SU1273473A1 - Unsplit prefabricated solid multispan girder - Google Patents

Abstract

A continuous prefabricated monolithic multispan beam comprising prefabricated elements and nadopornye monolithic portions fittings are made of high strength steel with a release coating, characterized in that, in order to increase the efficiency of the beam release coating vtolneno apart reinforcement length, the magnitude of the central the axes of the supports are determined from the equation al., 3 .. (lai a) 24V, 2B PR OL. 24i-2. . M, -I O, - M in „1.p on op where 1 is the calculated span of the beam, cm; q - evenly distributed load, kg / cm; - stiffness in flight, kg / cm; (L Вд „- rigidity - on the support, kg / cm; MD - moment on the support, kg / cm. S

Description

The invention relates to building structures, consisting of long bearing elements, for example beams and connecting elements for them, and can be used to create prefabricated monolithic multi-span beam structures in civil, industrial, energy, reclamation and other construction industries.

The purpose of the invention is to increase the efficiency of the beam.

The drawing shows a continuous precast-monolithic multi-span beam.

Continuous continuous monolithic multi-span beam 1 includes prefabricated elements 2 and abutment sections 3, the reinforcement 4 of which is made of high-strength steel with an adhesive coating 5 on the part of the length of the reinforcement 4, the value of which from the central axis of the supports is determined from the equation _211 ____ 2 -. (121 + -21 ) _

24V _OL 2V _OL H 3 DR__ __2 _ La ²

24V „“ 2V ~ ' ^k_ 2 ~

Pr Lr _ Μ _θ.’51ζ2_

Ί0 determine the value

those. at what distance from the ends of the spans should there be no adhesion between the concrete monolithic and reinforcement 4 on

Moreover, if it does not satisfy _{_} ____ Mol, ______

V-2 ’

F _H (h ₀ -f-) support 7.

moment on the support 7 condition R _H > _z fr ₀ = where is the design resistance of the reinforcement 4 on the support

7, kg / cm ² ; 6 _Q is the stress in the tensile reinforcement 4 when the value of a,

determined from the equation

-211 ____ 2 _, (_ 121 + -21-) _

24V _pr 2V _pr 2 3>

- and 2d51n2_ _ _m -2 '.

Forward RUB In _ol about, where 1 is the calculated span of the beam, cm;

q - uniformly distributed load, kg / cm;

In _LR - stiffness in flight, kg / cm ² ; VOP - stiffness on the support, kg / cm ² ; Мрп - Moment on the support, kg / cm.

then its reduction is not achieved in

Beam 1 is made of three-span, and its component elements 2 are prestressed, of rectangular cross section with reinforcement 6 made of ordinary steel of the class required for calculation. Elements 2 are installed with ends on supports 7 and their joints are monolithic with reinforcement 4 being placed in them from high-strength steel wire or from reinforcing bars of mineral fibers having an elastic modulus of the order of 3 10 ⁵ kg / cm ² . When designing continuous precast monolithic multi-span beams 1, based on the bearing capacity of the structure, its dimensions and the type of reinforcement 6 used in the factory for reinforcing spans, the bending moment in the span and stiffness in the span and on the support 7 are determined. Then, the increase in the distance from the ends of the spans, on which there is no adhesion between the concrete reinforcement and reinforcement 4 at a distance of a, and due to the use of reinforcement 4 on supports 7 with greater strength and smaller cross-section (steel high-strength reinforcement of a class not lower than B-Π, BP-H) or due to the use of reinforcement 4 on supports 7 with a lower modulus of elasticity and a smaller cross section (mineral fiber), which, as calculations showed, should be taken in 3-4 45 times smaller cross-section than conventional reinforcement 6 used in spans.

At the same time, in the support part, greater deformability is achieved for 50 due to the fact that the elongation of reinforcement 4 occurs in section 9 of a certain length, and due to reinforcement 4 of greater deformability, and the reinforcement design of the support part of the uncut beam 1 provides a predetermined distribution of moments c. span and support part.

Claims (1)

CUTTING MONOLITHIC MULTI-SPAN BEAM, including prefabricated elements and supporting monolithic sections, the reinforcement of which is made of high-strength steel with anti-adhesive coating, characterized in that, in order to increase the efficiency of the beam, the anti-adhesive coating is made on a part of the length of the reinforcement, the size of which is from the central axis the supports are determined from the equation ГH _____ a__ .. (121 ₊ _ * 1 24V „ _r 2V _PR ^V 2 3 where 1 - design beam span, cm; q - uniformly distributed load, kg / cm; In _op - stiffness in flight, kg / cm ² ; VOP - stiffness on the support, kg / cm ² ; Mop - support moment, kg / cm. bending moment on the support of h! 2 equations M + M = where M LR OD 8 pr the moment in flight, kg / cm. 5 Then from the equation