Full-scale experiment research on flexural behaviour of 30 m pre-tensioning prestressed concrete composite Ⅰ-girder
To investigate the flexural behavior of pre-tensioning prestressed concrete composite Ⅰ-girder,two full-scale 30 m models were designed,one was a single Ⅰ-girder and the other was a composite Ⅰ-girder with a concrete deck.Then,static bending loading tests were performed.The friction loss of prestressed,load versus deflection relationship,failure modes,crack distribution and crack width were investigated during the tests.The applicability of the design methods of JTG 3362-2018,GB 50010-2010,ACI 318-14 and Eurocode 2 specification were discussed based on the experimental result.The results show that the frictional forces are developed in the tensioning of the draped strands when the 16Mn plate-type bend device is used,and the friction coefficient is about 0.25.After combing the concrete deck,the cracking load,reinforcement yield load and flexural ultimate load of the Ⅰ-girder are increased by 23.8％,11.6％and 11.2％respectively,and the stiffness and ductility are also improved.The flexural load capacity of normal section of the composite Ⅰ-girder can be safely designed using four specifications mentioned above.JTG 3362-2018,Eurocode 2 and GB 50010-2010 are conservative in calculating the cracking moment,and can accurately calculate the maximum crack width,pre-cracking stiffness and post-cracking stiffness of the composite I-girder,respectively.
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