RU2325476C2 - Technique of replacing support parts of bridge - Google Patents

Abstract

FIELD: construction, road construction.

SUBSTANCE: invention pertains to the field of reconstruction of bridges with a concrete slab span continuous structure. The technical outcome is the increase in effectiveness of replacing supports of a continuous superstructure of a bridge due to the accuracy of installing it into the projected position and increased reliability due to lowering of the resultant stress in the superstructure during replacement of the supports. The technique of replacing the supports of the continuous superstructure of the bridge, implemented successively on each support of one superstructure and including construction of a device for temporary support of the superstructure in the form of a concrete pier with a dividing polymer layer for setting of the concrete of the pier with concrete support, and mounting on the pier, a sliding device in the form of a beaming metallic sheet with antifriction material on it. On the surface of the supports on the spots for mounting jacks and temporary support devices, concrete is removed down to the protective layer of the reinforcement. The jacks are mounted on a metallic sheet. The gap between the upper sheets, mounted on the jacks and the superstructure is filled with a plastic material. The jacks are joined to the battery for connection to different pumping stations. Lifting of the superstructure is done for a value not more than 10 to 15 mm, after which it is remounted on the device for temporal support. By removing the jacks, the old supports are removed. The superstructure is then raised on the jacks again and extra metallic sheets are cleared. The superstructure is lowered into the projected position. After mounting the new supports and strength gain of the plastic material in the gaps, the superstructure is raised, and the device for temporal support is dismantled.

EFFECT: increased effectiveness of replacing supports of a continuous superstructure of a bridge.

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Description

The invention relates to the field of reconstruction of existing bridges with reinforced concrete span continuous structure. As a result of operation, defective or damaged support parts under the span of the existing bridge can cause a change in the static structure of the structure and, thus, significantly change the working conditions of both the span and the supports for which they were designed during design. The need to replace the supporting parts on the existing bridge of the old building can be predetermined due to a change in the class of existing loads.

There is a method of replacing the supporting parts of the span, carried out by a device including a hydraulic cylinder and vertical movement elements, which are made in the form of support struts and a traverse with flexible rods, while the racks are placed symmetrically relative to the supporting sections of the beams, and their upper ends are passed through the holes formed in the beams and interconnected by a cross member, the hydraulic cylinder being placed between the crossbeam and the cross member, and flexible rods connected to the beams for lifting the beams (USSR Patent No. 1823892, 1993).

The closest known method is the replacement of the bridge support parts, carried out by a device including a lower support plate anchored in the support head or crossbar, an upper support plate with a new support part installed on it, and a lifting device located between the upper and lower support plates, the lower and upper base plates are equipped with retainer rings, and the lifting device is made in the form of high-strength bolts having threads fixed with the help of retainer rings on the lower base plate in the upper part, and nuts screwed in on them, extended in height, onto which, through the locking rings, vertically movably support the upper support plate, which, when the nuts rotate, interacts through the new support part with the lower surface of the span beam, and if the beam is located span on a longitudinal slope of more than 1%, a new supporting part is provided with a wedge-shaped gasket, the upper surface of which is combined with the lower surface of the span using a binder, e.g. Imer epoxy adhesive (RF №425 U1 Patent, 2004).

Known methods for replacing the supporting parts of the bridge are quite laborious, they do not allow to carry out technological operations without causing damage to the span during its lifting.

The objective of this technical solution is to increase the efficiency of work on replacing the supporting parts of a continuous bridge span by ensuring the accuracy of its installation in the design position and increasing reliability by reducing the stresses arising when replacing the supporting parts of the span.

This is achieved by the fact that in the method of replacing the supporting parts of a continuous bridge span, carried out alternately on each support of one span, including the construction of a device for temporarily supporting the span in the form of a reinforced concrete pedestal with a dividing polymer film to prevent the concrete from setting up of the pedestal with concrete supports and placement on the pedestal of the sliding device in the form of a polished metal sheet with antifriction material laid on it, while on the surface of the support in The installation of jacks and temporary supporting devices removes concrete of the existing structure to the reinforcing layer of the reinforcement, the jacks are installed on a metal sheet, the gap between the upper supporting devices and the span is filled with a mortar, which is used as a cement mortar with plasticizing additives , for example, C3, the jacks are combined into batteries by connecting to different pumping stations, the span is lifted by an amount not greater e 10-15 mm, after which they are supported by temporary supports, turning off the jacks, removing the old supporting parts freed from the load, the span is again lifted on the jacks and the additional metal sheets are removed, after which the span is lowered to the design position, and after installation new supporting parts and a set of strength of the solution in the gaps, the span is lifted and the sliding devices are dismantled.

The invention is illustrated by drawings, where:

figure 1 presents the layout of blocks of hydraulic jacks;

figure 2 - position before the rise of the span, intermediate supports;

figure 3 - position with a raised span, intermediate supports;

figure 4 - diagram of the installation of the jack on the existing support;

figure 5 - installation of sliding devices on a temporary support;

figure 6 - temporary support.

The road bridge is a four-span continuous bridge structure with a total length of 492 m, has a scheme (92.9 + 85.3 + 150.0 + 150.0 + 85.5 + 92.5) m.

The abutments (supports) of the gantry type have openers and cupboard walls made of precast concrete. The intermediate supports have a massive base and support body, the surface of which is lined with reinforced concrete slabs.

The bridge consists of two parallel continuous continuous reinforced concrete spans with V-shaped struts (girths) above the intermediate supports. Each span in cross section contains two boxes. On the intermediate supports, the girths are joined by rigid diaphragms. The axes of the intermediate supports make an angle of 75 ° with the axis of the span (see figure 2 and 3). The organization and methods of production of work on the replacement of supporting parts require a minimum time for closing the movement.

The combined statically indeterminate asymmetric bridge system required a complex calculation that takes into account the different load distribution between the supporting parts under different girths of one span. The replacement of the supporting parts was carried out alternately on each support of one span. When replacing the supporting parts, hydraulic jacks with a carrying capacity of 1750 tons and a height of 319 mm were used. Due to the fact that the cross section of the span is asymmetric, in accordance with this, the support reactions under different cinch of the same span are different, the jacks were combined into batteries and batteries from jacks under different cinch were connected to different pumping stations. To be able to continuously monitor the elevation of the span with high accuracy, manual pumping stations were used. Raising the span on one support was carried out using 12 jacks, connected by six jacks to one pump station.

To temporarily support the span during the replacement of the supporting parts, a temporary device was constructed consisting of a reinforced concrete pedestal and a sliding device. The stand was concreted in place through a polyethylene film to prevent the concrete from setting on the stand with the concrete support.

For the possibility of free movement of the span when changing the temperature of the outside air, a sliding device was arranged on the pedestal.

The slide device consisted of a polished sheet with slip cards laid on it with anti-friction material, for example, naphthene. The main objective of the preparatory work was to ensure uniform load transfer from the supporting parts to the jacks and from the jacks to temporary bearing devices. To do this, on the surface of the support in the places of installation of jacks and temporary devices supporting the span, a part of the loose layer of concrete of the support was cut down (to the protective layer of the reinforcement). The placement of reinforced concrete pedestals was carried out locally in such a way that the top of the supporting sheets did not go out of the dimensions of the girth spans and that the sub-trusses were not located on the facing blocks of the support. Jacks were mounted on dry cement preparation through plywood and metal sheet gaskets. The gap between the top sheets on the jacks and temporary bearing devices and the span was filled with a solution. The upper sheets on the pins were attached to the bottom of the span in order to avoid "sticking" of the solution from the span.

Using jacks, the span is simultaneously lifted by a value that excludes the disclosure of seams and joints, not more than 10-15 mm. Additional metal sheets are laid in the gap between the uppermost sheet and the bottom sheet of temporary supporting devices. The jacks are turned off and the span is supported by temporary bearing devices. Next, work is carried out to replace the supporting parts - cutting down from under the old concrete supporting parts of the old sub-trusses sequentially and symmetrically for the left and right half of the span. To facilitate concrete cutting, first select a place in the horizontal plane with minimal reinforcement (between horizontal reinforcing meshes) and then, using an electric drill with a diamond tip, form holes from the middle of the sub-fermenter to the edges. The concrete lintels remaining after drilling are removed using jackhammers.

Next, the old supporting parts are freed from the load. The span is lifted on the jacks and additional metal sheets are removed. The span is lowered to the design position.

They clean and repair the supporting surface of the span cinch with a mortar, and permanent sub-trusses are detonating. Their surface is leveled with a solution. After the design strength has been set with concrete, new sub-fermenters install new supporting parts. Next, a gap is filled under pressure between the support part and the areas of its support by the solution.

After the installation of the supporting parts and the set of design strength by the sub-trusses and the solution in the gaps, the span is lifted and the sliding device is dismantled. The span is lowered to new supporting parts. Dismantle all temporary devices.

Claims (1)

The method of replacing the supporting parts of a continuous bridge span, carried out alternately on each support of one span and comprising the construction of a device for temporarily supporting the span in the form of a reinforced concrete pedestal with a dividing polymer film to prevent concrete from setting up on the pedestal with concrete support and a sliding device placed on the pedestal in the form polished metal sheet with antifriction material laid on it, while on the surface of the support in the places where the jacks are installed and temporary abutment devices, concrete of the existing construction is removed to the reinforcing layer of the reinforcement, the jacks are installed on a metal sheet, the gap between the upper sheets placed on the jacks and the span is filled with a solution, the jacks are combined into batteries by connecting to different pumping stations, the span is lifted a value of not more than 10-15 mm, after which they are re-mounted on devices for temporary support, turning off the jacks, remove the old reference hours freed from the load Then, the span is again lifted on the jacks and additional metal sheets are removed, after which the span is lowered to the design position, and after the installation of new supporting parts and the strength of the solution in the gaps, the span is lifted and the devices for temporary support are dismantled.

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