Steel Box Girder Bridge Research Articles

Eccentric Shear Failure Mode and Mechanical Simulation Analysis of Web Bolts of Steel Box Girder Bridge

Eccentric Shear Failure Mode and Mechanical Simulation Analysis of Web Bolts of Steel Box Girder Bridge

Coordinate Monitoring Technology in the Process of Incremental Launching Construction of Curved Steel Box Girder Bridge

Based on the steel box girder curve incremental launching project of SW ramp bridge in Harbin East Third Ring Road, the geometric alignment and structural internal force of the steel box girder during the incremental launching process were monitored in the whole process. The curve incremental launching coordinate position control method was adopted, and the relevant parameters were modified according to the site construction situation and the initial stress conditions of the girders, and the corrected theoretical value was used as the control and evaluation basis of the monitoring value. The results showed that the original theoretical deflection value was −33.10 mm, the modified theoretical deflection value was −64.10 mm, and the actual monitoring value was −53.20 mm. The modified theoretical value agreed well with the monitoring value, and the error rate between the monitoring value and the theoretical value under each working condition was −17.82%∼14.48%. The geometric alignment and internal force of the steel box girder met the monitoring requirements, ensuring that the steel box girder can meet the design requirements under various working conditions.

Behaviour and Analysis of Horizontally Curved Steel Box-Girder Bridges

Various theories and analytical formulations were implemented and exploited in the 1980s and 1990s for the design of bridge beams or decks curved in the horizontal plane and subjected to out-of-plane loads. Nowadays, the Finite Element Method (FEM) is a valid tool for the analysis of structures with complex geometries and, therefore, the development of sophisticated analytical formulations is not needed anymore. However, they are still useful for the validation of FE models. This paper presents the case study of an existing viaduct built in North Italy, aiming to compare analytical approaches and numerical modelling. The bridge is characterized by an axis curved in two directions and a rectilinear segment. The global analysis of the viaduct is carried out with special attention to the attributes that cause torque action and bending moment. The theoretical developments focus on a deeper understanding of the torsional response under different constraint and loading conditions and aspire to raise awareness of the mutual interaction of flexural and torsional behaviour, that are always present in these complex curved systems. The examination of the case study is also obtained by comparing the response of isostatic and hyperstatic curvilinear steel box-girders.

Analysis on the Method of Cleaning the Pavement of Municipal Steel Box Girder Bridge Deck and the Application of Pouring Asphalt Concrete

Analysis on the Method of Cleaning the Pavement of Municipal Steel Box Girder Bridge Deck and the Application of Pouring Asphalt Concrete

Effect of cross-sectional rigidity on intermediate diaphragm spacing of steel-box girder bridges

To control the distortion of box girder bridges and minimize the distortional stresses due to the torsional behavior when eccentric live loads are applied, it is necessary to install intermediate diaphragms in the box sections in the design of box girder bridges. This study estimated the distortional bi-moments and stresses of single-span rectangular steel box girder bridges by conducting a three-dimensional finite element analysis (FEA) considering various cross-sectional rigidities of the box girder sections. Based on the FEA, improved design equations for determining the distortional stresses and the appropriate intermediate diaphragm spacing were established considering various design parameters, such as cross-sectional rigidity, live load combination, normal stress ratios, and magnitude of the torsional moment. Finally, design recommendations were presented for the intermediate diaphragm spacing based on various design parameters.

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.

Research on Application Effect Evaluation of Steel Box Girder Bridge Based on Combination Weighting

At present, the research on the application effect of steel box girder bridges is still only in the qualitative analysis link, and the calculation of index weights is greatly affected by personal subjective factors, and the quantitative evaluation of the application effect of steel box girder bridges has not been achieved. In this paper, we proposes a combination of subjective and objective combined weighting fuzzy evaluation model, which avoids the unreasonable problem of a single weighting method in determining the weight coefficients, and makes the weight distribution results more accurate and effective. Among them, the coefficient of variation method and the AHP method are used to calculate the subjective and objective weights of the indicators, and the linear combination calculation method is used to determine the comprehensive weights of the indicators. Then, combined with the fuzzy evaluation model, a comprehensive analysis of the application effect is carried out. Finally, the effectiveness of the combined weighting evaluation model is verified with a practical project case.

Development of a Reference-Free Indirect Bridge Displacement Sensing System

Bridge displacement measurements are important data for assessing the condition of a bridge. Measuring bridge displacement under moving vehicle loads is helpful for rating the load-carrying capacity and evaluating the structural health of a bridge. Displacements are conventionally measured using a linear variable differential transformer (LVDT), which needs stable reference points and thus prohibits the use of this method for measuring displacements for bridges crossing sea channels, large rivers, and highways. This paper proposes a reference-free indirect bridge displacement sensing system using a multichannel sensor board strain and accelerometer with a commercial wireless sensor platform (Xnode). The indirect displacement estimation method is then optimized for measuring the structural displacement. The performance of the developed system was experimentally evaluated on concrete- and steelbox girder bridges. In comparison with the reference LVDT data, the maximum displacement error for the proposed method was 2.17%. The proposed method was successfully applied to the displacement monitoring of a tall bridge (height = 20 m), which was very difficult to monitor using existing systems.

Effect of Load Combinations on Distortional Behaviors of Simple-Span Steel Box Girder Bridges

When eccentric live loads are applied on the deck overhang of steel-box girder bridges, torsional moments, comprising pure torsional and distortional moments are generated on the box sections. The torsional moment on the bridge girders distorts the box girder cross-sections, inducing additional normal stress components and causing instability of the box girder sections in severe cases. Hence, it is essential to install intermediate diaphragms in the box sections to minimize distortional behaviors. Although the applied live loads are critical parameters that influence intermediate diaphragm spacings, the effects of live load combinations have rarely been addressed in the design of intermediate diaphragm spacings. Thus, load combinations should be evaluated to design the intermediate diaphragm spacing of the box girder bridges more thoroughly. In this study, the load combination effects on the distortional behavior and adequate intermediate diaphragm spacing were evaluated through a finite element analysis (FEA). Composite rectangular box girder bridges with different cross-sectional aspect ratios (H/B) and spans (L) were analyzed in the parametric study. It was found that the truck load, which represents the concentrated load, significantly influences the distortional warping normal stress, normal stress ratio, and intermediate diaphragm spacing. In addition, the FEA results showed that the controlling load combinations could be varied with the span.

Analysis on the Stability of Top Pushing Construction of Curved Steel Box Beam of a Cross-sea Bridge

The curve steel box girder has the risk of instability in the jacking construction, especially in the case of big waves on the sea surface. It is very important to analyze the stress of the structure during the jacking construction. According to the Midas Civil finite element model, a bridge span is arranged as (49+60+49) m according to various unfavorable loads. The stability of the curved steel box girder bridge during jacking construction is analyzed, and the site construction is controlled according to the calculation results.

LSD에 기초한 강박스거더교 내하율 평가의 신뢰성 및 적용성 검토

LSD에 기초한 강박스거더교 내하율 평가의 신뢰성 및 적용성 검토

한계상태설계법에 기초한 강박스거더교 내하율 평가

한계상태설계법에 기초한 강박스거더교 내하율 평가

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.

Analysis of Static Characteristics of Steel Box Girder Bridge being composited High Strength Concrete at the Lower Flange of the Support

The steel box girder bridge has excellent applicability to curved bridges owing to its large torsional rigidity. In addition, because the weight of the segments is smaller than that of concrete bridges, it also has many applications for medium-range bridges. However, when a bridge with a span greater than 70 m is constructed, the height of the steel box girder increases, which is disadvantageous for the manufacture and transportation of girders and for bridge construction. Therefore, improvements in the construction methods are required to facilitate construction. Therefore, a structural system of a double composite box girder bridge with an upper slab and composite high-strength concrete at the lower flange of the support of continuous span was proposed, and the structural performance was verified by finite element analysis and a static loading test of an actual specimen. It was confirmed that such a structure minimizes the height of the girder of continuous support by optimizing the sectional efficiency and also improves usability.

Numerical performance assessment of Tuned Mass Dampers tomitigate traffic-induced vibrations of a steel box-girder bridge

In this paper, the effects of Tuned Mass dampers (TMDs) on the reduction of the vertical vibrations of a real horizontally curved steel box-girder bridge due to different traffic loads are numerically investigated. The performance of TMDs to reduce the bridge vibrations can be affected by the parameters such as dynamic characteristics of TMDs, the location of TMDs, the speed and weight of vehicles. In the first part of this study, the effects of mass ratio, damping percentage, frequency ratio, and location of TMDs on the performance of TMDs to decrease vertical vibrations of different sections of bridge deck are evaluated. In the second part, the performance of TMD is investigated for different speeds and weights of traffic loads. Results show that the mass ratio of TMDs is the more effective parameter in reducing imposed vertical vibration in comparison with the damping ratio. Furthermore, it is found that TMD is very sensitive to its tuned frequency, i.e., with a little deviation from a suitable frequency, the expected performance of TMD significantly decreased. TMDs have a positive and considerable performance at certain vehicle speeds and this performance declines when the weight of traffic loads is increased. Besides, the results reveal that the highest impact of TMD on the reduction of the vertical vibrations is when free vibrations occur for the bridge deck. In that case, maximum reductions of 24% and 59% are reported in the vertical acceleration of the bridge deck for the forced and free vibration amplitudes, respectively. The maximum reduction of 13% is also obtained for the maximum displacement of the bridge deck. The results are mainly related to the resonance condition.

钢箱梁顶推法顶推反力对桥墩桩基的影响分析——上海浦东新区某跨线桥工程案例分析

钢箱梁顶推法顶推反力对桥墩桩基的影响分析——上海浦东新区某跨线桥工程案例分析

Analytical study on the effect of horizontal stiffeners on the ultimate capacity of steel box girder bridges

Analytical study on the effect of horizontal stiffeners on the ultimate capacity of steel box girder bridges

Temperature gradient modeling of a steel box-girder suspension bridge using Copulas probabilistic method and field monitoring

A novel copula-based probabilistic model is proposed to establish the temperature difference analysis model for a long-span suspension bridge’s steel box girder. The key idea is to express a two-dimensional function of the temperature difference in flat steel box girder by using copulas. The maximum and minimum values of daily temperature difference model was developed using long-terms structural health monitoring data. Then, the correlation between adjacent temperature differences is investigated using five types of copulas. Akaike information criterion (AIC) is used to select an optimal model from five types of copulas, and the optimal joint function (two-dimensional function) for steel box girder’s temperature difference is established. Finally, the structure’s temperature gradient model is extrapolated for the service life of the structure by using Monte Carlo method. Moreover, this paper discusses the temperature gradient models using five types of common copulas and four types of time-varying copulas. The result shows that the t-copula is the optimal function to build the two-dimensional functions for steel box girder’s temperature difference, and the temperature model along the transverse direction can offer useful information that is not available in the design codes.

Experimental investigation of redundancy of twin steel box-girder bridges under concentrated loads

Experimental testing was performed to evaluate the redundancy of twin steel box-girder bridges under concentrated loads. Results from a series of elastic load tests, a cyclic load test, and ultimate load tests are presented. The results indicated that fracture of tension member(s) was not the immediate cause of collapse of the system. The deck and intact girder together were able to provide stability and reserve load-resisting capability for the bridge. The railings, continuity and external intermediate cross-frames were additional factors that improved the redundancy level in twin steel box-girder bridges when one girder was completed fractured.

Research on the Overall and Local Mechanical Behaviors of Steel Box Girder Cable-Stayed Bridge via Incremental Launching Construction

<p>In this paper, a large-span cable-stayed bridge with double pylons and double cable planes is employed to study the overall and local mechanical behaviors. The steel box girder bridge is constructed by incremental launching with the maximum span of 50 m. Through the overall stress analysis, the most unfavorable stress position of the structure in the incremental launching construction is identified; the refined local stress analysis is carried out for the girder section at this position, and the local stress characteristics of the structure are studied. The mechanical performance and the applicability of incremental launching are determined by comparing four kinds of elastic cushion. This paper aims at improving the safety of incremental launching construction of steel box girder bridge, and can provide reference for similar projects.</p>