CN109537472B - Precast beam end bottom die rotating hinge device and application method thereof - Google Patents

Abstract

The invention provides a precast beam end bottom die rotating hinge device and a using method thereof. The supporting seat is settled in the mounting groove, and the supporting seat includes the bottom plate, and the both ends of bottom plate all are provided with triangle-shaped's support arm, and two support arms symmetry set up, are provided with the connecting hole on the support arm. The rotary hinge template comprises a plate surface, and a through hole is arranged in the center of the bottom of the plate surface. The rotating hinge template can be connected between the two support arms, and the rotating shaft penetrates through the connecting hole and the penetrating hole so as to rotationally connect the plate surface to the support arms. When the concrete girder is used, the dead weight concentrated on the end part of the girder, which is generated after the girder is tensioned by prestress, can be converted, so that the damage caused by overlarge plain concrete shearing force of the end part of the girder is avoided, the stress balance of the concrete at the end part of the girder is ensured, the construction quality of the whole girder is improved, and the concrete girder has the advantages of simple structure, convenience in construction and remarkable effect.

Description

Precast beam end bottom die rotating hinge device and application method thereof

Technical Field

The invention relates to the field of prestress tensioning of beams, in particular to a precast beam end bottom die rotating hinge device and a using method thereof.

Background

The upper structure adopts prefabrication and assembly to gradually become a main method for ensuring the quality and accelerating the progress of the highway bridge, and especially when the number of beam plates is large, the factory prefabrication has great technical advantages and cost advantages. T-beam and small box beam are the main forms of bridges with small and medium spans, T-beam is used for span of 30-50 m, and small box beam is used for span of 20-40 m. The method comprises the steps of processing a plurality of beam manufacturing pedestals in a beam field, fixing templates on the pedestals, pouring concrete of the beam, carrying out prestress tensioning when the compressive strength and the elastic modulus of the concrete reach the design requirements, grouting a pore canal, and storing a precast Liang Zhiyu beam area or transporting to the field for installation after the slurry reaches the strength of the design requirements. As shown in fig. 1, a bottom formwork 2 is fixed on a pedestal 1, and during the prestress tensioning process, a midspan 3 of the beam is firstly arched upwards to separate from the bottom formwork 2, then a part far away from the midspan is separated from the bottom formwork in sequence, and finally only the end 4 of the beam is left to support the dead weight of the whole beam. The end of the beam is plain concrete without reinforcing bars, the area of the weight of the end supporting beam body of the beam is continuously reduced in the process of continuously arching the beam, finally the dead weight of the beam is completely converted into the shearing load of the end plain concrete, when the generated shearing stress reaches the shearing strength of the concrete, the shearing damage of the plain concrete can occur, a crack extends upwards from the bottom, sometimes the width of the crack reaches several centimeters, the length reaches several tens centimeters, the inclined beam is particularly protruded, and the anchorage device can be directly exposed in the environment when serious. The end of the beam is not easy to repair, a plurality of precast beams are installed on the bridge with the cracks, sometimes the precast beams are used for less than ten years, the anchor is obviously corroded, the prestress rib is retracted once losing the fixing function of the anchor, the prestress is relaxed, the bearing capacity of the prestress beam is obviously reduced, and the structural safety of the bridge is greatly compromised. In order to avoid such things, the end bottom templates need to be adjusted so that the end bottom templates can rotate to a certain extent along with the beam ends in the process of arching the middle parts of the beams, and the dead weight of the beams is borne by prestressed reinforced concrete after an anchorage device.

Disclosure of Invention

The invention aims to provide a precast beam end bottom die rotating hinge device which solves the technical problem that shear damage occurs to the existing precast beam end concrete due to overlarge shear stress of the contact between the precast beam end concrete and a die plate of a pedestal after prestress tensioning.

The invention adopts the following technical scheme:

the bottom die rotating and hinging device for the end part of the precast beam comprises a pedestal, a rotating shaft, a rotating and hinging die plate and a supporting seat, wherein mounting grooves are formed in the left side and the right side of the pedestal;

the support seat is arranged in the mounting groove and comprises a bottom plate, triangular support arms are arranged at two ends of the bottom plate, the two support arms are symmetrically arranged, and connecting holes are formed in the support arms;

the rotary hinge template comprises a plate surface, and a through hole is formed in the center of the bottom of the plate surface;

the rotating hinge template can be connected between the two support arms, and the rotating shaft penetrates through the connecting hole and the penetrating hole so as to rotationally connect the plate surface to the support arms.

Preferably, a boss is arranged between the two mounting grooves, and a bottom template is arranged on the boss; and after the rotary hinge template is installed on the supporting seat and is arranged in the installation groove, the upper surface of the plate surface is flush with the upper surface of the bottom template.

Preferably, the connection hole is provided at the top of the support arm.

Preferably, the bottom plate is adapted to the mounting groove.

The second object of the present invention is to provide a method for using the above-mentioned device for hinging a bottom die at the end of a precast beam.

The application method of the precast beam end bottom die hinge rotating device comprises the following steps:

step 1: the support seat is placed in the mounting groove of the pedestal and is firmly mounted, and the rotating shaft penetrates through the connecting hole and the penetrating hole so as to rotationally connect the rotating hinge template with the support seat;

step 2: pouring the beam on the pedestal by using concrete, preparing to perform prestress tensioning after the compressive strength and the elastic modulus of the concrete reach the design requirements, and enabling the hinged template and the bottom template to be in the same plane state under the pressure action of the beam to share the dead weight of the supporting beam before the prestress tensioning of the beam;

step 3: when the beam is prestressed and tensioned, after the middle part of the beam is arched, the hinged template can rotate on the supporting seat in a small range to adapt to the change of the end part of the arched beam, so that the gravity of the beam is borne by the prestressed reinforced concrete of the beam.

The invention has the beneficial effects that:

the bottom die rotating hinge device for the precast beam end part has the advantages of simple structure, convenient construction and obvious effect, can convert the dead weight concentrated on the beam end part generated after the beam is tensioned by prestress, avoid damage caused by overlarge plain concrete shearing force of the beam end part, ensure the stress balance of the concrete at the beam end part, improve the construction quality of the whole beam, and has good stability and reliable use, and the angle of the rotating hinge die plate can be freely changed to adapt to the bearing of the beams in different states.

Drawings

Fig. 1 is a structural diagram of a conventional apparatus.

Fig. 2 is a structural view of a preform end bottom die hinge device of the present invention.

Fig. 3 is a schematic structural view of the stand.

Fig. 4 is a schematic structural view of the support base.

Fig. 5 is a schematic structural view of a hinged template.

Detailed Description

The following description of the embodiments of the invention will be given with reference to the accompanying drawings and examples:

example 1

Referring to fig. 2 to 5, a rotary hinge device for a bottom die of an end portion of a precast beam comprises a pedestal 5, a rotating shaft, a rotary hinge die plate 6 and a supporting seat 7, wherein mounting grooves 8 are formed in the left side and the right side of the pedestal 5.

A boss 9 is arranged between the two mounting grooves, and a bottom template 10 is arranged on the boss.

The supporting seat 7 is arranged in the mounting groove and comprises a bottom plate 11 which is matched with the mounting groove.

Triangular supporting arms 12 are arranged at two ends of the bottom plate, the two supporting arms are symmetrically arranged, and connecting holes 13 are formed in the supporting arms. Specifically, the connecting hole is provided at the top of the support arm.

The hinge-turning template comprises a plate surface 14, and a through hole 15 is arranged in the center of the bottom of the plate surface.

The pivot hinge die plate can be connected between the two support arms, and the pivot shaft passes through the connecting hole 13 and the through hole 15 so as to rotatably connect the plate surface 14 to the support arm 12.

And after the rotary hinge template is installed on the supporting seat and is arranged in the installation groove, the upper surface of the plate surface is flush with the upper surface of the bottom template.

Example 2

The application method of the precast beam end bottom die hinging device in the embodiment comprises the following steps:

step 1: the support seat is placed in the mounting groove of the pedestal and is firmly mounted, and the rotating shaft penetrates through the connecting hole and the penetrating hole so as to rotationally connect the rotating hinge template with the support seat;

step 2: pouring the beam on the pedestal by using concrete, preparing to perform prestress tensioning after the compressive strength and the elastic modulus of the concrete reach the design requirements, and enabling the hinged template and the bottom template to be in the same plane state under the pressure action of the beam to share the dead weight of the supporting beam before the prestress tensioning of the beam;

step 3: when the beam is prestressed and tensioned, after the middle part 16 of the beam is arched, the hinged template can rotate on the supporting seat in a small range to adapt to the change of the end part 17 of the arched beam, so that the gravity of the beam is borne by the prestressed reinforced concrete of the beam.

It should be understood that the above description is not intended to limit the invention to the particular embodiments disclosed, but to limit the invention to the particular embodiments disclosed, and that the invention is not limited to the particular embodiments disclosed, but is intended to cover modifications, adaptations, additions and alternatives falling within the spirit and scope of the invention.

Claims (2)

1. The bottom die rotating and hinging device for the end part of the precast beam is characterized by comprising a pedestal, a rotating shaft, a rotating and hinging die plate and a supporting seat, wherein mounting grooves are formed in the left side and the right side of the pedestal;

the support seat is arranged in the mounting groove and comprises a bottom plate, triangular support arms are arranged at two ends of the bottom plate, the two support arms are symmetrically arranged, and connecting holes are formed in the support arms;

the rotary hinge template comprises a plate surface, a through hole is formed in the center of the bottom of the plate surface, and a beam end is placed on the plate surface of the rotary hinge template;

the rotating hinge template can be connected between the two support arms, and the rotating shaft penetrates through the connecting hole and the penetrating hole so as to rotationally connect the plate surface to the support arms;

a boss is arranged between the two mounting grooves, and a bottom template is arranged on the boss; after the rotary hinge template is installed on the supporting seat and is arranged in the installation groove, the upper surface of the plate surface is flush with the upper surface of the bottom template;

the connecting hole is arranged at the top of the supporting arm;

the bottom plate is matched with the mounting groove.

2. The method of using a preform end die turning device according to claim 1, comprising the steps of:

step 1: the support seat is placed in the mounting groove of the pedestal and is firmly mounted, and the rotating shaft penetrates through the connecting hole and the penetrating hole so as to rotationally connect the rotating hinge template with the support seat;

step 2: pouring the beam on the pedestal by using concrete, preparing to perform prestress tensioning after the compressive strength and the elastic modulus of the concrete reach the design requirements, and enabling the hinged template and the bottom template to be in the same plane state under the pressure action of the beam to share the dead weight of the supporting beam before the prestress tensioning of the beam;

step 3: when the beam is prestressed and tensioned, after the middle part of the beam is arched, the hinged template can rotate on the supporting seat in a small range to adapt to the change of the end part of the arched beam, so that the gravity of the beam is borne by the prestressed reinforced concrete of the beam.