Advances in Bridge Engineering

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EISSN : 2662-5407
Total articles ≅ 43
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Deyi Chen, Shiping Huang, Zhenyu Wang
Advances in Bridge Engineering, Volume 2, pp 1-14; doi:10.1186/s43251-021-00045-8

Abstract:
Pedestrian-induced footbridge vibration comfort level is a complex problem that has been studied for a long time. However, no consensus has been reached on a quantitative calculation index for assessing vibration comfort level. Only simple comfort limits, rather than specific relationships between comfort level and the vibration endurance capacity of pedestrians, are currently available for assessing vibration comfort level of footbridges. This article aims to propose a sensitivity model for pedestrian-induced vibration comfort calculation based on the vibration endurance capacity of pedestrians and the vibration response of footbridges. The concepts of “human body resistance” and “vibration effect” were established according to the principle of probability and statistics. Mathematical definition of sensitivity was put forward. Calculation expressions for a pedestrian and pedestrians were deduced respectively. A theory of pedestrian-induced footbridge vibration comfort level was proposed. Field survey and experiment were conducted, the results of the field survey demonstrated that sensitivity values were in good agreement with the international vibration comfort standards. Furthermore, the field experiment results showed that the errors between the experimental results and the calculated results were within 6%. The proposed sensitivity theory can be used for pedestrian-induced footbridge vibration comfort quantitative calculation.
Dinh Hung Nguyen, Hong Nghiep Vu, Thac Quang Nguyen
Advances in Bridge Engineering, Volume 2; doi:10.1186/s43251-021-00044-9

Abstract:
Increasing the number of small and medium-sized bridges is a need to improve accessibility in rural areas of the Mekong River Delta of Vietnam. Many types of bridge structures can be the suitable selection for rural bridges, on which the overall load of the operating truck is about 100kN. An objective of this paper is to propose a double-tee (DT) girder with the span length varying from 12 m to 15 m for the rural bridge types B and C in the Vietnamese standard. New concrete aggregate using crushed sand and fly ash for the DT girders is also examined to solve the scarcity of natural sand and environmental problem from industrial waste. A full-scale DT girder with a span length of 12 m is tested to confirm the capacity of the proposed design. Result finds out that the concrete sand, which the natural sand is replaced by 90% of the crushed sand and 10% of the fly ash by weight, could be well applied for the proposed DT girders. Another finding is a linear elastic uncracked response of the tested DT girder under loads of a rural vehicle and concrete blocks of 306kN. Therefore, the proposed DT girders are suggested to the rural bridges.
Qiulei Wang, Qi Jiang, Gang Hu, Xiao Chen, Chao Li, Yiqing Xiao
Advances in Bridge Engineering, Volume 2, pp 1-20; doi:10.1186/s43251-021-00042-x

Abstract:
This paper investigates the effect of fitting fins at the corners of a square cylinder on aerodynamic characteristics of the cylinder via wind tunnel tests and large eddy simulations (LES). Although it has been recognized that the corner fins have a remarkable effect on aerodynamic characteristics of a square cylinder, no study has been carried out to systematically evaluate this effect and reveal the underlying mechanism. Three types of corner fin configurations, i.e. fins fitted only to the leading corners, fins fitted only to the trailing corners, and fins fitted to both leading and trailing corners were studied. It was found that the corner fins significantly influence aerodynamic characteristics, such as mean drag coefficient, fluctuating lift coefficient, and vortex shedding of the cylinder. The influences of these corner fin configurations are very different. In general, the leading and trailing fins have an opposite effect on these characteristics. The mechanisms underlying these effects were clarified based on the flow regime visualized via LES. The interesting findings have practical significances not only for reducing aerodynamic forces and wind-induced vibration of infrastructures, but also for enhancing wind-induced vibration-based energy harvesting.
Man Liao, Bin Wu, Xianzhi Zeng,
Advances in Bridge Engineering, Volume 2, pp 1-16; doi:10.1186/s43251-021-00041-y

Abstract:
In the seismic design of long-span bridges, the classic bi-linear model was used to simulate the frictional restoring force of the rubber bearings. However, in actual earthquake, the rubber bearing suffered fluctuating axial pressure in earthquake, even separated from the beam when vertical component of the earthquake was too strong. Employing the bi-linear model for the bearing may incorrectly estimate the seismic response of the bearings, as well as the whole bridge. This paper developed a nonlinear frictional bearing model, which can consider the variation of the frictional restoring force in the bearings, even the separation with the beam in vertical directions. A typical continuous beam bridge was modeled in ABAQUS, and incremental dynamic analysis was conducted for the quantitative comparison of the seismic responses using different bearing models. The intensity measure was selected as the ratio of the peak ground acceleration (PGA) in the vertical direction to the PGA in the horizontal direction. The analysis results indicated that the different bearing model led to the significant different seismic response for the bearings and piers, even the vertical component was small. The bi-linear bearing model would underestimate the seismic demand of the bearing and piers.
Lei Tong, Rongxia Wang, Dongsheng Wang
Advances in Bridge Engineering, Volume 2, pp 1-25; doi:10.1186/s43251-021-00040-z

Abstract:
The box girder of the Miaoziping Bridge, a three-span prestressed concrete continuous rigid-frame bridge, suffered a serious crack in its box section’s web near the 1/6 to 1/2 length of the side span and the middle-span length of 1/4 to 3/4, as a result of the 2008 Wenchuan earthquake, which also caused large lateral residual displacements at both ends of the side span. In this study, eight strong-motion records near the bridge site and two other records (El Centro and Taft) are selected as inputs for time-history analysis of the bridge. The cantilever construction process and initial stress of the box girder are considered in a bridge model for seismic numerical simulation. Further, the simulation results are compared with the actual earthquake damage. The cracking mechanism, influencing factors and control of the girder crack damage are discussed. The high-stress zones of the box girder agree with the seismic damage observed, even various seismic inputs are considered. The findings reveal that the maximum (principal) tensile stress of the girder exceeds the tensile strength of the concrete under the seismic excitations, and cracks occur. Under various input directions of ground motions, the proportion of the main girder stresses induced by the earthquake shows differences. After the failure of the shear keys in the transverse direction of the bridge, the stresses of the girder decrease in the mid-span. However, the beams at both ends of the side spans revealed large lateral displacements. Considering that the uplift of the beam ends, stress and axial torque of the girder’s side span are greatly reduced. Setting bi-directional friction pendulum bearings on the transition pier is an effective damping measure to control web cracking of the mid-span and lateral drifts of the beam ends.
Suiwen Wu, Junfeng Jia, Chiyu Jiao, Junfei Huang, Jianzhong Li
Advances in Bridge Engineering, Volume 2, pp 1-19; doi:10.1186/s43251-021-00038-7

Abstract:
Skew bridges with seat-type abutments are frequently unseated in earthquakes due to large transverse displacements at their acute corners. It is believed these large displacements are due to in-plane rotation of the superstructure. Lack of detailed guidelines for modeling of skew bridges, many current design codes give empirical expressions rather than theoretical solutions for the additional support length required in skew bridges to prevent unseating. In this paper, a parametric study has been carried out to study the influence of skew angle, aspect ratio and fundamental periods of bridges on the additional support length requirements of single-span bridges due to skew using a shake table experiment validated Simplified Method, which is capable of simulating gap closure based on response spectrum analysis. This method is developed based on the premise that the obtuse corner of the superstructure engages the adjacent back wall during lateral loading and rotates about this corner until the loading reverses direction. A design response spectrum specified in AASHTO LRFD Specifications was employed to represent the design-level earthquakes. The results show the additional length required to prevent unseating due to skew increases with the skew angle in an approximately linear manner when the angle is less than a critical value and decreases for angles above this value. This critical skew angle increases with the aspect ratio approximately in a linear manner and shows negligible dependence on the fundamental periods of the bridges, and combination of span length and width. In addition, the critical skew angle varies between 58° and 66°, when the aspect ratio is varied from 3.0 to 5.0. The results also show that the empirical formulas for minimum support length requirements of skew bridges in current codes and specifications can not accurately reflect the influence of skew.
Wangqing Wen, , Aiguo Yan, Jiahua Zeng
Advances in Bridge Engineering, Volume 2, pp 1-16; doi:10.1186/s43251-021-00043-w

Abstract:
To analyze the time-varying temperature field distribution pattern of ballastless track steel-concrete composite box girders for a high-speed railway at ambient temperature, a numerical model for analyzing the time-varying temperature field of steel-concrete composite box girders was established based on the long-term monitoring data for the internal and external environments of the main girder of the Ganjiang Bridge on the Nanchang-Ganzhou high-speed railway. The influence of factors such as the deck pavement and the ambient wind speed on the time-varying temperature field of the steel-concrete composite box girders were considered. The results showed that there was a significant difference in the vertical temperature gradient patterns on sections at the side web and at the middle web at the same moment in time due to the hindering effect of the track board on the heat exchange between the ambient temperature and the main girder. Increasing the wind speed accelerated the rate of heat exchange between the main girder surface and the environment. In particular, when the internal temperature of the girder was higher than the ambient temperature, the higher the wind speed was, the larger the temperature gradient was. This study lays a foundation for accurate analysis of the structural response of ballastless track steel-concrete composite girder bridges at ambient temperature.
Wen-Yu He, Fan-Cheng Meng, Wei-Xin Ren
Advances in Bridge Engineering, Volume 2, pp 1-22; doi:10.1186/s43251-021-00037-8

Abstract:
Cable force estimation is essential for security assessment of cable-stayed bridges. Cable force estimation methods based on the relationship between cable force and frequency have been extensively studied and used during both construction phase and service phase. However, the effect induced by inclination angle of the cable is not included in the establishment of frequency-cable force relationship as horizontal cable model is normally employed. This study aims to investigate the influence of the inclination angle on vibration based cable force estimation and provide practical formulas accordingly. Firstly numerical examples of fixed-fixed and hinged-hinged cables are simulated to illustrate the necessity of considering the inclination angle effect on the modal parameters and cable force estimation for inclined cables with small sag. Then practical formulas considering the inclination angle effect to estimate the cable force of fixed-fixed and hinged-hinged cables via the fundamental frequency are established accordingly. For the inclined cables with unknown boundary conditions, the coefficients reflecting boundary condition are predicted via the practical formulas for fixed-fixed and hinged-hinged cables. And the cable force considering the influence of inclination angle and unknown boundary conditions is obtained by iteration method. Finally, numerical examples are presented to demonstrate the effectiveness of the proposed method.
Qingfeng Guan, Jingliang Xia, Faguang Leng,
Advances in Bridge Engineering, Volume 2, pp 1-24; doi:10.1186/s43251-021-00039-6

Abstract:
As a special type of cement that can provide construction with aesthetics, white Portland cement (WPC) is restricted by the high cost of its production. To reduce the consumption of WPC and carbon dioxide emissions without degrading the properties of mortar, this work produced various mortar mixes by replacing an equal volume of the paste (the total volume of WPC and water) with blast furnace ferronickel slag (FNS), the by-product of ferronickel smelting. The workability, 28-day compressive strength, carbonation depth, water permeability, and drying shrinkage test were conducted, and mercury intrusion porosimetry (MIP) test was used to characterize the pore structure. The results show that the paste replacement method is eco-friendlier and more effective than the traditional cement replacement technology in utilizing FNS to reduce WPC consumption, which may promote the development of white concrete construction.
Deming Zhu, Yaohan Li, , Peng Yuan
Advances in Bridge Engineering, Volume 2, pp 1-15; doi:10.1186/s43251-020-00030-7

Abstract:
Coastal highway bridge is an essential component of the transportation system but threatened by natural hazards such as hurricanes. Damaged highway bridges result in not only transportation disruption, but also tremendous financial, societal, and life loss. Therefore, vulnerability and loss assessments of bridges under hurricane events are becoming primary concerns for decision-makers. This study provides an elaborate framework to assess the vulnerability and long-term loss of coastal bridges subjected to hurricane hazards based on three-dimensional (3D) numerical analyses. A 3D Computational Fluid Dynamics (CFD) numerical model is established to investigate wave-bridge interaction and a Finite Element (FE) model is established for the bridge to calculate structural responses under wave impacts. Based on the numerical results, the effects of wave force and overturning moment on structural capacity are studied and a probabilistic vulnerability model is developed. Structural demand, capacity, and limit states are determined, respectively. Uncertainties associated with wave parameters, structural capacity, and material properties, and the resulting consequences are considered. Then, fragility curves are calculated, and long-term damage loss is assessed. The proposed approach can benefit the management and design of coastal bridges against the impacts of hurricane hazards.
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