Continuous Rigid Frame Bridge Research Articles

The influence of shear surface quality on the mechanical properties of long-span prestressed continuous rigid-frame bridge

PurposeThe long-span continuous rigid-frame bridges are commonly constructed by the section-by-section symmetrical balance suspension casting method. The deflection of these bridges is increasing over time. Wet joints are a typical construction feature of continuous rigid-frame bridges and will affect their integrity. To investigate the sensitivity of shear surface quality on the mechanical properties of long-span prestressed continuous rigid-frame bridges, a large serviced bridge is selected for analysis.Design/methodology/approachIts shear surface is examined and classified using the damage measuring method, and four levels are determined statistically based on the core sample integrity, cracking length and cracking depth. Based on the shear-friction theory of the shear surface, a 3D solid element-based finite element model of the selected bridge is established, taking into account factors such as damage location, damage number and damage of the shear surface. The simulated results on the stress distribution of the local segment, the shear surface opening and the beam deflection are extracted and analyzed.FindingsThe findings indicate that the main factors affecting the ultimate shear stress and shear strength of the shear surface are size, shear reinforcements, normal stress and friction performance of the shear surface. The connection strength of a single or a few shear surfaces decreases but with little effect on the local stress. Cracking and opening mainly occur at the 1/4 span. Compared with the rigid “Tie” connection, the mid-span deflection of the main span increases by 25.03% and the relative deflection of the section near the shear surface increases by 99.89%. However, when there are penetrating cracks and openings in the shear surface at the 1/2 span, compared with the 1/4 span position, the mid-span deflection of the main span and the relative deflection of the cross-section increase by 4.50%. The deflection of the main span increases with the failure of the shear surface.Originality/valueThese conclusions can guide the analysis of deflection development in long-span prestressed continuous rigid-frame bridges.

Investigation of the Mechanical Features of Steel–Concrete Composite Girder Rigid Frame Bridges with V-Shaped Piers during Construction Stages

Steel–concrete composite girder rigid frame bridges with V-shaped piers are a new type of bridge structure. Based on the traditional composite continuous beam bridge, part or all of the vertical piers are changed into V-shaped piers. This special structure makes them have the mechanical characteristics of both composite continuous beams and V-shaped piers. In this paper, the finite element model of the first steel–concrete composite continuous beam V-pier rigid frame bridge in China is established by simulation software, the construction process of the bridge is simulated, and the stress and deflection of the bridge in each construction stage are studied. At the same time, the stress of the completed bridge model considering the construction stage is compared with that of the completed bridge model without considering the construction stage. It is found that the stress difference between the two concrete slabs is as high as 2.7 MPa. The results show that the stress state of the bridge is greatly affected by the construction process. This study can provide guidance for the design and construction of such bridges, which is of great significance.

Shrinkage and creep effect analysis of beam-arch composite bridge based on field test

To study the time-dependent behavior of the beam-arch composite bridge under the effects of shrinkage and creep, this paper conducted field tests on C55 concrete with different reinforcement ratios at the bridge site environment. Based on the experimental results, the commonly used CEB-FIP-90 model in engineering was modified, and new shrinkage strain and creep coefficient values were proposed. These modifications allowed for an analysis of the long-term performance of the bridge. Finally, the influence of the arch rib stiffening on long-term performance was discussed. The results indicate that the modified model aligns better with the actual structure compared to the CEB-FIP-90 value. During the operation stage, the bridge exhibits an overall significant compressive stress reserve. Specially, it is worth noting that the concrete footings experience tensile stress, which indicates a risk of cracking during the operation stage. Furthermore, the deflection of the beam-arch composite bridge is 1/7 of that of the continuous rigid frame bridge while the stress distribution in the beam-arch composite bridge is more uniform. This paper provides important reference value for the maintenance and management of beam-arch composite bridges during their operation period.

Seismic performance analysis of long-span continuous rigid frame bridge with Engineered Cementitious Composite at expansion joints

In this paper, OpenSees software is used to establish a numerical simulation analysis model of a long-span continuous rigid frame bridge with Engineered Cementitious Composite (ECC) expansion joint reinforcement scheme. The seismic response characteristics and laws of structures with ordinary concrete and ECC concrete at expansion joints are compared and analyzed, and their seismic performance is evaluated. The results show that the use of ECC material at the beam end position can effectively reduce the peak response of the structure under earthquake action and reduce the number of collisions. ECC material has a strong energy dissipation capacity and can reduce the collision damage of the beam section near the bridge expansion joint under earthquake action.

Study on shrinkage and creep effect of steel truss-stiffened continuous rigid frame bridge considering variable temperature and relative humidity

In this study, indoor-outdoor comparison tests of shrinkage and creep were carried out in northwest China. The experimental results were compared with commonly used models of shrinkage and creep, some of which have adapted different methods for temperature and humidity correction. A finite element model for a continuous rigid-frame bridge with steel truss bracing was established. The calculated values from different shrinkage and creep models were then compared with the measured deflection values. An analysis was conducted to determine the influence of variable temperature and humidity on the long-term mechanical behavior of the steel truss-stiffened continuous rigid-frame bridge.The results show that when the concrete reaches the age of one year, the creep coefficient for the outdoor environment is 18.5% smaller than that in the indoor environment, while the outdoor shrinkage strain is 16.0% smaller. The CEB 90 model agrees best with the indoor test results. The corrected shrinkage and creep model (CSCM) is the closest to the outdoor test results, and the fib2010 model ranked second. The predicted values from CSCM exhibit the best agreement with the measured deflection values after the bridge completion. The CEB 90 model's predicted values for deflection of the main girder, longitudinal displacement of the pier, the maximum stress in steel trusses, and prestressing loss are lower than those in the CSCM after 20 years of construction, indicating that the influence of temperature and relative humidity variations on shrinkage and creep effect of the bridge can not be negligible.

Template-Guided Hierarchical Multi-View Registration Framework of Unordered Bridge Terrestrial Laser Scanning Data.

The registration of bridge point cloud data (PCD) is an important preprocessing step for tasks such as bridge modeling, deformation detection, and bridge health monitoring. However, most existing research on bridge PCD registration only focused on pairwise registration, and payed insufficient attention to multi-view registration. In addition, to recover the overlaps of unordered multiple scans and obtain the merging order, extensive pairwise matching and the creation of a fully connected graph of all scans are often required, resulting in low efficiency. To address these issues, this paper proposes a marker-free template-guided method to align multiple unordered bridge PCD to a global coordinate system. Firstly, by aligning each scan to a given registration template, the overlaps between all the scans are recovered. Secondly, a fully connected graph is created based on the overlaps and scanning locations, and then a graph-partition algorithm is utilized to construct the scan-blocks. Then, the coarse-to-fine registration is performed within each scan-block, and the transformation matrix of coarse registration is obtained using an intelligent optimization algorithm. Finally, global block-to-block registration is performed to align all scans to a unified coordinate reference system. We tested our framework on different bridge point cloud datasets, including a suspension bridge and a continuous rigid frame bridge, to evaluate its accuracy. Experimental results demonstrate that our method has high accuracy.

Effective length coefficient of pier of multi-span continuous rigid-frame bridge based on transfer matrix method with branch

Effective length coefficient of pier of multi-span continuous rigid-frame bridge based on transfer matrix method with branch

Response Characteristics of Irregular Continuous Rigid Frame Bridges with Long-Span and High-Rise Piers under Ground Motion Excitations with Different Fault Distances

An innovative seismic performance evaluation strategy for irregular rigid frame bridges with a long-span and high-rise piers under the action of ground motions with different fault distances is presented in this paper. A total of 129 mainshock records taken during the Wenchuan earthquake, from national seismic stations with different fault distances, were analyzed using statistical methods, to determine the attenuation characteristics of the intensity index of the Wenchuan earthquake records from the perspective of aseismic engineering, and the attenuation of the acceleration response spectrum is discussed. The Miaoziping Bridge on the Dujiangyan–Wenchuan Expressway, which was damaged in the Wenchuan earthquake, is taken as the analysis background; two sets of samples for long-span continuous rigid frame bridges with different pier heights are constructed, to discuss the seismic response characteristics of continuous long-span rigid frame bridges; and representative values for the natural periods of these two bridge structural groups are subsequently compared and analyzed. After the peak responses for various bridges with various pier heights are determined through a response spectrum analysis under the action of ground motions with different fault distances, and the surfaces for the obtained peak responses are fitted and the response characteristics for different fault distances are discussed. It is shown in the results that the seismic response characteristics of the continuous rigid frame bridges with long-span and high-rise piers were significantly different under the action of the ground motions with different fault distances, and the seismic responses of these two bridge groups were distinctly larger under the action of near-fault ground motions. Furthermore, based on the above research, suggestions for the pier arrangement and bridge site selection for continuous rigid frame bridges with long-span and high-rise piers are also discussed. The results of this paper also provide some theoretical guidance for the sustainable development of bridges with long-span and high-rise piers, from the perspective of bridge seismic response characteristics.

Structural damage identification under ambient temperature variations based on CNN and normalized modal flexibility-autoregressive coefficients hybrid index

This study proposes a novel method to identify structural damage considering ambient temperature variations. In this method, the normalized modal flexibility based index (nMFBI) and autoregressive (AR) coefficients are combined to form the nMFBI-AR hybrid index, and convolutional neural networks (CNN) are exploited to locate and quantify the damage. Moreover, the effects of ambient temperature variations and measurement noise are not considered in the training dataset, which is preferable in practical engineering. To verify the effectiveness of the proposed method, firstly, a numerical structure of a simply supported beam is investigated, and the performance of the nMFBI-AR index is evaluated by making a comparison with the nMFBI and AR indexes. Then, the proposed method is further verified by a test model of a three-story frame and a practical engineering example of a continuous rigid frame bridge. The results demonstrate that although the influence of ambient temperature variations and measurement noise are only considered in the test datasets, this approach has the best performance in locating and quantifying structural damage, and the errors are less than 16%, which is promising. In addition, this paper provides a guideline and a new idea for the study of damage index based on time-frequency hybrid information.

Structural Performance Evaluation After Cracking During the Construction of Long-Span Continuous Rigid-Frame Bridges

Structural Performance Evaluation After Cracking During the Construction of Long-Span Continuous Rigid-Frame Bridges

Design and Performance Evaluation of the Curved Hengjiang Avenue Pedestrian Bridge: Y-shaped Piers and Mixed Decks

Urban pedestrian bridges should contribute to the improvement of the overall image and function of the place where the footbridge is located. In order to establish a complete pedestrian access area of a Green Belt Park, an elegant pedestrian landscape bridge with Y-shaped piers and mixed decks was designed and built, providing an open and diverse viewing experience. Accelerated bridge construction technologies were adopted to build the footbridge. Finite-element models, including the full bridge model and local model, were established and a continuous rigid frame and continuous girder composite bridge system was proposed after scheme comparison. Preliminary statics and dynamics analysis, as well as detailed calculations for the local stresses of Y-shaped piers and the shear lag effect of the deck, were carried out aiming to demonstrate its safety and suitability.

Correction: Seismic response characteristics and performance improvement of near-fault continuous rigid-frame bridges

Correction: Seismic response characteristics and performance improvement of near-fault continuous rigid-frame bridges

A Study of the Mechanical Properties of Polyester Fiber Concrete Continuous Rigid Frame Bridge during Construction

This study investigates the mechanical performance of a polyester fiber concrete continuous rigid frame bridge during construction and the spatial stress distribution of the 0# block box girder, with a focus on the backdrop of the bridge in Pipa Zhou, Jiangxi Province. Stress monitoring at critical cross-sections during bridge construction was combined with FE simulations to analyze the stress and alignment deviation variations along the cantilevered construction process of the bridges. Subsequently, after validating the accuracy of the whole bridge model, the actual internal force of the box girder cross-section was extracted to act on the 0# block box girder solid model, and the spatial force of the 0# block box girder under the state of maximal cantilever and the completed bridge was further investigated. The results indicate that during cantilever construction, the top, and bottom plates of the box girder were subjected to compression, with the bottom plates having relatively low compression stress close to the critical values for compression and tension. Attention should be paid to controlling tensile stress application. After reaching a quarter of the bridge’s span in construction, the alignment deviation of the main beam increases, necessitating enhanced monitoring and adjustments of the main beam elevation. Furthermore, FE analysis shows that under maximum cantilever and the completed bridge states, the stress variations of the top and bottom plates of the 0# block box girder remain consistent, with the top plate stress varying by no more than 2.5 MPa and the bottom plate stress varying by approximately 1 MPa. Moreover, the 0# block box girder shrinkage cracks were mainly located in the bottom and web plate, and the number of cracks in the 0# block box girder with polyester fibers was reduced compared to the cracks in the ordinary concrete box girder.

Vibro-acoustic characteristics of a rail transit viaduct paved with trapezoidal sleeper track

To investigate the effects of a trapezoidal sleeper track (TST) on the vibration and noise of rail transit viaducts, the wheel–rail interaction model was first built according to the vehicle–track coupling dynamics theory. Subsequently, the vibration responses of the viaduct were analyzed using the beam–slab finite element method, and its radiated noise was calculated using the acoustic boundary element method. The modeling method was verified based on the test data of a 3 × 40 m continuous rigid frame bridge. Taking the Jialing River Bridge of Chongqing Rail Transit Line 9 as the background, the control effects of the TST on the vibration and noise of the viaduct and the effective laws of different track parameters on the bridge noise were analyzed. Results show that the simulated and measured values are in good agreement; for example, the modeling methods are reliable; the radiated noise of the viaduct is influenced by the vibration responses under the action of train load, which are jointly determined by dynamic wheel–rail force (external excitation) and displacement admittance (self-vibration characteristics); compared with embedded sleeper track (EST), the TST can reduce the overall vibration acceleration level and sound pressure level of the box girder web plate by 13.9 dB and 7.8 dB, respectively; the stiffness of the damping path is the primary factor influencing the noise of the elevated box girder, followed by the sleeper thickness and the fastener stiffness; taking the bottom plate as an example, the stiffness of the damping pad is reduced by 1 and the overall sound pressure level can be reduced by approximately 3 dB; the sleeper thickness is increased by 1, and the overall sound pressure level can be reduced by 1–2 dB; and the fastener stiffness is reduced by 1, and the noise reduction is within 1 dB.

Seismic response characteristics and performance improvement of near-fault continuous rigid-frame bridges

Seismic response characteristics and performance improvement of near-fault continuous rigid-frame bridges

Fatigue Safety Assessment of Concrete Continuous Rigid Frame Bridge Based on Rain Flow Counting Method and Health Monitoring Data

The fatigue of concrete structures will gradually appear after being subjected to alternating loads for a long time, and the accidents caused by fatigue failure of bridge structures also appear from time to time. Aiming at the problem of degradation of long-span continuous rigid frame bridges due to fatigue and environmental effects, this paper suggests a method to analyze the fatigue degradation mechanism of this type of bridge, which combines long-term in-site monitoring data collected by the health monitoring system (HMS) and fatigue theory. In the paper, the authors mainly carry out the research work in the following aspects: First of all, a long-span continuous rigid frame bridge installed with HMS is used as an example, and a large amount of health monitoring data have been acquired, which can provide efficient information for fatigue in terms of equivalent stress range and cumulative number of stress cycles; next, for calculating the cumulative fatigue damage of the bridge structure, fatigue stress spectrum got by rain flow counting method, S-N curves and damage criteria are used for fatigue damage analysis. Moreover, it was considered a linear accumulation damage through the Palmgren-Miner rule for the counting of stress cycles. The health monitoring data are adopted to obtain fatigue stress data and the rain flow counting method is used to count the amplitude varying fatigue stress. The proposed fatigue reliability approach in the paper can estimate the fatigue damage degree and its evolution law of bridge structures well, and also can help bridge engineers do the assessment of future service duration.

Sensitivity Analysis of Structural Parameters of Unequal-Span Continuous Rigid Frame Bridge with Corrugated Steel Webs

To investigate the effect of structural parameters of bridges with unequal spans on the bridge alignment, the finite element model simulating the full-scale bridge was developed, considering the construction process. For ease of finite element modeling and investigation, the section of composite beam with corrugated steel web was first converted into the section composed of the same material. For this purpose, an equivalent method of replacing corrugated steel webs with concrete webs was proposed based on theoretical derivation. After equivalent replacement, the influences of material bulk density, internal prestress, pipe friction coefficient, and pipe deviation coefficient on the main beam at the maximum cantilever stage were analyzed, and the influences of external prestress on the main beam after bridge construction were analyzed. The results show that the most sensitive parameter to structural response is bulk density, subsequently the external prestress, internal prestress, pipe friction coefficient, and pipe deviation coefficient. Among them, the bulk density, internal prestress, and external prestress are all sensitive parameters, while pipe friction coefficient and pipe deviation coefficient are non-sensitive parameters.

Study on the pier bottom self-centering seismic isolation structure of the high-pier continuous rigid frame bridges

Four seismic isolation specimens were designed, fabricated, and subjected to physical loading tests to enhance the seismic performance of a high-pier continuous rigid-frame bridge. A finite element model of the seismic isolation structure of the high-pier was established using numerical simulation software. The entire bridge model was established based on the multi-scale modeling method to investigate the seismic response of the high-pier continuous rigid frame bridge under different seismic waves. The results indicate that the seismic isolation pier has self-centering and energy dissipation capabilities. The seismic isolation pier has satisfactory energy dissipation capacity and ductility when the ratio of the long-axis and short-axis radii is 1.5. The results of the finite-element simulation corresponded well with the experimental results. Significant damage occurred to the concrete at the bottom and corner of the pier, and the reinforcement did not reach its yield strength throughout the loading process. Therefore, measures must be implemented to ensure the seismic performance of the structure. The pier bottom self-centering seismic isolation structure effectively absorbs shocks, as evidenced by reduced absolute acceleration and relative displacement at the pier top, decreased shear force and bending moment at the pier bottom, and minimized girder displacement. It was recommended that the ratio of the long-axis and short-axis radii be adopted as 1.5–2.0 and that the pier height be selected as 60 m–100 m. These results provide a reference for the research and applications of this type of structure.

Application of Bayesian Update Method in the Construction Control of Continuous Rigid Frame Bridge Girders with High Piers and Large Spans

In the construction process of large-scale bridges, there are uncertainties and time-varying factors in the environment and construction loads. It is difficult to make accurate estimates of the theoretical calculation models of construction control in advance. In view of this situation, Bayesian dynamic updating method is introduced to re-estimate the predicted results of the theoretical model. When applying this method, first, the finite element calculation model is determined based on the response surface method, and its calculation results are used as prior information. Then, combined with the actual detection data during the construction process, the Bayesian update formula is derived based on the conjugate prior distribution to correct the theoretical prediction results of bridge construction monitoring. Finally, the actual stress detection data of the control section of high-pier and large-span continuous rigid frame bridges during the construction process illustrate the application process of Bayesian updating in improving the theoretical prediction model. Results indicate that the internal force of the bridge control section obtained by re-evaluating by Bayesian theory not only incorporates the priori information models but also actual monitors sample information during the construction process. The predicted results reflect the true deformation and stress state of the bridge during the bridge construction process and improve the precision of construction monitoring.

Analysis of the Temperature Effect and Influence of Large Span Continuous Rigid Bridge in Mountainous Area

The temperature problem of large span bridges in mountainous areas is particularly prominent due to the large temperature difference. This paper addresses the problem of ambient temperature influence on the construction and operation of large span prestressed reinforced concrete continuous rigid frame bridges. Through finite element modeling and computational analysis of an example of a continuous rigid frame bridge, the simulation results reveal the law of temperature influence on large span continuous rigid frame bridges and provide reference for the subsequent analysis of temperature problems of continuous rigid frame bridges. Based on the force analysis of the model, a series of bridge temperature crack generation mechanisms are proposed in combination with the bridge construction process and concrete characteristics, and reasonable treatment measures are proposed for the control of temperature cracks during bridge construction to ensure the overall quality effect of bridge construction and operation.