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| Creep Effect Analysis of the Whole PC Box Girder for Railway Bridge |
| NING Gui-xia1, KONG De-yan2, XIE Zhi-yong1 |
| 1.Lanzhou Jiaotong University, Lanzhou, Gansu 730070, China; 2.The Third Survey and Design Institute of China Railway, Tianjin 300142, China |
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Abstract Research purposes: Creep of concrete has significant influence for prestressed concrete structures. During structural analysis, different models of analysis cause different results of internal force and deformation. The influence of loss of prestress which caused by creep of concrete to the internal force and deformation of structure need further study.
Research methods: Combining with the design code of railway bridges, internal force and deformation of a double lines railway bridge with PC box beam are analyzed at the stages of pretensioning, beam erecting and secondary dead load's acting under three analysis models using MIDAS/Civil program. The influence of loss of prestress caused by creep of concrete to structure is researched.
Research conclusions: Creep of concrete cannot caused secondary internal force for a simple supported beam, but can cause stress redistribution. The internal force of beam is reduced when loss of prestress caused by creep is concerned. The up-deformation caused by prestress is developing slowly according to time passing. The actions of secondary dead load reduce up-deformation significantly. The deformation caused by creep is nearly 50% of total deformation, which has disadvantage for down-deformation of structure but advantage for controlling of up-deformation.
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Received: 26 October 2005
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2006, Vol. 23 
