以有限元素及理論分析進行FRP人行橋力學行為之研究

Finite Element Analysis and Theoretical Analysis of All-FRP Composite Pedestrian Bridge

Sainey(Sainey Badjie)

指導教授 ： 李有豐

國立臺北科技大學/工程學院/土木與環境工程國際學生研究所專班/碩士(2014年)

https://doi.org/10.6841/NTUT.2014.00315

摘要

This thesis presents the finite element analysis (FEA) and theoretical analysis of the first all-FRP-composite pedestrian bridge in Taiwan. The bridge was constructed in Taijiang National Park, Tainan, where salt damage is causing severe structural degradation. Fiber Reinforced Polymer (FRP) composite material was used to build the bridge as a countermeasure to chloride attack. The superstructure of the bridge consists of four FRP I-girders as the bridge stringers, the deck and diaphragms. Diaphragms and FRP rods placed between the girders helped dissipate the loading to the other girders and prevent torsion respectively. This design enhanced the stiffness of the FRP composite bridge super-structure as well as allowed for the best performance of each component.
A 6-m girder was tested by using three-point bending test. Timoshenko Beam Theory (TBT), Euler Bernoulli Beam Theory (EBT) and the FEA were also used to analyze and compare the test results. In the meantime, the TBT, EBT and FEA (using ANSYS) were used to analyze an 8-m girder of the pedestrian bridge for validation of the finite element model. A detailed finite element model was then created to predict the static flexural behavior of the bridge superstructure under service live loads and also possible failure initiation points on the superstructure.
The theoretical results show a good correlation with the finite element results in predicting the static behavior of the pedestrian bridge under the designed live load. The pedestrian bridge met deflection criteria of a maximum deflection less than L/500. From the finite element results, the stress concentrated points were identified on the pedestrian bridge superstructure. These points, also known as the critical points, were found to be located at midspan the top and bottom of the girders; at the support points; slightly on the deck bottom at midspan; and around the support and diaphragm connection on the girders.

關鍵字

all-FRP composite ； pedestrian bridge ； finite element analysis ； ANSYS

並列摘要

This thesis presents the finite element analysis (FEA) and theoretical analysis of the first all-FRP-composite pedestrian bridge in Taiwan. The bridge was constructed in Taijiang National Park, Tainan, where salt damage is causing severe structural degradation. Fiber Reinforced Polymer (FRP) composite material was used to build the bridge as a countermeasure to chloride attack. The superstructure of the bridge consists of four FRP I-girders as the bridge stringers, the deck and diaphragms. Diaphragms and FRP rods placed between the girders helped dissipate the loading to the other girders and prevent torsion respectively. This design enhanced the stiffness of the FRP composite bridge super-structure as well as allowed for the best performance of each component.
A 6-m girder was tested by using three-point bending test. Timoshenko Beam Theory (TBT), Euler Bernoulli Beam Theory (EBT) and the FEA were also used to analyze and compare the test results. In the meantime, the TBT, EBT and FEA (using ANSYS) were used to analyze an 8-m girder of the pedestrian bridge for validation of the finite element model. A detailed finite element model was then created to predict the static flexural behavior of the bridge superstructure under service live loads and also possible failure initiation points on the superstructure.
The theoretical results show a good correlation with the finite element results in predicting the static behavior of the pedestrian bridge under the designed live load. The pedestrian bridge met deflection criteria of a maximum deflection less than L/500. From the finite element results, the stress concentrated points were identified on the pedestrian bridge superstructure. These points, also known as the critical points, were found to be located at midspan the top and bottom of the girders; at the support points; slightly on the deck bottom at midspan; and around the support and diaphragm connection on the girders.

並列關鍵字

all-FRP composite ； pedestrian bridge ； finite element analysis ； ANSYS

參考文獻

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[24] Li, Y. F., Yu, C. C., Chen, S. Y. & Badjie, S. (2013) “The Carbon Footprint Calculation of the GFRP Pedestrian Bridge at Taijiang National Park,” International Review for Spacial Planning and Sustainable Development, Kanazawa: SPSD Press, Vol. 4, pp. 13-28..

[5] Aref, A. & Parsons, I. (1996) “Design and Analysis Procedures for a Novel Fiber Reinforced Plastic Bridge Deck,” Advanced Composite Materials in Bridges and Structures, CSCE, Montreal, pp. 743-750.

[7] Bank, L., Yin, J. & Nadipelli, M. (1995) “Local Buckling of Pultruded Beams - Nonlinearity, Anisotropy and Inhomogeneity,” Construction and Building Materials , Vol. 9, No. 6, pp. 325-331.