Continuous Box Girder Research Articles

Slip analysis of prestressed steel-concrete continuous composite beam

To analyze the horizontal shear resistance participation degree of the shear studs on the web and diaphragm flange in the negative moment area of the steel–concrete continuous composite box girder, the steel–concrete composite girder specimen was designed and manufactured based on the existing codes. The shear deformation of the two parts of the studs in the composite box girder is studied by the finite element parameter analysis of the nonlinear shear deformation of the studs and the stress analysis of the diaphragm. The results show that web flange studs provide the horizontal shear capacity of the steel–concrete composite box girder. The installation of baffle flange studs cannot improve the shear connection degree of composite beams. Removal of the flange stud from the diaphragm can relieve the force on the diaphragm and provide a theoretical basis for reducing the stiffeners of the diaphragm.

Effect of lead rubber bearing on seismic performance of steel box girder bridge

Rubber isolation bearings have been proven to be helpful in reducing bridge seismic damage. The response of bridges with rubber bearings are complex under seismic action due to the varying characteristics of isolation bearings. The effect of using rubber isolation bearings on seismic performance of continuous steel box girder bridges exposed to near-field and far-field ground vibrations is the focus of this paper. For this study a four-span continuous steel box girder bridge isolated with lead rubber bearings in Delhi, India is considered for numerical study. Nonlinear Response history analyses are carried out on the selected bridge to evaluate the sensitivity impact of hysteric energy of rubber bearing, bearing displacement limit, deck acceleration, and base shear. The influence of seismic ground motion and lead rubber bearing parameters on the behavior of seismically isolated bridge is investigated using a parametric study. The goal is to look at the impact of ground motion on the lead rubber bearing as well as the bridge. Due to bearing hysteric energy, the bridge with seismic isolation, such as lead rubber bearings (LRB), has roughly 20%-30% lower seismic reaction than non-isolated bridge. This indicates that the isolation bearings improve the seismic performance of the bridge. The results also reveal that when the frequency content of ground motion increases, it results in a substantial risk of damage of the bearing as well as bridge. The near-field earthquakes significantly alter the energy ratio dissipated to total input energy by the lead-rubber bearings in comparison to far-field earthquakes. Finally, recommendations are presented that will be valuable for bridge designers during the early bridge seismic isolation design with lead rubber isolators for varying features of ground motions.

Research of construction monitoring technology of large-span variable cross-section prestressed concrete continuous box-girder bridge

With the advancing development of structural performance and construction techniques, continuous concrete box girder bridges have been widely used due to their advantages including their broad applications, good appearance, and reliable structural safety. However, as the bridge span and its construction demands are increasing, the bridge construction process tends to be more complex. Especially, the construction methods and bridge installation sequences of cantilever bridges not only exert structural internal force on the bridge construction process but also affect the internal force and line shape of the bridge structure of finally constructed bridges. Hence, it is essential to realize bridge construction control. Only in the presence of the excellent construction control performance, can the structural safety in the bridge construction process can be ensured while meeting the designed requirements of bridge line shapes and internal forces of constructed bridges. In this research, by taking the Weihe grand bridge located at Shandong Province, China as construction background, the specific targets and methods of bridge construction control were introduced for the reference of bridge construction and research.

Damage assessment of circular bridge pier incorporating high-strength steel reinforcement under near-fault ground motions

Bridge piers are typically the most vulnerable to damage during an earthquake, and the entire seismic performances of the bridge is determined to some extent by the hysteretic energy of its piers. It was discovered that partially embedding high-strength reinforcements in bridge piers is a reliable and efficient method to increase the ductility performance. The term “high-strength reinforcement” refers to reinforcement with a yield strength of (500 MPa) or above. The use of certain high-performance materials can help to enhance bridge pier seismic performance. Because of their strong and impulsive impact on structures, near-fault ground vibrations deserve special attention. These features are distinct from far-field ground vibrations, which are the basis of practically all seismic design requirements. The goal of this study is to evaluate the effects of near-fault ground vibrations on reinforced concrete bridge piers, as well as to develop a framework for evaluating bridge columns near active faults. The impact of Forward-directivity pulses effect on the behavior of a continuous steel box girder bridge pier is investigated in this work using fragility analysis. Damage measures such as pier displacement ductility and rotational ductility of pier are used to generate fragility curves and Probabilistic seismic demand model for bridge pier using high strength reinforcement bars under the ensemble of near-field forward- directivity earthquakes. The damage model presented may be assumed to be a well-versed model which may address the variability in earthquake ground motion while performing the bridges pier seismic vulnerability evaluation. Two sets of near-field forward-directivity records with peak ground velocity to peak ground acceleration ratio (high PGV: PGA > 150 cm/s/g and low PGV: PGA < 150 cm/s/g) are employed to carry out incremental dynamic analysis. The findings show that even at low PGA levels, near-field directivity pulses result in a substantial chance of pier damage exceedance.

Dynamic Response of a Road Bridge Subjected to Passing a Heavy Vehicle over a Standard Irregularity - Numerical Modelling and Experimental Testing

The paper presents an analysis of an actual problem related to dynamic effects to road bridges due to travelling a heavy vehicle over the bridge. Numerical simulations of the dynamic response are applied on a fictitious simple beam of the length Lb = 52 m with an artificial irregularity at midspan, corresponding to a characteristic span L (b5) = 52 m of the ten-span continuous box girder bridge. A heavy four-axle truck m v = 32 t is used for dynamic excitation, travelling over the bridge at passing speed of 70km / h. The obtained results are compared to results of the experimentally tested ten-span continuous pre-stressed reinforced concrete girder bridge at the same speed.

A new practical method for the flexural analysis of thin-walled symmetric cross-section box girders considering shear effect

This study proposes a new analytical flexure theory that considers the shear deformation of the web and flange of a thin-walled box girder. Starting with the relationship between the strain and displacement of each slab, the flexural displacement function of thin-walled box girders considering the shear deformation effect is derived by using the deformation continuity condition. Compared with the traditional flexural displacement model, this function obtained by the theoretical analysis is more rigorous and can be transformed into the flexural displacement function of the traditional shear lag or Timoshenko beam by eliminating some parameters. Then, according to the balance conditions of axial force and bending moment, the shear deflection deformation state and Euler–Bernoulli beam deflection deformation state are decoupled. On this basis, a new convenient method for calculating the warping stress and shear deflection of thin-walled girders is proposed. Furthermore, a simplified analysis method for converting continuous box girders into simply supported beams is proposed on the basis of continuity condition of shear deflection at middle supports. Taking into account the shear deflection deformation state, a beam-type finite element model considering the shear deformations of each box wall is developed by using Hermite polynomials to analyze the complex variable cross-section box girder. Finally, numerical examples are used to verify the effectiveness of the simplified method and the beam-type finite element model. Numerical examples show that the flexural stress and deflection calculated by the proposed method agree well with the three-dimensional finite element model analysis results. The shear warping normal stress has a larger value at the shear force discontinuity point. In the control cross-section, the normal warping stress and shear deflection caused by shear deformation both exceed 75% and 38% of stress and deflection of the Euler–Bernoulli beam, respectively.

Investigation and Control of Cracks in Wet Joint of Concrete Box Girders

AbstractTo investigate the causes of cracks in wet joints of continuous concrete box girders, we performed in situ analysis of the temperature and strain field of wet-joint concrete for a sea-cross...

BOX GIRDER BALANCE CANTILEVER CONSTRUCTION METHOD

&#x0D; &#x0D; &#x0D; &#x0D; The apporach bridge whose construction is a continuous prestressed box girder is part of the Suramadu bridge as a link between the cause-way and the cable bridge (main span), and consists of two parts, namely the Surabaya side and the Madura side, each of which has the same geometric (symmetric)In the sequence of implementation, the Surabaya side is slightly different from the Madura side, where the Madura side still refers to the initial design, while the Surabaya side changes slightly with the aim of speeding up the implementation time. In principle, this change does not affect the strength, durability and safety of the construction, only limited to the issue of implementation time.The two approach bridges (Surabaya and Madura sides) consist of 2 parts, the first is a continuous box girder with a side span of 2 x 40.00 and a middle span of 7x 80.00m, the second is a V-pier with a span of 32.00 m. The balanced cantilever construction method is applied to eliminate these difficulties. To shorten the implementation time on the Surabaya side approach, that is by rearranging the sequences in such a way that there are several closures that are done simultaneously without reducing the strength of the structure specified in the initial design. As for the Surabaya side, there are changes for both the West and East sides, theoretically this change will save about 10 days, which is the length of time it takes to complete 1 closure. The final optimization of the Suramadu Approach bridge is with a span of 80 m between piers with a longitudinal slope of 4%, with a single cell box girder shape that will speed up execution and reduce the quantity of work and has a hollow shaped pillar. There are several closures carried out simultaneously on the approach bridge on the Surabaya side. This is done to speed up the implementation, considering that the Surabaya side is already behind the schedule.) &#x0D; &#x0D; &#x0D; &#x0D;

STUDY ON SPATIAL STRESS EFFECT OF PC CONTINUOUS THIN-WALLED BOX GIRDER BRIDGE

In order to study the influence of spatial stress effect and shear lag effect on the cracking of PC continuous thin-walled box girder bridge, a spatial model was established by using ANSYS finite element software to analyze the internal stress distribution of the bridge. The test results are compared with the analysis results of spatial model and plane link system model through the load test of real bridge. The results show that the longitudinal stress is evenly distributed along the width direction, which means that the spatial stress effect and the shear lag effect have little influence on the downdeflection of the bridge. The shear lag coefficient at the longitudinal axis of midspan bottom plate and the intersection of bottom plate and web are larger than other positions, which is most likely to produce cracks caused by stress concentration, and should be strengthened here in practical engineering. The results of load test show that the results of spatial finite element analysis are more reliable than those of plane link system calculation, and the design and construction based on the results of spatial finite element analysis is safer.

Health monitoring of steel box girder bridges using non-contact sensors

This study investigates the behavior of simple and continuous span steel box girder bridges after various damage scenarios, including bracing failure and girder fracture, and develops a non-contact bridge health monitoring technique based on the bridge dynamic responses. A series of field tests were conducted to study the feasibility of using non-contact sensors to capture the bridge dynamic responses. Moreover, detailed finite element models of the bridges were developed and validated using the field test and available experimental test results and were used to investigate the bridge failure mechanisms, maximum load-carrying capacity, alternative load paths, and dynamic responses. The bridge dynamic analysis after damage showed that bridge frequencies are sufficiently sensitive for identifying partial or full-depth girder fracture in the simple span bridges. However, these significant damages may cause very small changes in the natural frequencies of continuous span bridges. The results show a significant change in the mode shapes after damage in both simple and continuous span bridges. The mode shapes are sensitive enough to detect damage at the inflicted locations, in most cases with better resolution when compared to the frequency changes. The comparison of the intact and damaged bridge mode shapes indicates that damage at different locations along the bridge has different amplitude changes in the mode shape that could be used to localize the damage. Moreover, the analyses show that either the individual modal sensitivities or combined sensitivities are indicative for most locations throughout the span. The results also indicate a clear pattern of changes in the frequency and mode shape for each damage scenario that can be used to detect the damage type, severity, and location along the bridge.

FORENSIC ANALYSIS OF THE WUXI 312 VIADUCT OVERTURNING COLLAPSE

On October 10, 2019, a three-span concrete continuous box girder on National Highway 312 in Xishan District, Wuxi City, overturned under the action of two vehicles. Investigated the accident site first, then established a geometrically nonlinear finite element model based on wreckage photos and construction drawings, and studied the overturning mechanism. An overload determination method based on the strength and overturning stability effects is proposed. The results include: the overturning test results based on the standard lane load demonstrate that the bridge does not meet the overturning test requirements specified in the Specification for Design of Highway Reinforced Concrete and Prestressed Concrete Bridge and Culvert (2018 edition); the superstructure under the action of the overloaded vehicle first rotated, then slid, and finally exhibited a combination of substantial rotation and sliding overturning mode; the superstructure has a certain safety margin between bearing separation and overturning; the calculation based on the strength and overturning stability effect proves that the overturning effect generated by the overloaded vehicle is greater than the overturning capacity of the structure, indicating that the overturning is mainly attributed to the overload. However, the structural bending capacity turns out to be sufficient through further calculation, indicating that the overturning damage occurred earlier than the occurrence of strength damage, and that the overturning resistance and bending resistance do not match.

Stressing state analysis of multi-span continuous steel-concrete composite box girder

This paper uses the theory of structural stressing state to study the working characteristics of three multi-span continuous steel-concrete composite box girder (SCCBG) models with different prestress levels. Firstly, the generalized strain energy density (GSED) is constructed to reveal the working state of the structure based on the experimental strain data, the Mann-Kendall (M-K) criterion is applied to distinguish the leap characteristics load points (P and Q) of the structural stressing state and defined as the “failure load”. It is used to update the existing structural “destruction” load to more clearly reflect the entire structural failure process. Then, the working state parameters of the cross-section are described (strain distribution mode, midspan deflection, crack width, etc.) to analyze the working behavior of the box girder model. Finally, the non-sample point interpolation method (NPI) is used to reasonably expand the experimental strain data, to verify the rationality of the characteristic load points, and the stressing state characteristics of box girders with different prestressed levels are further discussed.

Study on Calculation Method of Anti Overturning of Continuous Steel Box Girder

The self weight of steel box girder is light, and the stability effect is smaller than that of concrete bridge. In this paper, the anti overturning research of the main line bridge and ramp bridge is carried out. It is found that for the variable cross-section continuous beam bridge with wind barrier along the whole line, when the pressure reserve of the side pier is small under the action of self weight, the compression of the bearing under the action of basic combination can not ensure that the bearing will not be empty under the action of standard value combination; Centrifugal force, wind load and temperature load caused by vehicle load have great influence on bridge overturning, which can not be ignored; Temperature load and foundation displacement may lead to stability or instability according to the stiffness distribution of the main beam. In this paper, it is proposed that both the basic combination and the standard value combination should be considered when checking the bearing void. It is recommended to adopt the calculation method of “the stability effect is the standard value effect that makes the superstructure stable, and the instability effect is the standard value effect that makes the superstructure unstable” as the stability coefficient.

Research on Heat Dissipation and Insulation Measures of a Prestressed Continuous Box Girder Bridge Section

Taking a prestressed concrete box girder as the research object, aiming at the problem that the concrete bridge durability is reduced due to the appearance of temperature cracks in the concrete box girder, this paper adopted different types of heat insulation materials, and theoretically analyzed the structural temperature field of concrete box girder under high temperature difference and low temperature environment from the aspects of whether the heat source was set inside the concrete box girder, which provides a reference for the technical application and promotion of thermal insulation materials in concrete bridges.

Internal Forces Analysis of Prestressed Concrete Box Girder Bridge by Using Structural Stressing State Theory.

This paper analyzes the working behavior characteristics of a prestressed concrete transverse large cantilever continuous (PCTLCC) box girder bridge model based on structural stressing state theory and the numerical shape function (NSF) method. At first, the normalized generalized strain energy density (GSED) is established to model the stressing state of the bridge model. Subsequently, the Mann Kendall (M–K) criterion is applied to detect three characteristic loads, respectively, elastic–plastic branch load P (200 kN), failure load Q (300 kN), and progressive failure load H (340 kN), and the failure load Q is found to be the starting load of the damage process of the bridge model, rather than the ultimate load where the structure has been destroyed. Finally, the NSF method is adopted to interpolate the test data, and a detailed analysis for the variation characteristics of the working behavior of the bridge model under loads is performed based on the interpolation results. The characteristic load detection method and experimental data extension method for PCTLCC box girder bridge established in this study can provide valuable references for the design and analysis of such bridges.

Fatigue Performance of Steel-Concrete Composite Continuous Box Girder Bridge Deck

The fatigue performance of the bridge deck significantly affects the safety and durability of the overall steel-concrete composite beam bridge. Based on the vehicle flow information of the highway within 10 years, the fatigue performance of a two-way four-lane steel-concrete composite continuous beam bridge deck is studied in this research. The results indicate that the effect of the wheel track position is negligible for two-way four-lane bridge when the wheel track sways laterally, and the fatigue stress of bridge deck concrete is the most unfavorable while the loading position is 7.0 m away from the bridge center line. The fatigue damage decreases by 30%–40% when the centerline of the lane deviates from the most unfavorable stress position by 1 m. The punching fatigue of the concrete is more sensitive to the changes in slab thickness, and the thickness of the deck concrete slab is recommended to be ≥35 cm.

Temperature Effect on Main Girder of Strengthened Dongming Huanghe River Highway Bridge in Service

The main girder of Dongming Huanghe River Highway Bridge was the first prestressed concrete (PC) continuous box girder bridge strengthened by a cable-stayed system in China. In order to study the temperature effect of the main girder structure of Dongming Huanghe River Highway Bridge after reinforcement, based on the measured data of middle span deflection, key section strain and typical crack width, the curve equations of strain and temperature of main girder were obtained by the regression analysis method. The results show that the annual strain value of main girder changed with the acquisition time in a sinusoidal function, and was linearly related to the temperature. The variation of mid-span deflection decreased gradually from side span to middle span, and varied dynamically with temperature in the whole girder, which also has obvious correlation with temperature. The crack width fluctuated up and down in a certain numerical range, which belonged to respiratory cracks and had equally correlation with temperature.

Seismic Design Assessment of Bridge Piers Location Effect on the Structural Capacity of Supports under Earthquake Action

The objective of this study was to assess the seismic performance of two types of bridges structures under effect of earthquake by using different locations and numbers of piers. The results of D/C ratio showed that simply supported I girder bridge appeared higher structural capacity than continuous box girder bridge which was resisted the seismic demand. Continuous box girder bridge had higher seismic demand and lower structural capacity comparing with simply supported I girder bridge. Commonly, the seismic design for two types of bridges models with increasing of piers numbers was suitable to resist the earthquake action for region type B. The results of non-linear static analysis (pushover method) showed that the increasing of piers numbers had significant effects on the seismic design of bridges structures to increase the displacement capacity, force capacity, and decreasing of seismic demand to reduce the effects of earthquake action on the bridges structural members. The bridge type simply supported I girder had higher capacity in longitudinal direction than continuous box girder bridge. Whereas, for continuous box girder bridge appeared higher capacity in transverse direction than simply supported I girder. The performance points which were based on displacement were decreased with increasing the piers numbers for bridges structures supports.

Risk-Based Multiobjective Optimal Seismic Design for RC Piers Using the Response Surface Method and NSGA-II

In this paper, a risk-based multiobjective optimal seismic design method for reinforced concrete (RC) piers is proposed. This method is used to determine the size and reinforcement ratios of piers to minimize the seismic risk of bridge systems and the construction cost of piers. The Pacific Earthquake Engineering Research- (PEER-) based probabilistic seismic risk assessment approach and the response surface method (RSM) are adopted to develop the seismic risk response surface model, which represents the relationship between the design parameters of piers and the seismic risk of bridge systems. The Pareto optimal solutions of piers are determined by applying an improved version of the nondominated sorting genetic algorithm (NSGA-II). As a case study, the proposed optimal seismic design method is applied to a continuous concrete box girder bridge. The optimal design schemes of piers according to two strategies are determined from the Pareto optimal solutions. The results show that the seismic risk response surface model can be used to accurately describe the relationship between the design parameters of piers and the seismic risk of bridge systems. The case study demonstrates the effectiveness of the proposed optimal seismic design method. The analysis of the Pareto optimal solutions allows designers to more rationally conduct the seismic design of piers.

SHM-Oriented Hybrid Modeling for Stress Analysis of Steel Girder Bridge

Stress monitoring is always a challenging task in bridge structural health monitoring (SHM) since the measured pointwise stress is not enough for fully reflecting structural conditions. Therefore, a novel hybrid modeling technique was proposed in this paper, which calculates stress distribution with the aid of finite-element (FE) submodels from limited measured data. However, unlike common FE analyses, the requirement of complete input information is avoided by an FE model-based partial least-squares regression (FEM-PLSR) method. First, the regression equations among the FE model, unknown structural input, and output were set up, into which measured displacements, rotations, and strains were fused simultaneously. By solving the regression equations, the boundary conditions of the FE submodel can be precisely estimated. Then, the stress distribution can be calculated through FE analyses under the assumption of known local vehicular loads. Numerical simulations of a continuous steel box girder bridge were carried out for verification. Corresponding results indicated that the accuracy of the calculated stress distributions was competitive to the widely used multiscale FE model, even if the structural input information outside the submodel was not directly measured. Furthermore, the proposed method was also proved insensitive to random measurement errors. Finally, a large-scale experiment was designed to validate the accuracy of the hybrid model under three loading conditions. The strain distribution over both space and time accorded well with the measurement. Thus, the present hybrid modeling offered a novel way to obtain unmeasured structural responses, revealing great potential in the field of bridge SHM.