Steel Piers Research Articles

Greece's new high‐speed railway line: Detailed design and construction engineering of bridge SG26

AbstractThe paper presents the several aspects of the detailed design and the construction engineering procedure of the most important Railway Bridge of the New Double High‐Speed Railway Line connecting Athens and Thessaloniki, the two biggest cities in Greece. The total length of the bridge is 404.8m consisting of three simply supported tied arches with a width of 18.03m. The two piers, 45.5m height each, are supported on rigid caisson foundations. The bridge has been constructed using the incremental launching method due to the deep valley below. The special characteristic of the bridge is that it crosses an active fault zone, associated with large seismic events (e.g. 1954 magnitude 6.8). Seismic devices (Friction Pendulum System and Fluid Viscous Damper) are installed between the deck and the substructure in order to absorb the anticipated seismic energy and consequently reduce deck displacement and force transmission to the structural elements. I. MAVRAKIS & PARTNERS S.A. carried out the detailed design and construction engineering, including the design of the temporary steel piers, the incremental launching procedure, the precamber design of the arches, the prestressing sequence of the hangers, the seismic isolation design and the shop drawings of the whole structure.

Philly to the Steel Pier

Philly to the Steel Pier

Seismic performance of eccentrically-compressed steel pier under multi-directional earthquake loads

Seismic performance of eccentrically-compressed steel pier under multi-directional earthquake loads

Effect of Corroded Surface Morphology on Ultra-Low Cycle Fatigue of Steel Bridge Piers.

Corrosion is a common form of durability degradation of steel bridges. Corrosion morphology affects stress distribution under cyclic loads and causes strain concentrations in pits, thus affecting the mechanical properties of steel structures, including ultra-low cycle fatigue (ULCF). To precisely simulate corrosion morphology and investigate the ULCF failure mechanism of corroded steel piers, a sculpting method was applied to mesh units using three-dimensional surface morphology data of corroded steel specimens. Moreover, the ULCF crack-initiation life was numerically predicted using the finite element model based on the cyclic void growth model (CVGM). The cumulative equivalent plastic strain, cyclic void growth index, and critical void growth index of corroded steel piers with different corroded morphologies were compared. Results reveal that, regardless of whether the pier is corroded, fatigue cracks tend to initiate at the weld toe at corners when exposed to cyclic loads under an oblique direction at the pier top. Additionally, the ULCF crack-initiation life in a corroded pier is less than that in an uncorroded pier, and it is significantly affected by a reduction in the pier wall thickness. Corrosion pits affect the position of ULCF crack initiation in a steel pier and cracks tend to initiate at the bottom of pits with large depth-to-diameter ratios. In the case of minor corrosion, the corrosion morphology affects the seismic performance of piers to a small extent.

Predicting seismic performance of locally corrodedsteel box-section piers

This paper aims to propose a simplified method for predicting ultimate strength and ductility behavior of locally corroded steel box-section bridge piers. Firstly, the accuracy of the proposed 3-D elastoplastic finite element model for the steel piers subjected to a constant vertical load and cyclic lateral loading is verified by comparing the analytical results with test results. Then, a series of parametric study is carried out to investigate the effect of corrosion height ratio and corrosion thickness ratio of steel plates on the ultimate strength and ductility behavior of these piers. Finally, by establishing 2-D beam-column element models and comparing the calculation results with those of the 3-D models, correction coefficients for the ductility ratio and ultimate strength of 2-D beam-column element model under local corrosion are proposed. The research results indicate that there exists a most unfavorable corrosion height which makes the ductility ratio of steel piers the smallest. The ultimate strength of the steel piers will not have a distinct degradation when the corrosion height becomes larger than 0.5Ld. The correction coefficient formula for ductility ratio with respect to different aspect ratio of steel piers, and the linear relationship between correction strength coefficient and the corrosion thickness ratio are proposed. Correction coefficients for 2-D beam-column element model under the most unfavorable corrosion height are proven to have a rational accuracy, which provides a fast and simplified method to evaluate the ultimate strength and ductility behavior of such steel piers under local corrosion.

A Deformation History-Based Approach for Ultra-Low Cycle Fatigue Damage Evaluation of Steel Structures

Ultra-low cycle fatigue (ULCF) damage is one of the main failure modes of steel structures when subjected to intense earthquake action, such as near-field action. However, existing ULCF evaluation methods are based on the plastic strain history of structures, which requires fine numerical simulation and causes high calculation cost. In order to improve and simplify the ULCF evaluation process for steel structures, a new damage index based on the structure deformation history was proposed in this paper, with the application of structure life curve and Miner’s rule. Two types of steel components, notched round steel bar and steel pier, were employed as the research objectives to verify the accuracy of proposed damage index. The predicted ULCF life was compared with the results of tests and finite element simulations, which showed that the application of damage index was of acceptable accuracy. Compared with the traditional plastic strain history-based ULCF evaluation methods, the advantage of proposed damage index is that ULCF life of a given steel structure can be determined quickly according to the loading condition once its life curve is realized, thus eliminating the cumbersome numerical simulation process.

Hysteresis Model for Fiber Elements in Effective Damaged Zone of Square-Section Steel Piers Considering Local Instability Effect of Steel Plates

AbstractThe local instability of steel plates is the predominant seismic failure mode for steel bridge piers. However, the application of shell-based finite-element (FE) models in an engineering de...

Adaptive Kalman filters for nonlinear finite element model updating

This paper presents two adaptive Kalman filters (KFs) for nonlinear model updating where, in addition to nonlinear model parameters, the covariance matrix of measurement noise is estimated recursively in a near online manner. Two adaptive KF approaches are formulated based on the forgetting factor and the moving window covariance-matching techniques using residuals. Although the proposed adaptive methods are integrated with the unscented KF (UKF) for nonlinear model updating in this paper, they can be alternatively combined with other types of nonlinear KFs such as the extended KF (EKF) or the ensemble KF (EnKF). The performance of the proposed methods is investigated through two numerical applications and compared to that of a non-adaptive UKF and an existing dual adaptive filter. The first application considers a nonlinear steel pier where nonlinear material properties are selected as updating parameters. Significant improvements in parameter estimation results are observed when using adaptive filters compared to the non-adaptive approach. Furthermore, the covariance matrix of simulated measurement noise is estimated from the adaptive approaches with acceptable accuracy. Effects of different types of modeling errors are studied in the second numerical application of a nonlinear 3-story 3-bay steel frame structure. Similarly, more accurate and robust parameter estimations and response predictions are obtained from the adaptive approaches compared to the non-adaptive approach. The results verify the effectiveness and robustness of the proposed adaptive filters. The forgetting factor and moving window methods are shown to have a simpler tuning process compared to the dual adaptive method while providing similar performance.

Compression Performance of Newly Designed Replaceable Tubular Steel Piers

To rapidly restore the seismic behaviour of a portal steel bridge column after an earthquake, the installation of replaceable tubular steel piers at the root of a portal steel bridge column is proposed herein. In this study, various tubular steel piers with different structural measures were designed; an axial compression test and a numerical simulation of the newly designed tubular steel piers were performed. The effects of parameters such as the structure of stiffening rib, the strength of LYP steel plate, the size of low‐yield‐point (LYP) steel plate, and the size of outer constrained steel plate were discussed. The results indicate that local buckling of steel tubular plates is likely to occur at the upper or lower end of those specimens, which belong to type II‐A specimens with stiffened LYP steel tubular plates or type III‐A specimens with T‐shaped LYP steel plates, respectively. This led to the LYP steel plate cannot fully display its function. For type III‐B and III‐C specimens with embedded LYP steel plates and constrained steel plates on both sides, when the outer steel tubular plates buckle, the internally constrained LYP steel plates provide support for the outer steel tubular plates. The plastic deformation of the specimens is sufficient, and the deformation performance is good. For type IV‐A specimens with LYP steel tubular plates and constrained steel plates on both sides, the mechanical behaviour of the new tubular steel piers is significantly improved, and increasing the height of the constrained LYP steel tubular plate can improve the compressive behaviour of the new tubular steel pier. Considering the effect of the steel plate thickness on bearing capacity and deformation performance, the thickness tw of the outer constrained steel plate should be equal to the thickness t of the common steel tubular plate, and the thickness tf of the LYP steel tubular plate should satisfy t ≤ tf ≤ 2t. Finally, a design formula is proposed to calculate the axial bearing capacity of newly designed tubular steel piers with constrained LYP steel plates.

Lateral loading performance of the joint between a precast concrete girder and a steel pier

This paper proposes a novel bridge construction method that affords increased constructability. In the proposed method, only some of the concrete members of the bridge are cast in place and then joined with precast concrete copings with internal connectors or precast concrete girders. This method enhances constructability by facilitating field assembly and minimizing the field casting work. Furthermore, in the case of a bridge exposed to ocean loads, the structural stability can be improved by integrating steel piers with the precast concrete copings. To analyze the connection behavior of a bridge constructed via the proposed method, a full-scale specimen with a span of 3.0 m was fabricated and tested under lateral loading. A finite element analysis model was also developed for theoretical analysis. The experimentally and theoretically determined lateral behaviors of the bridge during each loading step were compared. The final failure mode of the bridge yielded to the reinforcement in the joint between a precast coping and a cast-in-place member. Nevertheless, the proposed method was found to offer improved structural performance, increasing the maximum lateral load of the bridge to 210% of the design value.

Implications of bidirectional interaction on nonlinear seismic response of steel piers

The seismic performance assessment of bridges by nonlinear time history analysis using unidirectional spectrum-matched accelerograms is generally adopted in Japan's specifications. However, the simultaneous action of two horizontal components is known to induce a potentially higher inelastic response in steel piers relative to that under unidirectional excitation. In this background, a rising concern within research communities is the bidirectional effect on the risk of bridge failure or damage under a given seismic intensity during the service life of a bridge. In this study, the difference in the risk of steel pier damage/failure between unidirectional ground motion and bidirectional ground motion is assessed using seismic fragility. Fragility curves are constructed by subjecting a single steel pier with various geometric designs to a large number of earthquake ground motions using the incremental dynamic analysis methodology. The study indicates that the damage state of collapse is not changed by bidirectional excitations, whereas the use of bidirectional excitations in less damaging states reduces the bridge seismic performance and induces higher fragility. The response difference is quantified by introducing an equifragility factor. This factor is calculated as the ratio of intensity of the unidirectional input to the bidirectional input, which causes the same fragility caused by the unidirectional counterpart. The constant characteristic value of the equifragility factor provides useful information for considering the bidirectional effect in seismic design.

Influence Factors and Repair Effects of Seismic Damage to a Box Section Steel Pier

The seismic performance of a steel pier of box section was studied through low-cycle cyclic testing. The damaged specimens were repaired by filling with concrete and welding steel plates. The low-cycle cyclic test was then repeated. The effects of repairs were investigated by comparison of failure mode, energy dissipation performance, and ductility before and after repair. To supplement the data, the influence of different factors on the seismic bearing capacity and ductility of steel piers were analyzed by finite element method. The repair effects were compared by threshold of the displacement from the experiment. Based on the displacement angle response of the nonlinear dynamic time history analysis, the seismic performance is checked. The results show that repair had favourable effects on the damaged specimens. The horizontal bearing capacity and ductility of the specimens filled with concrete are significantly enhanced. Reinforcement by steel plates can increase the ductility and cumulative energy dissipation of the steel pier. An axial compression ratio of 0.2 and a concrete filling ratio of 30% are suggested. The horizontal bearing capacity can be improved by increasing the steel strength while the concrete strength shows little effect. The angular displacement from nonlinear dynamic time-history analysis was less than the test threshold, so the existing methods used for seismic performance verification are safe.

A PREVENTIVE STRENGTHENING STRATEGY FOR AGED STEEL STRUCTURES

Steel columns are widely used in buildings, bridge piers, and railway platform roofs etc. With aging, those steel columns are vulnerable to corrosion and fatigue, and can deteriorate for a variety of reasons, especially in great earthquakes. In order to avoid the unrecoverable damage of existing steel columns, the high cost of the structure owners and the great impact on the public use, effective preventive maintenance methods on the aged steel piers are necessary. On this background, a strengthening method for aged steel columns by using new construction materials such as glass fiber reinforced polymer (GFRP) plates, rapid hardening concrete, rubber-latex mortar, and reinforcing bars, is introduced in this study. Depending on possible applied load directions and corrosion conditions, two specimens were used in the loading tests. Static loading tests were performed on steel columns with and without strengthening. Applied load and deflection relationship and strain distribution on original and strengthened columns were measured and compared. Moreover, three-dimensional FE models were built, and the numerical results were compared with the test results. Both experimental and numerical results indicate that the present strengthening method can significantly enhance both rigidity and ultimate load carrying capacity of aged steel columns.

Investigation and repair plan for abraded steel bridge piers: case study from Japan

This paper reports on a forensic investigation following the collapse of the Iwama Ohashi Bridge over the Shimanto River in Japan. The central section of the bridge failed in 2017 when a steel pier buckled. The investigation included thickness measurements using a new ultrasensitive magnetic non-destructive device. This revealed that the buckled pier and other bridge piers had been significantly abraded by fast-moving gravel. As a result, the steel plate of the downstream faces near the riverbed was considerably thinner than the upstream faces. The measurements indicated that the other piers were also likely to buckle in the near future if left unattended. This paper describes the details of the investigation and discusses a potential repair and reinforcement plan.

Hysteretic model for steel piers considering the local buckling of steel plates

The pier is a vital structural component of bridges and thus critically considered in the seismic design. In order to provide an accurate and efficient methodology in the analysis of seismic response, a hysteretic model considering the effect of local buckling of steel plates is proposed for steel piers. In the hysteretic model, the Giuffre-Menegotto-Pinto hysteresis model is employed to establish the hysteresis curve equation, and the energy-based Ibarra-Krawinkler degradation rule is followed to describe the deterioration rule of structural bearing capacity and stiffness. In this study, a widely used Chinese steel Q345qC was taken as an example to illustrate the proposed model for steel piers. At first, the seismic performance of steel piers under horizontal cyclic load was analyzed. Then, the empirical formulae of the vital limit state points for evaluating the structural seismic performance were established, and further the identification of the decisive parameter (degradation parameter) of the hysteretic model was carried out. Morever, the verification on the effectiveness of the proposed model was verified, and the results showed its applicability and accuracy for steel piers under horizontal cyclic loads. Finally, the application of the proposed model in the seismic calculation of steel piers was interpreted.

Basic Study on the Shear Deformation at the Center of the Beam with Steel Pier for the Absorbed Energy

Basic Study on the Shear Deformation at the Center of the Beam with Steel Pier for the Absorbed Energy

Experimental Study on Seismic Behavior of New Steel Box Bridge Piers with Embedded Energy Dissipation Shells

An investigation was conducted to evaluate the seismic behavior of a new type of steel box-section bridge piers with embedded energy dissipation shell plates. In this study, two sets of the new steel box-section bridge piers were designed and pseudo-static tests were carried out on ten steel box bridge piers under constant axial force, with a horizontal cyclic load on top of the piers. The change regularities of the failure mode, the patterns of local buckling, the load–displacement hysteresis curve and its curve skeletons, and the load-strain hysteresis curves of the specimens were analyzed. The rules of horizontal stiffener spacing on embedded shell plates, the axial compression ratio, the embedded shell strength, and the layout of longitudinal ribs in the box-section wallboards were obtained to evaluate their influence on the seismic behavior of the new-type steel piers. The test results indicated that, after installing the embedded shells, the deformation ability of steel box-section bridge piers was enhanced and their ductility was improved. The effects of axial compression ratio and the space of transverse stiffeners in embedded shells on the seismic behavior of the new steel piers were significant. When the space of the horizontal stiffeners on the embedded shells and the axial compression ratio become smaller, the bearing capacity and ultimate displacement capability of the specimens would be greater, the descent segment of the curve skeleton would be more gradual, and the deformability and ductility of the new-type steel piers would be better. The effects of setting longitudinal stiffening ribs and enhanced embedded shell strength on the bearing capacity and ductility of the steel box bridge piers were relatively small. Based on the experimental results, calculation equations were established for stable bearing capacity and maximum deformation of the new-type steel piers, under the constant axial force and horizontal cyclic loading, in order to promote their seismic design.

Numerical analysis of collision between a tractor-trailer and bridge pier

Accidents involving collisions of heavy-duty trucks with highway bridge piers occurred occasionally, in which the bridge piers might be subjected to severe damage, and cause the collapse of the superstructure due to the loss of axial loading capacity. The existing researches are mostly concentrated on the light- or medium-duty trucks. This article mainly concerns about the collisions between the heavy-duty trucks (e.g. tractor-trailer) and bridge piers as well as the evaluation of the impact force. First, by modifying the finite element model of Ford F800 single-unit truck, which was developed by National Crash Analysis Center, the finite element model of a tractor-trailer is established. Then, the full-scale tractor-trailer crash test on concrete-filled steel pier jointly conducted by Texas Transportation Institute, Federal Highway Administration, and Texas Department of Transportation is numerically simulated. The impact process is well reproduced and the established model is validated by comparison of the impact force. It indicates that the tractor-trailer impact force time history consists of two or three peaks and the corresponding causes are revealed. Furthermore, the parametric influences on the impact force are discussed, including the diameter and cross section shape of the pier, cargo weight, impact velocity, relative impact position, and vehicle type. Finally, the finite element model of an actual reinforced concrete highway bridge pier is established, and the impact force and lateral displacement of the pier subjected to the impact of the tractor-trailer are numerically derived and discussed.

A Time-Dependent Corrosion Characteristic of a Steel Member in Contact with Concrete

Steel members in composite structures of steel and concrete, such as composite girder bridges, guardrails, and steel piers, are often partially embedded in concrete members. The corroded steel members in contact with concrete were recently fractured because of corrosion damage. This study investigates the time-dependent corrosion behavior of a steel plate in contact with concrete by performing an accelerated cyclic corrosion test, which was specified in the ASTM D 6899-03, on four types of composite model specimens of steel plates with different painted areas and concrete blocks for 100, 200, and 400 cycles. The surface geometry of the corroded steel plates was measured at a 1 × 1 mm interval using an optical 3D measurement system after the corrosion productions were removed. The corrosion characteristic, that is, the changes in the corrosion growth, corrosion depth, and the corrosion depth distribution with testing time, was statistically analyzed. The application procedure of the present test results to atmospheric environments was also proposed based on the amount of flying salt.

Safety-check method for continuous elevated-girder bridges supported by hollow steel piers subjected to multi-directional seismic accelerations

Safety-check method for continuous elevated-girder bridges supported by hollow steel piers subjected to multi-directional seismic accelerations