Prestressed PBL stiffening-type steel box concrete composite beam and construction method thereof

Abstract

The invention discloses a prestressed PBL stiffening-type steel box concrete composite beam and a construction method thereof, and particularly relates to the technical field of composite structures.According to the composite beam, constraint on concrete is higher, and the bearing property is better. A box chamber used for filling of the concrete is formed by web plates and a bottom plate. The top of the box chamber is in an opening shape. The inner surfaces of the web plates and the upper surface of the bottom plate are provided with PBL stiffening ribs. The corresponding PBL stiffening ribsin a compressed area of the box chamber are connected through transverse pull rods. The edges of the two sides of a tensile zone of the box chamber are provided with axial prestressed tendons. Through joint action of the PBL stiffening ribs and the pull rods, the constraint degree on the concrete by the box chamber can be effectively improved, local buckling is avoided, the void area of the concrete and the box chamber is decreased, and interface slip is reduced accordingly; and the tensile zone of the box chamber is provided with the prestressed tendons, the bearing capacity and flexural rigidity can be obviously improved, so that the composite beam has good seismic performance and the stable later bearing capacity, and thus the suitable span of the structure is increased.

Description

technical field [0001] The invention relates to the technical field of composite structures, in particular to a prestressed PBL reinforced steel box concrete composite beam and a construction method thereof. Background technique [0002] Concrete-filled steel tube axial compression and small bias components have been widely studied, and the relevant theories are becoming more and more mature. They are mainly used in industrial, civil buildings and bridge structures. However, there are relatively few studies on steel pipe flexural members (beams), and the application in practical engineering fields is even rarer. Although relevant research results have shown that rectangular concrete-filled steel tube beams have good ductility and later bearing capacity, but after research and analysis, rectangular steel tube concrete is not suitable for flexural members (beams), which mainly has the following disadvantages: the concrete in the tension zone cannot exert its effect and increa...

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Problems solved by technology

However, there are relatively few studies on steel pipe flexural members (beams), and the application in practical engineering fields is even rarer.

Although relevant research results have shown that rectangular concrete-filled steel tube beams have good ductility and later bearing capacity, but after research and analysis, rectangular concrete-filled steel tubes are not suitable for flexural members (beams), which mainly have the following disadvantages: the concrete in the tension zone cannot exert its effect and increase the self-weight, the steel pipe in the compression zone is not strongly constrained to the concrete, and only at the corner, the concrete and the steel pipe are easy to be separated, and when the load exceeds a certain load, the top plate and web of the steel pipe in the compression zone buckle locally. Concrete and steel pipes slide a lot in the longitudinal direction; in addition, since the beam is a horizontal component and the steel pipe is a closed section, the concrete pouring is cumbersome and requires self-compacting concrete, and the concrete cannot be poured at the same time as the cast-in-place slab. It is difficult to weld the inner seam of the closed section

In summary, the existing rectangular concrete-filled steel tube structures generally have the following problems: First, the steel tubes in the compression zone do not constrain the concrete strongly, and local buckling is prone to occur, the interface between concrete and steel tubes slips relatively large, and the synergy between steel and concrete materials Poor workability; second, the concrete in the tension area cannot function and increase its own weight; third, the concrete pouring is cumbersome and requires self-compacting concrete, and the concrete cannot be poured at the same time as the cast-in-place slab

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