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The construction method of P.S.C beam

 The repairing methods of P.S.C beam which have been constructed were used by expxy resin injection, introduction of additional prestress by external cable, and addition of temporary support. However, These methods may cause the secondary stress by displacement of the support, and not prevent from additional crack and displacement with carelessness effectively, moreover they need to drill the main girder and diaphragm complicatedly and cut the top of the pier, so they have the disadvantages that take more time and expenses to dispense various methods. Specially the loss of prestress cause the bending crack and displacement, so it reduce the stiffness of prestress and has a big effect on the endurance and the serviceability, and it mars the appearance of the structure, therefore We need effective methods.

 Moreover, Existing method of constructing P.S.C beams is the simple support systems, so big moment on the positive moment section in the middle of the span is occurred by pouring the slab concrete after the beam fixed, and compositive action of beam and slab support only the lived load, therefore the member can not be used properly.

 Consequently, We introduce the design method and construction method of the single P.S.C beam which can make up for the problems that occur in the existing methods of P.S.C beam.

The secondary prestressing method of simple and continuous P.S.C beam

The secondary prestressing method of simple P.S.C beam by down-up method

 After the deck concrete has been poured and cured in the state of that additional compressed stress is introduced  into the low flange by adopting hinged ends as fixed ends and by the movable support downed on the simple beam system, the method that introduce the negative moment stress into deck concrete from fixed ends by upping the downed support.

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The secondary prestressing method of continuous P.S.C beam by down-up method(separation of beam and pier)

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The secondary prestressing method of continuous P.S.C beam by down-up method(integrated of beam and pier)

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The secondary prestressing method of continuous 3 span P.S.C beam by down-up method(separation of beam and pier)

 After the deck concrete has been poured and cured in the state of that P.S.C beam has been linked at each inner joints, and both end-joints at piers have been gotten down, the method that introduce the compressing stress which is against the tensioning stress that is occurred at the inner joints after compositing the beam to the deck concrete by upping both downed end joints.

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The secondary prestressing method of continuous 3 span P.S.C beam by down-up method(integrated of beam and pier)

 After the deck concrete has been poured and cured in the state of that both end-joints at piers have been gotten down after getting P.S.C beam linked at each inner joints, and integrating it with the pier at the same time, the method that introduce the compressing stress which is against the tensioning stress that is occurred at the inner joints after compositing the beam to the deck slab concrete by upping both downed end joints.

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