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Huge uncertainty exists in time dependent effects of deflection, especially for those concrete beam bridges in long-term service stage. The uncertainty has brought about great barriers to reliable assessment or reasonable prediction for the deflection. Most studies in this field focused on qualitative analysis rather than quantitative one. In order to realize the transformation from qualitative analysis to quantitative field of the uncertainty issue for bridge structure and expend the existing research, the Bayesian inference model was employed to conduct uncertainty quantification analysis based on the open-source database provided by Northwest University. The uncertainty coefficient was introduced to measure the differences between the test results and the theoretical ones for creep and shrinkage data. In the meantime, a surrogate model was proposed on deviation between long-term deflection for numerical value and experimental one, in which the former was calculated by ANSYS software and the latter was acquired by the in-door test on a simply supported beam, namely, Faber beam. After that, the uncertainty coefficient was introduced to update the model and the simulating process was performed again in which the corrected mean value of the posterior distribution was utilized. The results show that it narrows the error zone drastically, in which the relative reduction rate range from 49.83% to 82.76% for 95% lower confidence limit and from 11.46% to 98.73% for upper one. These outcomes prove the validity for the posterior distribution and also indicate that it could be a prospective way to improve the accuracy of the model significantly by utilizing the uncertainty coefficient. Besides, the method provided in this study could inspire the researchers who study in similar field and to do further exploration in the future.

Frequency variations are normally employed for damage detection as frequencies possess the advantages of the high accuracy and high anti-noise capability. However, the validity and applicability of such methods are restricted due to the limited order of frequencies. A damage localization and quantification approach is proposed for beam bridges by using the frequency variation of parked vehicle-bridge systems. Firstly, the phenomenon of frequency variation of parked vehicle-bridge systems is briefly illustrated. Secondly, a damage location index (DLI) is defined by the frequency change rate (FCR) of the vehicle-bridge systems with the vehicle parked at different positions before and after damage. Then the relationship between the frequency-parameter change rate (FPCR) and damage severity is established via finite element model (FEM) and further employed to formulate a damage equation(s) for severity estimation. The dimension of coefficient matrix in damage equations is reduced to large extent as the damage locations are determined by DLI in advance, which is meaningful in enhancing the effectiveness of severity estimation. Results of numerical and experimental examples with different damage scenarios indicate that the proposed approach can localize and quantify damages with high accuracy and efficiency by using frequency information only. The effects of measurement noise and FEM error are discussed to examine the robustness of the proposed approach. The cases when damage occurs in neighbor elements are analyzed to investigate the feasibility and robustness of the proposed approach.

This paper proposes a time-dependent probability method to predict the time-variant pounding risk, owing to this reason that the required separation gap width fails to accommodate the relative movement between two adjacent decks, of bridge systems subjected to non-stationary stochastic seismic excitations. Firstly the pseudo excitation method in random theory is utilized to transform the motion equation of system under the non-stationary stochastic seismic excitations into the transient response equation under deterministic external loads. And then the high precision direct integration method (HPDIM) is also employed to reduce the large number of transient analysis into two times for overcoming the challenges of strenuous computing effort. The time-dependent pounding system probability of bridges is derived by the combination of extreme value distribution theory and matrix-based system probability theory. Finally based on the proposed time-dependent probability method the numerical analysis of a real two span simply-supported beam bridge subjected to spatial and non-stationary ground motions is conducted herein for the pounding risk assessment. The results of this study provides in-depth insight into the time-dependent pounding probability of bridge systems subjected to spatially varying and non-stationary ground motions.

Traffic load monitoring (TLM) is one of important issues in bridge structural health monitoring (SHM), but there still exist such problems as lack of accuracy and efficiency for the existing methods. In this study, a sparse regularization approach is proposed for TLM based on analytical model and redundant dictionary. Firstly, an unknown moving traffic load is deemed as a combination of static and time-varying components so that a redundant dictionary can be established to independently express them. The static component is expressed by a basis vector whose elements are identical, and the time-varying one by wavelet functions for their good multi-resolution analysis characteristics. Then, the TLM problem is converted to determine a coefficient vector of dictionary, and the l 1 -norm regularization technique is adopted to obtain a sparse solution to the coefficient vector. Finally, a series of experimental studies on a hollow steel beam bridge under crossing a moving model car are conducted in laboratory to assess the effectiveness of the proposed method. Furthermore, comparative studies are carried out for assessing the effect of different measurement parameters, such as moving car speeds, car weights, strain and acceleration response data, redundant dictionaries as well as selection of regularization parameters, on the proposed method. The illustrated TLM results show that the dictionary used for TLM in this study can independently distinguish the static and time-varying components of moving traffic loads. The proposed method can effectively identify the total weight of moving traffic loads with a higher accuracy, which provides a great potential for monitoring moving vehicle loads on bridges.

The main objective of this study is to design a ZnO base beam bridge MEMS piezoelectric pressure sensor. A theoretical mathematical modeling of the design is derived for the structure. Factor effecting the output or efficiency is studied base on mechanical and electrostatics step by steps. A simulation is conducted on Comsol Multiphysics Simulator for the design for validating the theoretical modeling and a comparative study are made between the analytical and simulated result. This study will help to find the optimum design structure for piezoelectric pressure sensor base on bridge beam structure.

Moving force identification (MFI) is an important inverse problem in the field of bridge structural health monitoring (SHM). Reasonable signal structures of moving forces are rarely considered in the existing MFI methods. Interaction forces are complex because they contain both slowly-varying harmonic and impact signals due to bridge vibration and bumps on a bridge deck, respectively. Therefore, the interaction forces are usually hard to be expressed completely and sparsely by using a single basis function set. Based on the redundant concatenated dictionary and weighted l1-norm regularization method, a hybrid method is proposed for MFI in this study. The redundant dictionary consists of both trigonometric functions and rectangular functions used for matching the harmonic and impact signal features of unknown moving forces. The weighted l1-norm regularization method is introduced for formulation of MFI equation, so that the signal features of moving forces can be accurately extracted. The fast iterative shrinkage-thresholding algorithm (FISTA) is used for solving the MFI problem. The optimal regularization parameter is appropriately chosen by the Bayesian information criterion (BIC) method. In order to assess the accuracy and the feasibility of the proposed method, a simply-supported beam bridge subjected to a moving force is taken as an example for numerical simulations. Finally, a series of experimental studies on MFI of a steel beam are performed in laboratory. Both numerical and experimental results show that the proposed method can accurately identify the moving forces with a strong robustness, and it has a better performance than the Tikhonov regularization method. Some related issues are discussed as well.

In Chinese seismic design codes, soils are divided into four sites (I ~ IV), and each site is divided into three groups (G1 ~ G3) according to the design characteristic period (Tg) again. The current studies only present the near-fault inelastic input energy (SEI) spectra corresponding to each site, while those corresponding to G1 ~ G3 of each site have not been reported. Therefore, in this study, 210 near-fault ground motion (GM) records were selected and classified according to G1 ~ G3 of Sites I ~ IV. By inputting the records into the BISPEC software, the effects of the characteristics of near-fault GMs and the parameters of hysteretic models on the near-fault SEI spectra were studied, and then the near-fault SEI design spectra corresponding to G1 ~ G3 of Sites I ~ IV were established. Moreover, by improving the previous procedure and using the near-fault SEI design spectra, an energy-based procedure for estimating the near-fault input energy of beam bridges was proposed, and its feasibility and safety were verified through a case study.

Bridges that are posted for load can cause a variety of issues for the people that use them and the entities that manage them. Load postings generally create detours for routes between origins and destinations of freight trucks, thereby causing additional traffic and a major impact on economic vitality. Load-posted bridges also create management issues for the state departments of transportation as they may require more stringent monitoring, inspection, and maintenance. For these reasons, it is desirable for states to have as few load-posted bridges in their inventory as possible. This paper examines an individual steel beam bridge and presents a methodology that led to the improvement of the load rating of the bridge in a safe and appropriate manner through load testing and refined modeling. The results of the load tests were used to develop new rating factors for the test vehicle and finite element method analysis models were used to develop new rating factors for the HS-20 design truck. It was found that the bridge exhibited rating factors much higher than what it was posted for, and therefore the posting could be removed.

[EN] In this paper, a closed-form approximate formula for estimating the maximum resonant response of beam bridges on viscoelastic supports (VS) under moving loads is proposed. The methodology is based on the discrete approximation of the fundamental vertical mode of a non-proportionally damped Bernoulli-Euler beam, which allows the derivation of closed-form expressions for the fundamental modal characteristics and maximum amplitude of free vibration at the mid-span of VS beams. Finally, an approximate formula to estimate maximum resonant acceleration of VS beams under passage of articulated trains has been proposed. Verification studies prove that the approximate closed-form formula estimates the resonant peaks with good accuracy and is a useful tool for preliminary assessment of railway beam bridges considering the effect of soil-structure interaction at resonance. In combination with the use of full train signatures through the Residual Influence Line (LIR) method, the proposed solution yields good results also in the lower range of speeds, where resonant sub-harmonics are more intensely reduced by damping., This research was partly sponsored by the Swedish Research Council FORMAS and has also received funding from the Shift2Rail Joint Undertaking under the European Union's Horizon 2020 research and innovation program under grant agreement No 826255 which are gratefully acknowledged.

A novel strengthening method was proposed to improve the shear behaviors of hollow slab beam bridges through filling the hollow with high-performance self-consolidating cementitious composites. The strengthening effect was evaluated through a field loading experiment and long-term monitoring. Some important parameters were compared and analyzed before and after the strengthening, including the principal stress of the bridge web, the strain response of beam bottom, the mid-span deflection and the transverse connection between the beams. The experimental results showed that the principal stress of the bridge was decreased by more than 50% compared with that before the strengthening. Under different loading conditions, the strain response of each slab beam bottom was decreased in different degrees, with a reduction range between 20% and 60%. The mid-span deflection of the bridge decreased by 10%-25% after the strengthening. Through the analysis of the transverse distribution of the strain on the beam bottom, the strengthening method also improved the lateral connection of the bridge in a certain extent. In addition, it was found that the long-term effectiveness of the strengthening method is verified through more than a year of monitoring.

In response to long-term operation of prestressed concrete railway bridges, the girder body will arch because of creep, which may influence the running stability of high-speed trains. Usually, the deformation of the rail-bridge system under the creep effect is calculated by a finite element model with the rail geometry deformation input as additional irregularity. The original irregularity is superimposed to the coupled system of the train and bridge to calculate the dynamic response of the system. However, such a strategy is time-consuming and cannot accurately integrate the uncertainty of the original rail irregularity. This paper presents an analytical formula for predicting the rail deformation caused by concrete creep. The rail deformation caused by the bridge upper arch can be quickly predicted by the creep amplitude of the bridge. The creep deformation of the rail is applied as an irregularity excitation to the train-track-bridge coupled system (TTBCS). In addition to creep irregularities, original random irregularities also exist on the track. The Karhunen-Loeve expansion method is adopted to represent the random track irregularity that considers creep deformation. The results achieve good agreement with the initial samples. Subsequently, the TTBCS model is established to analyze the dynamic responses of different train speeds and different bridge creep deformations using a stochastic dynamic analysis method. This method achieves very high agreement with the Monte Carlo method, and the error rate of the mean bridge displacement calculated by both methods under the same working conditions was only 0.0351%. Finally, the upper probability limit value of the creep of the bridge is put forward: at a speed of a high-speed train of 350 km/h, the creep upper arch limit is only 7 mm. These probability limits at different train speeds have guiding significance for the design, maintenance, and repair of the actual medium–high-speed railway concrete supported beam bridge.

The seismically isolated simply-supported beam bridge (SISBB) with the seismic isolation bearing (SIB) is converted into an equivalent bilinear single-degree-of-freedom system. Then, by inputting the 139 near-fault ground motion (GM) records into the equivalent system, the parametric study on the near-fault seismic input energy spectra (SEI) of the SISBB is conducted by considering the equivalent system parameters and the near-fault GM characteristics. So, it can be found that: the increase of post-yield stiffness ratio (ηe) can slightly increase the peak values of the near-fault SEI, and ηe = 0.2 can be used to calculate the near-fault SEI design spectra of the SISBB; with the increase of the damping ratio (ξe) (or ductility ratio (μe)), the spectral values of the near-fault SEI increases, the hysteretic energy dissipation capacity of the SIB decreases, and the damping energy dissipation capacity of the equivalent system increases; when μe ≥ 10, the effect of μe on the near-fault SEI can be ignored; the softer the site soil or the smaller the Joyner-Boore distance to rupture plane (Rjb) is, the greater the near-fault SEI is; if the near-fault SEI with a standard peak ground acceleration (PGA) is known, the near-fault SEI with other PGAs can be obtained by multiplying the (PGAOther/PGAStandard)2 by the spectral values of the near-fault SEI with a standard PGA. Finally, the near-fault SEI design spectra of the SISBB are obtained, and the seismic isolation design for SISBB based on the energy balance method is proposed, the feasibility of which is verified by a case study.

Severe damages of curved bridge, such as pounding, unseating of superstructure and pier collapse, have been frequently observed in previous strong earthquakes. This paper demonstrates the effectiveness of a new type multi-level spring restrainer (MLSR) on reducing the seismic responses of a curved bridge. The optimal parametric values of the device are determined by response surface method (RSM). The numerical models of the curved bridge with and without MLSR are established using OpenSees. Three earthquake records are selected from PEER strong motion database matching the site condition of the bridge. Nonlinear time history analyses are performed for the bridge with and without MLSR. The force-deformation behavior of the bridge components, the relative displacements between adjacent girders, and the maximum pier curvature are evaluated. The numerical results show that the application of MLSR on the curved bridge will not only avoid the pounding and unseating of the superstructure, but also mitigate the pier damages of the bridge.

Reliable estimates of the failure modes of basic facilities, especially the seismically isolated bridge, are required for almost any form of analysis used for the seismic design and retrofit of bridge. The Hong Kong-Zhuhai-Macau (HZM) Bridge (HZMB), a seismically isolated continuous girder bridge with six spans, is a sea-crossing bridge, which is now under construction and will connect the Mainland China, Hong Kong, and Macau. Because the bridge is located in a highly active seismic zone, it is essential to evaluate the seismic performance of this bridge, in particular of its failure modes. Based on this practical engineering, this paper investigated the failure modes of isolated continuous girder bridge subjected to strong ground motions by developed weighted rank sum ratio method, in combination with developed 3D finite element bridge models. Firstly, three-dimensional finite element bridge models are developed and assessed using the incremental dynamic analysis method. Due to the flexibility of seismic isolation, both bending and rotational stiffness of isolation bearings are taken into account in the analysis. In addition, the rotational angle of bearings is found to be sensitive to seismic analytical results of isolated continuous girder bridges. Then, it conducted the nonlinear dynamic analysis on the HZM Bridge under sixteen strong earthquake records. Further, statistically significant failure modes and the weakest failure mode of this bridge are identified through the weighted rank sum ratio method. It resulted that, the final failure modes of this isolated continuous girder bridge are presented at the isolation bearings on a part of middle piers, at the isolation bearings on the abutments, at the isolation bearings at a side pier, and at the bottoms of side piers, respectively. The results of the failure mode analysis would greatly assist engineers to establish effective strategies for performance enhancement and seismic retrofit of bridge in the future.

In all ancient monuments, stone beams and architraves have unsupported spans that seldom reach 7 m, while ordinary spans are usually much less. These structural elements were and still are believed to be prone to failure, so that several relieving systems (arches, chambers, gaps) were adopted through history to prevent collapse. The perception that stone beams could not exceed a certain span is coherent with the so-called size-effect theory of rock and concrete, which predicts that large elements are proportionally weaker than small ones. While the rest of the world started using architectural design to avoid these problems, in the Fujian region of China (near Xiamen) from the XI to the XII century megalithic stone beam bridges with spans of up to 21 m were being built. These bridges have resisted over the centuries. A spectacular example of these bridges, tending to disprove the size-effect theory and challenging all previous ancient constructions, is the Jiangdong bridge, of which only a part survives, but which should be restored, preserved, and declared human heritage monument.

The late rise in global concern for environmental issues such as global warming and air pollution is accentuating the need for environmental assessments in the construction industry. Promptly evaluating the environmental loads of the various design alternatives during the early stages of a construction project and adopting the most environmentally sustainable candidate is therefore of large importance. Yet, research on the early evaluation of a construction project's environmental load in order to aid the decision making process is hitherto lacking. In light of this dilemma, this study proposes a model for estimating the environmental load by employing only the most basic information accessible during the early design phases of a project for the pre-stressed concrete (PSC) beam bridge, the most common bridge structure. Firstly, a life cycle assessment (LCA) was conducted on the data from 99 bridges by integrating the bills of quantities (BOQ) with a life cycle inventory (LCI) database. The processed data was then utilized to construct a case based reasoning (CBR) model for estimating the environmental load. The accuracy of the estimation model was then validated using five test cases; the model's mean absolute error rates (MAER) for the total environmental load was calculated as 7.09%. Such test results were shown to be superior compared to those obtained from a multiple-regression based model and a slab area base-unit analysis model. Henceforth application of this model during the early stages of a project is expected to highly complement environmentally friendly designs and construction by facilitating the swift evaluation of the environmental load from multiple standpoints.

A great number of studies have been conducted to study the loading rate effect on the behavior of reinforced concrete (RC) structures. A majority of these studies, however, are focused on the component behavior of an RC specimen by imposing a predefined cyclic displacement history on the specimen without considering the interaction of the specimen with the entire structural system. In this study, the rate-dependency effect of an RC pier on the global response of a bridge is experimentally investigated using the slow and real-time hybrid simulations. The RC pier is used to support a two-span prestressed concrete girder bridge. The nonlinear response of the bridge under earthquake loads is accounted for by physically testing the RC pier in a laboratory, while the upper structural system of the bridge including the bridge deck and girders are analytically modeled. A dynamic servo-hydraulic actuator is connected to the top of the pier to transfer the inertial force of the bridge deck and girders to the pier. Due to the lack of knowledge in real-time force control, the axial load effect on the dynamic response of the RC pier is not considered in this study. Prior to conducting the hybrid simulations, predefined cyclic displacement tests are conducted for the bridge pier specimens with the same displacement history, but with different rates, in order to investigate any change in strength and energy dissipation capacity of the RC pier. Then, a series of slow and real-time hybrid simulations are conducted to investigate the rate-dependency effect on the seismic response of the bridge. The results from the predefined cyclic displacement tests and hybrid simulations are provided and discussed along with the observation from these tests.

The Norwegian Public Roads Administration is running a “Ferry free coastal route E39” project to install bridges or tunnels across fjords in Western Norway. A floating bridge concept is proposed for the fjord-crossing project in Bjornafjorden. One of the key aspects in design is to ensure bridge safety under accidental ship collision loads. The objective of this paper is to study the dynamic behaviour of the floating bridge subjected to ship collision loads on bridge girders. Numerical models of the ship-bridge collision system are developed using the dynamic analysis software USFOS. The curved floating bridge is modelled by beam elements and the striking ship is represented by a nodal mass-nonlinear spring system. Numerical analyses of ship collision with a bridge girder are carried out for three impact locations, i.e. middle spam, a span in quarter position and at the end span of the bridge. Bridge responses including the displacement, axial and shear forces and bending moment are calculated. Results show that the floating bridge can endure the proposed ship collision energy of 250 MJ.

This paper discusses how cover thickness is selected based on values of diffusion coefficients regarding its durability by obtaining the limit concentration of chlorides at its surface, typical for Portland cement CEM I 42.5R and Portland cement with low alkali content CEM I 42.5N/SR3/NA, and considering the example of a beam bridge structure - the impact of cover on load- bearing capacity as a function of span.

The paper describes the behavior of the new railway bridge in the Czech Republic, located on the track between Hohenau and Přerov. The bridge is a net arch structure of span 97.5 m and skew angle 43°. The bridge is equipped with the steering bar Meyer – Wunstorf, because of the reduction of the stresses in the track, caused by the train-bridge interaction. Those unique features led to the throughout dynamic analysis and testing. The paper describes the results of the numerical model, where the bridge response to the trains with speed of up to 160 km/h was analyzed. The first results were not successful, as the transversal vibrations induced significant exciting of the tension bars. Thus several modifications had to be done, such as ballast weight, stiffening of the structure etc. Also, the impact of the skew supports was analyzed on the parametric study on various models with different angles. After the construction of the bridge, several extensive load tests were performed here. The main results are described and discussed here.

X International Conference on Structural Dynamics : EURODYN 2017 / Edited by Fabrizio Vestroni, Vincenzo Gattulli, Francesco Romeo X International Conference on Structural Dynamics, EURODYN 2017, Rome, Italy, 10 Sep 2017 - 13 Sep 2017; Amsterdam [u.a.] : Elsevier, Procedia engineering, 199, 2318-2323 (2017). doi:10.1016/j.proeng.2017.09.204, Published by Elsevier, Amsterdam [u.a.]

The paper presents aspects regarding the design and execution of the new bridge over the Cibin River, in the city of Sibiu. The new bridge has four traffic lanes and sidewalks for both pedestrians and cyclists. The superstructure is made of two circular arches with the cross-section O508x40 mm. Each arch is connected to an inclined secondary arch to prevent lateral buckling. The deck is a composite structure, steel cross girders being connected with a reinforced slab. The deck is suspended to the arches through vertical hangers made from solid circular steel bars of steel S460 M. The problems that arisen with the design and execution of the bridge are the following: ensuring local and global buckling for the steel arches with a tubular cross-section; replacing hot-rolled members H1000B, with welded steel members for the ties; choosing the steel grade based on the grades to be found in Romania.; finding methods to build the arches based on the technology found in our country, in order to keep the erection costs at a minimum.

Three-dimensional (3-D) aeroelastic effect is known as the main factor that leads to the discrepancy between the critical flutter states predicted by two-dimensional (2-D) deck section and 3-D full structure. The 3-D aeroelastic effect on flutter performance of long-span bridges was investigated through historical experimental data statistics, numerical flutter analysis and wind tunnel tests. The critical flutter wind speeds of 16 long-span bridges were statistically analyzed. Subsequently, numerical flutter analysis were conducted towards a 300m-span quasi-simply supported beam bridge, and the 3-D structural effect and the effect of additional static wind angle of attack were analyzed. Corresponding section and full aeroelastic model tests were both carried out for further investigation of 3-D aeroelastic effect. Real-bridge experimental results show that the 3-D aeroelastic effect may lead to a maximum relative deviation in critical flutter wind speed of more than ±30%. Numerical-analysis-based 3-D aeroelastic effect with the contribution of both the 3-D structural effect and the effect of additional static wind angle of attack presents positive but weak influence, while the test results present more significant 3-D aeroelastic effect. Some potential factors, such as the spatial correlation and amplitude-dependency of aerodynamic forces, may also play an important role in 3-D aeroelastic effect.

Since overload has become the main potential safety hazard for aging bridges, management of traffic load information is of great significance in safety insurance of bridges. Here, an array of lead zirconium titanate (PZT) sensors is utilized to capture the dynamic responses of beam bridge due to moving load, for which the details are identified based on electromechanical analysis and structural dynamics. The precision and feasibility of the proposed method are validated by experimental tests for a simply supported and a continuous steel beam respectively. Results show that the PZT sensor has the advantage of self-driving, fast response and high precision, which makes it possible for wireless sensing technology. Results also reveal that dynamic responses of the beam can reflect effectively the moving speed and magnitude of the moving force when the load approaches to the mid-span. Furthermore, the proposed method is applicable for different beam structures and insensitive to the noise interference. The current method may provide guidance for bridge moving load identification.

This paper describes a numerical study using the finite element method to evaluate the seismic performance of composite steel-concrete connections designed to protect critical welded interface areas between the steel pipe pile and cap beam bridge piers. Previous studies have indicated that welding the steel piles directly to a steel cap beam, regardless of weld configuration, does not avoid the undesirable brittle cracking failure mode in the welded region. Strengthening of the connection can a solution to shift the plastic hinge position from the connection to another point of the structure. Through static pushover and time-history analysis, the connection has been shown to adequately extend plastic hinging in the form of local buckling in the pipe pile wall, while avoiding unfavorable failure modes. The results of this study demonstrate that the use of composite connections can increase the shear capacity of a steel bridge; thus, improving its performance. Moreover, evaluation of the results shows that an increase in the length of the composite area will improve the overall ductility of the steel frame. Finally, a new composite connection has been proposed to improve the performance of the steel bridge; this will augment current efforts in strengthening bridges in earthquake-prone areas.

A new class of spread slab beam bridges has recently been developed and implemented in Texas. Due to the absence of appropriate design guidelines, moment and shear design actions have been based on those used for spread box beam bridges; however, their applicability remains in question. To develop new criteria, the load distribution behavior of this new bridge system is investigated. Comprehensive static and dynamic tests are performed on an in-service spread slab beam bridge located on US 69 in the city of Denison, Texas. Various experimental methods are used to infer the moments and shears resisted by individual beams that arise from a heavily loaded truck. Experimentally derived load distribution factors (LDFs) are compared with refined finite element model predictions. Satisfactory agreement is obtained. The experimental test results indicate that the existence of a sidewalk and guardrail markedly stiffens the structure leading to higher than expected moment values. The observed bridge responses under moving dynamic loads exceed the present design specifications impact factor of 33%. Thus, for service load design it is recommended the allowable tensile stress be slightly reduced.

The bridge across the Pavlovski potok stream in the village of Žerovinci in northeast Slovenia is a part of the investment into the modernisation of the Pragersko–Hodos railway line, one of the biggest investments in the infrastructure in Slovenia at the moment. Its design was accompanied by very short deadlines and a deep layer of soft foundation soil. For this reason the reinforced concrete abutments of a nearby railway bridge were founded on 24 m deep piled foundations. Short deadlines and a limited budget forced the authors of this paper to find an alternative solution. Deep piled foundations were replaced by shallow foundations made of compacted fill material reinforced with geosynthetics. The bridge was completed by the end of 2014. From the results of previous laboratory tests that were obtained within the scope of the EU co-funded research project “Research voucher”, the basic characteristics of the building materials for the geosynthetic reinforced soil (GRS) bridge abutments, as well as the deformation properties of the typical reinforced soil were obtained. These data were used for the design of the abutments. The staged construction procedure of full height rigid (FHR) facings for the GRS retaining walls (RW) was used for the construction of this GRS integrated bridge. Partial pre-stressing of geogrids and consequently the increased stiffness of the reinforced soil was achieved by following the staged construction procedure. The bridge system consisted of a cast-in-situ RC slab, which was placed on top of the GRS immediately behind the FHR facings, i.e. the bridge was constructed as a simply-supported slab supported by a pair of GRS abutments, without the use of bearings. Thus the described bridge across the Pavlovski potok combines two approaches for GRS integrated bridge design, one of which has been used in Japan (Tatsuoka et al., 2009), with full structural integration of the deck onto the pair of FHR facings, other being proposed by the FHWA (Adams et al., 2010), without full integration of the deck onto the GRS RWs. A system for the monitoring of structure performance was established in order to ensure optimization of this kind of structure. Data for this GRS integrated bridge, which were obtained during the construction works were compared to similar data obtained from the construction of a nearby railway bridge with reinforced concrete abutments. The comparison provides a good basis for future decisions when choosing the type of bridge abutments.

Bridge owners and engineers focusing on bridge design, management and maintenance continue to search for more efficient ways to design, construct, and maintain their bridge inventory. Recently, a folded plate girder system has been promoted as a cost-effective alternative for the design and construction of bridge superstructures due to merits such as low cost and facilitation of accelerated bridge construction. The folded plate girder system has a structural shape strategically press-brake formed from a single sheet of plate steel and achieves composite action with a concrete deck utilizing shear studs in between. To further facilitate the development and adaptation of the system for bridge application, this paper presents a systematic performance evaluation of the folded plate girder system through experimental and numerical programs. To this end, a folded plated girder specimen was designed, fabricated, and tested to evaluate the constructability and capacity of the girder specimen. Finite Element (FE) Analysis was performed to understand the behavior of the girder specimen under different loading conditions. The predictions using traditional design calculations and FE analysis were compared with the test results. After the FE models were validated against the test data, a full bridge model was established to further investigate the behavior of the bridge under loading condition up to the ultimate load. It was found that the ultimate capacity of the bridge girders were much higher than the bridge demand and the bridge had good ductility until failure. The predictions using the design calculations based on the AASHTO LRFD Bridge Design Specifications were in reasonable agreement with the test results. The FE models showed better predictions since more sophisticated modeling techniques and material constitutive models were used. Results obtained from the sophisticated non-linear bridge model indicated that the girder distribution factors varied along with an increase of the truck loading and especially their change trend was gradually reversed after the yield of the girder steel. And according to the FE results, the distribution factor based on the AASHTO LRFD Bridge Design Specifications was sufficient for the design of the folded plate girder bridge investigated in this study.

Two continuous lattice steel truss bridges spanning 190 m with subdivided top chord members were constructed on the same design across river Alaknanda at Dugadda and Srinagar, respectively, in Uttarakhand, India. Both bridges were similar in design and geometry having middle span of 110.0 m and two end spans of 40.0 m. Garudchatti bridge at Dugadda was constructed first and opened to traffic, but excessive vibrations and lifting of end supports under live load condition were observed. Construction of Chauras bridge at Srinagar started later, but it collapsed during casting of the deck slab due to buckling of one of its top chord compression members. Failure of Chauras bridge led to the serious concerns in the minds of people and technocrats about the safety of Garudchatti bridge also, because it was constructed using the same design of Chauras bridge. Therefore, it was decided to strengthen and carry out load testing of Garudchatti bridge before reopening to the traffic. In the present work analyses of Garudchatti bridge are presented to identify structurally unsafe members for most severe live loads given in IRC:6-2010 code, and recommendations for strengthening of the critical members. Finite element space frame analyses of the bridge were carried out using STAAD Pro. v8i software to find excessively stressed members beyond their permissible stress limit. The critical compression members were strengthened by welding additional channel sections. RCC anchor blocks were constructed to restrict lifting of end supports under live load. After strengthening, load testing of the bridge was performed to ensure the safety of the bridge. The bridge is now reopened for traffic. In the past a number of bridges have collapsed during load testing. In case of any shortcoming in the design or overloading during load testing, compression members of the truss may suddenly buckle and cause collapse of the bridge. Therefore, it is not advisable to load test steel truss bridges which do not have adequate margin beyond the service load condition.

Historical steel beam bridge over Gliwice Canal located in a small city close to the eclectic palace from 19th century has been strengthened by suspension to new steel arches. The old structure was insufficient for fulfilling current demands of road traffic and clearance. Another issue was its localization in the vicinity of the palace and the lake, which are attractive recreational areas. Therefore, the new structure should be also ready for safe pedestrian and bicycle traffic. To fulfil those conditions and also to create a landmark bridge in this interesting spot, an arch structure was chosen. Designer decided to use the old bridge and its abutments as a part of the new structure. The deck was renovated and suspended to two inclined hingeless steel arches. To accommodate pedestrian and bicycle traffic, two external footbridges were also suspended to the same arches on both sides. Static and dynamic load tests of the bridge were conducted. An Operational Modal Analysis method was used to identify the dynamic model of the bridge. Due to a limited number of transducers and the simple procedure of the test, the compromise between effort and quality was established. Good correlation between assumptions from the design stage and the response of the erected bridge was confirmed.

The article aims to present the challenging design tasks of the reconstructed Northern Danube railway bridge in Budapest. Besides, it gives an overview of the extraordinary construction and replacement process that was carried out within 3 months in 2008. The bridge is located on the Budapest-Esztergom railway line of MAV (Hungarian National Railways) that carries significant suburban traffic, therefore fast constructability was just as important design issue as load carrying capacity and travel comfort requirements. Meanwhile the design was also determined by cityscape and noise demands. The old temporary structure was removed and replaced by the new continuously supported 674.40 m long steel truss girder bridge in the summer of 2008. A special bearing system enabled the reinforced abutments to carry the increased horizontal loads induced on the continuous girder with the application of hydraulic shock transmission devices, whilst the old piers became released from the majority of horizontal effects. The contractor and the designer were both challenged by the available 3 months long period for the bridge replacement. 500 tons heavy prefabricated units had to be lifted by floating cranes to their position, while no disturbance of the shipping was allowed on the river. As the result of close cooperation between contractors, designers and the involved organizations such a bridge was given back to the traffic 8 years ago that absolutely satisfies all kind of modern demands.

The railway bridge over the Velika Morava River is located on the Belgrade – Nis main railway line, Gilje – Cuprija – Paracin section. It is a double-track bridge with track laid on crushed-stone ballast. The bridge over the Velika Morava River has five spans. The bridge structure is a steel truss continuous beam, with spans: 52.5 + 67.5 + 82.5 + 67.5 + 52.5, in the total length of 322.5 m. Truss structure height is constant (8.0 m), and the truss width is 10.0 m. Truss consists of diagonal members, without vertical members. All truss members are of box cross-section. Metal sheet is 12 - 36 mm wide. Steel grade is S 235 J2G3 for less stressed members and S 355 J2G3 for highly stressed members in the area of supports and in the middle of the bridge. The Bridge deck is orthotropic deck with longitudinal trapezoidal stiffeners and cross girders spaced at 3.75 m. The bridge structure is completely welded, only steel connections of cross girders and joints of bottom and top bracings are made with 10.9 high-strength bolts applying full tightening force. Bridge bearings are of neoprene (pot bearings). Piers are founded on HW piles, O1500, 34 m maximum length. The structure is assembled on embankment (in front of the bridge) and successively longitudinally launched over piers without use of auxiliary trestle. The bridge was completed and put into service in 2016.

A new bridge was required in the city of Sibiu, to ensure the crossing of Cibin River, in Sibiu, in the Cibin square, due to the fact that the old bridge, with only two traffic lanes, was having both a weight and height restriction and was also strangling the traffic in the area. The streets connected by the bridge are all with four lanes. This paper presents aspects regarding the design and the erection of the new bridge. The new bridge, designed with four vehicle lanes and two lateral pedestrian and cyclist lanes, is an arch bridge with arches having a circular cross-section section O508x40mm. The main arches are connected to two secondary inclined arches in order to prevent their lateral buckling. The span of the arches is 34.0 m and their rise 8.1m. The curvature of the arches was achieved by hot bending of the sections, through the electromagnetic induction phenomenon, at a factory from the field of extractive industry from another Romanian city, Ploiesti. The bridge deck is a composite structure consisting in cross girders and a reinforced slab. The slab loading is transmitted to the main arches through hangers made from solid circular steel bars of steel S460M. Some special issues that arisen during the design and execution of the bridge are addressed: prevention of the lateral buckling phenomenon and the adjustment of the execution of the steel deck to actual manufacturing conditions.

The paper describes the design of the reconstruction of the “Old Bridge to the Island” in Trencin, which spans the river Vah in the area of Kockovský channel. It is a road, reinforced concrete, three-span, girder bridge. The cross-section consists of three main girders of 1.55 m height, that increase to 2.4 meters in the support regions. The axial distance of the main girders is 2.8 meters. The total span of the bridge is 112.1 meters (35 + 42 + 35.1 m). In the ground plan the bridge is a skew one with a 79° angle. The vertical grade of the bridge is a polygonal curve (arch). The current width of the bridge is 5.0 meters with 1.0 m footways on both sides. The expansion of the “Ostrov (Island)” recreational zone requested an extension of this bridge and hence its extensive renovation. A part of the proposed solution is a strengthening of the structure by external pre-stressing strands, reinforcement of the structure to shear, widening of the carriageway to 6.0 m, construction of steel footways for pedestrians and cyclists, the exchange of bearings, an extensive renovation and widening of the abutments and re-profiling of all surfaces on the bridge. The proposed steel footway will be 3.08 m wide for the cyclists and 2.33 m for the pedestrians. These walkways will be directly connected to the supporting bridge structure and will extend the width of the bridge by almost a double. The steel footways itself will be anchored to the RC structure by a transverse pre-stress through reinforced concrete anchor blocks. All proposed solutions are designed with the requirement of maintaining the traffic on the bridge during the entire period of reconstruction.

In spite of the economic downturn in Hungary the development of infrastructure has continued. Thanks to the support of the European Union and the scheduled investments several roads and bridges have been designed in Hungary. The paper discusses four bridge designs. Some of these bridges are in the planning phase and some of them are in the realization phase. However it is important to point out that all of these bridges create connections, they ensure relationships between regions and countries. Basically all discussed bridges are composite structures with steel girders and concrete deck, however in the case of two bridges they have an arch superstructure as well. The arch and the main girders are connected by cables for one of the bridges and rods for another bridge. As the bridges cross rivers floodplain bridges are also designed with them and they are discussed in this paper. The paper presents the beam bridge at Magyarcsanad over the river Maros, the arch bridge at Helemba over the river of Ipoly. Two other bridges are also introduced in the paper: the composite bridge on highway M43 over the floodplain of Tisza, the arch bridge on highway M44 at Harmas-Koros.

The presented paper describes the overall design philosophy, the choice of construction technology and the construction itself of one of the longest bridge in Slovakia. The two post-tensioned prestressed concrete beam bridges with 30+ spans, with the largest span of 110,0 m are being built these days near the city of Žilina. Two separate bridge constructions are being built, each for one route direction. The bridge has been divided into four parts depending on different construction technology. The bridge cross section of technological parts Nr. 1, 2 & 4 consists of twin-T beam girder, whereas the part Nr. 3 is formed by box girder with continuously changed height of the cross-section. The overall width of the superstructure is the same for both bridges and equals 13,10 m. The superstructure is being built over dense area of the highway crossing, railway with frequent traffic and over the reservoir that serves as the energy source for water-based power station. Above the supports the cross-beams are designed with indirect support scheme. Internal post-tension prestress tendons are to be anchored in end cross-beams and in construction joints.

The new Harosi Danube bridge on the M0 highway around Budapest has been designed and erected between 2010-2012. The superstructure of the bridge is a continuous steel box girder with 3 spans (3 x 108.5 m). The independent static check in the final stage and during the launching phases are made by the BME Department of Structural Engineering. The current paper focuses on the numerical modelling technique and on the specialities of the static check of this bridge structure during launching. An additional research program is also related to the static check of this bridge structure, which was made in cooperation with the University of Stuttgart and the Universitat Politecnica de Catalunya. During launching nearly all cross-sections come at least once over a support where a concentrated reaction force, large bending moment and shear forces are introduced and hereby buckling problems may arise in the slender web panel. In the current version of EN1993-1-5 [1] there is no standard design method to take the interaction of these three effects into account. Therefore our research work focuses on the interaction behaviour of longitudinally unstiffened and stiffened steel girders under the combination of bending, shear and patch loading.

Owing to widespread applications of continuous welded rail (CWR) in high-speed railway bridges, the studies on the seismic response of high-speed railway simply-supported beam bridges (HSRSSBB) considering track constraint is of greatest importance. In order to ensure the high efficiency and high precision of calculations under the consideration of constraint of a long track system, based on the consideration of longitudinal constraint and beam-track interaction, an equivalent model for the HSRSSBB was established, which can simultaneously achieve high calculation efficiency and calculation precision. Also, the sensitivity for seismic response of the HSRSSBB had been proposed, and a judging formula to rapidly determine the bridge-subgrade longitudinal constraint range for the HSRSSBB was established. Finally, after an analysis of a large number of cases, the relationship between the equivalent boundary characteristics and the bridge-subgrade longitudinal constraint range was studied, indicating that the subgrade length of 90 m can be used as the reasonable subgrade length in the longitudinal seismic analysis for the HSRSSBB.

The paper presents development, testing and on-site implementation of a new CFRP (Carbon Fibre Reinforced Polymer) post-tensioning system for flexural strengthening. Main elements of the system include the tensioning device and steel anchorages mounted on both ends of a single CFRP strip. Development of the system itself and the results of a system efficiency examination on full-scale beams in the lab have been briefly described in the paper. After laboratory testing, the system has been implemented on site to strengthen two beam bridges, built of reinforced concrete and steel. Bridge load tests before and after strengthening have been carried out to assess system efficiency.

The scope of this paper is to evaluate different approaches for the prediction of the probability of failure of uncertain railway bridges subjected to high-speed trains. The peak acceleration of a bridge, which is commonly the governing response quantity for dynamic bridge design and failure, depends strongly on the type of train and the train speed. Since in many cases the critical speeds related to response maximums are below the design speed and failure, and during operation the speed varies up to the design speed, the assessment of the probability of failure is not straightforward. In this contribution, several more sophisticated measures of the probability of failure of the bridge-train interaction problem are proposed, considering the peak acceleration as a function of the speed in a certain interval and the distribution of the actual train speed. These measures are tested on two random test bridges, taking into account the main sources of uncertainty, i.e. damping, track irregularities, and the environmental impact. The mechanical model used for the prediction of the dynamic bridge response is composed of a beam bridge crossed by a planar mass–spring damper model of the train. In this simplest approach that considers explicitly dynamic bridge-train interaction, random irregularity profiles capture the effect of track irregularities. It is shown that in certain speed intervals the predicted probability of failure strongly depends on the underlying measure of the probability of failure. In the first example bridge, whose response is governed by a pronounced resonance peak, exceedance of the serviceability limit state is predicted by all measures at virtually the same speed. The second example problem, where track irregularities lead to considerable response amplifications, only some of the measures predict failure. The results of this study may serve as an impulse for a more in-depth discussion on the appropriate prediction of the probability of failure of bridge-train interaction.

Shear keys are used in the bridge abutments and piers to provide transverse restraints for bridge superstructures. Owing to the relatively small dimensions compared to the main bridge components (girders, piers, abutments, piles), shear keys are normally regarded as secondary component of a bridge structure, and their influences on bridge seismic responses are normally neglected. In reality, shear keys are designed to restrain the lateral displacements of bridge girders, which will affect the transverse response of the bridge deck, thus influence the overall structural responses. To study the influences of shear keys on bridge responses to seismic ground excitations, this paper performs numerical simulations of the seismic responses of a two-span simply-supported bridge model without or with shear keys in the abutments and the central pier. A detailed 3D finite element (FE) model is developed by using the explicit FE code LS-DYNA. The bridge components including bridge girders, piers, abutments, bearings, shear keys and reinforcement bars are included in the model. The non-linear material behaviour including the strain rate effects of concrete and steel rebar are considered. The seismic responses of bridge structures without and with shear keys subjected to bi-axial spatially varying horizontal ground motions are calculated and compared. The failure mode and damage mechanism of shear keys are discussed in detail. Numerical results show that shear keys restrain transverse movements of bridge decks, which influence the torsional–lateral responses of the decks under bi-axial spatially varying ground excitations; neglecting shear keys in bridge response analysis may lead to inaccurate predictions of seismic responses of bridge structures.

Thermal load, especially vertical temperature gradient is an important factor that should be considered during the bridge design procedure. In the world several researches focusing on thermal influences was performed, mostly in USA and China, but only a few analyzed real measured cross-section temperature gradient at European bridges. In this paper, short overview of thermal loading on concrete bridge structures was analyzed. The measurement of real temperature gradient along the cross-section of concrete box girder bridge realized by balanced cantilever method has been analyzed and compared to the five different bridge design codes.

In this paper a methodology to compare two point clouds of an object, obtained with different equipment or in different conditions, is proposed. First, the point clouds are registered to the same reference system using an iterative algorithm that performs a rigid body transformation. Then, the standard deviation of the measurements is estimated, in order to evaluate the uncertainty in the measurements. Afterwards, two surfaces are adjusted to each of the point clouds by means of a kernel smoothing technique and compared. Finally, the effect of uncertainty in the point coordinates is considered by means of a bootstrap analysis. The methodology was used to compare two point clouds of a beam bridge measured using two different types of terrestrial laser scanner (time-of-flight and phase-shift based systems). According to the results obtained, some statistically significant differences exist between both point clouds.

A hybrid FRP-aluminum space truss structure system was designed as a modular emergency bridge with a span of 12 m. The bridge has a light weight of only approximately 1.2 tons and contains 8 structural units, which are composed of an aluminum bridge deck supported by FRP trussed members and connected by male jugs and female jaws based on the pre-tightened teeth connection (PTTC) technique. In the paper, the conceptual design of the bridge, assembly of structural units and bridge erection are described in detail. To understand the actual flexural behavior of the bridge, 4 prototype structural units were fabricated and mounted as a single-span simply supported structure and subjected to the four-point bending loading test. Structural computational models, including two FE models and a simplified analytical planar model, were constructed and validated by the experimental results. The results indicated that (1) the specimen displayed linear behavior under the ultimate-limit-state loading level, and both the strength and stiffness satisfied the design requirements; (2) the bridge deck exhibited an unexpected complex strain distribution, which is different from that of the analogous structure; and (3) the “beam-grillage” FE model and simplified analytical planar model provided effective calculation methods for the proposed bridge.

Melt-electrospinning is a cost-effective and flexible process to fabricate micro-scaled polymeric fibers. Melt-electrospun microfiber structures have been receiving considerable attention from various fields due to their numerous advantages. However, the application of melt-electrospinning is limited by various factors, such as the sagging behavior and unstable whipping motion of microfibers. Here, we presented an experimental approach called beam bridge test to identify the sagging behavior of melt-electrospun microfibers for preparing 3D lattice structures with controllable architecture and well-defined pores in transverse direction. Consequently, the sagging behavior of melt-electrospun microfibers could be identified in a systematic manner. Moreover, the melt-electrospun 3D microfiber lattice structures with various grid sizes had sagging, which agreed well with the beam bridge test results. In addition, fibroblast cells (NIH-3T3) were cultured on the fabricated 3D microfiber lattice structures with various grid sizes. Cell culture results indicated that the cell growth was considerably influenced by microfiber sagging and the grid size of lattice structures. Also it was shown that the cell population for location could be controlled.

In this study, after giving short information about historical bridges, finite element model of Palu Bridge, which is located near the Palu county of Elazig province, is generated with SAP2000. Deformations and stresses of the bridge are determined under dead loads and linear elastic earthquake response of this bridge is investigated. In this study, failures result from the materials used in repairing, structural system of the bridge and the effect of water to structural elements are examined. Earthquake acceleration is used as load for the mathematical model of the bridge constructed for dynamic analysis and calculations are made. Finite element method, which is accepted as one of the most precise methods currently, is used in calculations. Finally, analysis of planned reinforced bridge is made.

Two integral abutment bridges in Vermont, USA were instrumented and monitored to report behavior under seasonal thermal load. This paper describes substructure response from 30 months of field data. The bridges are single span steel girder bridges of approximately 40 m on pile foundations. One bridge is straight while the other has a 15° skew. Variations in substructure displacements, backfill pressures and pile moments are reported under hot, cold and moderate ambient temperatures. Abutment and pile deformation plots highlight maximum displacements at the top of piles that are often only 1/3 to 1/2 of the values at the top of the abutment. Maximum pile moments correspond to concentrated curvature at the pile–abutment interface which did not correspond to peak temperatures. Substructure deformation response was predominantly elastic under bridge contraction, but highly non-linear under bridge expansion and varied from year to year. No indication of soil ratcheting was observed in the backfill materials and design for full passive pressure appears to be overly conservative for these single span structures. No indications of pile yielding were observed in the Grade 345 steel piles. Backfill pressures were consistent across the abutment in the straight bridge, but highly variable in the 15° skew bridge.

The hereby discussed bridge span consists of steel truss elements prepared in a workshop, equipped with corrugated sheets, which make formwork for a concrete bridge deck slab. Truss elements, of which the upper chord makes reinforcement of bridge deck slab, will be supplied to the construction site in their final form, and then placed on pre-executed abutments. Truss elements placed side by side will assume the role of a self-supporting structure for execution of concrete bridge deck slab made of fresh concrete mixture. After hardening of concrete in the deck slab, the bridge span will create a steel-RC truss composite element, where: • the upper part of the steel truss element is the bridge deck slab reinforcement which carry the service loads of the bridge, • the bottom part of the steel truss element (not braced), together with RC deck slab is the composite truss-slab load carrying structure of the bridge span. After hardening of the concrete, the whole span works as a 3D truss-slab structure supported by rubber bearings. This solution represents a high potential in executing and it significantly speeds up the process of construction of the bridge.

Optical stereoscopic measurements were performed on a real size 14 m long fibre-reinforced polymer composite vehicular beam bridge submitted to four-point bending. The field of view was 6 m, with a pixel resolution of ∼4 mm. The 3-D displacements were monitored by targets and texture tracking. Optical measurements show good correlation with traditional sensors. They allowed measuring 3-D displacement and strain fields, evidencing the out-of-plane buckling displacement of the beam web, sensing unforeseen displacements and giving insight in the boundary conditions of the experiment.

The frequent occurrence of accidental collisions between over-height trucks and bridge superstructures in recent years has seriously affected the safety of bridge infrastructure and traffic systems in metropolitan areas. Such collisions highlight the importance of scientific research in this field and therefore the performance of three typical bridge superstructures subjected to collision by an over-height truck is studied in this paper through scaled model tests. A steel box girder, a steel plate girder and a reinforced concrete (RC) T-beam girder are adopted to represent different types of bridge girders while a cylindrical tank with counterweight is adopted to represent a typical over-height truck. Finite element simulation is also conducted and the results are compared with the experimental findings. The results obtained by test and simulation are consistent and both of them indicate that under collision conditions local failure is found to be the main failure mode for the steel plate and RC T-beam girders, whilst global failure is found to be the main failure mode for the steel box girder bridge model.