RU2263176C1 - Protective case for bridge pier grillage and erection method thereof - Google Patents

Abstract

FIELD: bridge building, particularly ice-resistant structures built on pile foundations and piers erected in rivers with variable ice drift level and overhead transmission line poles adapted to cross watercourses.

SUBSTANCE: protective case comprises composite horizontal three-dimensional blocks having orifices in central parts thereof and fastening members which connect the blocks one to another. Each orifice is formed of metal member, which defines cavity for pile installation. Lower block is provided with pile guiding cells arranged in lower part of block cavity. The metal members have welded joints. Method of grillage erection involves assembling case of building members, namely blocks, which are lowered and laid one onto another along guiding means; connecting blocks one to another as they are laid with fastening members. The case is assembled above water body surface and then is lowered in water to design level. Vertical piles previously driven in water body bottom through guiding cells of lower block are used as the guiding means for case lowering in water.

EFFECT: increased reliability and service life, as well as improved load-bearing capacity of the grillage along with reduced costs for grillage structure fabrication, assemblage and simplified erection.

7 cl, 9 dwg

Description

The invention relates to bridge construction, in particular, to the construction of ice-resistant structures on pile foundations and supports constructed on rivers with a variable level of ice flow. The invention can also be used in the construction of towers of overhead power lines at crossings through waterways.

Known bridge support containing a monolithic high grillage, to which is attached with gaps a team of blocks of vertical reinforced concrete wall with the formation of a cavity for placing piles and designed to protect piles from ice drift and other floating objects. (Way and construction of railways. - Express information. - M.: VNITI, 1974, - No. 22. - P.28-30).

However, this design of the support grill is not reliable enough, it does not allow to reduce the thickness of the ice in the cavity due to the location of the blocks in the wall with gaps, which does not allow to achieve a milder microclimate in the cavity and thereby reduce the pressure of the internal ice on the enclosing wall. This design is acceptable mainly for the climatic conditions of Western Europe.

Known bridge support containing two separate grillages, installed one after the other with long diagonals along the river with a gap throughout the height and connected to each other by a spacer installed above the level of high ice drift, each grillage made in a diamond-shaped plan, and at the junction an elastic waterproof and frost-resistant gasket is installed between the strut and grillages, while the internal cavity of each ice-protective shell is divided into sections by continuous diaphragms-ties such that in the bow and stern sections of the shells one pile is located, and in the intermediate two, the diaphragms-screeds are installed with a horizontal air gap relative to the bottom of the grillage plate, while the lower end is constantly immersed in water (RF Patent No. 2099467, IPC E 01 D 19/02, E 02 D 27/12).

This invention provides constructive solutions that increase the strength of the shell, as well as creating a milder microclimate in its cavity compared to the external environment and air circulation from section to section. This limits the increase in the thickness of the inner ice and helps to reduce its pressure on the walls of the shell.

However, this grillage structure does not allow increasing its bearing capacity, especially in soft soils, due to the impossibility of using more piles in it. In addition, the construction process of this grillage is complex, requires significant labor and material costs.

An ice protection fence of a bridge support with a monolithic slab of a pile grillage is known, including a reinforced concrete vertical protective wall made of blocks, reinforced with a top face along the contour in a monolithic slab of a support, and a reinforced concrete slab vertically located along the longitudinal axis of the support, rigidly fixed with an upper face in a monolithic slab of a grill and the upper end face - in the facade block of the protective wall from its inner side. The protective wall blocks are made on the inside with a thickening in their upper part (AS USSR No. 1032085, IPC E 01 D 19/02).

However, this design is not reliable enough, because the side walls are made in the form of consoles - without diaphragms or lower struts, and is characterized by significant overall dimensions, which complicates the installation work.

Known bridge support, built on rivers with ice drift and a variable level of water flow, mainly in areas with severe climatic conditions. The support contains a bush of piles of a high grillage located at a variable level of water and ice drift and an ice-protective envelope that surrounds them, repeating the grillage plate in appearance. Piles are placed in a plan along a single closed line forming the outline of the internal cavity, and the ice-protective shell is made of variable height, increasing smoothly or stepwise in the direction of the flow so that the height from the lower edge of the stern (lower) part is greater than the height of the lower edge of the bow (upper) part shell on the value of 0.25-0.5 of its largest diameter. In this case, the ice-protective shell is combined with the piles in such a way that its inner vertical surface enters the cavity between the piles of at least 1/4 and no more than 1/3 of the diameter of the pile (RF Patent No. 2209870, IPC E 01 D 19/14).

This design is more reliable and durable by reducing internal ice formation in the shell cavity. However, its construction requires high precision immersion piles.

Closest to the claimed device is a protective sheath grill bridge support, consisting of prefabricated volumetric horizontal blocks with holes in the Central part and on the periphery and the mounting elements of the blocks together (Patent No. 2063497, IPC E 02 D 27/12, 29/09).

However, this design is not sufficiently reliable and difficult to implement, including due to structurally complicated elements of fastening blocks to each other, locking spontaneously under water.

Closest to the claimed method is the construction of the foundation, including the assembly of the shell from building elements, lowered one on top of the other from the bottom of the water area to the level of its surface along the guides located around the perimeter of the support shell, drilling wells in the ground through the cavity of the support shell and filling them with structural material . Cables are used as guides, the upper ends of which are fixed on a conductor held by two floating cranes above the water surface, and the building elements are pulled together by locking elements (Patent No. 2063497, IPC E 02 D 27/12, 29/09).

This method is characterized by complexity in implementation and requires at least three floating cranes, which leads to a significant increase in the cost of the process of constructing the shell of the support. Complicated quality control of installation work of the underwater shell.

The objective of the invention is to increase the reliability, durability of the shell structure, increase the bearing capacity of the grillage while reducing the cost of manufacturing and installation of the structure and simplifying the process of its construction.

An increase in the bearing capacity of a high grillage is achieved due to the possibility of using driven piles, especially in soft soils, while protecting the bridge support from a pile of ice and ships. The inventive method allows to simplify the construction and installation processes of the construction of the grillage, reduce labor costs and construction time.

The problem is solved in that in the protective sheath of the bridge support grillage, consisting of prefabricated horizontal blocks made three-dimensional with holes in the central part, and fastening elements of the blocks together, according to the invention, the hole in each block is formed by a metal cavity-forming element with the possibility of placing piles, and the lower block is equipped with guides for piles cells, while the cavity-forming elements are welded.

The cavity-forming element is made of steel and equipped with external anchors to ensure collaboration with the concrete block. Some of the fastening elements of the blocks can be made in the form of rod ties fixed in the body of the lower block, and the upper blocks are equipped with channels for skipping them, while the number of rod ties in each block is at least 6, four of which are located in the longitudinal plane, and two are transverse diagonals. Guide cells for piles are formed by steel transverse-longitudinal beams located in the lower part of the cavity of the block with the possibility of ensuring structural rigidity. One of the options for the execution of the volume unit in the plan is a diamond shape with rounded corners.

The shear strength of the structure is ensured by the implementation of the cavity-forming elements of the blocks protruding beyond their upper edge, and the upper blocks indented from the lower edge equal to the protrusion of the cavity-forming element associated with the block, while the protrusion is not less than 100 mm, and the indentation is not more than 100 mm.

The problem is also solved by the fact that in the method of erecting a grillage with prefabricated protective shells in the water area, including assembling the shell from building elements - blocks, lowered one on top of the other along the rails, while the blocks are pulled together by locking elements as they lower, according to the invention, the assembly of the shell from blocks they are carried out over the surface of the water area, which is then immersed in the water area at the design level, while vertical piles, previously submerged through ulation cell in the waters of the ground.

The invention is illustrated by drawings, where in Fig.1 shows a General view of a high grillage with a two-row arrangement of precast blocks; figure 2 is a section aa in figure 1, figure 3 is a view of figure 1 in plan; figure 4 is a node pair plate grillage with a pile and cavity-forming element; vertical dashed lines show the reinforcing bar outlets made of concrete piles and the upper block of the containment; 5 is a General view of a high grillage, for example, with a three-row arrangement of prefabricated blocks, a view across the bridge in FIG. 6 is a view of the support of FIG. 5 from the facade; Fig.7 is a General view of the protective shell before immersion in the water; in FIG. 8 is a section BB in FIG. 7; figure 9 is a General view of the protective shell, immersed in the water at the design level.

The positions in the figures indicate: 1-3 blocks of the protective sheath of the grillage, 4 - cavity-forming element, 5 - guide cells of the block 1, 6-9 fasteners (6 - insert bolt, 7 - pin, 8 - coupling, 9 - nut with washer) 10 - channels in the upper blocks, 11 - vertical piles, 12 - removable guide, 13 - inclined piles, 14 - pallet, 15 - grillage plate, 16 - support body, 17 - lighthouse pile, 18 - crossbar, 19 - scaffolds, 20 - hydraulic lift.

The protective shell of the high bridge bridge grillage consists of prefabricated horizontal reinforced concrete blocks 1-3 (Figs. 1, 5, 6), each of which is made with a central cavity-forming element 4, which is equipped with external anchors that ensure the joint operation of the element 4 with the concrete of the block. Element 4 performs the functions of formwork and reinforcing cage of the cavity of the block during manufacture and is one of the main supporting elements of the protective shell during operation of the support. The number of blocks and their height are determined depending on the amplitude of the fluctuation in the levels of ice flow in the water area and the capacity of the assembly floating crane. The upper block is connected to the grill plate 15 by means of reinforcing outlets from the concrete block. The lower block 1 is equipped with guide cells 5 (figure 1) located in the lower part of its cavity on the periphery. Guide cells 5 are formed by longitudinal and transverse steel beams. Blocks 1, 2, 3 are interconnected by fasteners 6-9 (Fig. 1,5), while in block 1 embedded bolts 6 are placed, and subsequent blocks are equipped with channels 10 (Fig. 4) for accommodating bolts 6 or studs 7 with couplings 8. For tightening the blocks between each other, nuts with washers 9 are used. When carrying out installation work, a removable guide 12 is used, made in the form of longitudinal and transverse beams fixed in a steel ring (Fig. 8). Four peripheral cells are intended for vertical piles 11 and four central ones for inclined piles 13. A removable guide 12 is attached to the protrusion of the cavity-forming element 4 of the upper block adjacent to the grill plate 15.

The volumetric block can be made on the outer contour oval or diamond-shaped with rounded corners. In this case, the optimal block size is determined from the ratio:

ak = b, where a is the length of the longitudinal diagonal of the block; b is the length of the transverse diagonal of the block, k is a coefficient equal to 0.6-0.7;

b = d + 2δ, where d is the diameter of the cavity-forming element; δ is the block wall thickness in cross section, with δ <40 cm.

The constructive implementation of the bridge support grillage with a protective shell covering the pile bush allows maintaining a microclimate in the shell cavity, which excludes the increase in ice thickness and ice solders to structures by using the thermal conductivity of the pile material and the cavity-forming element. The presence of block guide cells in the cavity, in its lower part, gives the structure additional rigidity. This minimizes the transverse dimensions of the side walls (δ) to 40 cm.

The manufacture of containment blocks is recommended at the construction site of the bridge, for example, in a temporary workshop. First, a block 1 is prepared, with embedded bolts 6 and a cavity-forming element 4, to which external rod anchors and internal guide cells 5 for piles 11, 13 are pre-welded. In this case, embedded bolts with a length exceeding the height of block 2 by 130-150 mm are used, on which polypropylene pipes are strung to insure channels with a diameter of 80-90 mm.

After the concrete block 1 has set the required strength on the protrusion of its cavity-forming element, a similar element 4 of the next block is mounted to it. Before concreting of block 2, the upper face of block 1 is covered with a black plastic film to prevent adhesion of materials of blocks 1 and 2, and the protrusion of element 4 from block 2 is isolated. After a set of concrete block 2 of a given strength, it is removed and the channel-forming pipes are removed. Then, on block 2, the next block 3 (etc.) is concreted in a similar manner. Moreover, the channels 10 in subsequent blocks are formed using studs 7 and couplings 8 of the same pipes. The length of the stud should correspond to the height of the manufactured block.

The method of construction of the proposed high grillage is as follows.

In the water area for the construction of the grillage, scaffolds 19 are mounted, for example, on lighthouse piles 17 surrounded by crossbars 18 (Figs. 7, 8), which are mounted on pontoons or a catamaran is placed at the place of work. On the platform 19 using a floating crane install block 1 in the axes of the support. A layer of cast polymer concrete 5-6 mm thick is applied to the surface of block 1 to compensate for the shrinkage of concrete blocks, then block 2 is installed by stringing channels 10 onto bolts 6. Then the channels 10 are filled with molded polymer concrete, and each bolt 6 is strained by tightening the nuts 9. Cavity-forming elements 4 are connected by a continuous weld. In the case of assembling a shell of three or more blocks, when connecting them, studs 7 with couplings 8 are also used, and the couplings 8 are screwed onto the ends of the bolts 6 protruding above the nut 9. The bolts 6 and the studs 7 are strained in order to achieve a high density of the horizontal joint between the blocks. The total force of the tension of the bolts 6 (studs 7) in tons should exceed the mounting mass of the protective shell by 5-10%.

After the protective sheath is assembled, a removable guide 12 is mounted on the protrusion of the cavity-forming element 4 of the upper block, through which four vertical piles 11 are immersed, two of which are cut in a predetermined level in the plane of the longitudinal diagonal of the protective sheath. A hydraulic elevator 20 is mounted on the cut piles, with the help of which the protective shell is immersed in the water at the design elevation below the low-water level (UWW). Then cut the two remaining piles at the design level with the appropriate preparation of their heads and attach a protective sheath to them. Then dismantle the elevator 20 and secure the protective shell to the piles freed from it. Then inclined piles 13 are immersed through the guides, which, after immersion, are cut at the design level also with the appropriate preparation of their heads. The upper guide 12 is removed for reuse. The connection plate 15 grillage and the upper block of the shell is carried out by their monolithic. Why in the cavity of the upper block above the water level mount the pallet 14 (Fig. 4) and concrete the cavity above the pallet simultaneously with the plate 15 grillage dry above the working water level (RUV). In addition, reinforcing outlets from the upper block of the containment are involved in monopolization.

The proposed solution of a high grillage can be feasible using either driven reinforced concrete hollow piles with a diameter of 0.6 m, or concrete pipes with a diameter of up to 1.2 m, or bored piles, and the supports can be rack-mountable, massive, or combined. The support in the form of two racks on a grillage with reinforced concrete hollow piles is applicable for bridges with steel-reinforced concrete, steel and reinforced concrete box-shaped spans for two-lane traffic or single-track railway bridges.

With a large depth of the water area, for example, 8 or more meters from the low-water level, and a large amplitude, fluctuations in the levels of ice drift in high grillages use bored piles, for example, with steel shells or driven pipe-concrete piles. These piles are used mainly for long-span combined, urban, multi-lane road or double-track railway bridges. The proposed grillage can be built using one pile of piles with a single protective sheath made of prefabricated blocks (or several such grillages connected by spacers) for a one-pillar support with a developed head.

Claims (7)

1. The protective sheath of the bridge support grillage, consisting of prefabricated horizontal blocks made volumetric with holes in the central part, and fastening elements of the blocks together, characterized in that the hole in each block is formed by a metal cavity-forming element with the possibility of placing piles, and the lower block is equipped with guide cells for piles located in the lower part of its cavity, while the cavity-forming elements are welded. 2. The protective shell according to claim 1, characterized in that the cavity-forming element is made of steel and equipped with external anchors to ensure collaboration with the concrete block. 3. The protective shell according to claim 1, characterized in that some of the fastening elements of the blocks are made in the form of rod ties fixed in the body of the lower block, and the upper blocks are equipped with channels for skipping them, and the number of rod ties in each block is at least 6, four of which are located in the plane of the longitudinal diagonal and two in the transverse diagonal. 4. The protective shell according to claim 1, characterized in that the cells are formed by steel transverse-longitudinal beams located in the lower part of the cavity of the block with the possibility of ensuring structural rigidity. 5. The protective shell according to claim 1, characterized in that the volumetric block along the outer contour in plan has a diamond shape with rounded corners, while the dimensions of the block are selected from the relation ak = b, where a is the length of the longitudinal diagonal, b is the length of the transverse diagonal , k is a coefficient equal to 0.6-0.7, b = d + 2δ, where d is the diameter of the cavity-forming element, δ is the block wall thickness in cross section, and the quantity δ <40 cm. 6. The protective shell according to claim 1, characterized in that the cavity-forming element of the lower block of the shell is made protruding beyond its upper face flush with the lower face of the following blocks with a protrusion above the upper face and indentation relative to the lower face of the block, while the protrusion is not less than 100 mm, and indentation no more than 100 mm. 7. A method of erecting a grillage with prefabricated protective shells in the water area, including assembling the shell from building elements - blocks, lowered one on top of the other along the guides, while the blocks are pulled together by locking elements, characterized in that the shell assembly from the blocks is carried out above the surface of the water area , which is then immersed in the water area at the design level, while vertical piles preliminarily immersed through the guide cells of the bottom are used as guides for immersing the shell his unit in the waters of the ground.

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