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Structural Engineering and Mechanics
  Volume 75, Number 1, July10 2020, pages 49-57
DOI: http://dx.doi.org/10.12989/sem.2020.75.1.049
 


Full-scale testing on the flexural behavior of an innovative dovetail UHPC joint of composite bridges
Jianan Qi, Zhao Cheng, Jingquan Wang, Yutong Zhu and Wenchao Li

 
Abstract
    This paper presents a full-scale experimental test to investigate the flexural behavior of an innovative dovetail ultra-high performance concrete (UHPC) joint designed for the 5th Nanjing Yangtze River Bridge. The test specimen had a dimension of 3600 × 1600 × 170 mm, in accordance with the real bridge. The failure mode, crack pattern and structural response were presented. The ductility and stiffness degradation of the tested specimens were explicitly discussed. Test results indicated that different from conventional reinforced concrete slabs, well-distributed cracks with small spacing were observed for UHPC joint slabs at failure. The average nominal flexural cracking strength of the test specimens was 7.7 MPa, signifying good crack resistance of the proposed dovetail UHPC joint. It is recommended that high grade reinforcement be cooperatively used to take full advantage of the superior mechanical property of UHPC. A new ductility index, expressed by dividing the ultimate deflection by flexural cracking deflection, was introduced to evaluate the post-cracking ductility capacity. Finally, a strut-and-tie (STM) model was developed to predict the ultimate strength of the proposed UHPC joint.
 
Key Words
    composite bridge; ultra-high performance concrete (UHPC); joint; flexural behavior; STM model
 
Address
Key Laboratory of Concrete and Prestressed Concrete Structures of the Ministry of Education, School of Civil Engineering, Southeast University, Nanjing, China
 

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