Prestressed Concrete Continuous Girder Bridge Research Articles

A Stress Index-based Tendon Optimization Method for Prestressed Concrete Continuous Girder Bridges

PDF HTML XML Export Cite reminder A Stress Index-based Tendon Optimization Method for Prestressed Concrete Continuous Girder Bridges DOI: 10.59238/j.pt.2023.01.001 Author: Affiliation: (1. Department of Bridge Engineering, Tongji University, Shanghai 200092, China; 2. Anhui Transport consulting & Design Institute Co., Ltd. Anhui 230088, China) Clc Number: Fund Project: Article | Figures | Metrics | Reference | Related | Cited by | Materials | Comments Abstract:Traditional tendon design methods for prestressed concrete (PC) continuous girder bridges are tedious since they obtain feasible solutions based on trial calculation, and the existing optimization methods that can obtain the optimal solution have deficiencies regarding structural stress. In this study, based on research on the refined bridge design conducted in the Department of Bridge Engineering at Tongji University in recent years, a stress index-based tendon optimization method for PC continuous girder bridges is pro-posed. First, various tendon layouts are summarized, and a reasonable tendon layout is selected. Then, a mathematical tendon optimization model is established. After meeting the specifications and construction feasibility requirements, a genetic algorithm is used to find the optimal solution. This method not only realizes tendon forward design but also obtains a satisfactory solution. Finally, this method is used to successfully optimize the tendons of a three-span PC continuous girder bridge, which verifies the ration-ality of the method. Reference Related Cited by

Construction monitoring of a long-span prestressed concrete continuous box girder bridge with variable sections

The structural behaviors in each construction stage were monitored and analyzed against the background of a long-span prestressed concrete continuous box girder bridge with spans of 55+100+55 m. At first, the formwork erection elevation and pre-camber of the bridge in each stage, as well as stress values of key cross-sections were determined by simulating the whole construction process using the finite element software. Then, the design parameters were identified and the model was corrected by field data collection and considering various influencing factors, so as to ensure effectiveness of the model. Finally, the formwork erection elevation was adjusted according to the stress and altitude in each construction stage, followed by closure of the bridge. According to field monitoring and adjustment, the measured alignment and stress of the bridge conform to the design and the error meets the requirements of specification, indicating a favorable monitoring effect. The research can provide reference for construction of similar bridges.

Semi-Active Control of Seismic Response on Prestressed Concrete Continuous Girder Bridges with Corrugated Steel Webs

To improve the seismic capacity of prestressed concrete (PC) continuous girder bridges with corrugated steel webs (CSWs), suitable damping control measures can be used to effectively reduce the seismic response of the bridge. Based on the semi-active control theory, the semi-active control system of a three-span PC continuous girder bridge with CSWs is designed, and the semi-active control system program of the three-span PC continuous girder bridge with CSWs is compiled by MATLAB. The time–history curves of damper energy consumption of active optimal control algorithm and three different semi-active control algorithms are compared and analyzed, as are the time–history curves of main girder displacement, acceleration, and pier internal force with or without semi-active control. The study shows that the rational determination of the weight matrix coefficient can make the active control achieve a better vibration absorption effect and economy. The semi-active control algorithm of Hrovat has the best vibration absorption effect, which is closest to that of the active optimal control algorithm. Under the state of semi-active control, the average vibration absorption rate of displacement and acceleration of the main girder with CSWs are 71% and 20%, respectively. The time–history curve of bending moment and shear force in the pier bottom is similar, and the average vibration absorption rate of bending moment and shear force at the bottom of pier #2 is 70%. At the same time, the average vibration absorption rate of bending moment and shear force at the bottom of pier #3 is between 42% and 48%. The semi-active control measure has a good vibration absorption effect on the overall seismic response of the PC continuous girder bridges with CSWs. This study provides a certain reference for the seismic reduction and isolation design of composite structure bridge with CSWs.

Stiffness identification of deteriorated PC bridges by a FEMU method based on the LM-assisted PSO-Kriging model

Stiffness identification from measured responses is an important part of structural health monitoring, in which finite element model updating (FEMU) is a widely studied method. However, the practicability of this method still needs to be improved when applied to large deteriorated civil structures. In this paper, a new FEMU strategy based on the PSO (particle swarm optimization)-Kriging model assisted by the Levenberg–Marquardt (LM) algorithm is proposed for the stiffness identification of deteriorated long-span prestressed concrete (PC) continuous girder bridges. The strategy is implemented in two phases: global stiffness identification based on the LM algorithm is adopted in phase I to determine the sampling interval of the identification parameters; then, in phase Ⅱ, the girder is divided into segments, and the accurate value of each segment stiffness is determined. The PSO-Kriging model is employed to facilitate the high accuracy and efficiency of the method. The effectiveness of the proposed method is demonstrated through comparison studies in an existing experiment and a full-scale test, and the parameter selection of the method is also discussed.

Replacing the deck slab on a post-tensioned, prestressed-concrete composite girder bridge in Japan

Repairs were required to a corroded post-tensioned prestressed-concrete continuous-girder bridge that had been in service for over 35 years in the Chuo Expressway in Japan. The work included reinforcing the bridge girders with external cables and partially replacing the bridge deck slab at intermediate piers. The load-carrying capacity of the existing bridge and reinforcement design for the replacement slab sections were based on a soundness assessment following detailed investigations. This paper describes the considerations for examining, planning and designing the replacement of large sections of slab on a post-tensioned, prestressed-concrete, continuous-girder bridge.

Deflection analysis of long-span girder bridges under vehicle bridge interaction using cellular automaton based traffic microsimulation.

Deflection is a crucial indicator to reflect the operating condition of girder bridges, which can be used to evaluate structure condition and identify abnormal loading. The paper analyzed the deflection characteristics of long-span girder bridges based on the coupling vibration between stochastic traffic stream and bridge. First, the latest research advances were integrated to form an analytical model of the coupling vibration between stochastic traffic stream and bridge. Then, a generalized Pareto distribution model based on peaks-over-threshold theory was established to predict the extreme girder deflection. Next, a cellular automaton based microsimulation method was proposed to model the traffic loads on bridges, which utilized the intelligent driver car-following model and acceptance distance based lane-changing model. Finally, these theories were applied in the case study of a long-span prestressed concrete continuous girder bridge. It is discovered from the study that, under the coupling vibration between stochastic traffic stream and bridge, the predicted extreme deflection of the case bridge is far lower than the specified design value. Hence, a grading warning model was established and employed to the analysis of deflection monitoring data of the bridge, showing a wide potential prospect of application.

Application research of seismic isolation device in long-span continuous beam bridge

The three-dimensional finite element model of pre-stressed concrete continuous girder bridge with span (76+144+76)m is established by using finite element structural analysis software Ansys in this paper. The dynamic time history analysis method is used to study the influence of viscous dampers and friction pendulums with different parameters on the seismic response of long-span continuous beam bridges, which provides a basis for rational selection of seismic isolation measures. The results show that reasonable seismic isolation measures can effectively reduce the seismic response of long-span continuous beam bridges; both the viscous damper and the friction pendulum can have good seismic isolation effects, but the damping effects are related to their parameter settings.

Seismic fragility and risk assessment of high-speed railway continuous-girder bridge under track constraint effect

The prestressed-concrete continuous-girder bridge is one of the major high-speed railway bridges that plays an essential role in the railway. Using a typical high-speed railway continuous-girder bridge as a case study, a track-bridge longitudinal interaction model has been initially established with a comprehensive consideration of the components including rail, track slab, bed plate, rail fastener, cement asphalt mortar, sliding layer, and bridge structure. The damage states of the bridge and the seismic capacity model for key structural components of the bridge under various damages were defined. A probabilistic seismic demand model was constructed for structural components according to the incremental dynamic analysis of a suite of selected ground-motion. The fragility curves of the bridge components were derived and compared with that of the bridge model without a track system. Then, the failure probability of the bridge system was estimated using the first-order boundary method. Finally, the risk of the bridge was assessed via the numerical convolution method using both the fragility curves and seismic hazard function. The results are drawn as follows: (1) Owing to the longitudinal constraint of the track system, the dynamic characteristics of the bridge are changed; (2) A total of four damage levels occurred on the bridge pier without the track system, but only light and moderate damage levels appear due to the track constraint; (3) Under the same peak ground acceleration, the damage exceeding probability of the model without the track system is significantly greater than that with the track system; (4) Under the slight and moderate damage states, the upper and lower limits of the system fragility curves are governed by bridge pier. They are governed by the bearing with very low failure probability under the extensive and complete damage states; and (5) Within the 100-year design period, the probability that the bridge structure subject to slight and moderate damages is “occasional”, while it is “very unlikely” that the structure will suffer from the extensive and complete damages.

悬臂现浇预应力混凝土连续梁桥合拢段施工技术与工艺计算

悬臂现浇预应力混凝土连续梁桥合拢段施工技术与工艺计算

Research on Temperature Effects of the Pre-Stressed Concrete Box Girder Bridge

The distribution of the temperature gradient and temperature change of the pre-stressed concrete box girder are extremely complicated because of the multiplex environment. Temperature load has attached great importance in the field of engineering, and it has a great influence on the bridge’s structure, especially the box structure. The engineering background of this paper is a typical three-dimensional pre-stressed concrete continuous box girder bridge with variable cross section, comprising five spans in one continuous unit. Experiment on it and research the change rules of the temperature distribution, as well as the influence of the structure’s internal force resulted by temperature. Finite element software-Midas/FEA is used to model and calculate the bridge in order to analyze the temperature influence on structure’s stress in contrast to the measured data from the experiments

Reliability Analysis of Pre-Stressed Concrete Continuous Girder Bridges Using Cantilever Construction on Different Codes

The object of this paper analyzes the reliability level of pre-stressed concrete continuous girder bridges designed with the Chinese codes including the code for design of highway reinforced concrete and pre-stressed concrete bridges and culverts of JTG D62-2004 and JTJ 023-85 using cantilever construction method. Typical cross-sections used in the example bridge are considered at service stage. Load and resistance parameters are treated as random variables. The statistical parameters are based on the available literature, test data and survey results. Reliability indices are calculated by iterations using the first-order second-moment method. The calculated results indicate that the reliability indices on the code of D62-2004 vary considerably to the code of JTJ 023-85. And it could provide the references for the reinforcement of old bridges and the design of new bridges using the cantilever construction.

Reliability Analysis of Pre-Stressed Concrete Continuous Girders Bridge Using Incremental Launching Method on Different Codes

The object of this paper analyzes the reliability level of pre-stressed concrete continuous girder bridges using incremental launching method during construction stages. Typical cross-sections used in the example bridge are considered at construction and service stages, respectively. The calculated results indicate that the reliability indices on the code of D62-2004 vary considerably to the code of JTJ 023-85. Comparing the reliability indices between the constructions shows the different regularity.

Research on Construction Control of Long-Span Prestressed Concrete Continuous Girder Bridge

On the background of 318 highway bridge of the Yinjiang Jihan Navigation Project, it introduces the methods and contents of the construction control of long-span prestressed concrete continuous girder bridge, it adopts Midas/Civil softwares to have a simulation analysis and effective control for the construction process of whole bridge. The result indicates that safety of the bridge construction, linear and the variation of prestress are all in control. Finally, the condition of structure of bridge suits for computational state theoretically.

Research of Intersection Bridge Span Arrangement of Urban Expressway

Based on the problems of development and modernization of urban transportation in China, it introduces the fact that the widely construction of expressway over the past decade as a starting point to analyze its characteristics. Firstly, it analyzes the features of intersection and general design principles of intersection, and studies the specific design methods of intersection. Secondly, the paper studies the span arrangement of Prestressed Concrete Continuous Girder Bridge based on the structural characteristics of the bridge itself. Finally, it studies the span arrangement concerning the traffic design of intersection, and the writer designs the traffic arrangement of intersection and the span arrangement of the bridge above, which is located at the middle ring expressway, Kunshan, Jiangsu and eastern part of Jianghai expressway, Nantong, Jiangsu to give an example.

Procedure Inversion Effect Analysis of Final System Transformation of Prestressed Concrete Continuous Girder Bridge

When the cantilever construction is adopted by the prestressed concrete continuous girder bridge, the order of two key procedures between removing temporary support and tensing remanent prestressed cable is used to be ignored. In order to study the influence of procedure inversion, the influences on bridge shape, stress distribution and prestressing loss were calculated for one common prestressed continuous concrete box girder bridge by MIDAS CIVIL 2006, respectively. The obtained result presents that: the influence on the bridge shape and the prestressing loss are not apparent, but the influence on the stress distribution is serious; the maximal compressive stress of procedure inversion is more 42.3% than common construction procedure only by tensing the remaining steel beams at box girder; especially, the combining area between the box girder and temporary support is easy to pull out. So, the procedure inversion construction method cant be accepted.

Application of Displacement Back Analysis in Geometry Monitoring of Segmental Construction of Prestressed Concrete Continuous Girder Bridge

This paper apply displacement back analysis theory for geometry form monitoring and calculating work of segmental construction of prestressed concrete continuous girder bridge, making use of displacement back analysis method to optimize bridge structure parameters, ensuring accuracy of geometry form control with calculated results of every girder segment in entire construction. This method is used in the construction monitoring and supervision for Yuanyichang circular curved rigid frame bridge on Pingan-Adai highway, to make the closure accuracy and the bridge geometry form reaches the effect of aspiration. Through the result of the finished bridge, what we can obtain is that the displacement back analysis theory could fulfill the requirement of factual project and be widely used for geometry monitoring of segmental construction of prestressed concrete continuous girder bridge.

Research on Deflection and Cracking of Prestressed Concrete Continuous Girder Bridge

Through the checking comparison of example bridge, to analysis the major causes of the cracking and too much deflection for prestressed concrete continuous box girder bridge. Calculated weak position and the current presence of cracks in the bridge position basically consistent, so cracks mainly caused by the prestress loss, concrete creep and the temperature effect, the structure stiffness weakened after cracking, then the actual mid-span deflection is greater than the calculated values bound. Therefore, the cracking and too much deflection appear simultaneous and mutual promote. The view that by improving the mechanical behavior of box girders, design parameters optimization, just the fundamental solution to cracking and too much deflection, also, several key issues need study to be addressed.

Analysis of the Causes of the Formation of Crack in Inclined Web of Prestressed Concrete Continuous Girder Bridge in Cantilever Construction

The crack in inclined web of the prestressed concrete continuous girder bridge which is constracted by the way of cast-in-place cantilever method that become one problem that should be more cared about[1-2]. This paper analysis the bridge in three different conditions which are according to the pratical and special engineering to find the causes of the formation of crack in inclined web of prestressed concrete continuous girder bridge in cantilever construction. The results of the analysis show that the additional stress caused by the different temperatures between internal and external components leads to the formation of the crack in inclined web of the bridge.

Prestressed Concrete Continuous Girder Bridge Reinforcement Simulation Analysis and Carrying Capacity Assessment

This article simulates prestressed concrete continuous girder bridge reinforced many times and evaluates carrying capacity after reinforcement. Taking the FuFeng bridge for an example, we analyze the bridge’s stress state in using by Midas software, evaluate the concrete ability of crack resistance, check the reinforced concrete structure ultimate carrying capacity, the cracking resistance and the stiffness, assess reinforcement effect and verify the accuracy and reliability of the simulation results. The maximum main compressive stress, maximum compressive stress, maximal main tensile stress and maximum tension stress of mid-span cross-section of the bridge are 1.6Mpa, 1.6Mpa, 0.3~0.5Mpa, and -1.2Mpa respectively, the mid-span center cross-section of deflection is 2.89cm. Reinforcement suppresses the development and expansion of the crack; the mid-span deflection tends to stabilize; the ultimate bearing capacity meets the Standard requirement basically; the emergency capacity is not enough; and the car whose weight over 55 tons is prohibited from passing.

Influence of Cracks Parameters on Bearing Capacity for Prestressed Concrete Box Girder

For long-span pre-stressed concrete continuous box girder bridges, cracks and other damage problem are often found because of influence of loads, climate, operations management and other factors during operation. The problem of cracking is serious increasingly, which has a direct impact on usability, durability and security. In order to analyze the bearing capacity of the bridge with cracks under different parameters, such as cracks width, cracks height and cracks spacing and provide the basis for the safety assessment and reinforcement, the paper puts forward the cracking reduction coefficient that evaluates the bearing capacity of the damaged bridge based on the tensile stress control. A three-span continuous rigid frame bridge is analyzed and the result shows that the bearing capacity of the bridge is in inverse proportion to cracks width and cracks height. The bearing capacity of the bridge is in direct proportion to cracks spacing.