RU1825837C - Steel-reinforced concrete span - Google Patents

Abstract

The steel-reinforced concrete span includes bearing steel tubular main beams, a reinforced concrete slab of the carriageway, and non-removable sheet formwork. The span is provided with horizontal transverse ties located between the main beams, which are provided at the ends with plates with holes. The main beams at the places where the plates are adjacent to them are made with holes coaxial with the holes of the plates and are provided with horizontal high-strength tensile wires with tension nuts at the ends passed through these holes. Supporting elements are mounted on horizontal transverse connections, and the formwork is located in the upper part of the main beams with support on the supporting elements. 2 ill.

Description

The invention relates to civil engineering and can be used in structures of small and medium spans, in particular bridges, overpasses, floors.

The purpose of the invention is to reduce the material consumption of steel-reinforced concrete span and increase its bearing capacity.

This goal is achieved in that in the proposed span, consisting of steel tubular main beams connected to a reinforced concrete slab of the carriageway, laid in an unextractable thin-sheet formwork, steel tubular shells are crimped by horizontal high-strength strands, passed through holes in opposite pipe walls, between the main beams have horizontal transverse connections with plates rigidly fixed at the ends with holes coaxial with the holes in the walls of the beams that are pressed against yakov surfaces of the tubes by the tension strands of nuts and antihandling formwork located on top of the main beams on the supporting members stacked on horizontal crosslinks.

Such a span construction allows the constancy of the pipe elastic shell contour to be achieved during operation under operational loads, preliminarily stressing the force required for the calculated redistribution of stresses in the pipe walls. In this case, due to the redistribution of tangential, tangential, and normal stresses along the pipe contour, the material of the side walls is included in the work and its bending stiffness is increased, which makes it possible to abandon the iron-fixing elastic ring section

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concrete clips. As a result, the consumption of reinforced concrete for the span is reduced by a factor of 1.5-2, which leads to a decrease in the constant load and a corresponding decrease in the consumption of metal of the main beams, which, taking into account the additional weight of the strands and bonds, is 25-30%.

The use of temporary pads located on the transverse connections also makes it possible to significantly reduce the thickness of the non-removable sheet formwork, which is supported on them until the concrete of the slab is completely hardened, which does not require the installation of transverse stiffeners on the formwork.

Figure 1 shows the span; figure 2 is a section aa in figure 1.

The span includes steel tubular main beams 1 and reinforced concrete slab 2, combined for joint work by flexible stops 3. Between the tubular main beams 1, having holes 4 in the side walls, are horizontal transverse joints 5 of rolled steel with plates 6 rigidly attached at the ends 6 having coaxial holes m 4 holes through which high-strength rods 7 are passed, compressing the pipes and receiving parts 6 with tension nuts 8. A thin sheet is laid between the pipes formwork 9 The supported on the concreting step support members 10.

Installation of the structure is carried out in the following order.

Steel tubular beams 1 with pre-installed in drilled holes 4 rods 7 with acquired nuts 8 are installed in the design position on the supports. Then, cross-links 5 are fastened, passes through holes in plates b, for which tension nuts 8 are removed and again screwed onto threads of threads 7. After that, nuts 8 are tightened with a torque wrench or pneumatic wrench for the calculated force. Upon reaching the desired compression of the cross-section of the pipe, the plates 6 are welded along the contour to its side surface. Support elements 10, for example, made of a wooden beam with a hook or inflatable balloons, on which, in turn, are installed non-removable, are laid on horizontal ties

formwork 9. The pin stops 3 are welded to the upper parts of the pipes and to the inner surface of the formwork, which are monolithic to the reinforced concrete plate 2.

The span of the invention makes it possible to significantly reduce the material consumption of the structure and increase its bearing capacity by compressing the cross section of the pipe with high-strength strands, redistributing the stresses arising in the elastic contour of the pipe. The reduction in the dead weight of the structure is 30-60% depending on the span to be covered, and the metal consumption is reduced by 25-30%.

At the same time, stressing the elastic contour of the pipe in the transverse direction gives an increase in the stability of the thin-walled shell and its load-bearing capacity when working at constant and temporary

variable load.

Claims (1)

SUMMARY OF THE INVENTION Steel-reinforced concrete span, including bearing steel tubular main beam, reinforced concrete slab of the carriageway laid on them and between them, and non-removable sheet formwork, characterized in that, in order to reduce material consumption and increase bearing capacity, the span is equipped with a horizontal span located between the main beams, and along the highlanders, transverse connections are made with rigidly attached to them and adjacent to the side surfaces of the main beams with plates with holes, and the main beams in the places adjacent to the plates are made with holes coaxial with the holes of the plates, and equipped with horizontal high-strength ropes passed through these openings with tension nuts at the ends, while supporting elements are installed on horizontal transverse connections, and the formwork located at the top of the main beams based on these elements, / Yo figure 1 Aa 9 J /// W1