Method for controlling changes in three-truss height difference of combined highway and railway bridge for structural system

Abstract

The invention discloses a method for controlling changes in three-truss height difference of combined highway and railway bridge for a structural system. Slide beams and slides are precisely hoisted before construction of a main bridge, and a three-truss height difference of lower bearing structures of steel trusses is controlled within 10 mm. The impact of the three-truss height difference upon the main bridge is analyzed by using finite element software analysis according to a design scheme and field initial data, and a safety limit of the three-truss height difference under various construction conditions is calculated; after each pushing, slider reversing is performed and point reading is redone according to field calculated elevations, and the three-truss height difference is precisely controlled within 1 mm; the bottom of each steel beam is contacted with sliders through elastic rubber pads, limiting relative vertical displacement of three main trusses during pushing and dynamically controlling the three-truss height difference. In the method, a three-truss large-span steel truss bridge is constructed by using a three-truss height difference control system, and the method is highly operable, convenient to construct, safe and reliable, economic and reasonable and is worthy of popularization in the construction of multi-main-truss large-span steel bridges.

Description

technical field [0001] The invention relates to the technical field of construction of long-span rigid truss girder bridges, and specifically belongs to a method for controlling the structural system of the height difference of the three trusses of road-rail dual-purpose bridges, and is mainly used in the erection and jacking construction stages of long-span continuous steel truss girder bridges. Internal force adjustment. Background technique [0002] With the in-depth advancement of my country's railway construction by leaps and bounds, rigid suspension cable-stiffened steel truss bridges, as novel long-span road-rail bridge structures, are The advantages such as beautiful appearance have become an important development direction in the construction of railway bridges. At present, there are two bridges with this structure in China, namely Dongguan Dongjiang Bridge and Jinan Yellow River Bridge. Dongguan Dongjiang Bridge is a (112+208+112) m double-layer highway bridge, er...

AI Technical Summary

Problems solved by technology

[0003] The three-truss structure bears complex forces, the space effect is obvious, the load sharing ratio of the middle and side trusses is different, the force of the middle truss is obviously greater than that of the side trusses, and it is difficult to ensure that the height of the three trusses is exactly the same during the construction process

The increase of the reaction force of a single main truss will easily cause the local stress of the main beam joints to be too large, and cause a huge safety risk to the lower support system

At the same time, if the construction is controlled by the single-piece main truss with a large internal force, the strength of the other two main truss members will not be fully utilized, resulting in waste of materials

The control of the height difference of the three trusses is very important for bridge construction, but there is still no very mature technical means for this

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