A method of manufacturing prestressed concrete products and form for implementing the method

 

(57) Abstract:

A method of manufacturing prestressed concrete products is that rod valve with integral anchors pull and place in installed on the working surface of the pallet forms the stops. When installing rebar in the design position to the end portions of each of the rebar at the same time at a distance of 0,15 0,01 ... their length from the ends exert a deforming load, upward and perpendicular to the axis of the rod and at an angle of 45 ... 85oto the horizontal plane, which provides the contact bars with supports and secured to the sides of the form-locking position. When uprochenie rebar them deform bending moments from the forces of eccentric tension, which arises from the execution of the support surfaces of the lugs inclined at an angle greater than the angle of friction between the anchor and the surface of the stop. To implement the method in the form of every stop made forklift, the height of one of the teeth exceeds 1.1 ... 8.5 times the height of the second tooth, and the abutment surface of the stop angle is 4 ... 25oto the vertical plane, and a surface release the current emphasis 0.3 ... 1.2 distance between the axes of the teeth of the stop. 2 S. and 3 C.p. f-crystals, 5 Il.

The invention relates to the construction and production of precast prestressed concrete products.

Various methods of manufacture of prestressed products with tension reinforcement on the inner and outer lugs of the forms:

- using a tensioning device (and.with. USSR N 1209801, class E 04 G 21/12, 1986);

- without the use of special tension device, i.e., manually, when the tension bar reinforcement on the outer stops using electrothermal heating and hydraulic method of tension, which is widely used in many factories;

- without the use of special tension device when using forms with internal stops, including stops having a supporting surface which is inclined in the direction opposite to the fixed base lock (patent of Russian Federation N 2017911, class E 04 G 21/12, 1992).

With pre-tensioners hard rod fittings can be installed in both external and internal lugs forms. The application of external lugs forms associated with a variety of disadvantages: the need to cut the staff, the presence of holes in the sides of the forms to pass pre-tensioned rods and flow of the concrete mix through them, the inevitable loss of some of the materials and labor, and others.

The tensioning forces on the internal stops of the form causes the application form more complex structures compared to forms with an external stops, as the dismantling of products in all known structures of forms is preceded by the removal of the stops of the hardened concrete. This requires significant design complexity of the forms, which consequently complicates their operation and became the reason of rejection of application forms with the inner movable stops.

There are various constructive solutions devices for tension reinforcement at the supports forms.

However, long production operation, none of them survived: difficult conditions in forming prices (insufficient level of staff, the presence of dust and concrete mixes, the use of electronic devices and others) were the cause of the short life of use of the device for tensioning reinforcement.

Closest to the proposed method and device for its implementation are technologists who tion intense products contained in the invention protected by the patent of Russian Federation N 2017911 from 07.04.1992,

The above-mentioned technical solution is quite simple and reliable, as it does not require placing stops on any of the movable elements of the form. When tense tension rod on the inside is placed on the pallet stationary lugs rods are additionally secured by means of retaining clips located on the sides of the form. This is done in the following order: pre-tensioned rod, an elongated thermal or mechanical way, put the plugs all the way to the end anchors were located externally relative to the stops, and the end of the pre-tensioned rod to the anchor dropped below plastics latch located on Board forms. At this point, a special bracket on round reinforcing steel placed at a height between the end of the rod and plastics latch to prevent arbitrary displacement of the rod with the stops and ensure the design provisions (see Alexandrov E. F., Granika Century BC, Dmitriev A. N. Manufacture of prestressed floor slabs on environmentally friendly technologies on the mill conveyor. Industrial and civil engineering, 1996, N is the mouth shape is closed and locked by the locks after laying the rod in the rests of the form.

In the process of shortening of the rebar when it is cooled, either by reducing tensile forces, end anchors begin to interact with inclined support surfaces stops and moving them up, transfer rod in the design position. In this state, the end portion of the rod located behind the anchors rest on the tabs on the sides of the form.

As shown, at the same time can be put in the stops form four, maximum six rods, and then quickly close the Board until such time as end anchors, moving up the inclined bearing surfaces of the lugs will not raise the rod above the design position, then the locking tabs on the sides will not be able to secure the rods in the desired location along the height (thickness) of the product.

Therefore, the design of the forms made according to the technical solution, and a method of manufacturing prestressed concrete structures, implemented with the use requires a special sequence of stacking rods into stoppers forms, quick closing sides and screwing castles or the use of additional fastening elements rods and additional drugstrategy for fixing rods in a project position, associated with some probability of its rapid movement from the design position up if not careful you perform some operations, so as to clamp acts upward-directed component of the tension rod parallel to the support surface stops. Bounce brackets can cause personal injury.

The aim of the invention to develop a simpler method of making prestressed concrete products and structures in compliance with the safest working conditions, and design forms with internal fixed stops, ensuring implementation of the new method.

This goal is achieved due to the fact that in the proposed method of manufacturing prestressed concrete structures, comprising a tension rod valve with integral anchors, placing them in the lugs installed on the working surface of the pallet and in contact with the inner surface of anchor washers, installing rebar in the design position by application to the ends of the last loads, providing their contact with the stops and clamps position, fixed on the sides of the form, the tension reinforcing the frame of the product and the transfer of straining effort with rebar in concrete in the casing, it is envisaged that in the process of installing rebar in the design position to the end portions of each of the rebar at the same time at a distance of 0.01 to 0.15 of their length from the ends attach at an angle of 45 - 85oto the horizontal plane deforming load, upward and perpendicular to the axis of the rod, equal to 3 - 15 kg, while the shortening of rods last deform bending moments from the forces of eccentric tension resulting from the inclination of the support surfaces of the lugs at an angle greater than the angle of friction between the anchor and the surface of emphasis, in the form for the manufacture of prestressed concrete structures containing the longitudinal and transverse side locking position rebar, United by hinges with the pallet, with each pre-tensioned rebar secured on the opposed internal lugs with inclined support surfaces, each focusing executed fork, the height of one of the teeth of which exceeds 1.1 - 8.5 times the height of the second tooth, and the abutment surface of the stop in contact with the anchor rod, inclined to the vertical plane at an angle 4 - 25owhile working surface fix the fence 0.3 - 1.2 distance between the axes of emphasis.

The attributes making up the difference of the proposed method of manufacturing prestressed concrete products and designs forms for its implementation in the prototype, a method of manufacture, and forms are not included, which allows to make a conclusion about the relevance of the proposed solutions to the criterion "novelty". Current methods of manufacturing prestressed concrete products and forms do not provide optimal work and completely safe technology of manufacture of prestressed products in forms with internal fixed stops. This allows to make a conclusion about the relevance of the proposed solutions to the criteria of the invention "significant differences".

In Fig. 1 shows a General view of the form with the internal lugs; Fig 2 is a section along a-a in Fig. 1; Fig. 3 is a view along b-B in Fig. 2; Fig. 4 and 5 are two options section along b-b In Fig. 3.

The form consists of the pallet 1, the longitudinal and transverse sides 2, connected to the pallet by means of hinges 3, 4 locks, internal lugs 5 on the pallet and retainers rod position 6. Internal stops are located along the axes of the 7 pre-tensioned rods 8. At the ends of the rods placed anchors Torah provisions pre-tensioned rods height 6 (the thickness of the vertical formation of products), on the sides of the form are located so that their working area 10 in contact with the terminals or end anchors on them, which is offset from the axis of the corresponding emphasis horizontally 0.3 - 1.2 distance between the axes of the teeth of emphasis in the direction of less of the tooth. Working platforms clamps rod position can be down slope (Fig. 4) from its free end in a vertical plane.

A method of manufacturing prestressed concrete structures, involving the use of forms with the internal lugs and clamps the rod position, as follows.

In shape with closed sides 2, prepared by charging valve, carry elongated thermal or mechanically pre-tensioned rod 8 is held in two places at a distance from its ends 0,01 - 0,15 its length. The ends of the rod down under the working platform 10 of the securing rod position height section 6. Then in the places of holding the rod to make him force 3 - 15 kg (depending on the diameter of the rod), upward at an angle of 45 - 85operpendicular to the axis of the rod, moving it in the direction of the axis stops. In this case the rod, drawing the ends or anchors about working plaatsvinden moving over the lower tooth of the emphasis in the design position, i.e., the axis stops. Coracias during cooling or removal of the tensile forces, the rod begins to rely on the support surfaces of end anchors on the inclined support surface stops form, and a part located behind the anchor - clamp. Directly support surface interacting elements are in contact in the lower part of the supporting surface anchors, so the pre-tension force is transmitted to the stop dezentrale, and with some eccentricity relative to the axis of the rod. As a result, the rod coracias, bending towards the surface, where the stops. In the case of the manufacture of prestressed products in the form, in horizontal position, the rod in the Central part has a deflection down.

The proposed method for the manufacture of prestressed concrete structures can be implemented as in non-motorized version of its execution, and the use of various mechanical and hydro-mechanical tensioners pre-tensioned rod and cable fittings.

The proposed design allows the use of a fundamentally new method of producing prestressed concrete izdeliye stops having an inclined bearing surface.

In the case of manufacturing prestressed concrete products with pre-tensioned reinforcement of small diameter at the working spans of the order of 3.0 - 3.5 m weight one rod is 2.0 to 3.0 kg As shown, when charging forms like rods, they can be placed in the internal stops of the form, when deforming perpendicular to the axis of the rods, the load will be a 3.0 - 4.0 kg and is attached at an angle of 45 - 50oat a distance of 0.15 - 0.1 length of the rod from its ends.

Laying in the lugs form pre-tensioned rods length 6,0 - 8,0 m when the weight of 10.0 - 12.0 kg will require the application of force, deforming the rod with a curvature up and move it ends on the working surface of the latch in projected position, order 12,0 - 15,0 kg Deforming force in this case can be applied at a distance of 0.01 to 0.15 length of the rod from its ends.

When charging the form tense stem, an elongated thermal or mechanically placed so that it was located on the side of the axis stops above the top of the fence and below the bottom of the retainer. Then the elongated rod is moved horizontally in a Central position in the emphasis and placed in the groove Mesa bottom end anchors on the support surface rests, as part of the next anchor in the latch. If full settlement shortening of the rod it takes a design position, coming into contact with the catch on Board forms. The pre-tension force transmitted from the anchor on the abutment surface of the stop, is decomposed into a force perpendicular to the supporting surface of the focus and parallel to it, i.e. upward. The latch takes this component of the efforts of pre-tension and prevents any movement of tense stem from the design position.

When dismantling the finished product, after the opening of the sides form the tabs cease to hold the ends of the rods and the product can be freely removed from the form, if the component of the tension force that is parallel to the supporting surface of emphasis, will exceed the force of friction anchor on the surface of the emphasis that is provided when the angle of inclination of the support surface stops at a more vertical angle of friction of the end of the anchor rod on the surface of emphasis.

Experimental studies have shown that free movement of the end anchor tense rod on a support surface of emphasis in addition to the angle TNA is their particles of concrete, the degree of prorabotannosti support surface, the presence of grease on the surface and others. Given the above reasons, the angle of inclination of the support surface anchors form may differ from the angle of friction of the anchor on the support surface all the way and make 4,0 - 25,0o.

For the convenience of institutions pre-tensioned rods into stoppers forms and further secure the valve in the design position, the teeth of the fork lugs perform various heights. From the proposed filing of a pre-tensioned rod placed less high tooth, as well as above it must pass the rod. In order to further movement of the rod horizontally he not jumped outside of focus, the second tooth is provided higher. Its height is made such that the gap between the top higher tooth and low lock - its working surface would be less than the diameter tense stem.

The upper size limit higher tooth stops is its height, some of the design considerations that it is impractical to take exceeding half the diameter of the pre-tensioned rod.

Based on these considerations, the ratio of the heights of the teeth of the fork stops that the mayor, to the height of one of the teeth above the height of the second tooth 1.1 - 8.5 times.

Since when laying pre-tensioned rod stops form, as was shown above, at the beginning of the movement in the design position its ends it is necessary to bend down, to meet this condition, the working space of the position lock rod in contact with the stem end or end anchor, should be offset horizontally from the axis of the corresponding emphasis towards less high tooth stops. Depending on the size of pre-tensioned rod displacement axis working area of the latch from the axis of the corresponding emphasis should be 0,3 - 1,2 distance between the axes of the teeth of the internal fork stops. With smaller diameters pre-tensioned rods correspond to the stops with the smaller size of this parameter.

In the process of moving the rod in a design position its ends, bent down, slipping on the work surface of the retainer. In this case, if the working surface is horizontal, the contact between the end of the rod and the latch will be held on the same line, the line of intersection of the free surface of the retainer facing the center of the form, with the working surface. After placement of the rod in the design of the upper point of an end section. From consideration of the process of moving the end of the pre-tensioned rod tensioning process it becomes apparent that when the inclined work surface clamp down on the free end of the latch facing the center of the form, move the rod above the lower tooth of the emphasis in the design position can free than when horizontal working surface.

Therefore, the working surface of the retainer, it is advisable to perform inclined in the vertical plane downward from the free end of the latch 5,0 - 15,0o. Moreover, for products with a length of 6.0 - 8.0 m the slope of the working surface can be 5.0 - 7.0oand for short products, for example, a length of 3.0 - 3.6 m angle of inclination of the working surface should be 12,0 - 15,0o.

As demonstrated by field tests of the developed method of manufacturing prestressed concrete products, adopted the design parameters of the nodes forms for the implementation of the proposed method provided solely technological operations on the tension rod of the valve and its reliable and secure fixation in the design position on the lugs of the form.

The application of the developed method of manufacturing prestressed visit rebar retainers in the manufacture of structures, having five or more pre-tensioned rods, such as floor slabs.

1. A method of manufacturing prestressed concrete structures, comprising a tension rod valve with integral anchors, placing them in the lugs installed on the working surface of the pallet and in contact with the inner surface of anchor washers, installing rebar in the design position by application to the ends of the last loads, providing their contact with the stops and clamps position, fixed on the sides of the form, the tension rebar when shortening, laying in shape and compaction of the concrete mix, heat and humidity treatment of the molded product and the transfer of straining effort with rebar in concrete in the casing, characterized in that in the process of installing rebar in the design position to the end portions of each of the rebar at the same time at a distance of 0.01 to 0.15 of their length from the ends attach at an angle of 45 - 85oto the horizontal plane deforming load, upward and perpendicular to the axis of the rod, equal to 3 - 15 kg, while the shortening of rods last deform bending moments from the forces of eccentric stretching what ncera and the surface of emphasis.

2. The method according to p. 1, characterized in that the pretensioning of each terminal is produced by mechanical means to values not exceeding the limit of elastic deformation of the material of the rod.

3. The method according to p. 1, characterized in that the pretensioning of each terminal is produced by heating it to a temperature not exceeding the temperature causing the softening of the material of the rod.

4. The form for the manufacture of prestressed concrete structures containing the longitudinal and transverse side locking position rebar, United by hinges with the pallet, with each pre-tensioned rebar secured on the opposed internal lugs with inclined support surfaces, wherein each stop made a fork lift, the height of one of the teeth of which exceeds 1.1 - 8.5 times the height of the second tooth, and the abutment surface of the stop in contact with the anchor rod, inclined to the vertical plane at an angle 4 - 25owhile the working surface of the retainer in contact with the armature rod or anchor, is displaced horizontally in the direction of a smaller tooth corresponding emphasis 0.3 - 1.2 rasstoianiia position of the rebar is inclined downward from its free end in a vertical plane at an angle of 5 15o.

 

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SUBSTANCE: the mould has a tray, longitudinal girders, partitions installed in the slots of the longitudinal girders, and clamps coupling the longitudinal girders. Restricting strips coupled to the tray are installed on the tray along the longitudinal girders. The longitudinal girders and the partitions are installed at an angle of 60 to 120 deg to the tray. The clamps are made in the form of U-shaped clincher having a horizontal cross-piece and a pair of struts, and they are located at an angle of 60 to 120 deg to the tray and fit the outer surface of the longitudinal girders.

EFFECT: reduced time of assembly of the mould and striking, possibility of use of one mould for production of concrete blocks of different geometry.

11 cl, 5 dwg

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