Vol.36/No.3 (141) (2021)
Special issue: Bridge engineering
Guest editor: Dzong-Chwang Dzeng
| Title | Planning and Design of AnShin Bridge, the Ankeng LRT System Xindian River Crossing Bridge |
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| Author | Teo Eng-Huat, Chang Jhih-Bin, Chang Jung-Tzu |
| Keywords | Cable-Stayed Bridge, Steel Truss Bridge, Wind Tunnel Test |
| Abstract | Ankeng LRT, located in New Taipei City, is a part of the “3 ring & 6 line railway project”. The route goes through Xindian and Ankeng area, and the section crossing Xindian River is the AnShin Bridge. Since the route crossing Xindian River has a skew with the river channel in 41 degrees, and there is a big turn in the Xindian side in order to enter the K9 station, it makes distance crossing river over 500 m. Moreover, there is a restriction which allows only 2 piers in the Xindian river reservation. In order to fulfill the requirement of the hydrographic as well as the railway system, a cable-stayed and truss composite bridge is used, which is the first in Taiwan and are seldom used in the foreign as well. AnShin Bridge crosses the deep trench area with a big span, a three-span continuous truss girder is used (225m+150m+127m=502m) for the bridge, not only can fulfill the deflection restriction of the railway structure, but also can keep the deformation continuity of the rail and structure at the curve route section. Since the location of the pier is restricted, the A-shaped inclined tower with single pier and the arrangement of the cable was well designed to surmount the imbalanced force due to unbalanced span. Last but not least, the analysis and modeling of the cable-stayed bridge with truss girder, the design detail of the curve and gradient steel truss, and the extra consideration for the railway bridge are some of the design features of AnShin Bridge which is different from the usual. The Anshin Bridge are special not only in the scale, span and design features, but also in the steel details and construction challenge. The design of AnShin Bridge is carried out in this article, some railway bridge design feature including seismic design, wind resistance design as well as the structural detail are also introduced, provide as a reference for the future engineering related project. |
| Title | Planning, Design and Construction of the Sanying Second Bridge in New Taipei City |
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| Author | Kang-Yu Peng, Ming-Sing Wu, Tien-Jen Hsiao |
| Keywords | Adjacent precast PC inverted T-beam, Accelerating Bridge Construction, Construction crossing over the railroad |
| Abstract | In recent years, New Taipei City Government has made great efforts to develop various constructions and promote tourism. The rapid growth of traffic volume in Tucheng District, Shulin District, Sanxia District and Yingge District must be actively responded and improved, facing the factors such as urgency of transportation construction, road safety requirements, bottleneck section improvement and the demands for access roads to tourism-developing districts. Among other things, the Sanying Bridge is an important one connecting Yingge and Shulin to Sanxia City Road No.110 and Sanying Interchange of National Highway No. 3. As the current service level of traffic has reached F-level during peak hours, in order to actively improve the traffic bottleneck, New Taipei City Government promotes the construction of the Sanying Second Bridge (hereinafter referred to as this project) to connect the 40m road (Dayi Road) in the Designated Area of Taipei University to share the traffic flow of City Road No. 110 and the Sanying Bridge. The planned route of the Sanying Second Bridge connects City Road No. 114 in a turning manner after crossing National Highway No. 3, the Dahan River and the track of Taiwan Railway. It adopts the first domestic inverted T-shaped, precast and prestressed beam to strive for the clearance under the bridge and to boost construction to ensure maintaining smooth traffic of national highway. By using large-span steel box girder for the bridge to cross the Dahan River and the track of Taiwan Railway, the design overcomes the risks of construction during the flood season and railway adjacency. This article aims to provide the design considerations and construction experience of this project which is expected to give a constructive reference to the domestic construction community. |
| Title | Development of Computer-aid Design System for Prestressed Concrete Bridges Considering Weight-minimum |
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| Author | Guan-Chun Chen, Po-Hsin Lee, Guan-yu Sung, Jia-Hsuan Li, Chih-Hsing Peng, Zheng-Hong Chen, Yu-Chi Sung |
| Keywords | Prestressed concrete bridges; Weight-minimum design; Program development |
| Abstract | Based on the specifications of railway bridges and highway bridges, this study developed the computer-aid design system for weight-minimum of prestressed concrete railway bridges. Creep, shrinkage, and relaxation would cause variation of the prestress tendons and deflection of the structure, leading to a lot of analyses in design. Through the computer-aid design system, complicated analysis can be performed quickly to obtain results, reduce human errors, and improve design efficiency.The results show that the optimized section is valid for reducing the superstructure section area by around 20 % and reducing the area of the pier section by around 2.5%.” |
| Title | Seismic Performance Design of New RC Bridges subjected to Near-Fault Earthquakes |
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| Author | Kuang-Yen Liu, Chen-Yang Wu |
| Keywords | high-strength concrete, bridge column, near-fault earthquake, strain rate, seismic performance assessment |
| Abstract | This study adopts the stress-strain relationship of localized high-strength reinforced concrete to explore the effect of replacing general-strength concrete with high-strength concrete on the reduction of the cross-sectional dimensions of the bridge column and the amount of steel under the same superstructure load. Case analysis shows that the increase in material strength reduces the crosssection of the bridge column, resulting in an extension of the structural period and a decrease in seismic force, which further achieves the dual goal of reducing the main reinforcement of the bridge column. In addition, when the bridge site is located near the fault, if conventional and high-strength reinforced concrete materials are used, and the contribution of the speed pulse to the high strain rate and the enhancement of the material strength is incorporated, it can also effectively reduce the cross-section of the bridge column and save the amount of main reinforcements. The design results adopt the ATC-40 capacity seismic spectrum method and the Fu-R-T strength and ductility reduction method, and the seismic performance assessment are consistent, verifying that the crosssectional size and the amount of steel reinforcement of the high-strength concrete bridge column are more economical. |
| Title | Effects of Longitudinal Reinforcement and Aspect Ratios on Deteriorated Hysteresis Behaviors of Reinforced Concrete Bridge Columns |
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| Author | Ping-Hsiung Wang, Wei-Chung Cheng, Kuo-Chun Chang |
| Keywords | reinforced concrete, bridge column, longitudinal reinforcement, aspect ratio, hysteresis behavior, deteriorations |
| Abstract | To study the effects of longitudinal reinforcement and aspect ratios on the deteriorated hysteresis behaviors of reinforced concrete (RC) bridge columns, five rectangular RC column specimens with hoop and tie reinforcements are tested under cyclic loading considering longitudinal reinforcement ratios of 0.75%, 1.5%, and 3.0% and aspect ratios of 3, 6, and 10. Furthermore, another five circular RC columns with spiral reinforcement and similar test scheme obtained in the literature are included to further compare the differences of deterioration characteristics resulting from various confining mechanisms. Test results show that the stiffness degradation and pinching severity of column would increase as its longitudinal reinforcement decreases. The pinching severity of column would also increase with decreasing aspect ratio, but the stiffness degradation is barely affected by the aspect ratio. Moreover, due to the well confinement effects, the severity of deteriorations of circular columns are less than those of rectangular columns with the same longitudinal reinforcement ratio and the minimum transverse reinforcements required by seismic design codes. Besides, the failure of rectangular columns is mainly caused by the loosening of transverse reinforcements at seismic hooks, leading to gradually deteriorated confinement and strength. In contrast, the failure of circular columns is primarily induced by the fracture of spirals, resulting in destruction of confinement mechanism and sudden strength loss. |
| Title | Recommendations of Pushover Analysis and 𝑭𝒖- 𝑹- 𝑻 method for Bridge Seismic Capacity Evaluation and its Algorithm |
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| Author | Dzong-Chwang Dzeng, Dzong-Chwang Dzeng, Ching-Yu Liu, Tsan-Hsiang Chou |
| Keywords | dynamic time history analysis, pushover analysis, capacity curve, capacity spectrum curve, bilinearization, EPA (Effective Peak Acceleration) |
| Abstract | While the approach combined pushover analysis with 𝐹௨- 𝑅- 𝑇 process is universally adopted in examination and evaluation of seismic capacity for domestic bridge, there are still many aspects to be reviewed, clarified, expanded and improved to further recognize its applicability and variation and to ensure the reliability of the analyzed results. This work presents an algorithm expanding the period 𝑇 at the end of constant spetral design acceleration plateau to obtain the 𝐸𝑃𝐴 (effective peak acceleration) corresponding to any spectrum displacement 𝑆ௗ ), establishing the continuous 𝐸𝑃𝐴 and load condition curve (e.g. displacement and plastic hinge ductility ratio) and verifying its applicability and reliability by comparing the results of simplified regular bridge model analysis with nonlinear dynamic time-history analysis. Combining this continuous EPA and load condition curve with seismic hazard at bridge site, it could be the basis for quantified calculation of bride seismic risk costs and the benefits of retrofit. In addition, this work also studies and reviews the bilinearization method of capacity spectrum curve. It proves that a much greater seismic capacity would be obtained by the “non-elastoplastic bi-linearization method” than the “elastoplastic bi-linearization method” . It should be cautious in practical applications. |
| Title | Hysteretic Model Parameters with Using Support Vector Regression |
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| Author | Tzu-Kang Lin, Tzu-Hui Yang, Hao-Tun Chang, Ping-Hsiung Wang, Kuo-Chun Chang |
| Keywords | support vector regression, smooth hysteretic model, pinching, stiffness degradation |
| Abstract | This study developed artificial intelligence–based models for predicting smooth hysteretic model (SHM) parameters. Recently, an SHM based on the Bouc–Wen model was developed to determine damage accumulation and path dependence of reloading. The model comprises five main parameters that describe the seismic behavior of ductile, flexure-dominated reinforced concrete (RC) bridge columns. However, each time-variant parameter can be derived only through practical experiments and cannot be tested on actual structures; therefore, the SHM is not very practical. In this study, support-vector regression (SVR) was adopted to capitalize on the advantages of the developed SHM, which exhibits superior performance to other existing hysteresis models. Nine different RC bridge columns were tested under displacement time histories, and a total of 119 samples were acquired. Of the samples, 80% were used for training and the remaining 20% were used for testing. The longitudinal reinforcement ratio, aspect ratio, and displacement or residual displacement of individual columns were set as the inputs to the SVR models, and the pinching and stiffness degradation parameters were set as the model output. Time-variant parameters could be predicted accurately with low deviation and error percentages. Moreover, hysteresis loops were generated using the identification parameters, and the SVR prediction results were compared with experimental data. The results indicated that the seismic behavior of the RC bridge columns could be estimated with high reliability using the proposed method without the support of experimental progress and support the SHM to predict the degree of damage. “ |