RU165499U1 - FRAMES AND STAIN SUPPORT WITH SHADOW-SHAPED SUMMARY OF THE TEMPORARY BRIDGE - Google Patents

Abstract

A frame-and-bed support with a shade-forming canopy of the temporary bridge, consisting of a frame superstructure, a lay foundation, and a shade-forming canopy, characterized in that the lay foundation is placed on an earth cushion, which is arranged on a geotextile panel laid directly on the shaggy cover.

Description

The utility model (hereinafter referred to as the PM) refers to the construction of temporary (with a service life of up to 5 years) road bridges. In particular, it can be used for the construction of supports for temporary road bridges on permafrost soils, used as a foundation according to principle I, requiring the preservation of permafrost soil in the frozen state during the entire period of operation of the bridge [1 and 2].

Such supports should be arranged on dry lands outside the channels of constant and periodic watercourses, as water has, as you know, a warming effect on permafrost soils, contributing to an increase in their temperature and, as a result, a decrease in bearing capacity.

Temporary bridges, as you know, are arranged on temporary, including highways and military roads, as well as on the detours of the destroyed sections of capital roads with bridges and in other cases.

Known design "Bridge support with a shade-forming canopy for permafrost soils" (RF patent for PM No. 52604 from 04/10/2006) [3]

The specified support is taken as a prototype of the proposed PM.

The disadvantage of this support is the need to perform drilling operations for the installation of wells under the foundation of bored (or drilling) wooden piles. At the same time, the depth of the wells should ensure the placement of the lower ends of the piles in the thickness of the permafrost soil, which, as is known, has a high bearing capacity in the frozen state.

Drilling wells, as well as moving heavy drilling and crane equipment around and around the site, can lead to a violation of the integrity of the vegetative cover, which can lead to an increase in the temperature of permafrost soil.

The technical task of PM is to create a frame-and-bed support with a shadow-forming canopy of a temporary bridge with a surface foundation on permafrost soils, used as a base in a frozen state.

The specified technical problem is solved due to the fact that the frame-and-bed support with a shadow-forming canopy of the temporary bridge, consisting of a frame superstructure, a lay foundation and a shadow-forming canopy, is characterized in that the lay foundation is placed on an earth cushion, which is arranged on a geotextile fabric laid directly on mossy cover.

The design of the PM is shown in the figure, where it is indicated:

FIG. 1 is a view of the support across the axis of the bridge; FIG. 2 - view of the support along the facade of the bridge; pos 1 - frame superstructure of the support; Pos 2. - shade-forming canopy; pos. 3 - lay; pos. 4 - soil cushion; 5 - geotextile.

PM is arranged in the following technological sequence.

At the location of the support, a geotextile cloth 5 is laid. A pillow 4 is arranged on it, as a rule, from large-fragmented unfrozen (thawed) soil (stone, rock mass, gravel, gravel, etc.). Pillow 4 should be a height within 1 m or more. It should be sealed with rammers or other other mechanical means to the design density. The upper platform of the pillow should be larger than the size of the laying foundation in all directions for at least 1 m. In winter, the area under the pillow should be cleared of snow (and ice). Its dimensions should exceed the size of the sole of the pillow 4 in all directions at least 2 meters.

On the prepared pillow 4 are laid 3 of logs (logs, sleepers and other materials). The number of beds, their sizes are determined by calculation in accordance with the requirements of SNiP 2.05.03-84 Bridges and pipes [4] and “Technical conditions for the design of military road bridges and crossings (TUVAM)” [5 Ch. 2]. It is advisable to previously combine the stubs 3 into blocks for laying them in place by cranes.

Then, on the bed 3, a frame superstructure 1 made outside the pillow 4 is installed in a assembled form or mounted from blocks. The superstructure 1 is attached to the rods by 3 pins against its displacement when horizontal (braking) forces are applied to the support.

The last operation is the device on the beds around the superstructure 1 shade canopy 2. The surface of the canopy must be continuous with the obligatory coating of its waterproof material. The canopy should be given a downward slope for water to drain from rains and snow melt. If the support is located on a slope, then from the top side it is advisable to arrange drainage rollers from the ground (for example, clay) or from lying logs to protect the pillows from flooding. The length of the rollers (logs) must exceed the length of the canopy on both sides by at least two meters.

Shade-forming canopy (TON) is essentially a constructive all-weather measure for intermediate supports of temporary bridges, designed to keep permafrost in the frozen state, used as the base of bridge supports according to principle I.

Its effectiveness is as follows.

In the warm period, it obscures the surface of the soil around the support, thereby reducing the depth of thawing of the active layer. In the cold season (usually lasting 7-9 months in the permafrost zone), the canopy keeps the snow on itself, providing a bare surface around the support, contributing to this deeper freezing of the soil of the active layer and lowering the temperature of permafrost in its upper layers. The canopy should count on snow load.

The overall result of the installation of the canopy is not only the preservation of the frozen state of permafrost, but also a gradual increase in its upper boundary. As a result, the high bearing capacity of permafrost soil used as a base in the frozen state according to principle I is maintained.

Thus, the proposed PM allows the use of permafrost soils in a frozen state during the entire period of operation of a temporary road bridge due to the installation of a lay foundation on an earth cushion and a shadow-forming (snow-holding) canopy.

Literature

1. SNiP 2.02.04. Foundations and foundations on permafrost soils

2. JV 32-101-95 Design and construction of foundations of bridge supports in areas of permafrost distribution.

3. RF patent for a utility model. “A bridge support with a shade-forming canopy for permafrost soils” (No. 52604 of 04/10/2006)

4. SNiP 2.05.03-84 Bridges and pipes

5. Technical conditions for the design of military road bridges and crossings (TUVAM) M. 1974

Claims (1)

A frame-and-bed support with a shade-forming canopy of the temporary bridge, consisting of a frame superstructure, a lay foundation, and a shade-forming canopy, characterized in that the lay foundation is placed on an earth cushion, which is arranged on a geotextile panel laid directly on the shaggy cover.

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