Alternate Load Path Research Articles

Evaluation of blast-induced progressive collapse in steel structures with conventional braces, moment-resisting braces, and buckling-restrained braces using LS-DYNA software

Today, considering the increased cases of terroristic operations, structural design engineers are starting to acknowledge blast-induced loads alongside other design parameters. Since a blast-induced load exhibits a much shorter period than the natural period of the structure, it is unlikely to induce general damages or stimulate the entire structure immediately after the loading, but rather local damages in individual structural elements are the common form of damage. These local damages, however, can set the scene for the gradual failure of the structure. The present study on structures with moment-resisting frames, buckling-restrained braces (BRBs), and conventional steel braces was conducted through an alternative load path (ALP, also known as column elimination) and exact modeling of the blast on the steel frames was undertaken using LS-DYNA software. In this work, the behavior of three five-story steel frames under a blast-induced load of 100 kg TNT equivalent at a distance of 10 m from the structural columns for a period of 100 ms was investigated. Results of analyzing the blast-induced effect on the frames showed that the frame equipped with buckling-restrained braces (BRB) exhibited improved overall peak displacement across the entire frame, peak induced velocity, and peak induced acceleration by 30%, 30%, and 46%, respectively, as compared to other steel frames exposed to blast loads.

Blast-Induced Progressive Collapse Analysis: Accounting for Initial Conditions and Damage

The paper presents the progressive collapse analysis of structures, focusing on the impact of the initial conditions (particularly initial velocity) and the damage. It proposes a method that calculates the residual axial load capacity and damage of columns based on their strain profile and considers the effects of multiple blast locations. The methodology involves the conventional design of a three-story moment-resisting frame, selecting blast parameters, calculating blast pressures, and performing structural and progressive collapse analyses. The findings reveal that the Alternate Load Path Method (APM) overestimates the capacity compared to a benchmark blast–structure interaction analysis, especially when unsuitable initial conditions and damage properties are used. To address this limitation, the paper concludes the recommendations for incorporating appropriate initial conditions and damage considerations for a relatively accurate progressive collapse analysis.

Experimental study on progressive collapse behavior of frame structures triggered by impact column removal

In the research field investigating the progressive collapse of building structures, event-dependent collapse processes have gained increasing attention in analytical and numerical studies. Different events could cause varying effects on progressive collapse resistance. The alternate load path could be related to events that could also lead to variations in load actions. However, experimental studies on reinforced concrete (RC) frame structures triggering structural column removal by the low-velocity impact have not been reported. Therefore, this paper performed an initial experimental study employing impact loading as the extreme event to investigate subsequent progressive collapse behavior of structures. Tests were conducted on six RC substructures consisting of a two-span beam and a structural column. Gravity loads were applied to the top of substructures, and a pendulum impact setup was utilized to remove RC columns by low-velocity impact. When the column underwent lateral failures, the downward force exerted by longitudinal steel bars of the column, before they fractured, pulled the two-span beam beyond the compressive arch action (CAA) stage, leading to a collapse process entirely different from their event-independent counterparts. The parametric study based on experimental results indicated that low-elevation impact and increase of column longitudinal bars detrimentally affected the performance of two-span beams resisting progressive collapse, while the increase in concrete strength partially improved the residual bearing capacity after impact column removal (ICR). Based on a dynamic model, a simplified calculation method is proposed for quantifying the downward force.

Robustness of a Steel Truss Bridge Subjected to Sudden Member Breakage during the Continuous-to-Simply-Supported Transition

Steel truss bridges are especially vulnerable in the event of a sudden loss of a load-carrying element, which can trigger a chain of failures. This paper describes a unique case study of a steel truss bridge under construction subjected to sudden member breakages with an extensive monitoring system. The failures occurred during the dismantlement of temporary members that had been used to transform a three-span simply supported steel truss bridge into a three-span continuous structure during incremental launching. These temporary members needed to be removed once the bridge reached its final position. The robustness of the bridge was assessed using computer simulations of various failure scenarios to evaluate its capacity to effectively activate alternative load paths (ALPs). The results demonstrated the structural redundancy of the steel truss bridge. However, the dynamic response resulting from the failure of the temporary upper chord, due to the initially high tension in the rods, should not be overlooked. To mitigate this issue, a structural retrofitting method was proposed, involving jacking the truss girder above the side pier to reduce the tension in the temporary upper chord above the middle pier. The effectiveness of this method was demonstrated through both simulated and formal experimental tests.

Using the load distribution between girders to monitor the condition of bridges

This study looks at the load distribution among beams in a 3-dimensional bridge Finite Element Model under normal traffic loading and the resulting effect of damage, modelled as a localised loss of elements in a beam. The load distribution is captured, both transversely across the girders and also longitudinally along the girders, and used to identify damage that is remote from the strain sensor location. When there is a loss of elements in a section of the bridge (e.g. due to a strike from a vehicle passing underneath), a portion of the load will redistribute along alternative load paths in the structure. This is most pronounced when the position of the loading and the location of the damage align but also happens when they do not. The study examines the effect of vehicles of different weight and axle configuration on the load distribution, and how grouping results by axle configuration can overcome this. A further novelty of this approach is that the strain response can be transformed into an influence line, which then allows data from large populations of general traffic to be used irrespective of axle configuration. The effect of various transverse positions of vehicles within the driving lane is overcome by combining data from large populations of vehicles. An advantage of this method is that the load distribution from a vehicle crossing is calculated as a ratio i.e. when the bridge is experiencing the same general environmental conditions, and thus reducing the difficulty in controlling the effects of varying environmental conditions when comparing results to a healthy baseline.

Numerical predictions of progressive collapse in reinforced concrete beam-column sub-assemblages: A focus on 3D multiscale modeling

The progressive collapse of reinforced concrete (RC) beam-column sub-assemblage under catenary action (CA) using the alternate load path method to evaluate structures' robustness has raised much attention in the past decade, both in experimental tests and finite element (FE) simulations. However, a comprehensive multiscale method within concrete to assess structural robustness against progressive collapse, explicitly surrounding concrete matrix under CA, is generally lacking and has not been thoroughly explored in the relevant literature. This study aims to develop an FE macromodel to reliably simulate the progressive collapse resistance of seismic and non-seismic RC beam-column sub-assemblages. The proposed macroscale FE models are extensively validated by experimental results dominated by the CA and excessive deformation of RC beam-column sub-assemblages. Then, the macroscale FE model is further partitioned at the critical region with high-stress concentration to establish a sub-model and elucidate the underlying mesoscopic mechanism to motivate the CA by performing sub-modeling analysis. A 150 mm × 150 mm × 150 mm mesoscale heterogeneous model is established to be composed of aggregates, interfacial transition zone (ITZ), pores, and mortar by 3D voxel and Voronoi-based methods. The numerical predictions of the three macroscale models demonstrate good agreement of the overall deformation and load resistance trends with experimental results at both structural and sectional levels, but an overestimation of the load resistance peak is observed when concrete is crushed. Compared to the macroscale models, the sub-modeling analysis provides a more in-depth understanding of localized phenomena such as cracks and fractures. The 3D mesoscale model is further investigated with different aggregate volume fractions following the Fuller gradation. It is found that aggregates and ITZ (higher porosity, lower elastic modulus, and lower tensile strength compared to the bulk mortar) are more prone to concrete failure mechanisms without considering the role of reinforcement leading to the CA at the mesoscale, maintaining the concrete properties of the three macroscale models. In terms of the material constitutive model, the concrete damage plasticity model, and cohesive elements for mortar and ITZ, respectively, under uniaxial compression and tension behavior, the importance of interface bonding in CA of the surrounding concrete matrix is underlined. Additionally, the established mesoscale modeling method facilitates comprehension of the responses exhibited by macroscale RC sub-assemblies, ultimately shedding light on fracture initiation and propagation mechanisms.

Determination of dynamic collapse limit states using the energy-based method for multi-story RC frames subjected to column removal scenarios

The Alternative Load Path method is widely adopted to perform progressive collapse analyses for reinforced concrete (RC) frame structures subjected to column removal scenarios. Considering that the progressive collapses are usually dynamic phenomena, nonlinear dynamic analyses can yield the most accurate results. However, the associated computational cost is high. Alternatively, the energy-based method (EBM) can be employed to efficiently calculate the maximum dynamic responses. Unfortunately, collapse or dynamic limit states (DLS) cannot be directly determined when the EBM is adopted for the progressive collapse analyses, because it is essentially a quasi-static approach. To tackle this issue, in this paper an EBM-Intersection Point-based (EBM-IP-based) method is proposed to effectively determine the DLS. The method is considering that the dynamic instability will occur once the dynamic capacity curve exceeds the corresponding static capacity curve. Hence, it is possible to determine the DLS by making a correction on the intersection point of the aforementioned two curves without performing nonlinear dynamic time-history analyses. Compared with the other energy components, the kinetic energy at the moment of the peak displacement response is relatively small and the effectiveness of the EBM is verified. Through both static pushdown analyses and incremental dynamic analyses for 48 column removal scenarios of six different multi-story RC frames, the effectiveness of the proposed EBM-IP-based method is verified and the associated coefficients are calibrated. Statistical information and (joint) probabilistic density functions (PDF) of the coefficients are identified. Further, stochastic analyses are carried out in order to quantify the model uncertainties when adopting the EBM-IP-based method. On the basis of all the calculation results, a Gumbel distribution is adopted to capture the PDF of the model uncertainty in relation to displacements, while a lognormal distribution is adopted to fit the PDF of the model uncertainty in terms of resistances. Moreover, a multi-variate Gaussian distribution model with two components is employed to fit the joint PDF.

ALTERNATIVE LOAD PATH AVOIDING BRIDGE COLLAPSE AFTER DEMOLITION OF A PIER BY COLLISION

Present codes require structures to be designed sufficiently robust, either by creating alternative load paths, or by increasing resistance of members. In the case of collision of column piers, alternative load paths seem to be an unworkable solution, since the loss of an essential support cannot be replaced by some other column or bracing. If all the columns of the same pier are destroyed, the adjacent beams of a concrete bridge are no longer in equilibrium, unless they become continuous and thus a corresponding bending moment can arise. The latter can be delivered by a couple of forces. The compressive force on top of the beams is provided by the bridge slab itself. The tensile force can be provided by a steel plate, below the bearings of the adjacent beams. Once the damaged condition comes about, there is a slight further shift of the bearings and the steel plate acts as a tensile element. A small-scale test has allowed us to confirm this principle experimentally. This idea has been tested for two cases of concrete bridges. A standard road bridge of multiple 34 m span of 39 precast prestressed hollow core girders and a 22.5 m span with classical I-section girders. Dummy cables are necessary to compensate the effect that bonded tendons are inactive at the ends of the PC-beams. Other details are still to be worked out, yet the general idea appears to be working and could meet the requirement for robustness.

ALTERNATIVE LOAD PATH AVOIDING BRIDGE COLLAPSE AFTER DEMOLITION OF A PIER BY COLLISION

Present codes require structures to be designed sufficiently robust, either by creating alternative load paths, or by increasing resistance of members. In the case of collision of column piers, alternative load paths seem to be an unworkable solution, since the loss of an essential support cannot be replaced by some other column or bracing. If all the columns of the same pier are destroyed, the adjacent beams of a concrete bridge are no longer in equilibrium, unless they become continuous and thus a corresponding bending moment can arise. The latter can be delivered by a couple of forces. The compressive force on top of the beams is provided by the bridge slab itself. The tensile force can be provided by a steel plate, below the bearings of the adjacent beams. Once the damaged condition comes about, there is a slight further shift of the bearings and the steel plate acts as a tensile element. A small-scale test has allowed us to confirm this principle experimentally. This idea has been tested for two cases of concrete bridges. A standard road bridge of multiple 34 m span of 39 precast prestressed hollow core girders and a 22.5 m span with classical I-section girders. Dummy cables are necessary to compensate the effect that bonded tendons are inactive at the ends of the PC-beams. Other details are still to be worked out, yet the general idea appears to be working and could meet the requirement for robustness.

Progressive Collapse of Typical and Atypical Reinforced Concrete Framed Buildings

This paper investigates the progressive collapse potential of eight-story reinforced concrete framed buildings with several atypical structural configurations and compares results with a typical structural configuration. The alternative load path mechanism, the linear-static analysis procedure amplified by dynamic increase factors, and the demand capacity ratio criterion limits from the U.S. General Services Administration guideline were used to evaluate the vulnerability of the different atypical and typical framed structures. Variations in bay size, plan irregularity, and closely spaced columns were used to represent the atypical structural configurations. The extracted demand-capacity ratio (DCR) of the global structural response showed that the demand-capacity ratio for the longitudinal frame with short-span beams had a larger DCR than the transverse frame with longer beam spans with significant potential for progressive collapse. Furthermore, atypical building configurations with closely spaced columns failed by shear and showed the highest DCR limits. In addition to the global structural response, the local member end actions were also evaluated. The evaluation showed that the critical atypical frame configuration with closely spaced columns had a 91% and 127% maximum shear force and support bending moment value difference, respectively, when compared to a baseline typical frame configuration.

Robustness of Reinforced Concrete Slab Structures: Lessons Learned from Two Full-Scale Tests

Within the research project ITSAFE, two full-scale structures were built, one consisting of a single-storey, two-span, 7.00 × 14.00 m2 RC frame with a solid slab and another consisting of a two-storey, 7.00 × 7.00 m2 RC frame with solid slabs. In the two-span frame, one of the central supports was first demolished using a pneumatic hammer, resulting in rather limited damage (a 14–15 cm deflection at the removed support location). However, torsional cracks appeared at the interface between a column and slab in one of the outer supports. When the second central support was removed, the structure collapsed with the failure of the support–slab connection. The same type of cracking was observed in the two-storey structure, where the column removal was dynamic, and a 22 cm deflection was measured. These experimental results question current practice in which, for internal supports, alternative load path mobilizing membrane forces in the slab are said to prevent their collapse, or in the cases of edge and corner columns, rupture line analysis is used and suggests that special reinforcement at the column–support connection is also needed to prevent the premature failure of the structure.

Evaluation of progressive collapse resistance performance of steel OMF with WCPF connections

A welded cover plated flange (WCPF) connection, which is a pre-qualified connection detail improving a weak weld access hole and the ductility of a welded unreinforced flange-bolted web (WUF-B) connection, has a simple and efficient advantage in construction. In this study, a new modelling approach of the WCPF connection by employing 1-D element was proposed for the evaluation of progressive collapse resistance capacity performance. The model was developed by substituting the average width of trapezoidal shapes of cover plates welded to the top and bottom flanges and by assessing the equivalent flange thickness based on the moment of inertia. The proposed model was verified through comparisons with experimental and 3-D numerical results, showing discrepancy within 5.7%. To evaluate the performance of the WCPF connection, a prototype structure was adopted from the previous study for the appraisal of the WUF-B and reduced beam section (RBS) connections. The alternative load path method was performed using an energy-based approximate analysis considering the dynamic effect of sudden column loss. The performance of the structure was evaluated in terms of structural robustness and sensitivity. Furthermore, the results were compared to those of the structures with the WUF-B and RBS connections analyzed in the previous study. The structure with the WCPF connections showed 33% more improved structural robustness and 11% less sensitivity to progressive collapse when one column was removed. In a two-column removal scenario, only the structure with WCPF connections indicated to have proper progressive collapse resistance capacity. The WCPF connection was deemed more reliable than WUF-B and RBS ones.

Progressive Collapse Resistance Assessment of a Multi-Column Frame Tube Structure with an Assembled Truss Beam Composite Floor under Different Column Removal Conditions

To estimate the progressive collapse resistance capacity of a multi-column frame tube structure with an assembled truss beam composite floor (ATBCF), pushdown analysis and nonlinear dynamic analysis are conducted for such a structure using the alternate load path (ALP) method. The bearing capacities of the remaining structures under three different work conditions, which are the side middle column removal, the edge middle column removal, and the corner column removal, are individually studied, and the collapse mechanism of the remaining structures is analyzed based on the aspects of the internal force redistribution and the failure mode of the second defense line. Simultaneously, the influence of the column failure time on the dynamic response of the remaining structure and the dynamic amplification coefficient is discussed. The results indicate that the residual bearing capacity of the remaining structure following the bottom corner column removal is higher than that of the one following the side or edge middle column removal, while the latter has a stronger plastic deformation capacity. When the ALP method is adopted to operate the progressive collapse analysis, it is reasonable to take the column failure time as 0.1 times the period of the first-order vertical vibration mode of the remaining structure, and it is suitable to set the dynamic amplification coefficient as 2.0, which is the ratio of the maximum dynamic displacement to the static displacement of the remaining structure under the transient loading condition.

Robustness assessment of precast concrete connections using component-based modelling

Employing highly optimised precast concrete product-based building solutions increases on-site productivity through elimination of formwork and reduction in propping as well as reducing waste, accidents and embodied carbon. The construction related benefits of precast concrete product-based building solutions are maximised by eliminating structural topping and designing connections between members for ease of assembly. A key challenge in the design of precast concrete buildings is the achievement of robustness under accidental loading. In this paper, sudden column removal is used to assess the robustness of a precast-concrete building system without structural topping. In this case, the development of an alternative load path under sudden column removal relies on the joint response. Joint behaviour is replicated using a component-based design procedure which captures localised failure modes. Robustness is evaluated using a ductility-centred approach and quantified in terms of the pseudo-static resistance. Two types of connection are considered for the provision of continuity at a critical half-lapped joint. The first is a plated connection which was designed initially to meet the tying requirements outlined in Eurocode 2. Under sudden column removal the plated connection’s deformational capacity is limited, which in turn reduces the pseudo-static resistance. An alternative bracketed coupler connection is proposed in which the ductility supply is controlled through debonding of reinforcement. The design concept for the bracketed connection is validated with test results from two full scale sub-assemblies. The experimental results are used to validate a component-based numerical model which is subsequently used to investigate the influence of boundary conditions, and debonding length on the pseudo-static resistance following sudden column loss. The paper shows that the pseudo-static resistance can be significantly enhanced by flexure and compressive membrane action. Consequently, the authors suggest that connection design in precast concrete structures without topping should be based on a realistic assessment of the ability of the structure to develop alternative load paths following instantaneous column removal rather than simplified tying rules.

Optimal risk-based design of reinforced concrete beams against progressive collapse

Risk analyses addressing consequences of progressive collapse have shown that, due to the small probabilities of element loss due to abnormal loads, structural strengthening for alternate load paths has negative cost-benefit for most buildings subjected to typical threats. This study addresses optimal risk-based design of reinforced concrete beams subjected to supporting column removal, with specific focus on reinforced concrete behavior. Nonlinear finite element analysis (NLFEA) is carried out, allowing both compressive arch and catenary actions to be predicted under large deflections. NLFEA results are compared to experimental data, showing good agreement and allowing quantification of model errors. Risk optimization results show that optimal beam designs change significantly with local damage probability, which is considered an independent parameter. More importantly, the study shows how different failure modes compete for limited construction and strengthening budgets. In case of intact structure, optimal design is governed by serviceability displacements, bending failure at midspan, and bending-shear failure at beam ends. Optimal design of the damaged structure is controlled by shear failure at beam ends and tensile rupture of steel rebar due to either catenary action or snap-through instability. Results highlight that, under significant column-loss probabilities, progressive collapse resistance is reached by larger beam depth, greater reinforcement area and reduced stirrup spacing. Such design measures against progressive collapse also provide greater safety margins against all failure modes of the intact structure.

An analytical framework for the evaluation of the progressive collapse resistance of precast concrete hollow-core floors

Buildings may be subjected to extreme events such as earthquakes, tsunamis, explosions, fires, or terroristic attacks during their service life. The current codes and guidelines provide three methods for the structural robustness assessment of buildings subjected to unidentified accidental actions: (i) the Tie Force, (ii) the Alternate Load Path and (iii) the Key Element methods. In particular, the Alternate Load Path is a direct method based on the evaluation of the ability of the structure and/or sub-assembly to effectively redistribute the applied loads and develop alternate load paths after the loss of a load-bearing element. In the literature, several studies aimed to investigate the progressive collapse performance of monolithic reinforced concrete structures, with almost no attention paid to precast concrete structures. In this work, in the context of the Alternate Load Path methods, an analytical framework is proposed and validated for the assessment of the progressive collapse resistance of precast concrete floors composed of hollow-core units and precast concrete beams, where the role played by tying reinforcement is analysed. Firstly, the study focuses on double-span hollow-core floor units by providing: (i) the static pushdown response, (ii) the dynamic capacity curve as well as the dynamic amplification factor and (iii) a practical robustness indicator, based on geometrical and mechanical features through the calculation of the chord rotation capacity, a fundamental parameter to be adopted for progressive collapse resistance. Finally, the method is extended to an entire hollow-core floor system, where both distributed ties in slab units and concentrated ties in beams are considered in the system resistance. Due to its simplicity, the analytical framework is considered useful for practical purposes, as reported with an example in the Appendix.

Alternate load path behaviour in structures with non-symmetrical design under column missing scenario

In the design and assessment of reinforced concrete (RC) structure against progressive collapse via single column removal scenario, also known as “alternate load path method”, development of secondary mechanisms, i.e. compressive arch action (CAA) and catenary action (CA) in double-span beams has been investigated and identified in many previous researches. The majority of the experimental tests are conducted on symmetrical double-span beams (identical span length and reinforcement detailing at both beam span). However, variations in details of beams adjacent to one another are not uncommon in RC building designs and constructions. Hence, a research study (as presented in this paper) with total of 5 RC frame tests are conducted to investigate the development of secondary mechanisms (CAA and CA) in a double-span beam with unsymmetrical 1) span length and 2) beam detailing. For each unsymmetrical case (span length and beam detailing), there will be 1 unsymmetrical double-span beam, and 2 symmetrical double-span beams (each representing one side of the unsymmetrical double-span beam) to serve as reference for quantifying the development of secondary mechanism in unsymmetrical double-span beams. The behaviour and development of secondary mechanisms are thoroughly analysed based on test observation, measured forces and displacements, etc.

Rehabilitation of Corroded Steel Bridge Girder Ends using Partial-Height Ultra-High-Performance Concrete Encasement

Beam end corrosion is one of the most prominent types of deterioration on simple-span steel bridges. To address this concern, the Connecticut Department of Transportation and the University of Connecticut have jointly developed a repair method for corroded steel girder ends using ultra-high-performance concrete (UHPC) encasement. In this repair, shear studs are welded to the undamaged portion of the web and encased in UHPC to create an alternate load path for bearing and shear forces. This novel repair method has been implemented in multiple states. The widespread promotion of steel girder end repair with UHPC demonstrates the need for literature on field implementations and alternative designs. This paper advances the findings from a field implementation completed in Connecticut in October 2021, which was the first instance of a partial-height repair in the country, the first application of the repair to a weathering steel bridge, and the first use of flange studs to restore shear capacity at the junction of the web and bottom flange. Two of the girder ends were fully instrumented to collect data on the performance of the repaired locations. The paper presents an overview of the bridge, discusses the design and implementation of the repair, provides short-term monitoring data showing its successful activation, and discusses lessons learned throughout the process. It is anticipated that the findings put forward provide support for the use of UHPC encasement as a promising method for the repair of corroded steel girder ends.

A honeycomb panel-based protective device for steel parking structure against transverse impact

With escalating demand for urban parking structures, the columns within these structures are more susceptible to hazards resulting from vehicle collisions compared to other public buildings. Moreover, it is crucial to emphasize the significant increase in the risk of collapse in parking structures subjected to vehicle collisions, primarily owing to their heightened dynamic response and low required bearing capacity. Consequently, to prevent vehicles from directly crashing on the columns, besides providing an alternate load path, urgent implementation of protective measures utilizing energy-absorbing materials is necessary for parking structures. This study proposes a honeycomb panel-based (HP) protective device for steel parking structures aimed at absorbing energy and mitigating damage resulting from vehicle collisions. A simplified multi-scale simulation, considering reasonable material models and boundary conditions, is employed to study the performance of parking structures under transverse impact. The deformation patterns, impact loads, transverse deflections, internal energies, and horizontal reactions are compared for the parking structures with and without the HP protective devices. Innovatively, a classical progressive collapse loading scheme is employed to simulate the vertical residual resistance of the beam-column substructure after the transverse impact. Finally, a comprehensive investigation is conducted on the effects of critical parameters of HP protective device. The results demonstrate that a properly designed HP protective device can significantly enhance the resistance of parking structures to transverse impact, thereby effectively mitigating the risk of progressive collapse in such structures after impact.

DETECTING ANOMALIES IN STRUCTURAL RESPONSE OF CABLE SUPPORTED BRIDGES: AFTER EXTREME EVENTS

AbstractThe safety of cable‐supported bridges primarily depends on cable design, proper tensioning during construction, and regular maintenance. Over the past decade, numerous cable‐supported bridges have faced various issues, including aging, poor tensioning practices, coping with heavy traffic loads, insufficient maintenance, and exposure to accidents or extreme conditions. Despite these challenges, these structures often withstand such problems due to the inclusion of redundancy and alternative load paths in their design. Detecting anomalies in bridge monitoring data can aid in identifying potential issues. Typically, only specific cables are monitored in a cable‐supported bridge monitoring system. The conditions of non‐monitored cables are usually estimated based on the data from adjacent cable sensors. The structural response of the tower and the deck can also be indirectly estimated. This research aims to present a methodology for detecting anomalies in structural responses following extreme events. It is crucial to differentiate temporary changes in cable measurements caused by expected seasonal temperature fluctuations, regular winds, and normal traffic patterns from permanent changes resulting from extreme events. Additionally, one must consider that a permanent change in measurements might also occur due to sensor loss after an extreme event. The paper will discuss tools to form a detection that can identify whether the source of change is due to a real extreme event or not.