• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.10a
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• pp.195-201
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• 2003

A fibered element for the material and geometric nonlinear analysis of three-dimensional reinforced and prestressed concrete frame is presented. The fibered frame element is idealized as an assemblage of concrete and reinforcing steel fibers in order to account for varied material properties within the cross section of the frame element through elastic, cracking and ultimated stages of materials. Prestressing tendon is modeled as an assemblage of multilinear prestressing steel segments each of which spans a frame element. The contribution of each prestressing steel is added directly to the fibered frame element. Numerical results from the ultimate analysis of three-dimensional PSC box girder are compared with those obtained from other investigator. The validity and the capability of the present nonlinear analysis model is well demonstrated.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.6A
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• pp.495-502
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• 2010

A study for the nonlinear analysis method of flexural behavior of concrete girders strengthened with unbonded prestressed CFRP plates is presented. The concrete girders strengthened with unbonded prestressed CFRP plates exhibit more complex nonlinear behavior due to the slip between the concrete girder and the CFRP plates than the case of bonded CFRP plates. The unbonded CFRP plate is modeled as an assemblage of the curved elements both ends of which are rigidly linked to the nodes of fibered frame elements. The slip effect of the unbonded CFRP plate is taken into account using the force equilibrium relationship at each node. To evaluate the validity and the capability of the proposed analysis method, the ultimate analysis results of the concrete beams strengthened with unbonded prestressed CFRP plate are compared with the experimental results obtained from other investigators. The proposed analysis method is found to predict ultimate behaviors of these beams fairly well. Additionally the time-dependent deformations of the concrete beam seems to have little influence on the ultimate behaviors of concrete beams strengthened with unbonded prestressed CFRP plate, and the cracks of the concrete beam which occurred before strengthening it with CFRP plate are found to have almost no influence on the ultimate capacity of the beam.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.1
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• pp.1-13
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• 2009

A study for the nonlinear solution strategies to predict the ultimate behavior of a curved PSC cable-stayed bridge with complex geometry and highly nonlinear characteristics is presented. The load and displacement control strategies are used and found to be stable for the nonlinear solution of the PSC bridge up to the moderately excessive load. The ultimate analysis of curved PSC cable-stayed bridge using these solution strategies is not converged due to the propagation of the cracks in the wide range of the concrete elements and excessive variation of the stresses in the concrete elements and cables according to the complex geometry. The load control strategy using scale-down of the unbalanced loads is proposed as an alternative method for the case that the solution is not converged due to the severe nonlinearities involved in the PSC structures like a curved PSC cable-stayed bridge. Through the ultimate analysis of the PSC girder, the accuracy and the stability of the proposed solution strategies are evaluated. Finally, the numerical results for the ultimate analysis of the curved PSC cable-stayed bridge using scale-down of the unbalanced loads are compared with those obtained from other investigator. The validity of the proposed nonlinear solution strategy is demonstrated fairly well.