Method for exerting pre-stress to bracket-free steel anchor beam in electrically-heating mode

Abstract

The invention discloses a method for exerting pre-stress to a bracket-free steel anchor beam in an electrically-heating mode. The method includes the following steps: (1) splitting the bracket-free steel anchor beam, and manufacturing and forming the two parts of the bracket-free steel anchor beam; (2) carrying out temporary solidification and integral hoisting; (3) installing the bracket-free steel anchor beam in position, and releasing the solidification; (4) carrying out concrete pouring, and carrying out heating to enable the steel anchor beam to be longitudinally stretched; (5) carrying out permanent fixed connection; (6) carrying out natural cooling to enable the steel anchor beam to be contracted to achieve the pre-stress exerting effect; (7) carrying out quality testing. The method has the advantages that a force transmission path of a cable bent tower anchor structure is clear, stress of the integral structure is clear, and the aim of improving the stress of the bracket-free steel anchor beam structure is achieved; the pre-stress is exerted with a non-mechanical method, and the operability is high; heating is carried out at the low temperature, the selection range of electrical heating devices is wide, the devices are easy to operate, the heating temperature is easy to control, and meanwhile convenience is brought to midspan permanent solidification construction of the heated steel anchor beam; horizontal component force, borne by tower walls, of stay cables is small, and only some anti-cracking tower wall horizontal pre-stress steel bundles/reinforcing steel bars need to be arranged according to the structure.

Description

technical field [0001] The invention relates to the technical field of bridge member design and construction, in particular to a construction method for a steel anchor beam connected at the ends of cable-stayed cable towers of a cable-stayed bridge. [0002] Background technique [0003] The steel anchor beam anchorage structure of the cable-stayed bridge cable pylon originated from the Annasis Bridge in Canada, and has been applied in the Nanpu Bridge and Guanhe Bridge in my country. The anchor steel beam itself is an independent component, supported on the inner corbel of the tower column, Most of the horizontal component force of the cables on both sides is balanced, and the unbalanced horizontal component force is transmitted to the tower wall through the friction resistance supported under the beam and the horizontal limit device, and the vertical component force of the cable is transmitted to the inner corbel of the tower column. The main advantage of the conventional ...

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Problems solved by technology

The rigidity of this corbelless steel anchor beam is smaller than that of the conventional steel anchor box, and at the same time far less than the rigidity of the concrete tower wall. The original intention of the design of the beam anchorage method is contrary

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