Concrete Continuous Rigid Frame Research Articles

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.

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.

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.

Load Test Analysis and Research on Long-Span Concrete Continuous Rigid Frame Bridge

Based on the as-built load test of a large bridge, this paper introduces the procedure of the prestressed concrete continuous rigid frame bridge load test. Numerical analysis of the bridge was carried out by simulating and establishing a finite element model, and comparative analysis was carried out with the measured values. The results show that the calculated values were basically consistent with the measured values, which showed that the establishment method of the model was reasonable, and the mechanical performance of the bridge met the service requirements of the designed live load.

Application of construction monitoring for three-span pre-stressed concrete continuous rigid frame bridge

Pres-tressed concrete continuous rigid frame bridges are widely used in valley and river crossings, and the issues of alignment, stress and safety control during their construction are receiving increasing attention. Taking a continuous steel structure with a main span of 96m+180m+96m as an example, this paper discusses the monitoring scheme, alignment and stress measuring point arrangement; establishes a construction monitoring model and calculates the stress and deformation of all construction stages; conducts construction monitoring of the whole process. The results show that in the bridge construction process, through reasonable construction supervision to ensure that the bridge is smoothly united and the bridge structure alignment meets the design requirements, effectively controlling the construction quality of the bridge.

Seismic Vulnerability Analysis of Long Span Prestressed Concrete Continuous Rigid Frame Bridge

Seismic Vulnerability Analysis of Long Span Prestressed Concrete Continuous Rigid Frame Bridge

Curing parameters’ influences of early-age temperature field in concrete continuous rigid frame bridge

The unstable change of early temperature field during concrete curing of box girder could lead to the thermal deformation and autogenous shrinkage deformation of concrete, make the concrete crack early, and even affect the subsequent mechanical performance. In order to study the variation law of the early-age temperature field of the box girder concrete and to seek the method to control the variation of the temperature field of the box girder concrete, the No.0 box segment with the most complex structure and the largest volume in the bridge was selected as the research object. The early-age temperature field of No.0 box segment after pouring was simulated by Midas/FEA and the correctness of the simulation was verified by field measurement. Then the time-history law of early-age temperature field of the box girder under the coupling effect of hydration heat and ambient temperature was studied, and the time-history law of the early-age temperature field of the box girder was investigated by changing different concrete curing parameters. The results show that the larger the local size is, the larger the temperature difference is. The selection of formwork's material and thickness should integrate the factors of formwork bearing capacity and thermal insulation performance. The reasonable selection of formwork can effectively control the core temperature and the temperature difference between the inside and outside of the box girder. Formwork installation temperature and wind velocity have a great influence on the temperature difference between the inside and outside of the box girder. The research results can provide technical support for controlling the early-age temperature field changes of box girder concrete, be used to provide a theoretical basis for the best selection of formwork and the selection of the best concrete curing conditions, and help to improve efficiencies in the uses of human capital, energy, and building materials in engineering construction.

Maintenance Management Research of a Large-span Continuous Rigid Frame Bridge Based on Reliability Assessment by Using Strain Monitored Data

When the bridge components needing maintenance are the world problem at present, and the health monitoring system is considered to be a very helpful tool for solving this problem. In this paper, a large number of strain data acquired from the structural health monitoring system (SHMS) installed on a continuous rigid frame bridge are adopted to do reliability assessment. Firstly, a calculation method of punctiform time-dependent reliability is proposed based on the basic reliability theory, and introduced how to calculate reliability of the bridge by using the stress data transformed from the strain data. Secondly, combined with “Three Sigma” principle and the basic pressure safety reserve requirement, the critical load effects distribution function of the bridge is defined, and then the maintenance reliability threshold for controlling the unfavorable load state which appears in the early operation stage of this type bridge is suggested, and then the combination of bridge maintenance management and health monitoring system is realized. Finally, the transformed stress distribution certifies that the load effects of concrete bridges practically have a normal distribution; as for the concrete continuous rigid frame bridge with C50 strength grade concrete, the retrofit reliability threshold should be valued at 6.13. The methodology suggested in this article can help bridge engineers do effective maintenance of bridges, which can effectively extend the service life of the bridge and bring better economic and social benefits.

Pushover analysis in different lateral force distribution patterns of bridge piers

Basic principles of pushover analysis method and several different lateral force distribution patterns are briefly described in this paper. A long span concrete continuous rigid frame bridge is taken as an example to carry out the pushover analysis under rarely occurred earthquake. The demand curve and the capability curve are combined to form the capability spectrum to evaluate the seismic performance of the bridge. Analysis results show that different lateral force distribution patterns have great influence on Pushover analysis results.

Time-varying Reliability Analysis of Long-span Continuous Rigid Frame bridge under Cantilever Construction Stage based on the Monitored Strain Data

Abstract: In general, the material properties, loads, resistance of the prestressed concrete continuous rigid frame bridge in different construction stages are time-varying. So, it is essential to monitor the internal force state when the bridge is in construction. Among them, how to assess the safety is one of the challenges. As the continuous monitoring over a long-term period can increase the reliability of the assessment, so, based on a large number of monitored strain data collected from the structural health monitoring system (SHMS) during construction, a calculation method of the punctiform time-varying reliability is proposed in this paper to evaluate the stress state of this type bridge in cantilever construction stage by using the basic reliability theory. At the same time, the optimal stress distribution function in the bridge mid-span base plate is determined when the bridge is closed. This method can provide basis and direction for the internal force control of this type bridge in construction process. So, it can reduce the bridge safety and quality accidents in construction stages.

A Study on Analysis of Long Span Continuous Rigid Frame Bridge

A case study of a large span pre-stressed concrete continuous rigid frame bridge (Ba-Mao-Chong bridge) of GUI DU high speed railway. Finite element program Midas/Civil is used to simulate the construction process and operation phase, the influence of concrete overweight, pre-stressing loss, concrete shrinkage and creep, stiffness loss and other factors that related the long-term deflection of bridge are analyzed. The calculation results show that: (1) The overweight concrete and Bridge deck pavement construction error could cause the bridge long-term deflection increases. (2) The creep coefficient, environment humidity, and other factors on the bridge have significantly influence on long-term mid-span deflection, (3) The beam stiffness reduction could lead to the bridge long-term mid-span deflection increase.

Analysis on dynamic characteristics and wind-induced buffeting response of Hezhang Large-span Bridge

Hezhang Large-span Bridge is a concrete continuous rigid frame bridge with super high pier. The highest pier reaches 197m and stands the peak among the similar bridges. In order to study the wind resistance capacity of the bridge, ANSYS, a finite element software, is applied to establish models at the stage of the largest cantilever constructing and completing of the bridge. The dynamic characteristics of the models are solved by subspace iteration method and the fluctuating wind velocity time history was generated by modified Fourier spectrum method. After that, the buffeting load time history is calculated based on the theory of quasi-steady state and the buffeting time history of the stage of the largest cantilever constructing and completing of the bridge is gained respectively by time history analysis.

Modified Multi-Support Response Spectrum Analysis of Structures with Multiple Supports under Incoherent Ground Excitation

This study develops a modified multi-support response spectrum (MSRS) method, in order to efficiently and accurately calculate the response of multi-support structures under incoherent ground motions. The modified MSRS method adopts three ancillary processes, constructing structural displacement vectors or constructing infinite stiffness members or increasing the degrees of freedom at structural supports. Then, the modified MSRS method is verified in a comparison with the existing MSRS method through a model of a five-span reinforced concrete continuous rigid frame bridge. Finally, the collective structural response spectrum, the structural power spectrum, and the simplified structural power spectrum are deduced from the equation of the motion taking ground motion displacements as the input, and validated through the same bridge model.

Research on durability of a concrete continuous rigid frame bridge

The research on the durability of concrete structures has also become one of the most important topics for discussion at international academic institutions and conferences. This paper summarizes and reviews the current research on the durability of bridge structure of the bridge at the index relationship between state lifetime and structure durability. According to the actual situation in this paper on a continuous rigid frame bridge China of Yunnan as an example, this bridge was completed and opened to traffic during the first half of the year, a series of tests are carried out for the durability problem. It is found that all the indicators are good within six months after the bridge opened to traffic, but durability issues should be further studied in future monitoring efforts.

Seismic Performance Analysis of Continuous Rigid Frame Bridges in Expressway under Non-linear Interactions of Soil-Piles

Taking the three-span pre-stressed concrete continuous rigid frame bridge as an engineering example, MIDAS Civil was utilized to establish a spatial finite element model and the interaction between pile foundation and the soil was simulated by equivalent soil spring. In addition to analyzing shearing force, bending moment and stress of the primary beam's characteristic section under different loads, a response spectrum method and time history analysis were adopted to conduct seismic response analysis respectively. In this case, performance of the bridge could be comprehensively evaluated. Relevant analysis results indicate that internal force of the large-span pre-stressed concrete continuous rigid frame bridge is mainly induced by gravity and pre-stress of the structure; section stresses of the primary beam satisfy the corresponding specification and structural safety can be achieved in a state of operation. Moreover, computed results obtained by the response spectrum method is more conservative than those of the time history analysis. In terms of continuous rigid frame bridge, different seismic directions should be taken into consideration during structural seismic analysis at different construction stages.

Experimental Study on Loading Features of Continuous Rigid-Frame Bridge with Corrugated Steel Webs

Two comparison models of single cell box variable cross-section continuous rigid frame bridge with corrugated steel webs and the equivalent ordinary concrete continuous rigid frame bridge were designed and constructed. The loading features are contrastively researched. The results show that with same loading condition, strain of roof and floor of box girder with corrugated steel webs is increased when the load is increased, while the strain value of corrugated steel web is very low and nearly unchanged when the load is increased. The bending stiffness of box girder with corrugated steel webs was main supply with roof and floor and the bending stiffness is lower than box girder with concrete webs. Continuous rigid-frame bridge with corrugated steel webs box girder integrated the advantages of rigid-frame bridge and box girder with corrugated steel webs. This new structure has larger span capacity; lighter self-weight, excellent seismic performance and higher effective prestressing system, etc, which is suitable for large span bridge in high seismic intensity[1]. Static characteristics of box girder with corrugated steel webs have been further researched with theory and test method by foreign scholars[2-4]. On the aspect of bending performance, the damage characteristics of simply supported box girder bridge with corrugated steel webs have been researched[5]. Three simply supported box girder bridge with corrugated steel webs have been designed and constructed to research it’s static effect[6]. The applicability of “Quasi plane assumption” has been verified with FEA method and model test of simply supported box girder bridge with corrugated steel webs[7]. Ignoring the bending contributions of corrugated steel web, the calculation formula of ultimate bearing capacity of box beam is deduced[8]. Combined with the model test and the FEA method, the calculation formula of normal stress and shear stress of box girder bridge with corrugated steel webs are deduced[9]. Considered the shear slip of shear key between the corrugated steel webs and the roof and floor concrete, the formulas of the ultimate flexural capacity of the externally prestressed box girder with corrugated steel webs were derived[10]. On the aspect of inner lining concrete research, the method of shear calculation of steel concrete composite segment is researched with contrasting of shear distribution method of steel concrete combination[11]. The impact of the thickness of concrete lining to the shear bearing capacity of the corrugated webs was analyzed via theoretical calculation and finite element analysis[12]. In summary, a large number of theory and experimental research on prestressed concrete box girder with corrugated steel webs at home and abroad, but most of model test are simply supported box girder bridge, very few are continuous box girder. In this paper, the loading features are contrastively researched depend on the model of continuous rigid frame bridge with corrugated steel webs and the equivalent ordinary concrete continuous rigid frame bridge.

Finite element model validation of bridge based on structural health monitoring—Part II: Uncertainty propagation and model validation

Because of uncertainties involved in modeling, construction, and measurement systems, the assessment of the FE model validation must be conducted based on stochastic measurements to provide designers with confidence for further applications. In this study, based on the updated model using response surface methodology, a practical model validation methodology via uncertainty propagation is presented. Several criteria of testing/analysis correlation are introduced, and the sources of model and testing uncertainties are also discussed. After that, Monte Carlo stochastic finite element (FE) method is employed to perform the uncertainty quantification and propagation. The proposed methodology is illustrated with the examination of the validity of a large-span prestressed concrete continuous rigid frame bridge monitored under operational conditions. It can be concluded that the calculated frequencies and vibration modes of the updated FE model of Xiabaishi Bridge are consistent with the measured ones. The relative errors of each frequency are all less than 3.7%. Meanwhile, the overlap ratio indexes of each frequency are all more than 75%; The MAC values of each calculated vibration frequency are all more than 90%. The model of Xiabaishi Bridge is valid in the whole operation space including experimental design space, and its confidence level is upper than 95%. The validated FE model of Xiabaishi Bridge can reflect the current condition of Xiabaishi Bridge, and also can be used as basis of bridge health monitoring, damage identification and safety assessment.

Research on Prestressed Loss in Curving Hole of Prestressed Concrete Structure Caused by Frictional Resistance

Excessive prestressed loss in prestressed concrete continuous beam bridge and continuous rigid frame bridge causes structures appearing different types of diseases. By theoretical analysis on computational expression of effective prestress in curving hole, and distribution of contact stress and experiment about prestressed loss caused by frictional resistance, this paper points out the disadvantages of current effective prestress formula in curving hole. According to the research on the major influencing factors of prestressed loss in curving hole-contact status and friction coefficient μ, it plays a remarkable role on the further analysis of prestressed loss in curving hole.

Simulation Analysis on Construction of Liangjiang Great Bridge

Liangjiang Great Bridge is the prestressed concrete continuous rigid frame bridge with high pier and long-span. It adopts the segmented cantilever construction method. The process of its construction is the key to the construction control simulation analysis. In this paper, based on the characteristics of the bridge construction, finite element method is used to establish the simulation model. Cantilever construction stages and closure stages of bridge are simulated and analyzed. The structure deflection diagrams in the each section construction and the later construction considering the creep and shrinkage of concrete are obtained. The initial camber of each segment is given in the construction. The stress characteristics of key section are analyzed in the construction process. It provides a basis for monitoring and on-site construction of bridge and the reference for similar bridge construction.

Comparison of Structural Type and Economics of Super-High Pier for Continuous Rigid Frame Bridge

Three kinds of structural pier forms – double thin wall pier, combined pier and single pier – were designed for prestressed concrete continuous rigid frame bridge with pier height that overs 100m. Taking an example of Hezhang bridge which is located in Guizhou province, the elastic stability at the largest cantilever stage under action of wind loads were analyzed and concrete volume of pier and cushion cap were calculated. The results indicate that the variable cross-section pier has a better performance of elastic stability than that of uniform pier. Considering the construction difficulty, stability performance and material consumption, recommendations for selecting the structural type of pier with height between 100 m~200 m were given.