Steel Arch Bridge Research Articles

Structural-Health-Monitoring-Oriented Finite Element Model for a Specially Shaped Steel Arch Bridge and Its Application

To rigorously evaluate the health of a steel bridge subjected to vehicle-induced fatigue, both a detailed numerical model and effective fatigue analysis methods are needed. In this paper, the process for establishing the structural health monitoring (SHM)-oriented finite element (FE) model and assessing the vehicle-induced fatigue damage is presented for a large, specially shaped steel arch bridge. First, the bridge is meticulously modeled using multiple FEs to facilitate the exploration of the local structural behavior. Second, manual tuning and model updating are conducted according to the modal parameters measured at the bridge’s location. Since the numerical model comprises a large number of FEs, two surrogate-model-based methods are employed to update the model. Third, the established models are validated by using them to predict the structure’s mode shapes and the actual structural behavior for the case in which the whole bridge is subjected to static vehicle loads. Fourth, using the numerical model, a new fatigue analysis method based on the high-circle fatigue damage accumulation theory is employed to further analyze the vehicle-induced fatigue damage to the bridge. The results indicate that manual tuning and model updating are indispensable for SHM-oriented FE models with erroneous configurations, and one surrogate-model-based model updating method is effective. In addition, it is shown that the fatigue analysis method based on the high-circle fatigue damage accumulation theory is applicable to real-world engineering cases.

Experimental investigation on the vortex-induced vibration of an arch steel bridge tower

This paper reports the wind tunnel study of the vortex-induced vibration (VIV) of a free-standing steel arch bridge tower with pentagon cross-section. The tests were carried out at different yaw angles β (0°–90°) of wind flow by employing a 1:50 scaled aeroelastic model. A series of aerodynamic measures were studied to mitigate the VIV of the tower at the most unfavorable yaw angle. Effects of turbulence intensity and structural damping on the VIV performance of the tower were evaluated. A sleeve-type eddy current damper (ECD) for increasing the structural damping of aeroelastic model was designed for reserved emergency measures. Experimental results indicate that the VIV occurs for a few yaw angles at wind velocity of 15–18 m/s and the maximum VIV amplitude happens for β = 35°. The aerodynamic measures are effective for some yaw angles but become invalid for other yaw angles. Compared to those in smooth flow, the VIV amplitude drops by 65% for a turbulence intensity of 8.5%. The VIV of the tower can be effectively suppressed by the eddy current damper which provides additional damping to the aeroelastic model. The sleeve-type eddy current damper is shown to be a convenient device to adjust the damping for aeroelastic models.

Reclassifying Fracture Critical Members (Non-Redundant Steel Tension Members) to System Redundant Members in a Steel Arch Bridge

The American Association of State Highway and Transportation Officials (AASHTO) Load and Resistance Factor Design Bridge Design Specifications define fracture critical members (FCMs) as steel primary members, which are subject to tension and whose failure would probably cause the collapse of a portion of or the entire bridge. FCMs not only lead to additional material procurement and fabrication quality requirements, but bridges with FCMs need to meet the requirements of special mandatory bi-annual hands-on inspections in additions to the routine planned bridge inspections per the National Bridge Inspection Standards. The special mandatory inspections for FCMs are a considerable budgetary constraint for asset owners while still not providing definite safety proofs within the period in between the inspections. Designation of FCMs should be carefully scrutinized in a new bridge constructed with high-quality materials and well-designed details. In 2012, the Federal Highway Administration published a memorandum introducing system redundant members (SRMs), which are identified through refined analysis and exempted from the inspection requirements for FCMs. A new AASHTO Guide Specification released in 2018 outlines a detailed procedure for the reclassification of FCMs as SRMs. This paper summarizes the analyses and results of a detailed FEA performed for a newly designed steel arch bridge. The analyses considered potential failure scenarios at the edge girder of the steel arch bridge and demonstrated the available redundancy in the system to distribute the loads by satisfying the performance criteria set forth in the AASHTO Guide Specification. Reclassification of the FCMs as SRMs could help the asset owner to reallocate their strained resources more efficiently.

Theoretical Analysis of Ultimate Main Span Length for Arch Bridge

The advancement of construction techniques and high-performance sustainable materials enables the increase of span length for arch bridge. It is of great importance to study the theoretical ultimate span length of arch bridge. Based on the parabolic and catenary arch axes, the analytical solutions of ultimate span length of arch bridge are solved using theoretical derivation accounting for the strength, in-plane stability and out-plane stability conditions, respectively. Then, the use of high-performance concrete, reactive powder concrete and high-strength steel is considered to study the relationship between theoretical ultimate span length and rise-span ratio as well as material strength for concrete and steel arch bridges. The results show that the theoretical ultimate span length derived by catenary arch axis is smaller by about 2–6% than that obtained by parabolic arch axis, but the difference is insignificant. When the rise-span ratio is 1/5, the theoretical ultimate span length for concrete arch bridge using R200 reactive powder concrete can reach 2000 m (2161 m for catenary arch axis and 2099 m for parabolic arch axis) while the main span of steel arch bridge using Q690 high-strength steel can be longer than 2500 m (2948 m for catenary arch axis and 2865 m for parabolic arch axis).

Critical Analysis of the Chenab Bridge, India

Chenab river is one of the big rivers in Northern India. Indian Railways has undertaken to make a bridge in the state of Jammu and Kashmir (JandK) over the Chenab river. This bridge is one of the perfect examples of steel and concrete arch bridge, which is in under construction at the height of 320m above the river. This construction has announced as National Project. According to the plan, after completion, the bridge can be declared as the World’s highest rail bridge. Its steel arch main span is 467m long, which is the main key feature of the bridge. This bridge is aim to complete within December 2021. This paper provides an informative review and critical analysis along with conceptual design, the problem faced during the construction of the bridge.

Evaluation of Criteria for Out-of-Plane Stability of Steel Arch Bridges in Major Design Codes by FE Analysis

The provisions for out-of-plane stability of steel arch bridges in three major design codes are presented in this paper. By employing an existing steel arch bridge as a model, the influence of bridge type, arch rib to lateral bracing stiffness ratio, rise-to-span ratio, arch rib spacing, and range of lateral bracing arrangements on the out-of-plane critical axial force of the arch rib is studied using FE analysis. The accuracy of the critical axial force provisions is then evaluated against the FE analysis. The results show that the influence of the rise-to-span ratio on critical axial force is generally small. The critical axial force decreases with increasing arch rib spacing when the stiffness ratio is relatively large. A smaller ratio of arch rib length provided with lateral bracing (γ-value) significantly reduces the critical axial force and normalized critical axial force decreases with increasing stiffness ratio. The critical axial force of half-through type arch bridges is lowest when the stiffness ratio is relatively small. A deck-type bridge has a larger critical axial force than a through-type bridge when the stiffness ratio is relatively large, while the results are the opposite when the ratio is small. The different assumptions made in the provisions result in the various parameters having different impacts on the out-of-plane critical axial force in each code, thus affecting code accuracy. Considering the influence of the rise-to-span ratio, ratio of lateral bracing, and arch rib spacing with different stiffness ratios, factors to improve the accuracy of the critical axial force obtained by the three codes are proposed for a practical design process.

Influence of frost and local stiffness variations on the strain mode shapes of a steel arch bridge

Natural frequencies are probably the most widely used modal characteristics in vibration-based monitoring. However, they can be highly influenced by temperature and this influence can completely mask the effect of even severe damage. This translates into a necessity for time-consuming data-normalization techniques to remove the influence of temperature and identify damage. Displacement mode shapes of homogeneous material structures are less influenced by temperature, but obtaining them in a dense grid, which is required for damage localization, is cumbersome due to the large number of sensors needed. Strain mode shapes on the other hand can be insensitive to temperature variations, while obtaining them in a dense grid is possible when fiber-optic sensors such as fiber-Bragg gratings (FBG) are used. This work presents the results of the continuous monitoring of a steel railway bridge for a period of almost two years, where modal data were collected for a wide temperature range. The bridge is instrumented with eighty FBG strain sensors, multiplexed in four fibers. The natural frequencies and strain mode shapes of ten modes have been automatically identified from operational strain time histories, on an hourly basis. A clear influence of temperature on the natural frequency of most modes is identified, especially during frost periods. On the contrary, the strain mode shapes are mostly insensitive to temperature changes and only these of some higher-order modes are slightly and uniformly influenced when frost occurs. This behavior is confirmed also by a finite element model (FE) of the bridge. Furthermore, the FE model is used to investigate the influence of local stiffness changes on the modal characteristics. A clear and local change of the modal strain amplitude is observed at the location of the reduced stiffness, especially when information from all modes is combined in a sensitive damage index.

Study of Periodical Temperature Change Induced Deformation of an Inclined Steel Arch Bridge Exposed to Actual Environment Based on Synchronous Multi-Member Thermal Simulation

Structures exposed to the environment are affected by periodically changing temperature, and will undergo reciprocating deformation under the action of actual temperature. Steel structures are sensitive to temperature, and the effects on structure induced by changing temperatures are even more significant. The accurate calculation of temperature effects is very important to enable engineers to understand the state of a structure. However, the value of the temperature load in the current specification is set as constant, which can neither reflect the real state of the temperature field, nor its time-dependence in the actual environment. In this paper, an inclined steel arch bridge is chosen as an engineering example in order to analyze the actual temperature field of the structure in different seasons, and its deformation under the action of temperature, and the effects are compared with results based on other specifications. The comparison results show the synchronization of thermal deformation among different components and indicate the conservation of the specification. In order to further determine the most unfavorable situation under the effect of temperature changes, the deformation of multiple examples are compared, according to a standard load combination method, which verifies the feasibility of the load combination method in the calculation of temperature effects. It is found that the result can reflect, to a certain extent, the combined effect of the temperature changes of different components.

The construction of the Cross Bay Link bridge in Hong Kong

The Cross Bay link (CBL) bridge is a 1 km sea crossing that forms the centrepiece of the new east–west express highway link in Hong Kong. This £250 million project features an iconic 200 m span butterfly double-arch bridge and a series of concrete box girder spans supported on specially sculpted V-piers and large piled foundations. This paper describes the innovative construction methods adopted for building the bridge safely and efficiently in an extremely challenging marine environment, a process that relied on the extensive use of design for manufacture and assembly solutions, with most of the bridge elements above the sea level being prefabricated or precast off site. This includes the construction of the 10 000 t steel arch bridge, which was fully prefabricated near Shanghai, then transported to Hong Kong by a semi-submersible barge, and eventually erected onto the piers using the float-over method. In addition, most of the concrete decks, piers and the pile cap shells were precast off site and then lifted into position on site. This project holds a number of engineering records in Hong Kong, including the longest arch bridge, the first-time adoption of S690QL high-strength steel for major bridge elements and the largest scale implementation of the float-over erection method.

Fatigue Analysis of Long-Span Steel Truss Arched Bridge Part II: Fatigue Life Assessment of Suspenders Subjected to Dynamic Overloaded Moving Vehicles

In a half-through steel arched bridge, the suspenders are the critical load transfer component that transmits the deck system and traffic load to the arch rib. These suspenders are subjected to traffic and environmental vibrations and are prone to fatigue failure, especially for overloaded moving vehicles. This paper aims to study the impact of moving vehicles’ overloaded rate on the fatigue performance of suspenders in a long-span three steel truss arch bridge. Based on the Mingzhu Bay steel arch bridge, a 3D finite element bridge model was first established and seven types of moving fatigue vehicle models were considered. Then the stress amplitude and dynamic response of the suspenders on the middle steel truss arch were studied under a standard, 25%, and 50% overloaded moving vehicles load. Following that, the Miner fatigue cumulative damage theory was employed to evaluate the fatigue life of the suspenders. The results show that the short suspenders in the middle steel truss arch have the shortest fatigue life but can still meet the design requirements under the standard load. However, the fatigue life of the suspenders decreases by 20% and 30% when the overloading rate reaches 25% and 50%. The fatigue life cannot meet the design requirement when the overload rate is 50%.

EFFECT OF USING LEAD RUBBER BEARING ON A STEEL ARCH BRIDGE

A study was conducted to evaluate the application of Lead Rubber Bearing (LRB) on bridge structures. The length of steel arch bridge is 80 m, width of 10 m, and height of 19.6 m. The bridge is simply supported with two bearings on each support. Structural analysis reveals that the lateral force on the bearing is more than 400 tons (835 tons in longitudinal direction). The original designer’s intention is to use pot bearings. However, the pot bearing was required to undergo some mechanical test to verify its properties prior to installation. Due to its size, this scheme is not applicable due to the limitations of the testing facility. Therefore, an alternative design was evaluated using LRB to reduce the reaction force, hence downsize the bearing size. The LRB used is of LRB 7500 characteristics, and the calculation refers to AASHTO Guide Specifications for Seismic Isolation Design (GSID), 4th edition 2014.The analysis shows that applying LRB on the bridge lengthened the structural period from 0.76 seconds to 1.67 seconds. It also increased the damping ratio from 5% to 43 %. With these significant changes in structural parameters, lateral forces due to earthquake loads on the bearing and foundation can be greatly reduced. The study found that replacing pot bearings with LRBs can reduce the lateral force to 80 tons, approximately one fifth from the previous design. Correspondingly, the internal forces of some major structural components of the bridge can be reduced due to the application of LRB.

EFFECT OF USING LEAD RUBBER BEARING ON A STEEL ARCH BRIDGE

A study was conducted to evaluate the application of Lead Rubber Bearing (LRB) on bridge structures. The length of steel arch bridge is 80 m, width of 10 m, and height of 19.6 m. The bridge is simply supported with two bearings on each support. Structural analysis reveals that the lateral force on the bearing is more than 400 tons (835 tons in longitudinal direction). The original designer’s intention is to use pot bearings. However, the pot bearing was required to undergo some mechanical test to verify its properties prior to installation. Due to its size, this scheme is not applicable due to the limitations of the testing facility. Therefore, an alternative design was evaluated using LRB to reduce the reaction force, hence downsize the bearing size. The LRB used is of LRB 7500 characteristics, and the calculation refers to AASHTO Guide Specifications for Seismic Isolation Design (GSID), 4th edition 2014.The analysis shows that applying LRB on the bridge lengthened the structural period from 0.76 seconds to 1.67 seconds. It also increased the damping ratio from 5% to 43 %. With these significant changes in structural parameters, lateral forces due to earthquake loads on the bearing and foundation can be greatly reduced. The study found that replacing pot bearings with LRBs can reduce the lateral force to 80 tons, approximately one fifth from the previous design. Correspondingly, the internal forces of some major structural components of the bridge can be reduced due to the application of LRB.

Effect of blast load on the structural integrity of steel arch bridge slab

In order to know the safety margins and the critical zone of an important infrastructure such as a bridge, the response of the construction typology to extreme forces must be investigated. In this sense, in the literature, few numerical and experimental data are available concerning the response of steel bridges under explosive loads. The purpose of this work is to develop a coherent model, using the finite element analysis method, to verify the behaviour of such a structure and to focus on the collapse mechanism. As a case study, a typical network arch bridge was defined and meshed. Information about stresses, strains and displacement were collected as a function of the position and intensity of the slab damage. Finally, some useful observations were collected regarding the slab response, damage mechanisms and the role of the concrete class.

Wind-Induced Response Analysis for a Fatigue-Prone Asymmetric Steel Arch Bridge with Inclined Arch Ribs

Steel arch bridges with inclined arch ribs under strong wind fields are prone to fatigue damage due to the stress concentration at the position of hanger connections. Therefore, it is essential to perform the wind-induced response analysis for specified shape hangers, such as inclined hangers, to determine the stress distribution and corresponding influencing factors. In this study, wind-induced response analysis for a fatigue-prone asymmetric steel arch bridge with inclined arch ribs is performed by the numerical simulation approach. The investigated bridge hangers’ models are established by using the COMSOL Multiphysics software. The wind-induced stress of the bridge hangers under different wind directions is obtained based on the finite element method. The influential factor of the stress distribution of the bridge hangers on both the windward side and the leeward side is discussed. In addition, the stress peaks of the long hanger and short hanger are achieved for further fatigue analysis. This paper provides a reference for determining the critical fatigue-prone position of an asymmetric steel arch bridge with inclined arch ribs.

ESS-based probabilistic fatigue life assessment of steel bridges: Methodology, numerical simulation and application

The selection of an appropriate S-N curve for a specified type of welded joints is an essential part for the fatigue reliability assessment of steel bridges by means of a stress-life approach. However, this is still a challenging issue in the real engineering applications due to the complexity of the structural components and the lack of the available numbers and types of S-N curves. In this study, a generalized fatigue reliability model based on equivalent structural stress (ESS) is proposed, which has the merit of taking no account of the selection of the S-N curve. An ESS-based probabilistic S-N formulation is first derived by introducing a probability index to the expression of the S-N curve. Then, the fatigue reliability model, which incorporates the random variables of the ESS range, the number of cycles and material properties, is deduced by combining the Miner’s rule. Numerical case studies and sensitivity analyses on the effects of the ESS range, the number of cycles and the growth in traffic volume are performed to evaluate the practicability and the effectiveness of the proposed fatigue reliability model. Finally, the proposed method is applied to an instrumented steel arch bridge with the aid of field dynamic strain data. The fatigue failure probability and the fatigue reliability index versus fatigue life are achieved through random samples generated by means of the Monte Carlo (MC) simulation on the basis of the joint probability density function (PDF) of random variables. The results show that the proposed method provides a viable way of resolving the difficulty in selecting a suitable category for the evaluation of the probabilistic fatigue life of the welded details in steel bridges. In addition, it can be found that both the PDF of stress spectrum and the growth of traffic volume are sensitive to the failure probability and reliability index obtained by the proposed fatigue reliability model.

In‐Plane Instability of Parabolic Arches under Uniformly Distributed Vertical Load Coupled with Temperature Gradient Field

In civil engineering, arches, such as steel arch roofs and arch bridges, are often subjected to linear temperature gradient field. It is known that the in‐plane instability of parabolic arches is caused by the significant axial force. The arch under the linear temperature gradient field produces complex axial force, and so the instability of arches would be affected by temperature gradient field significantly. However, the analytical solutions of in‐plane instability of parabolic arches being subjected to the uniformly distributed vertical load and the temperature gradient field are not solved in the opening literature. In this paper, in‐plane instability of a fixed steel parabolic arch under linear temperature gradient field and vertical uniform load is analyzed theoretically. Firstly, the cross‐sectional effective centroid and effective stiffness of the cross section for arches under the linear temperature gradient field are derived. Secondly, the preinstability internal force analysis of the parabolic arch under the linear temperature gradient field and the vertical uniform load is carried out based on the force methods. Novel theoretical solutions for in‐plane instability load for fixed steel parabolic arches under the linear temperature gradient field and the vertical uniform load are obtained. It is found that the gradient temperature, slenderness, and rise‐span ratio have important influences on the critical in‐plane instability load of the shallow parabolic arch, while there is no significant effect on the deep parabolic arch.

Dynamic Behavior of a Historic Metallic Bridge under Metro Vehicles Based on Advanced Interaction Models

The present article focuses on the evaluation of the dynamic behaviour of a centenary steel arch bridge, located in Portugal, under light railway traffic loads. The work aims to assess the dynamic behaviour of the bridge subjected to an alternative type of railway vehicle, more specifically, a typical underground vehicle that is currently in service in the Lisbon Metro. The dynamic response of the system has been evaluated using two distinct methodologies, namely a moving loads model and a vehicle-bridge interaction model. To achieve this goal, finite element (FE) models from both the bridge and the vehicle have been developed and a comprehensive study has been carried to evaluate the influence of distinct factors in the dynamic response of the bridge-train system, namely the methodology used to assess the dynamic response, the location of the response reference point in the deck, the train speed and the vehicle configuration (single or double vehicle). Moreover, both the traffic safety, passenger comfort and pedestrian comfort have also been evaluated using normative criteria based on acceleration responses. The results shown that the normative limits related to traffic safety and passenger comfort were never exceeded in any condition analysed in the study. However, the pedestrian comfort was jeopardized when the train speed exceeded 20 km/h.

Calculation model including time-varying coefficients for calculating the lateral pressure of bottom-up pumping self-compacting concrete

The accuracy of concrete lateral pressure predictions affects the safety and economic aspects of constructions. For the prediction of the maximum lateral pressure of bottom-up pumping self-compacting concrete, based on the graph multiplication method, a calculation model with time-varying coefficients was proposed, which considers the friction effect. The time-varying characteristics of the key coefficients of self-compacting concrete with slumps of 600 mm, 700 mm, and 800 mm were studied by simulating the concrete pouring process and, then, applied to the calculation model. In two dumbbell-shaped steel arch bridges, pressure sensors were placed in the inner wall of the typical steel pipe’s section to measure the lateral pressure during the pumping process and, hence, verify the accuracy of the calculation model. The applicability of the calculation model was verified by comparing the calculated results with other specifications. Results indicate that, as the liquid level increases, the effect of friction will cause a significant increase of pressure at the bottom. In predicting the maximum lateral pressure of bottom-up pumping self-compacting concrete, the calculation model can be well applied in the case where the liquid level was higher.

Study on the Calculation Method of Bearing Capacity of Old Steel Arch Bridge

Due to the long-term action of load, the material properties and structural shape of bridge structure will gradually change during service, resulting in the change of bearing capacity. In this paper, a calculation method of maximum bearing capacity is proposed for old steel arch bridges. The calculation method considers the material nonlinearity and geometric nonlinearity, as well as the residual deformation of the structure of the old bridge caused by the overload vehicle, collision of the vehicle and ship, resulting in the difference between the actual structure and the design drawing. Taking an 85 year old steel arch bridge in Ningbo as an example, the current material properties and the current configuration of the structure are actually tested, and the bearing capacity is calculated. The results show that: (1) The steel used in the bridge is well protected, and the properties of steel still meet the requirements; (2) For steel arch bridges, the deformation of arch ribs, especially the deformation out of plane, may greatly weaken the bearing capacity of the bridge; (3) It is necessary to consider the material nonlinearity and geometric nonlinearity for the calculation of the maximum bearing capacity of the old bridge.

Marginal Hilbert spectrum and instantaneous phase difference as total damage indicators in bridges under operational traffic loads

The challenges and future trends in the development of signal processing tools are being widely used for damage identification in bridges. Therefore, it is important to analyse the vibration signals in order to attain effective damage characterization. In this paper, the non-linear and non-stationary dynamic response of bridges under operational loads is studied. First, the signals are decomposed into intrinsic mode functions (IMF) by a novel Improved Completed Ensemble EMD with Adaptive Noise technique (ICEEMDAN). Hilbert-Huang transform is used to obtain their corresponding Hilbert spectra. The marginal Hilbert spectrum (MHS) of each IMF and the instantaneous phase difference (IPD) are proposed as total damage indicators (DI), in the sense that they are able to detect, localize and quantify damage under transient vibration due to traffic. The methodology was tested in two case studies: (i) a numerical model of a two-span steel bridge (ii) a dynamic test conducted on a real steel arch bridge subjected to a series of artificial damages. The experimental and real case results from the damage indices based on the extracted features demonstrate the robustness and more sensitivity of the novel Improved Completed Ensemble EMD with Adaptive Noise technique (ICEEMDAN) in addressing the damage location.