An Experimental Investigation on Performance of Externally Prestressed Concrete end Blocks
IR@SERC: CSIR-Structural Engineering Research Centre, Chennai
View Archive Info| Field | Value | |
| Title |
An Experimental Investigation on Performance of Externally Prestressed Concrete end Blocks
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| Creator |
Lakshmanan, N.
Saibabu, S. Ramachandra Murthy, A. Chitra Ganapathi, S. Jayaraman, R. Senthil, R. |
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| Subject |
Prestressed concrete
External presteressing Analytical model Material nonlinearity slope slip |
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| Description |
External prestressing is a widely employed technique for enhancing the strength of existing/distressed prestressed concrete girders and the prestressing force is transferred to existing concrete structures through end anchorages and
deviators. This paper presents the details of an innovative external prestressing technique for strengthening of pre-
stressed concrete (PSC) girders. The technique is developed for anchoring the external prestressing to the sides of the
end block and transfer of force to the end block is in shear mode. To validate the proposed technique, an experimental
investigation is carried out on post-tensioned end blocks. Detailed design calculations are provided for PSC end block.
Steel brackets are provided on either side of the end block for transferring external prestressing force and these are
connected to the anchor blocks by expansion type anchor bolts. Performance of the end blocks is examined for design,
cracking and ultimate loads. Slip and slope of steel bracket are measured at various loading stages during the exper-
iment. A simplified analytical model is proposed to compute load-deformation of the steel bracket with respect to the
end block. Yield and ultimate loads are computed based on force/moment equilibrium equations. Deformation analysis
is carried out based on the assumption that the ratio of axial deformation to vertical deformation of anchor bolt would
follow the same ratio at the corresponding forces such as yield and ultimate. It is observed that the computed slip and
slopes are in good agreement with the corresponding experimental observations.
External prestressing is a widely employed technique for enhancing the strength of existing/distressed prestressed concrete girders and the prestressing force is transferred to existing concrete structures through end anchorages and deviators. This paper presents the details of an innovative external prestressing technique for strengthening of pre- stressed concrete (PSC) girders. The technique is developed for anchoring the external prestressing to the sides of the end block and transfer of force to the end block is in shear mode. To validate the proposed technique, an experimental investigation is carried out on post-tensioned end blocks. Detailed design calculations are provided for PSC end block. Steel brackets are provided on either side of the end block for transferring external prestressing force and these are connected to the anchor blocks by expansion type anchor bolts. Performance of the end blocks is examined for design, cracking and ultimate loads. Slip and slope of steel bracket are measured at various loading stages during the exper- iment. A simplified analytical model is proposed to compute load-deformation of the steel bracket with respect to the end block. Yield and ultimate loads are computed based on force/moment equilibrium equations. Deformation analysis is carried out based on the assumption that the ratio of axial deformation to vertical deformation of anchor bolt would follow the same ratio at the corresponding forces such as yield and ultimate. It is observed that the computed slip and slopes are in good agreement with the corresponding experimental observations. |
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| Date |
2009
2009 2008 |
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| Type |
Article
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| Identifier |
Journal of Structural Engineering, Vol.35, No.4, October-November 2008, p.300-307
http://hdl.handle.net/123456789/403 |
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| Language |
en
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| Rights |
It is tried to respect the rights of the copyright holders to the best of the knowledge. If it is brought to our notice that the rights are violated then the item would be withdrawn.
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| Publisher |
Structural Engineering Research Center, Chennai
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