High Seismic Regions Research Articles

Performance-based plastic design and seismic fragility assessment for chevron braced steel frames considering aftershock effects

Observations from past earthquakes demonstrated that buildings in high seismic regions might be exposed to several aftershocks following the mainshock which can significantly increase the damage level. Since aftershocks have the potential to increase the vulnerability of buildings damaged under mainshocks, it is crucial to consider aftershock effects in the structural design phase. Performance-based Plastic Design (PBPD) method is an innovative seismic design method in which the building designed by this method shows a desirable performance under severe ground motions. PBPD allows the designer to avoid time-consuming trial and error process of analyses that are usually done in Performance-based Design method to reach a desirable performance. However, this efficient method is only valid for mainshocks only and does not consider aftershock effects in the structural design process. In this study, initially, the seismic performance (interstory drift and plastic hinges distribution) of the three 3-, 6-, and 9- story PBPD designed Chevron-braced Steel frames (CBSF) are compared under mainshocks (MS) and mainshock-aftershock (MS-AS) sequences. Subsequently, a PBPD method is developed for CBSFs considering the aftershock effects in the structural design process. Incremental dynamic analysis (IDA) has been performed using a suite of mainshocks and aftershock ground motions to develop a design base shear modification factor. Using the developed method, the performance of CBSFs under MS and MS-AS sequences is evaluated and compared with the existing PBPD method. Fragility curves are developed to compare the seismic vulnerability of the frames designed based on PBPD and proposed PBPD methods under MS-AS sequences. The outcomes of this study provide a practical design approach for CBSFs under MS-AS sequences and shows that the structures designed using developed PBPD method show more desirable behavior under MS-AS sequences compared with the structures designed using the conventional PBPD method.

Understanding the behavior of the Thin Lightly-Reinforced Concrete Wall (TLRCW) building system

ABSTRACT Thin lightly reinforced concrete wall (TLRCW) buildings are commonly used to mitigate the housing deficit in developing countries. The TLRCW system comprises slender walls with a thickness lower than 150 mm, a high aspect ratio, limited or no confinement at the edges of the walls, and web reinforcement with limited ductility. This paper describes and discusses the main geometric and mechanical characteristics of 207 TLRCW buildings constructed in intermediate- and high-seismicity regions. Variables considered in the study are the number of stories, wall-area index, axial load ratio, slenderness, aspect ratio, and the type of reinforcement at wall edges. Statistical analyses of the database and global performance indices are correlated with the expected seismic performance of TLRCW buildings. The results of the analyses aided at developing a useful toolbox for rapid assessment of design and structural configuration to prioritize intervention strategies for existing TLRCW buildings.

Slab Reinforcement Contributions to Negative Moment Strength of Reinforced Concrete T-Beam with High Strength Steel at Exterior Beam-Column Joints

Previous studies have revealed that the contribution of slab reinforcement to the T-beam flexural strength in negative moment regions are not negligible for the seismic capacity design. An effective slab width (i.e., effective width of flanged section) has been proposed, within which the slab reinforcement needs to be included in the calculation of the beam nominal flexural strength in negative moment regions. These studies mainly focused on the cases using normal-strength steel in moment resisting frames. However, recently high-strength steel has been widely used in reinforced concrete moment resisting frames in high seismic regions to avoid congestion near beam-column joints. The use of high-strength steel may affect the beam stiffness due to the fact that it will require less amount of reinforcement, and result in a different normal stress distribution compared to the case with normal-strength steel. Therefore, this paper investigates the slab reinforcement contribution to the flexural strength of the reinforced concrete T-beam designed with high-strength steel in negative moment regions at exterior beam-column joints, for which nonlinear pushover analyses were conducted. Beam reinforcement grade was considered as a primary parameter with several other design variables including slab thickness, height, and span length of the beam. Analytical results show that the use of high-strength steel can result in a wider effective slab width than the case of normal-strength steel for calculating the beam nominal flexural strength under the negative moment. Based on these results, new design equations were proposed.

Physical damage‐hysteretic response correlation for steel sheet sheathed cold‐formed steel‐framed wall‐lines

AbstractUse of cold‐formed steel (CFS) framing as load‐bearing system for gravity and lateral loads in buildings is becoming increasingly common in the North American construction industry, notably in high seismic regions where light‐weight construction is an attractive option. Buildings framed with closely spaced and repetitively placed CFS members can be detailed to develop lateral resistance using a variety of sheathing options. A relatively new option involves the use of steel sheet as sheathing. Steel sheet sheathed CFS shear walls offer high lateral strength and stiffness, and provide ductility courtesy of tension field action within the steel sheet. Despite their acceptance, gaps in the understanding of their behavior do exist, notably, behavior under dynamic loading, the contribution of nonstructural architectural finishes, and the behavior of wall‐lines: shear walls placed inline with gravity walls. To this end, a two‐phased experimental effort was undertaken to advance understanding of the lateral response of CFS‐framed wall‐line systems. Specifically, a suite of wall‐lines, detailed for mid‐rise buildings, were evaluated through simulated seismic loading imposed via shake table and quasi‐static cyclic tests. Damage to the wall‐lines was largely manifested in the form of damage to fastener connections used for attaching the sheathing and gypsum panels, and separation of exterior finish layer. This paper documents and quantifies the progressively incurred physical damage observed in the tested wall‐line assemblies, and correlates it with the evolution of dynamic characteristics and hysteretic energy dissipated across a spectrum of performance levels.

Parameter identification of hysteretic model of UHPC-connected precast segmental columns under cyclic loading

Due to their numerous advantages, precast segmental columns have emerged as an important development direction in bridge engineering. Understanding and researching their hysteretic characteristics holds great significance. Precast columns connected with UHPC achieve performance similar to cast-in-place (CIP) monolithic columns, making them suitable for use in constructing bridges located in high seismic regions. In this study, the Bouc-Wen-Baber-Noori (BWBN) model was employed to characterize the hysteretic behaviors of UHPC-connected precast segmental columns, considering strength degradation, stiffness degradation, and pinching effects. The Nelder-Mead simplex (NMS) algorithm was utilized to identify the parameters of the BWBN model, demonstrating its computational efficiency. The proposed parameter identification method was validated using experimental data derived from cyclic loading tests performed on five UHPC-connected precast segmental columns of three structural types. Comparative analyses encompassing force-displacement relationship, residual drift and energy consumption convincingly affirmed the applicability and precision of the proposed method for UHPC-connected precast segmental columns.

Life-cycle assessment and prediction on ultimate capacity of corroded Q690 steel columns with H-section under bi-directional cyclic loading

The structures or structural members made of high-strength steel may have time-varying mechanical properties in whole life-cycle due to the ageing effects. In particular, the corroded steel structures in high-seismicity regions could have unexpected failure modes when subjected multi-directional excitations. Therefore, in this study, the mechanical properties of Q690 steel H-section columns during the life-cycle under bi-directional cyclic loads are investigated. Firstly, a refined finite element (FE) model is built, which takes the time-varying of corrosion characteristics into consideration. Then, the degradations of mechanical property and failure mechanisms of steel columns with different design parameters at whole life-cycle are analysed by the FE models. Finally, a quantitative calculation method of ultimate resistance and damage index of steel columns considering ageing effects is proposed. The findings demonstrate that several factors affect the ultimate strength of steel columns during the life-cycle stage, with the axial compression ratio and flange width-thickness ratio having the greatest impacts on the ultimate capacity. The ageing effect decreases the plastic flow capacity of steel columns, increases the stress concentration, and induces the failure mode transition from plastic flow to buckling failure. The ageing effect may be accurately estimated by the suggested calculation method for the ultimate capacity and damage index of steel columns at the life-cycle stage. The findings of this study highlight the significance of taking into account the ageing effects of steel columns in the seismic design.

Persistent asperities at the Kermadec subduction zone controlled by changes in forearc structure: 1976 and 2021 doublet earthquakes

To what degree large earthquakes are ‘characteristic’ is a critical question in understanding the fundamentals of earthquake physics and the seismic cycle. Here we study the ruptures of the 2021 Mw7.4 and Mw8.1 doublet earthquake sequence in the Kermadec subduction zone and compare them with the 1976 doublet that occurred at the same location. We find that although the 2021 mainshock likely re-ruptured the same asperity as the 1976 Mw7.9 event, the detailed slip distribution is different. Other ruptures in the doublets also differ in character and location. Our observations indicate the variability between large earthquakes on the same segment of the plate boundary in each earthquake cycle. All earthquakes occur in an isolated area of the megathrust, which is bounded by changes in the lithospheric structure of the overriding plate as indicated by bathymetric and gravity data. This high-seismicity region is coincident with an isolated forearc sedimentary basin, possibly formed by basal erosion related to seismogenesis, suggesting that seismic slip has persisted here for several million years. Refined up-dip aftershock and background seismicity focal mechanisms have a steeper dip angle than the slab interface, suggesting these events are located within the subducting oceanic slab, possibly forming a rougher plate interface that facilitates basal erosion. We conclude that the stress heterogeneity within this bounded seismogenic zone is long-lived and has produced a rich spectrum of earthquake ruptures.

MAGNETIC POLE REPULSIVE DAMPER (MPRD): A PROMISING SOLUTION FOR SEISMIC PROTECTION OF STRUCTURES

Owing to its high energy dissipation characteristics, the passive damper is an effective means of mitigating natural hazards for structures. In this study, a novel magnetic pole repulsive damper (MPRD), designed for reducing structural responses during natural hazards such as earthquakes, was developed and its performance was validated. The MPRD is an effective solution for seismic protection that works on the principle of magnetic repulsion and has a higher energy dissipation capacity than conventional dampers. The MPRD was fabricated using mild steel, neodymium magnets, and a set of helical springs. Two scaled reinforced concrete frames were tested using a 50 kN loading actuator. One frame was equipped with the MPRD, while the other served as a conventional frame for comparison. The frame with the MPRD showed reduced displacements. Compared with the conventional frame, that with the MPRD exhibited an increase in load of 40 % and an increase in energy dissipation of 6,44 %. Further, an increase in lateral stiffness, a 19,23 % increase in stiffness degradation, and changes in crack patterns were observed in the frame with MPRD compared to the conventional frame. The study's success in validating the MPRD performance in reducing structural responses in moderate to high seismicity regions makes it a promising solution for building seismic protection.

Seismic vulnerability and inventory of at-risk elements in the wine industry: Auckland region case study

Seismic vulnerability is a major threat to New Zealand's winery industry. Many studies have assessed the vulnerability of New Zealand wineries, especially in high seismic regions. However, few studies have been conducted to assess the earthquake susceptibility of wineries in low seismic regions, such as Auckland. This study investigated the earthquake vulnerability of wineries in the Auckland region by (i) creating an inventory of the elements at risk in the wineries and (ii) assessing the level of vulnerability of these elements. As case studies, twenty-one wineries from various parts of the Auckland region were chosen. The research findings identified key elements at risk of seismic hazard in Auckland wineries using a field survey, including buildings, storage tanks, catwalks, and barrel racks. Furthermore, the findings revealed that at-risk elements are vulnerable to moderate to high levels, emphasising the need for resilience strategies to reduce potential earthquake losses. This study concluded that low seismic risk does not imply low vulnerability, and that Auckland winery owners should reconsider their views on seismic risk mitigation. The study's findings benefit both winery owners and industry professionals by providing insights into the Auckland winery's vulnerability level and recommending approaches to improving the winery's organisational resilience.

Seismic Response of Reinforced-Concrete One-Storey Precast Industrial Buildings with Horizontal Cladding Panels

An extensive parametric study of the seismic response of one-storey precast buildings with horizontal cladding panels frequently used in Central Europe was conducted to analyse the panels’ influence on the overall response of buildings and to find out if the panels can be considered non-structural elements when they are attached to the main building with the connections typically used in practice in Central Europe. The studied structural system consisted of reinforced concrete columns and beams connected by dowels. Horizontal cladding panels were attached to columns using one of the most frequently used isostatic fastening systems. The top connections provided out-of-plane stability, and the bottom connections supported the panel in the vertical direction. The parametric study was preceded by extensive experimental research, including cyclic tests on connections and full-scale shaking table tests of whole buildings. The results of experiments were used to reveal the basic response mechanisms of panels and connections and to develop, validate and calibrate numerical models employed in the parametric study presented herein. Fifteen generalised structures with different masses and heights were subjected to 30 accelerograms with two peak ground acceleration (PGA) intensities of 0.3 g and 0.5 g, corresponding to significant damage and near-collapse limit states. The effects of the construction imperfections in connections, the silicon sealant panel-to-panel connections and different types of connections of the bottom panel to the foundation were analysed. The crucial parameter influencing the response was the displacement capacity of the connections, which was considerably affected by the construction imperfections and, consequently, difficult to estimate. It has been observed that in some buildings, particularly in shorter structures with smaller mass, cladding panels can have a somewhat more notable influence on the overall response. However, in general, when the considered types of connections are used, the panels can be considered as non-structural elements, which do not importantly influence the response of the main building. Owing to structural imperfections and relatively short available gaps, the failure of the considered top connections and falling of the panels is very likely in the high seismicity regions. In the most adverse cases, it can occur even in the moderate seismicity regions.

Development of seismic fragilities for a base station steel lattice cellular tower

A large portion of the country of Turkey is located in a very high seismic region known as a first-degree earthquake zone where earthquakes occur frequently. Earthquakes result in damage to infrastructure including base station towers and subsequently failure of mobile communication networks. The loss of functionality of mobile communication networks following an earthquake has a direct impact on emergency response and both short and long-term recovery phases. Understanding both these phases requires systematic modeling of infrastructure components, which rely on fragility curves representing the probabilistic relationship between seismic intensity and damage. This study focuses on the development of damage fragility curves (fragilities) for an archetypical mobile cellular tower, namely a 55 m tall steel lattice tower (SLT) used in base station towers in Turkey. Nonlinear time history analysis was performed using a robust suite of far field ground motion records to model the performance of the archetype tower and develop damage fragilities for five specific damage states which were defined in terms of likely performance: damage state 0 (no damage), damage state 1 (uninterrupted communication), damage state 2 (communication interruption), damage state 3 (communication failure), damage state 4 (structural failure). While fragility curve has been developed for lattice towers of different types and sizes in the literature, there is no specific study for 55 m SLT and the novelty of this study is that the resulting SLT archetype fragilities can serve as a benchmark dataset for use in community-level risk and resilience analyses to improve response and recovery planning following earthquakes.

An innovative model to estimate the tension field inclination considering crack growth for steel plate shear wall

The Steel Plate Shear Walls (SPSWs) are known as a capable system to use in steel structures due to their significant advantages. Despite extensive studies concerning this system, few researchers have scrutinized thecrack effect on SPSW behavior. However, the crack dramatically affected the experimental results. In the currentpaper, the effect of central and edge cracks, therefore, has been studied in jointed plates at mid-height of SPSW.Results indicated that the central crack is more destructive than the edge crack. The central crack having a long initial length also makes a sudden wall fracture in the elastic zone and consequently cannot be used in high seismic regions. Due to the dependence of the wall on the diagonal tension field and its angle, an equationis proposed taking into account shear, axial, and moment actions in columns, axial and moment actions in beams, as well as shear and axial actions in the plate which conform to finite element results. Because of thecomplication of the stress intensity factor for mode I and mode II calculations, this confidence is derived and offered.

Novel self-centering cold-formed steel composite wall: Concept, theoretical analysis, and numerical investigation

Cold-formed steel (CFS) structures exhibit considerable superiority in efficient and environmentally friendly building construction in high-seismic regions. The objective of this study is to develop and validate the concept of self-centering cold-formed steel composite (SC-CFSC) wall structures, and to characterize the lateral behavior of an SC-CFSC wall through numerical and theoretical analyses. Based on tests on shape memory alloy wires and CFSC walls, their hysteretic behavior is applied in ABAQUS to construct a finite element (FE) model of an SC-CFSC wall. The FE and theoretical analysis results of the SC-CFSC wall are in reasonable agreement, and valuable information regarding the design of the SC-CFSC wall is summarized. This study not only aims to provide a novel concept of self-centering CFS structures, but also to provide comprehensive explanation regarding the theoretical derivation and simulation procedures for characterizing the lateral behavior of both CFSC and SC-CFSC walls.

Experimental recognition of seismic performance of simple bolt-connected precast frame by comparing with equal stiffness cast-in-situ frame

Multi-story industry buildings composed of precast concrete members and simple bolt-type connections are widely constructed in the world, and there is enormous need for future construction market. Based on the equal stiffness and stiffness distribution along the height, a 1/5-scale precast RC frame utilizing simple bolt-type connections and a reference cast-in-situ monolithic RC frame were designed and constructed to conduct shaking table tests. According to the test results, the seismic responses, failure modes and energy dissipation behaviors of the two models were analyzed and compared. The vibration modes of the precast frame performed bending deformation pattern, while the cast-in-situ one presented shear deformation pattern. The damage and inter-story drift of the precast frame was comparatively uniformly distributed along the stories, whereas that of the cast-in-situ frame was concentrated in the first story. The energy dissipation capacity of the precast frame was inferior to that of the reference frame, as the bolt-type connections couldn't have plastic damages and plastic hinges that occurred in the cast-in-situ joint zones. In general, the global seismic performance of the precast frame was close to the reference frame and its collapse resisting capacity under severe earthquakes was reliable. Some serious local failure modes and less of energy dissipation capacity of the precast frame should be concerned in high seismic regions.

Performance-based Analysis of Building Structures in Various Earthquake Zones

The structural design of an eight-story building was examined to determine its performance in resisting ultimate loads. This was necessary for applying the building design in Indonesian regions with low to high seismic hazard levels. Studies have indicated that pushover analysis is suitable to assess the capacity of building structures against earthquake loads. However, as the structural design of each building produces its nominal strength, performance analysis must always be conducted. This study aimed at comparing the structural performance of buildings in regions with low, medium, and high seismic hazards, represented by the cities of Palembang, Jakarta, and Palu, respectively. A performance-based analysis was conducted using the pushover method to obtain the performance points. The responses of the building structures were the base shears, floor drifts, and inter-story drifts. The structural performance levels in the three regions were between immediate occupancy and life safety or were categorized as damage control, indicating minor damage. Because the structures exhibited high stiffness and ductility, they resisted the ultimate forces up to the damage control performance level in all regions. The greatest lateral drifts of 79.744 mm and 51.656 mm in the X- and Y-axis directions, respectively, occurred in Palu’s high seismic hazard region. The lowest lateral drift occurred in Palembang’s low seismic hazard region, in the X- and Y-axis directions of 59.401 mm and 38.378 mm, respectively.

Seismic performance of full-scale self-centering reinforced concrete beam-column joints: Experimental, numerical and theoretical analysis

A reinforced concrete (RC) frame system with a self-centering joint connected with post-tensioned (PT) tendons and bolted angles was developed to overcome the limitations of precast system without reliable connection. The self-centering beam-column joints with a gap at the beam-column interface are capable to resist severe earthquake with negligible residual deformation and minimal mechanical damage. However, a comprehensive understanding on effect of joint connectors including bolted angles and PT tendons on the seismic performance of self-centering joint (SCJ) is lacking. Three full-scale SCJ specimens were thus designed and tested under cyclic loading to determine the mechanical performance of SCJ and its influencing factors. The effects of bolted angles as energy dissipater and PT tendons as displacement controller were separately explored. The structural performance of SCJ was analyzed by finite element model, showing good agreement with the experimental results. A parametric study was conducted to further analyze the contribution of PT force and bolted angle to hysteretic response. Finally, the lateral load model of SCJ was established and the contribution of bolted angle and PT tendon was theoretical studied. The results indicate that the component elements (beam and column) remained undamaged after cyclic test, while the bolted angles experienced large deformation, dissipating substantial seismic energy. The gap at the beam-column interface of joint equipped with PT tendons was closed and the joint was perfectly self-centered by PT force exhibiting minor residual displacement after unloading. The PT tendons and bolted angles cooperated well, which enable the SCJ to be used as a connection in RC frame at high seismic region. Furthermore, the validated numerical model can be further used to predict the seismic performance of similar types of beam-column joints. The simplified analysis model can provide a potential design reference in the application of RC self-centering systems.

Optimal Properties of Nonlinear Viscous Dampers in Steel Structures Considering the Life Cycle Cost

ABSTRACT Recent studies demonstrated that high-frequency earthquakes have the most effect on the economic losses during seismic events. However, code-based seismic design criteria mainly aim to provide the occupants’ life safety. In this regard, code-compliant structures may result in significant economic losses during their life span. These damages contribute to the higher repair costs and lengthy functional disruptions of these structures. Improving the seismic behaviour of the structures by control devices could be one of the most efficient solutions. On this subject, applying fluid viscous dampers (FVDs) is an economical and reliable method. Optimizing the properties of these devices contributes to more efficient seismic behaviour of the structures. In this study, the key design parameters of viscous dampers, including damping coefficient and velocity exponent, are considered as optimization variables to achieve minimum life cycle cost (LCC) using the genetic algorithm (GA). To investigate the efficiency of the proposed approach, four-, eight- and twelve-story structures in high-seismic regions are investigated to consider different assumptions. The Endurance Time method (ETM) is adopted to conduct nonlinear analysis due to its high computational cost-efficiency and reliability. The results show that the nonlinear viscous dampers would decrease the total seismic loss of the structures by up to 40% in comparison with linear dampers. The optimal amount of velocity exponent is also obtained as a function of variation with the height and seismic region of the structures.

Quasi-Static Cyclic Tests of Precast Two-Column Bent Connected with Both Grouted Splice Sleeves and Grouted Central Tenon

Owing to the advantages of accelerated construction, reduced traffic disturbance, and enhanced quality control, precast segmental two-column bents are extensively utilized in urban and highway bridges, particularly in areas of low-to-medium seismicity. However, the application of this technique in high-seismicity regions is limited owing to insufficient knowledge about the seismic performance of such precast bents. To address this, the present study investigates the seismic performance of precast segmental two-column bents, focusing on the connection of “grouted splice sleeves and grouted central tenon”, namely the proposed GSS-GCT connection. For this purpose, three large-scale two-column bent specimens were fabricated and subjected to quasi-static cyclic tests: one cast-in-place bent, one precast two-column bent with conventional grouted splice sleeves, and another with the GSS-GCT connection. The benefits of the GSS-GCT connection under high seismic activities were demonstrated regarding lateral load-carrying capacity, displacement ductility, energy dissipation capacity, and residual displacement. Moreover, five levels of damage states were qualitatively and quantitatively divided based on experimental observation, which can be evaluated with lateral displacements. Furthermore, seismic assessments of the two-column bents were obtained using the capacity spectrum method. The proposed GSS-GCT connection could significantly improve the seismic performance of precast segmental two-column bents under high-level earthquakes.

Optimum Shear Walls Distribution in Framed Structures for Buildings Subjected to Earthquake Excitations

Reinforced concrete shear walls, which are vertically oriented plate-like elements, are efficient members in controlling the response behavior of buildings against seismic actions. In this research work, the performance of reinforced concrete buildings with shear walls having different shear wall-to-frame stiffness ratios is investigated. The considered buildings were designed in compliance with the requirements of the Algerian seismic code RPA99v2003 and were supposed to be located in regions of high seismicity. Seven 3D finite element models with different shear wall-to-frame stiffness ratios were developed and assessed using the nonlinear static analysis. Engineering Demand Parameters (EDPs) such as lateral displacement, inter-story drift ratio, shear force, and bending moment along the building height were presented. The results clarified that the induced responses can be classified into two major groups: force-based and displacement-based EDPs. Moreover, as the shear wall-to-frame ratio increases, the observed force-based EDPs increase whereas the displacement-based EDPs decrease. From a force point of view, distributing shear walls so that the packet of stiffness is lumped at the center of the building, model G with a stiffness ratio of 6.0906, amplifies the induced forces. This distribution requires more reinforcements and can lead to a conservative design. From a displacement point of view, distributing shear walls so that the packet of stiffness is lumped at the periphery of the building, model C with a stiffness ratio of 1.7879, minimizes the induced shear force and bending moment and produces the lowest values. This represents the optimum case with maximum performance and minimum strength.

Numerical Assessment of the Seismic Vulnerability of Bridges within the Italian Road Network

The safety of existing bridges represents a serious problem in Italy since these structures are fundamental for the national transportation system and, at the same time, can be subject to significant deterioration phenomena linked to the fact that the construction period typically dates back to the 1960s. This study involves the seismic analysis of five case study bridges belonging to the Italian Road Network. Using nonlinear time–history analysis with sets of code-spectrum compatible ground motions, analytical fragility curves have been constructed for each of the five bridges. The results obtained interpreting the analytical fragility curves agree with the fact that the seismic behavior of existing bridges can be problematic and that higher seismicity can be associated with more detrimental behavior. In particular, the results reveal that in regions with higher seismicity, the main problems in bridges are related to bearings and connecting elements located in the piers. Five case studies have also been analyzed to determine the Structural and Foundational Class of Attention and Seismic Class of Attention, following the approach proposed by the 2020 Italian Guidelines. In this way, it is possible to compare two different assessment approaches with different safety levels. The results obtained with the two approaches are in good agreement considering bridges in high seismicity regions, while the procedure of the Guidelines could lead to not reflecting the seismic behavior of bridges when the seismicity of the area is lower.