite Panels</title>
      <link>https://trid.trb.org/View/2727413</link>
      <description><![CDATA[Assembled cold-formed steel modular walls are the main lateral force-resisting elements of cold-formed steel homes. In this paper, low-cycle reciprocating loading tests were carried out on cold-formed thin-walled steel shear walls without sheathing panels and clad with three different types of sheathing panels (fire-resistant straw, gypsum, and oriented strand boards [OSB]). This paper analyzes the damage modes, shear strengths, and load–displacement curves of these shear walls, the influence of the sheathing panels’ strengths and elasticities, and the effect of the panels’ nail withdrawal resistance on the skin. The influence of different sheathing panels on the shear capacity of shear walls and the use of screws significantly improves the ratio of shear capacity to ultimate displacement, but reduces the energy dissipation coefficient of the combination of walls. By comparing the three different sheathing panels, fire-resistant strawboard provided the greatest increase in shear capacity for the modular wall, and gypsum board provided the least increase in shear capacity for the modular wall.]]></description>
      <pubDate>Tue, 14 Jul 2026 09:40:07 GMT</pubDate>
      <guid>https://trid.trb.org/View/2727413</guid>
    </item>
    <item>
      <title>Design Guidelines for Bridge Pile Foundations Subjected to Combined Inertial and Liquefaction-Induced Lateral Spreading Loads</title>
      <link>https://trid.trb.org/View/2724825</link>
      <description><![CDATA[Earthquake induced soil liquefaction can result in significant displacements in sloping ground. This type of displacement is referred to as lateral spreading and is considered a substantial hazard to Oregon bridges. One current challenge facing bridge foundation design is the knowledge gap regarding appropriate selection of load factors for combining lateral spreading loads (kinematic) and superstructure inertial loads (inertia). Unfortunately, there is no consensus in design codes for how to combine inertial and kinematic loads. Failure to address this knowledge gap presents challenges for Oregon Department of Transportation (ODOT) engineers and designers. If lateral spreading and superstructure inertial loads interact during an earthquake, neglecting their combined effects could lead to inadequate and unsafe designs. Conversely, overconservatively combining these loads may result in costly, non-constructible foundations, particularly for piles passing through stiff, non-liquefiable crusts overlying deep liquefiable soils on sloped grounds. 

The primary objective of this research is to solidify ODOT’s design guidelines for combining superstructure inertial and lateral spreading loads in a pseudo-static analysis. The inertial and kinematic load interaction factors will be characterized by accounting for differences in seismicity in Eastern and Western Oregon, foundation types, and the complexity levels of design methods utilized in various ODOT projects. The proposed methodology for combining superstructure inertial and lateral spreading loads in a pseudo-static analysis will be detailed in a practice-ready recommended amendment to the ODOT Geotechnical Design Manual (GDM) and ODOT Bridge Design Manual (BDM).]]></description>
      <pubDate>Wed, 08 Jul 2026 14:50:18 GMT</pubDate>
      <guid>https://trid.trb.org/View/2724825</guid>
    </item>
    <item>
      <title>Experimental study and seismic resistance design of fluid viscous dampers in long-span suspension bridges considering device performance degradation</title>
      <link>https://trid.trb.org/View/2680173</link>
      <description><![CDATA[Fluid viscous dampers (FVDs) are extensively researched and utilized for the longitudinal seismic response mitigation of long-span suspension bridges. Nevertheless, serviced dampers are prone to degradation due to environmental and operational factors. This study aims to develop a parameter design framework for FVDs in suspension bridges that guarantees structural safety in the presence of performance deterioration caused by the gap-thermo-mechanical effect. Cyclic tests were conducted to characterize the mechanical behavior of FVDs under varying temperatures and gap conditions. A damping degradation (DD) model was established to simulate the gap-induced force loss and the temperature-dependent damping variations. A simplified beam-spring-mass (BSM) model was proposed to reproduce the girder-pylon longitudinal relative motion of the suspension bridge under seismic excitations. Based on this, a three-factor modification strategy for the FVD damping coefficient was suggested by integrating stochastic vibration analysis with the energy equivalence principle, taking into account the operation temperature, self-heating, and gap modifications. The results indicate that the damper force is negatively correlated with temperature, while the gap leads to incomplete hysteresis loops, which can be simulated by the proposed DD model. The BSM model can accurately reproduce the girder-pylon relative seismic responses while significantly reducing computational complexity. Gaps have the most significant impact on the damper performance, followed by operation temperature and self-heating. When experiencing degradation, the modified FVD achieves nearly identical vibration mitigation performance to that of the ideally designed damper, thereby ensuring structural safety. The findings can support the parameter design of FVDs considering life-cycle performance changes.]]></description>
      <pubDate>Thu, 25 Jun 2026 09:40:59 GMT</pubDate>
      <guid>https://trid.trb.org/View/2680173</guid>
    </item>
    <item>
      <title>Seismic Performance Assessment of Self-Centering Tall Piers: Cyclic Loading Test and Numerical Analysis</title>
      <link>https://trid.trb.org/View/2709387</link>
      <description><![CDATA[This paper introduces the cyclic loading test and numerical model of a novel self-centering (SC) tall pier. This tall pier system is connected to the girder and foundation, respectively, through pre-embedded unbonded post-tensioned tendons at both ends. The pier base features a cast-in-place expanded base to enhance the overturning resistance, while energy dissipation is achieved through externally replaceable energy dissipators (EDs). The energy-dissipating connection devices also serve as shear keys, reducing construction time and costs. Experimental and numerical results show that the SC tall pier has excellent seismic performance. After loading cycles with a maximum drift ratio of 4%, the tall pier is basically undamaged, and the residual displacement can be ignored. The designed EDs demonstrate a stable energy dissipation capacity. However, it is crucial to correctly select the diameter of the weakened section of the EDs to prevent premature fracture, which could compromise the structure's energy dissipation capacity. Additionally, unlike low-height piers, the bending deformation of the self-centering tall pier is significant and cannot be ignored in the experiment. Numerical results show that the increase in pier height enhances the self-centering capability of self-centering bridge piers, while reducing their energy dissipation capacity, delaying the initiation of base gap opening, and shifting the displacement mechanism from base rotation dominance to flexural deformation dominance.]]></description>
      <pubDate>Tue, 23 Jun 2026 13:50:27 GMT</pubDate>
      <guid>https://trid.trb.org/View/2709387</guid>
    </item>
    <item>
      <title>Life-cycle cost assessment of self-centering tall-pier bridges</title>
      <link>https://trid.trb.org/View/2706336</link>
      <description><![CDATA[Self-centering (SC) tall-pier bridges show strong potential for application in high-intensity seismic regions because of their excellent recentering ability and rapid post-earthquake functional recovery. However, their more complex structural system and additional components generally lead to higher initial construction costs than conventional reinforced concrete (RC) tall-pier bridges. To evaluate their practical feasibility, this study proposes a life-cycle cost assessment framework that accounts for initial construction cost, operation and maintenance cost, end-of-life cost, earthquake-induced loss, and environmental cost. Based on extensive nonlinear time-history analyses, probabilistic seismic demand models are established, and system-level fragility assessments are performed. The life-cycle costs of SC and conventional RC tall-pier bridges are then systematically compared. Results indicate that the SC tall-pier bridge has lower system fragility at all damage states, reflecting superior seismic resilience and post-earthquake recoverability. It also significantly reduces earthquake-induced economic losses and life-cycle carbon emissions. The initial construction cost ratio and discount rate are identified as the primary factors governing life-cycle economic performance. The SC bridge remains economically advantageous when its initial cost is controlled within 1.31 times that of the RC bridge, while this threshold decreases to 1.15 when a 10% target return is required. Overall, despite a higher initial cost, the SC bridge provides better life-cycle economic and environmental performance.]]></description>
      <pubDate>Mon, 22 Jun 2026 07:29:02 GMT</pubDate>
      <guid>https://trid.trb.org/View/2706336</guid>
    </item>
    <item>
      <title>Experimental investigation of the seismic performance of corroded reinforced GO-modified concrete bridge columns</title>
      <link>https://trid.trb.org/View/2711443</link>
      <description><![CDATA[Coastal bridges face reduced bearing capacity due to prolonged seawater erosion, a pressing safety concern. Chloride‑induced oxidation of reinforcing steel leads to material degradation and continuous ion exchange, significantly deteriorating bridge column performance. To investigate the effects of varying graphene oxide (GO) incorporation levels on the seismic performance of reinforced concrete bridge columns under chloride ion erosion, four specimens were designed in this study for quasi-static testing, including comparisons of GO content and degrees of chloride ion erosion. The specimens were designed in accordance with Chinese codes, incorporating two GO proportions and three corrosion levels (including a zero‑corrosion control), with the two non‑zero corrosion rates corresponding to 10% and 15% mass loss. Based on the experimental results, the failure process, displacement ductility, energy dissipation, the confined concrete strength and residual displacement of each specimen were analyzed. Furthermore, the ductility and residual displacement of the specimens without GO were discussed. The results indicated that as the corrosion degree increased, the energy dissipation capacity of the specimens gradually decreased, and the confinement strength of the core concrete was also reduced accordingly. Moreover, the average corrosion rate of spiral hoops was generally significantly higher than that of the longitudinal bars, and the corrosion of the reinforcement exhibited notable non-uniformity, leading to a substantial reduction in displacement ductility. Compared to the specimens without GO, those incorporating GO exhibited an improvement in load-bearing capacity, regardless of the occurrence of corrosion. However, after the incorporation of GO, the specimens developed larger residual displacements at the same drift ratio, accompanied by a slight decrease in ductility. As a preliminary reference, code‑based shear design equations and design recommendations were proposed, along with the limitations of this study and suggestions for future research.]]></description>
      <pubDate>Wed, 17 Jun 2026 16:14:25 GMT</pubDate>
      <guid>https://trid.trb.org/View/2711443</guid>
    </item>
    <item>
      <title>System-level post-earthquake functional recovery function and seismic resilience assessment of high-speed railway track-bridge systems</title>
      <link>https://trid.trb.org/View/2677704</link>
      <description><![CDATA[Accurately assess the post-earthquake functional recovery function (PFRF) and quantify the seismic resilience are essential for resilience design of engineering structures. Conventional methods are mainly focused on the component-level damages in railway bridges, however, the damages of high-speed railway track-bridge systems (HSRTBS) are complex and relate to bridge structures as well as track structures. Thus, this paper proposes a novel system-level framework for PFRF and resilience assessment of HSRTBS taking basis of the product of conditional marginal method for functions (PCMMF) method. Firstly, seismic fragility analyses are conducted for obtaining component-level recovery function of ten key components using cloud analyzing method and the expert surveys-based damage-state-dependent functional recovery paths. Then, the PCMMF method is employed to integrate the component functions to obtain system-level PFRF and resilience indexes. Finally, the effects of different components and energy-dissipating devices on seismic resilience of the system are quantified. The results indicate that: (1) Except for the responses of bridge structure, the responses of track structures also exhibited significant effects on system-level function recovery as well as seismic resilience; (2) By integrating component correlations into assessment framework, the nonlinear accumulation and smoother trajectories of the recovery process are presented in proposed function model compared to conventional independent-based step-function one. (3) The proposed U-shaped energy dissipation devices (UEDDs) enhance the system-level seismic resilience of HSRTBS by reducing system-level responses and shortening functional recovery time, where the residual functionality improves from 0 to 0.4, and the recovery duration to exceed 0.9 reduced by approximately 30 days meanly.]]></description>
      <pubDate>Wed, 17 Jun 2026 12:23:20 GMT</pubDate>
      <guid>https://trid.trb.org/View/2677704</guid>
    </item>
    <item>
      <title>Hysteretic behavior of UHPC hollow piers and seismic fragility analysis of corresponding bridge system</title>
      <link>https://trid.trb.org/View/2706051</link>
      <description><![CDATA[Compared with conventional normal-concrete (NC) piers, ultrahigh-performance concrete (UHPC) hollow piers may offer a lightweight, high-strength alternative. However, their seismic performance has not been systematically investigated. In this study, quasi-static tests were conducted on four hollow pier specimens, including one NC and three UHPC piers, with material type, stirrup ratio, and wall thickness as key parameters. Test results demonstrate that UHPC hollow piers exhibit superior yield and peak strength, ductility, energy dissipation capacity, and initial stiffness. Numerical models were developed in OpenSees to perform parametric analyses, indicating that reduced stirrup ratio mainly degrades ductility, whereas reduced wall thickness primarily decreases stiffness. Bridge-level fragility analyses further suggested that replacing conventional RC piers with UHPC hollow piers can reduce pier damage probability, while potentially increasing seismic demand on other bridge components. Overall, these findings support the seismic application of UHPC hollow piers.]]></description>
      <pubDate>Tue, 16 Jun 2026 07:28:34 GMT</pubDate>
      <guid>https://trid.trb.org/View/2706051</guid>
    </item>
    <item>
      <title>Implementing Displacement-Based Seismic Design and Streamlining Low Seismic Zone Design Requirements in the AASHTO LRFD Bridge Design Specifications</title>
      <link>https://trid.trb.org/View/2712168</link>
      <description><![CDATA[Seismic design for roadway bridges has evolved over the past several decades, moving away from traditional force-based approaches toward displacement-based and performance-based methodologies. The current force-based provisions in the AASHTO Load and Resistance Factor Design (LRFD) Bridge Design Specifications (BDS) rely on approximate relationships between force reduction factors and expected structural performance, which have been shown to be conservative in some cases but not others. In contrast, displacement-based seismic design provides a more direct and reliable relationship between design methods and expected bridge performance.

The American Association of State Highway and Transportation Officials (AASHTO) allows both force-based and displacement-based approaches, potentially resulting in different design outcomes depending on the method selected. Additionally, recent advancements in performance-based seismic design and seismic isolation have not been fully integrated into the BDS. For example, current performance-based guidelines reference outdated ground motion models, while the Seismic Guide Specifications lack sufficient detail in areas such as steel substructures and emerging design approaches for bridge pier walls. Additionally, the seismic provisions are distributed across multiple sections of the BDS and related guide specifications, making it difficult for practitioners to identify pertinent requirements. There is a need for research to develop a streamlined framework for seismic bridge design for all seismic regions that reflects current research and practice, and to update current guidance.

The objectives of this research are to (1) develop a guide suitable for practitioners in all seismic regions that synthesizes recent advances in seismic analysis and design, and consolidates seismic design requirements; (2) provide a streamlined framework for a performance-based approach to seismic bridge design and seismic isolation; and (3) prepare a standalone memorandum with language suitable for AASHTO’s consideration in evaluating potential updates to the AASHTO Guide Specifications for LRFD Seismic Bridge Design and a new seismic design section within the BDS.]]></description>
      <pubDate>Tue, 09 Jun 2026 12:36:02 GMT</pubDate>
      <guid>https://trid.trb.org/View/2712168</guid>
    </item>
    <item>
      <title>Seismic Retrofit of a Reinforced Concrete Arch Bridge Using Low-Mass Tuned Mass Dampers</title>
      <link>https://trid.trb.org/View/2703999</link>
      <description><![CDATA[Reinforced concrete (RC) arch bridges constructed prior to modern seismic codes often exhibit severe vulnerabilities under earthquake loading due to brittle detailing, geometric irregularities, and long-term material degradation. This design-feasibility oriented paper concerns the proposal of a retrofit solution for a case-study RC arch bridge built in the late 1950s in Northern Italy and designed by Riccardo Morandi. The bridge features a 90-m span arch and short, shear-deficient spandrel columns above the arch keystone, which were identified as the most critical elements. Indeed, nonlinear time-history (NLTH) analyses of the as-built configuration predicted their premature brittle failures under life safety limit state seismic demand. The novelty of the proposed retrofit solution lies in the combination of (1) the use of low-mass (total mass ratio μ = 1.9%) tuned mass dampers (TMDs), typically employed for serviceability or wind-induced vibration control rather than for seismic strengthening of bridges, and (2) the implementation of a mechanically decoupled layout, in which the TMDs’ sliding masses are supported by the massive arch extrados, while the spring–damper units are connected to the above slender deck, allowing transverse seismic control without increasing gravity demands on the superstructure. Optimal TMDs’ tuning frequency is identified through NLTH parametric analyses, as classical linear tuning rules are inadequate for structures exhibiting nonlinear seismic response. In the examined case study, the proposed TMDs’ configuration is effective in reducing the transverse drift demand of the most critical piers, achieving reductions of up to 49% under oscillatory seismic ground motions. Conversely, a markedly lower effectiveness is observed under pulse-like events. Given the specific characteristics of the investigated bridge and the limited number of seismic records (five oscillatory and five impulsive) employed in NLTHs, further investigations are required to assess the robustness and broader applicability of the proposed solution.]]></description>
      <pubDate>Thu, 04 Jun 2026 15:13:32 GMT</pubDate>
      <guid>https://trid.trb.org/View/2703999</guid>
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