Prefabricated reinforced concrete pipes, depending on the cross-section, are divided into round cylindrical, round with a flat base heel, rectangular and ovoidal (Fig. 7.4).
Round culverts used at a height of an embankment, mainly no more than 8 m. Round pipe links under railway embankments rest on shallow or deep foundations, prefabricated, prefabricated-monolithic or monolithic. The construction of the pipe foundation depends on the bearing capacity of the foundation soil. prefabricated reinforced concrete pipes: a - round, rectangular and ovoidal, fig. 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
When a round cylindrical link rests on a flat foundation, a curved block is used (Fig. 7.5).
Reinforcement cage of round links consists of two rows (external and internal) of working spiral reinforcement, transverse reinforcement - clamps, as well as distribution longitudinal reinforcement (Fig. 7.6).
Rice. 7.6. Scheme of the reinforcement cage of a circular pipe for a link with a length of 1 m: a- cross section; b- view 1-1 and facade; v- spiral; d k- frame diameter; d H k , d B k- diameter of the location of the outer and inner spirals
The reinforcement cage consists of the same number of spirals located along the outer and inner contours of the link, which is determined by calculation. The Lengiprotransmost Design Institute has developed the following standard designs for reinforced concrete pipes of circular cross-section:
№GS 3.501.1-144- round reinforced concrete culverts for railways and highways;
№GS 3.501.1-144. Issue 0-1. Inv. No. 1313/2- round reinforced concrete culverts with flat support for railways in normal climatic conditions.
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Rice. 7.7. Reinforcement scheme for a round link with a flat base: a- cross section; b- view along the pipe axis; d sq. ,
d book- diameters of inner and outer frames
Links round pipes with flat base have a more economical reinforcement, the diagram of which, according to the development of Lengiprotransmost, is shown in Fig. 7.7.
The design of the inlet and outlet heads reinforced concrete round pipes from the unification condition are assumed to be the same. Heads consist of sloping walls (wings), located at an angle to the pipe axis, and portal walls (Fig. 7.8).
Reinforcing frame of sloping wings made of nets (Figure 7.9).
Rice. 7.8. Round tube head design: a- facade; b - section along the pipe axis; v - plan (embankment not shown); 1 - conical link; 2 - portal wall, 3 - slope wall; 4 - pattern block; 5 - foundation
Rice. 7.9. The design of the reinforcement cage of the sloped wings of the head of the round pipe: a - facade; b - plan
The sloping walls of the heads are installed on reinforced concrete slabs laid on crushed stone or gravel-sand preparation. Between the sloping wings, place a concrete tray on a gravel-sand preparation (see Fig. 7.8).
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Rice. 7.10. Diagram of a section of a rectangular reinforced concrete pipe: a- cross section; b- cut along the pipe axis
The typical design provides for an increase in elevated links by 0.5 m in comparison with the normal ones. The following standard projects of prefabricated reinforced concrete pipes of rectangular section have been developed:
№GS 3.501-177.93- Reinforced concrete rectangular culverts for railways and highways (JSC Transmost, 1994);
№GS 3.501-177.93. Issue 0-2- rectangular pipes for railways in moderate and severe climatic conditions (JSC Transmost, 1994);
№GS 3.501-107. Inv. No. 1130 / 1,2- rectangular concrete culverts for railways and highways.
Reinforcement cage of a rectangular pipe link includes meshes, consisting of working and distribution fittings, located along the outer and inner contours, taking into account the provision of a protective layer of concrete, which are combined using clamps (Fig. 7.11).
Rice. 7.11. Reinforcement cage diagram of a rectangular link: a- cross section; b- view along the pipe axis
In the middle part of typical pipe structures, the length of the sections is 2.01 and 3.02 m. The links rest on the foundation over a layer of cement mortar. The foundations of the sections can be monolithic, prefabricated reinforced concrete or from concrete blocks, shallow or deep. An expansion joint with a thickness of 3 cm is arranged between the sections.
In reinforced concrete pipes of rectangular cross-section, they use bell heads with sloping wings located at an angle of at least 20 about (Fig. 7.12).
On railways built in areas with harsh climatic conditions, the most widespread are rectangular reinforced concrete and concrete culverts. Currently, standard projects of rectangular pipes have been developed for harsh climatic conditions:
№GS 3.501.1-177.93. Issue 0-3. Pipes for railways and highways in particularly harsh climatic conditions. (JSC Transmost, 1994);
№GS 3.501-65. Inv. No. 1016... Culverts for railways and highways at a design temperature of minus 40 ° C and below, deep seasonal freezing and ice formation. Rectangular concrete pipes. (Lengiprotransmost, 1976).
Rice. 7.12. Design of the outlet head of a rectangular pipe: a - facade; b - section along the pipe axis; v - plan (embankment not shown)
Links reinforced concrete rectangular pipes used with a hole from 1.5 to 6.0 m. They rely on precast-monolithic foundations, consisting of precast reinforced concrete blocks L- or T-shaped (Fig. 7.13, 7.14) and monolithic concrete, as well as deep foundations on piles and pillars (Fig. 7.15, 7.16).
Rice. 7.13. Rectangular reinforced concrete pipe with L-shaped and T-shaped foundations: a - section cross-section; b- head facade
Rice. 7.15. Rectangular reinforced concrete pipe with foundations on piles and pillars: a - head; b, c - section cross-section
Rice. 7.16. General view of a rectangular reinforced concrete pipe with foundations on piles
Concrete rectangular pipe structures they are used with an opening from 1.5 to 6.0 m, which provide a cultivation capacity of up to 150 m 3 / s. The middle sections of pipes are 3-4 m long. The structures of such pipes consist of reinforced concrete floor slabs, concrete wall blocks, nozzles, a tray and a foundation (Fig. 7.16, 7.17). Pipes with a hole of 1.5–3.0 m have solid foundations, and the rest are separate on a natural foundation, monolithic, prefabricated, as well as deep-laid on piles or pillars. The trays are concreted using sand preparation. The pipes have bell heads with increased inlet and normal outlet links.
Typical concrete culverts have similar foundations as reinforced concrete (Fig. 7.17, 7.18).
Rice. 7.17. Rectangular concrete pipes: a, b - section and head cross section; v - with L-shaped and T-shaped foundations
In the typical design of rectangular culverts, foundations from reinforced concrete blocks of L-shaped and T-shaped sections are provided for the depth of freezing of the base soil equal to 2.3 and 4 m.
In harsh climatic conditions, in the presence of thawed and weak soils at the base, the extreme sections and head openings are preferred to be installed on pile foundations (see Fig. 7.16). The use of pile foundations increases the rigidity of the base and protects the pipes from stretch marks. In case of weak foundation soils, it is advisable to use foundations with inclined piles in the extreme sections and openings of the head ends.
When constructing culverts on permafrost soils, they ensure the preservation of the natural regime of the foundation, without disturbing natural conditions. In this case, preference is given to pipes with foundations on drill posts with a diameter of 0.6-0.8 m (see Fig. 7.15, v).
Rice. 7.19. Ovoidal section concrete pipe head design: a - cross section; b- facade; 1 - opening cut; 2 - general form
Concrete and reinforced concrete pipe structures ovoidal section are used with a hole from 1.0 to 3.0 m (Fig. 7.19, 7.20). Reinforced concrete links of ovoidal pipes have reinforcement in the form of closed spirals (Figure 7.21).This type of reinforcing cage ensures reliable operation of the structure, taking into account the full range of loads. All sections of the ovoid tube links work as eccentrically compressed elements.
The use of concrete ovoid pipes can reduce the labor intensity of factory production and the consumption of reinforcing steel. They are used for embankment heights up to 20 m.
Reinforced concrete pipes of ovoidal cross-section are more efficient structures when compared to round structures in terms of reinforcement consumption on average up to 40–45%.
In a monolithic foundation slab, compressive and tensile forces are observed during operation. If concrete easily copes with the first on its own, then reinforcement must be used to compensate for stretching. This structural material increases the tensile strength of the slab base by 10 times. Moreover, the rods must be knitted correctly, in accordance with the standards, according to the reinforcement scheme, lay the nets in two layers with a minimum vertical distance of 10 cm, a protective layer of 3 cm.
The basic requirements for a monolithic slab are given in. They indicate how to correctly position and knit reinforcing mesh, which supports to use to provide the lower protective layer. The use of rods with flaking rust is not allowed.
Bars of periodic section provide high adhesion, knitting wire is more reliable than plastic clamps. However, reinforcement should be started in stages: the choice of a rational scheme, the calculation of the cross-section of the bars, the fixation of the frames in space using special elements.
Reinforcement schemes
Due to the complexity of the calculations and the small dimensions of buildings in low-rise construction, a simplified scheme is recommended. Two nets at a distance of 10 cm vertically with at least the same cells. If the developer wants to save on pouring the slab, the calculation should be ordered by specialists who will calculate the minimum required reinforcement, use thin reinforcement in the center of the foundation, strengthen the perimeter, the places where the internal walls pass.
If the dimensions of the foundation are more than 3 m on either side of the slab, it is recommended to use rods of at least 12 mm. To determine the minimum possible cross-section, the following method is used:
- calculation of the section of the slab - the length multiplied by the thickness (for example, 6 mx 0.3 m);
- calculation of the minimum allowable bar area in the section - the previous figure is divided by the minimum reinforcement percentage (0.3% for B20 concrete, 0.15% for B22.5 grade, 0.1% for B15 grade), for this example 1.8 m2 / 0 , 15 = 27 cm²;
- calculation of the area of reinforcement in each row - the result is divided in half (in the example 27/2 = 13.5 cm²);
- determination of the minimum allowable bar section depending on the grid spacing (13.5 cm² / 31 bars every 20 cm for a 6 m long slab = 0.42 cm²;
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Pipes with flow rates up to 100 m3 / s are the most common type of culverts on highways. For technical and economic reasons and traffic safety conditions (continuity of the carriageway), pipes on roads are preferable to small bridges, especially on road sections with a concave profile. In addition, the presence of soil filling over the pipe ensures a favorable distribution of concentrated pressures from the wheels of cars and reduces their dynamic effect. Only if there is an ice drift and a grubber, pipes cannot be used. The smallest backfill thickness above the links of all types of pipes on highways and city roads is taken equal to 1 m, and when the backfill thickness is less than 1 m, the dynamic coefficient must be taken into account in the calculations of the link design.
Rice. 5. Cross-sections of pipes:
1 - filling; 2 - waterproofing with a slope of 30-40 ° / oo; 3 - tray
Distinguish between free-flow pipes, working as part of the cross-section, and pressure pipes, working with full cross-section in cases where the water inflow is greater than their capacity.
The most widespread are round and rectangular pipes (Fig. 5). At flow rates more than 40 m3 / s, rectangular (sometimes ovondal) are used, as a rule. The culvert has links that make up its body and two heads - inlet and outlet. Links and heads are laid on a rigid or flexible base (Fig. 6). Rigid foundations include stone, concrete, rubble concrete, reinforced concrete monolithic or prefabricated foundations and natural rock foundations. Under favorable soil and hydrological conditions, under pipes of small diameters and an embankment height of up to 7 m, an artificial soil foundation made of a gravel-sand cushion can be used. Pipes with a diameter of 0.5-0.75 m, located under small embankments with gravel-pebble, medium-grained and other reliable soils, are allowed to be laid on a soil bed cleared from the vegetation layer and profiled.
To ensure watertightness, the seams between the pipe links are filled with tow soaked in hot bitumen, and glued on the outside on hot bitumen mastic with two layers of roofing material 25 cm wide.In addition, from the inside, the seams are coined with cement mortar to a depth of 3-4 cm. The outer surface of the pipe is covered with a coating waterproofing consisting of two layers of bitumen mastic.
The most important part of the pipe is the head, which determines its hydraulic properties. Distinguish between portal, collar, bell-shaped and streamlined heads.
Portal heads (Fig. 7, a) in the form of a retaining wall supporting the embankment slope are the simplest in design, but do not provide smooth flow through the pipe opening. They are used 'at low flow rates and low flow rates.
The collar head (Fig. 7.6), which is an extreme link cut off flush with the embankment slope (bordered by a belt - a collar), is more complicated to manufacture than a portal head, also has low hydraulic performance and is used at low flow rates and low flow rates. A bell head (Fig. 7, c) in the form of a portal wall with two diverging flaps, providing better flow conditions, is used in gravity and pressure pipes. A streamlined head (Fig. 7, d) in the form of a truncated pyramid, although difficult to manufacture, nevertheless provides the most favorable conditions for the flow of flow through a pipe that can operate in a flood with a full cross section. Streamlined heads are used mainly for round pressure pipes. In rectangular pipes, the heads are usually of the socket type.
Rice. 6. Trumpet:
a - with a monolithic concrete foundation; b - with a prefabricated foundation made of concrete or reinforced concrete blocks; c - on an artificial sand and gravel base; d - on a natural basis; 1 - strengthening the channel of the stone pavement; 2 - entrance head; 3 - pipe links; 4 - exit head; 5 - strengthening the channel with monolithic concrete; 6 - sand and gravel pastel under the foundation
Rice. 7. Round tube heads:
1 - link in the form of a truncated cone; 2 - link in the form of a truncated pyramid
In order to avoid stagnant water, it is necessary that the mark of the inlet chute under all conditions be higher than the mark of the chute of the middle section of the pipe. In addition, the pipes must be given a building lift, taking into account the fact that the middle links settle more over time than the extreme ones.
The embankment slopes and the channel at the pipe must be reinforced. The greater the depth and speed of the flow, the more powerful reinforcement must be given. Usually, concrete reinforcement is provided at the entrance heads for the channel within the slope wings, and the adjacent parts are reinforced with single paving or sodding. At the exit heads, the channel works in more difficult conditions, therefore it is strengthened more firmly. The embankment slopes at both heads are strengthened to a width of at least 1 m on each side. At the lower heads, the paving is brought to their top, and at the horse-riding ones - 0.25 higher than the level of the water backwater plus the wave run.
The most common on highways are reinforced concrete pipes constructed according to the standard design of unified round reinforced concrete pipes1 with a 0.75 hole; 1.0; 1.25; 1.5 and 2.0 m. The temporary vertical load is taken according to the standard design for links with a hole of 0.5 and 0.75 m - MAZ-525, and for links with a hole of 1.0-2.0 m load N-30 and NK -80. The pipes are provided with and without foundations, depending on the specific engineering and geological conditions.
In the standard design of unified prefabricated culverts, the features of the operation of pipes under road embankments are most fully taken into account.
The most common defect in exploited round reinforced concrete pipes (especially of large diameter) are cracks, which sometimes cause not only deformation of the links in the form of flattening, but also their complete destruction. The crack resistance of the links largely depends on the hardness of the pastel. Coars laid on Rigid concrete foundations have 1.5-1.7 times fewer cracks compared to baseless ones. The use of semi-rigid foundations, which are crushed stone-gravel cushions filled with cement mortar, gives positive results. In 25-30% of the surveyed baseless round pipes, subsidence of the links adjacent to the heads was noted by an amount of 3 to 15 cm. Most often, subsidence occurs in foundationless pipes built in humid regions with harsh climatic conditions.
The reliability of the operation of round pipes largely depends on the quality of the manufacture of their elements and the performance of construction work.
Rectangular reinforced concrete pipes are also arranged, as a rule, with prefabricated ones. Only with a small amount of work, the availability of local materials, and the absence of nearby precast concrete bases does it make sense to erect monolithic pipes or pipes with a precast concrete coating on the monolithic walls of rubble, rubble concrete or concrete. Rectangular pipes are distinguished by the type of links - closed and open (completely prefabricated, consisting of walls, floor slabs and a lower element). The sinuses between the links in the multi-point pipes are filled with a gravel-sand mixture, and under unfavorable conditions, with M-75 concrete. At the inlet and outlet of the pipes, trays made of monolithic concrete of grade 150 are arranged on a sand and gravel base.
The foundations of rectangular pipes are usually made of ready-made blocks laid on a gravel-sand interlayer with a thickness of at least 10 cm. the location of the groundwater level not less than 0.3 m below the gravel-sand base, foundationless pipes can be used. In this case, their links are laid on a gravel-sand layer; waterproofing is done the same as for round pipes. The joints are covered with three layers of insulation: the outer one is made of hot asbestos mastic, the middle one is made of tow impregnated with bitumen, and the inner one is made of cement mortar penetrating into the joint to a depth of 3 cm.All surfaces of the heads that are in contact with the ground are covered with a coating waterproofing.
In a typical project of precast reinforced concrete unified rectangular pipes, holes are provided: 2.0; 2.5; 3.0 and 4.0 m (one-point) and 2X2.0 (Fig. 8); 2 × 2.5; 2X3.0; 2X4.0 m (two-point) with embankments up to 20 m high.In order to increase the culvert capacity of the pipe, three raised links with a height of 2.5 m are provided on the upper side.
Rice. 8. Design of a unified rectangular pipe with a hole of 2 × 20 m:
1 - elevated pipe links at the inlet head; 2 - foundation block of links; 3 - preparation of crushed stone and gravel; 4 - foundation blocks of heads; 5 - concrete tray within the head; 6 - seam; ^ 7 - coated waterproofing
The length of the normal and elevated * links is assumed to be the same - 1.0 m each.Along the length, the pipe is every 3 m, and at the ends - every 2 m, it is divided by sedimentary seams 3 cm wide. round pipes. The links are reinforced with welded frames. Hydraulic concrete M-300. Heads of pipes are bell-shaped, prefabricated; the head consists of flaps and an extreme pipe link with an upper plate thickened in the form of a cornice to stop the embankment slope.
The foundations for these pipes are stiff - prefabricated from reinforced concrete slabs 20 cm thick, as well as ‘monolithic concrete. Foundation slabs with a depth of 0.4 m are laid on a gravel-sand preparation 10 cm thick.Under the extreme pipe links, which are part of the heads, the thickness of the concrete foundation is increased so that its seams are 25 cm below the freezing level.
Lengiprotransmost has developed a standard project for unified concrete prefabricated rectangular pipes with a reinforced concrete slab with a hole 1.5; 2; 3; 4; 5 and 6 m. Material of wall blocks - concrete М-200, floor slabs - concrete М-300 and reinforcement of ВСт.5 and ВСт.З. The foundations are given in two versions of precast concrete blocks and M-200 in-situ concrete. Pipes with hole 1.5; 2 and 3 m are provided on solid foundations, the rest - on separate foundations. The minimum foundation depth for pipes with a hole of 1.5 and 2 m is taken as 1.35 m, and for pipes with a hole of 3 m or more, it is taken depending on the depth of soil freezing.
In 1951-1953 on highways began to use four-hinged round concrete pipes proposed by A.K.Godyna. The stability of the links of these pipes depends mainly on the condition of the backfill adjacent to the side surfaces of the pipe. With high quality construction work and favorable climatic conditions, the pipes work normally for a long time. Analysis of operating experience, tests, as well as survey results allow us to recommend round concrete pipes with four imperfect hinges, holes up to 1.25 m in areas with dry and low-humidity climates, i.e. in IV and V road-climatic zones (SNiP P-D 5-72), when filling from drainage soils and the height of the embankment above the pipe is 0.7-3 m. In this case, special attention should be paid to the technology of compaction of the drainage filling on the sides of the pipe.
For vaults, walls and foundations, pipes with vaults are used on roads relatively rarely and mainly in areas remote from precast concrete bases, and in the presence of local building materials. The opening of stone and concrete pipes reaches 5 m and is usually formed by two massive walls covered with a vault. Depending on the soil conditions, the walls are made separate or combined with the foundation. To improve the operation of the foundation, a reverse arch is arranged in the lower part of the pipe, which simultaneously serves as a tray for the flow of water. The minimum thickness of the arch of the pipe: for rubble laying - 30 cm, and for concrete - 20 cm.The ligation of the joints of the stones of the vaults should be at least 10 cm, and for corner stones - at least 15 cm.
For vaults, walls and foundations of pipes with vaults, rubble masonry made of stone of a grade of at least 400 or masonry of natural stone of a grade of at least 600 are used; for concrete vaults, concrete is allowed at least M-200, for concrete foundations - at least M-150. Expansion joints are placed every 3-6 m along the length of the pipe and filled with insulating material (bitumen mastic, tow). The outer surface of the pipes is covered with a coating waterproofing.
Rice. 9. Structural elements of a corrugated pipe:
a - a diagram of the connection of sheets; b - steel profiles; 1-8 - numbers of elements (sheets)
Abroad and in our country, metal corrugated culverts have been used on railways and highways. Such pipes have different cross sections: round, elliptical with an elongated vertical diameter, ovoidal or arched; the most common are round with a diameter of 2-2.5 m to 6 m (Fig. 9). Metal pipes are built both without a special head with pipe outlets from the embankment, and with heads made of stone, concrete or reinforced concrete. The body of metal pipes is prepared from corrugated (corrugated) metal. Their peculiarity is their low lateral rigidity. Deformations in the pipes are limited by the surrounding embankment.
The body of the pipe along its entire length has a continuous solid structure with tight joints between the elements. Under embankments of roads, they are laid on a soil cushion without a special foundation. Corrugated pipes with a diameter of more than 2.0 m, as a rule, are laid in separate elements - in links and combined on site. Smaller pipes are pre-assembled at the construction site.
The main element of the pipe is a corrugated sheet of standard width - 975 mm, bent along a given radius. The sheets are overlapped on bolts usually 16 mm in diameter made of steel 20. The longitudinal joint is arranged in double-row or single-row, and the transverse joint is in single-row. Adjacent longitudinal joints are displaced relative to each other by one, two or more steps, which ensures the dispersal of the joints and improves the conditions for pipe assembly. The thickness of the corrugated sheet is taken as 1.5-2.5 m, depending on the diameter of the pipe and the height of the embankment. For the manufacture of pipes, steel sheets are used with a sheet height and wavelength of 32.5 and 130 mm, respectively.
Copper sheet steel is used with increased corrosion resistance of steel grade 15 according to GOST 1050-60 with a yield point of 24 kgf / mm2, a tensile strength of 40 kgf / mm2 and a relative elongation of up to 22% (cold bend at an angle of 180 °). To protect against corrosion, a zinc coating with a thickness of 80-100 microns is applied to the metal, which is applied hot, usually after bending and perforating the metal. To do this, use zinc grade CZ in accordance with GOST 3640-65.
Operating experience has shown that the construction of a pipe chute made of rigid materials, such as concrete, does not ensure the durability of the chute. The concrete chute in these pipes deforms and collapses faster than the chute made of resilient materials. Therefore, asphalt concrete is recommended for the corrugated pipe tray.
To protect the metal surface from corrosion in the event of rust appearing in it, as well as in places of increased aggression of soil or water, the metal should be covered with bitumen-rubber mastics (MBR) according to GOST 15836-70 or bitumen-mineral (bituminol) grades N-1 and N-2 consisting of bitumen, filler and plasticizer. As a filler for these mastics, grade 6 asbestos is recommended in accordance with GOST 12871-67. Bitumen-cutting mastic can be used for the device of a protective coating when performing work in summer and winter conditions up to a temperature of -25 ° C. Before use, it is recommended to add 10-15% of industrial oil STU-50 to it.
The number of mastic layers applied to the surface is determined by the degree of aggressiveness of the environment. With a small and medium aggressiveness of the environment inside the pipe, they are limited by the device of a tray made of cement concrete or asphalt concrete, and a primer layer and one layer of MBR mastic are arranged on the outer surface. In case of increased aggressiveness, an asphalt-concrete tray is arranged on the inside of the pipe and one layer of primer and MBR mastic is applied over the metal, and a primer and two layers (2 mm each) of mastic are applied on the outside.
If the pipe is covered with drainage soil in the absence of an aggressive environment, protective coatings can be arranged from two layers of bituminous mastics (primers) as for reinforced concrete and concrete pipe structures. Before applying the primer, the metal surface must be free of dirt, dust, ice, oil and oil stains. The primers are applied on a dry surface in an even layer without a gap. The temperature of the mastic should be in the range of 160-180 ° C. A new layer of primer is laid on the hardened surface of the previous one. Bituminous rubber mastic is applied no later than a day after the priming layer is installed. Work is performed using special sprayers.
It is advisable to arrange concrete and asphalt concrete trays in the pipe after the erection of the embankment and soil stabilization in order to avoid deformation of the pipe and the tray. Concrete trays are arranged in dry weather at positive temperatures directly on the cleaned surface of the pipe, and asphalt concrete trays - on a dry surface of a primer or mastic over the entire width of the tray.
When repairing a road embankment above a corrugated pipe, great attention should be paid to the quality of backfill and soil compaction.Since pipes are very flexible, the soil is covered in layers of 15-20 cm along the entire width of the embankment simultaneously from both sides of the pipe, i.e. so as to avoid deformations its design. For backfilling, drainage soils (for example, sand and gravel) with a particle size of no more than 50 mm are preferred. Weakly bonded soils are allowed if they are compacted at optimal moisture content. Non-draining soils should not be used for backfilling corrugated pipes.
Compaction is carried out only with mechanical rammers. The degree of compaction of the soil should be at least 95% of its maximum standard density. The movement of vehicles over the pipe is possible only after filling the soil above it by at least 0.5 m.
The experience of operating corrugated pipes built under the embankments of railways has shown that, subject to the necessary requirements for the assortment of metal, its protection with zinc coatings and the arrangement of asphalt-concrete coatings of trays, these pipes have been successfully operated for 60-80 years.
At present, working drawings of corrugated pipes with a diameter of 1-3 m have been developed and at one of the enterprises of the USSR Ministry of Transport-System they have mastered their production with a design capacity of 2.5 thousand tons. highways.
Small reinforced concrete bridges are currently being built mainly according to standard designs from precast concrete. Elements-blocks of prefabricated structures are made, as a rule, in factories and landfills. Monolithic reinforced concrete small bridges are rarely erected and only when it is justified by local conditions (remoteness from centralized bases for the manufacture of elements, the presence of local materials, etc.) and the simplicity of manufacturing structural elements at the construction site. In some cases, prefabricated monolithic spans are used. Prefabricated beam bridges, made of conventional and prestressed reinforced concrete, slab and ribbed, with and without diaphragms, are widely used.
For overlapping small spans (3 and 6 m), structures developed by the Belgiprodor of Gushosodor of the BSSR are recommended. Single-span bridges of this type (Fig. 10) each consist of a slab span and two pile abutments. Piles with a section of 30 × 35 cm are united by nozzles with a section of 40X60 cm and slab fence walls. Slab spans are given in two versions - from solid slabs and hollow ones.
Rice. 10. Reinforced concrete slab bridge with a span of 6 m
Rice. 11. Precast concrete four-pivot bridge with explicit hinges:
1 - superstructure block; 5 - anchor pin; 3 - upper strut; 4 - bordering beam; 5 - bottom strut; 6 - block of the support cushion, attached to the foundation with anchor pins; 7 - foundation; 8 - support-wall block with a height of 100 cm; 9 - bitumen; 10 - resin impregnated felt; 11 - cement key in the grooves of the blocks, walls
For spans of 2-6 m, structures with lightweight supports are also used - four-hinged bridges of the N.A. Slovinsky system, in which the spans simultaneously act as upper struts between the wall supports and perceive the horizontal pressure of the soil. Spacers are also arranged in the lower part of the abutments, and the walls are made of lightweight elements. These four-pivot bridges are easy to manufacture and offer material savings of up to 50% compared to bridges with backwall abutments. Certain shortcomings discovered during the operation of these four-hinged bridges were taken into account when creating the design of four-hinged bridges with explicit hinges and increased spacers (Ukrdor-transnias). The prefabricated version of such bridges with obvious hinges with a span of 3-5 m at an embankment height of 2-3.5 m (Fig. 11) is provided with abutments in the form of walls with straight sloping wings, slab spans and struts uniting abutments-walls at the level of the supporting pillows. The walls of the abutments and sloping wings are prefabricated reinforced concrete.
Small bridges with lightweight supports are recommended for use in areas with dry and low-moisture climates, i.e. IV and V road-climatic zones (according to SNiP N-D.5-72). The walls must be separated from the openings with sedimentary seams and it is imperative, as provided by the technical conditions (СН 200-62), to fill part of the embankment behind the abutments with drainage soil; it is also necessary to provide a smooth entrance to the bridge.
For overlapping spans 6; nine; 12; 15 and 18 m, a standard design of unified prefabricated hollow slab spans with pre-stressed reinforcement from strands and strings from high-strength cold-drawn wire of periodic profile and bar reinforcement of class A-IV with a diameter of 18 mm was developed. Currently, new standard designs of diaphragm and diaphragmless unified reinforced concrete ribbed spans with frame reinforcement A-II with a span of 12, 15 and 18 m from ordinary reinforced concrete are used.
The experience of examining and operating bridges has shown that in ribbed diaphragm spans, a breakdown of the joints of the diaphragms often occurs, mainly due to the mismatch of the diaphragms of adjacent beams. Out of 1005 joints of diaphragm beams surveyed by Giprodornia in various regions of the RSFSR, there were 300 joints with diaphragm mismatch, in 900 joints there were various defects associated with the installation and welding of overlays. In some cases, when passing heavy loads, there is a shear of the weld overlays. It is noted that diaphragm beams become separately working in nature (without diaphragm) and, therefore, less reliable in operation.
Therefore, in bridge construction, non-diaphragm spans are more widely used, in which spatial rigidity is achieved by continuous homogenization of the joints of the roadway slab. In non-diaphragm spans, defects are found mainly in the places where the flanges of the beams are consolidated, but their condition is generally quite satisfactory (out of 1020 surveyed beams, 50 were with only minor defects).
For spans with spans up to 15-18 m, pile and pile-drain supports can be used. Intermediate supports up to 4-5 m in height are usually made from one row of piles, united on top by a nozzle, and at a height of more than 5 m - from two rows.
For unified ribbed reinforced concrete spans with a length of 12-24 m with dimensions from G-7 to G-10.5 with an embankment height of 4-11 m, Soyuzdorproekt developed in 1972 a standard design of bridge supports. There are three types of abutments: gantry abutments, column abutments on massive foundations, and gantry pile abutments. The intermediate wall support is given in two versions - with a solid wall and with openings. Wall supports are allowed to be used in all climatic regions with the exception of areas with permafrost.
Expansion joints in small reinforced concrete bridges provide free deformation of the superstructure from the action of temporary loads and temperature changes. The seams are arranged at the junctions of the span structures with each other and with the extreme abutments. The design of deformed seams (Fig. 12) depends on the magnitude of the linear and angular deformations of the mating elements. When overlapping seams located above fixed support parts, or seams with a displacement of up to 10 mm, when the spans are not more than 15-20 mm, it is recommended to use closed seams. Recently, rubber expansion joints have been used in closed seams (see Fig. 12, a). When moving more than 10 mm, the seams are usually open; Of these, the most perfect are the seams with rubber expansion joints (see Fig. 12.6), proposed by Soyuzdorniya.
Interfacing the bridge with the approach embankment is a crucial detail. Its design should ensure smooth movement of vehicles during operation. Directly at the abutment, the embankment is poured from well-draining soil, it is reliably compacted and transitional reinforced concrete slabs 14-20 cm thick with a slope of 10% are laid along the entire width of the carriageway. One end of the slab is placed on the ledge of the abutment or end of the console, the other on a reinforced concrete bed (Fig. 13).
Rice. 12. Types of expansion joints when moving:
a - up to 10 mm; b - from 10 to 20-30 mm; 1 - asphalt concrete; 2 - bituminous mastic; 3 - waterproofing; 4 - insulation in the area of 2.5 m; 5 - compensator tray; 6 - protective layer; 7 - asbestos fiber (filter); S - reinforcing mesh; 9 - three-cam rubber compensator; 10 - pipe rubber expansion joint
Rice. 13. Detail of the bridge-embankment interface:
1 - asphalt concrete pavement; 2 - the base of the pavement; 3 - adapter plate; 4 - bed; 5 - gravel and crushed stone pad; 6 - drainage soil; 7 - coarse and medium-grained sand
Small wooden bridges are quite common on the roads. The experience of using bridges built of raw wood without antiseptic treatment shows that they do not last long - from 8 to 12 years. However, by means of constructive measures and chemical protection of wood from decay, the service life can be extended to 40-50 years. Modern structures of wooden bridges of a permanent type, that is, providing a service life of 50 years, with wood impregnation with an oily antiseptic, can be produced only in factories.
To extend the service life of bridges operated and built in the field, Giprodornia developed recommendations for deep local pressure antiseptic treatment of wood using a simple installation using a new water-soluble antiseptic XM-5 - copper chromate.
For spans up to 6 m, it is recommended to use beam bridges with scattered single-tier girders (Fig. 14, a) of round cross-section of natural conicity. The design of the carriageway of such bridges consists of a lower transverse bearing deck, which distributes the pressure from the wheels of a moving load, and an upper one, which works for wear. It is very advisable to cover spans up to 6 m with a glued slab structure made of boards laid on the edge and covered with asphalt concrete or a layer of special plasto concrete.
For overlapping a span of 6-8 m, beam bridges with scattered two-tier girders are most appropriate. With a two-tier arrangement of the girders, the building height of the superstructure increases and the design becomes somewhat more complicated due to the need to mount the girders. All other elements of the superstructure and carriageway of the ANA; logical to the previous design.
With spans of 8-10 m, concentrated complex (batch) runs are recommended, made up of 2-3 logs in height, stacked with butts in different directions and fastened with bolts (Fig. 14.6). For lateral stability, the girders are compressed with clamps and tied together with transverse anchor elements. Runs of three or four logs can be tied into stable packages (Fig. 14, b), which do not require transverse fastenings - clamps and anchors. For overlapping spans of more than 10 m, plank-nail or glued beams (trusses) are advisable. Such trusses can be delivered in whole or in large blocks to the place of their installation. The construction of the roadway in the form of a plank-nail slab with an asphalt concrete 'coating protects the span structures well from wetting and contamination.
The most modern are wooden bridges protected from decay with glued timber spans. These are permanent structures. Glued beams are completely manufactured in the factory, they are lighter in comparison with other structures, since they have fewer structural elements of any kind.
In the glued structures of the constructed road bridges, predominantly rectangular beams from stacked and glued boards are used (Fig. 15, a). They are easier to manufacture, transport and operate more reliably. They cover spans up to 16 m. To cover spans up to 20-30 m, you can use I-beams with belts glued from boards along vertical seams and a wall of bakelized plywood with a thickness of at least 10 mm. Depending on the span, the wall is made single (Fig. 15.6) or double (Fig. 15, b). The stability of the wall is increased by setting stiffeners.
Rice. 14. Wooden girder bridges:
1 - fence wall; 2 - curb (wheel) bar; 3 - top flooring; 4 - lower transverse flooring; 5 - runs; 6 - nozzle; 7 - contractions; S - pile; 9 - anchor; 10 - compression
Supports of wooden small bridges, depending on local conditions, the type and purpose of the structure, can be: pile, frame, cricket and massive. If the soils allow pile driving, then the supports are usually piled. Such supports are the most reliable in work. The piles are driven into the ground to a depth of at least 3.5-4 m. When the supports are not more than 2-2.5 m high, the piles are not tied together, with a support height of up to 3 m, horizontal contractions are placed to increase the lateral rigidity (Fig. 16, a), and at a height of more than 3-4 m, even diagonal ones (Fig. 16.6). If the height of the supports is more than 5 m and exceeds their width, in addition to contractions, jibs are placed (Fig. 16, c). With supports more than 6 m high, the contractions are placed in two tiers (Fig. 16, d), while the lower contractions are placed 30-50 cm above the low-water level. Pile-frame supports are sometimes used. The frames are prepared in advance at the construction site and then installed on the pile foundation (Fig. 16, (3).
With dense sandy and sandy-gravel soils, as well as soils that do not allow pile driving (rocky, stony), frame pile and stony ones (Fig. 16, e), as well as cage supports are arranged. In bridges over hollows, dry lands with less dense soils, the base of the frames can be foundations made of concrete or masonry with the laying of at least a depth of freezing of the soil (Fig. 16, g).
Rice. 15. Section of glued beams:
1 - bakelized plywood; 2 - stiffening rib
Rice. 16. Diagrams of supports for small girder bridges:
1 - root pile; 2 - slope pile; 3 - jib; 4 - frame; 5-pile base; b - jelly; 7 - massive foundation -
Wooden supports on rivers with ice drift are protected with ice cutters (Fig. 17). On small rivers with weak ice drift, cluster ice cutters located at a distance of 1.5-2.0 m from the support are sufficient. In ryazhs, the ice-cutting part is combined with the support. With a low intensity of ice drift, such a combination is possible in pile supports. With a more intensive (average) ice drift, flat ice cutters with an inclined cutting edge are arranged in front of a flat support at a distance of 4-4.5 m. Wide supports with medium and strong ice drift are protected with hipped-roof ice cutters.
CENTRAL INSTITUTE REGULATORY
RESEARCH AND SCIENTIFIC AND TECHNICAL
INFORMATION"ORGTRANSSTROY"
MINISTRIES OF TRANSPORT CONSTRUCTION
ASSEMBLY DEVICE
REINFORCED CONCRETE WATER PIPE
DIAMETER 1 m UNDER THE AUTOMOBILE ROAD
I. SCOPE
The technological map is developed taking into account the progressive methods of organizing construction and production of work, as well as methods of scientific organization of labor and is intended for use in the development of a project for the production of work and the organization of work and labor at the facility.
The technological map provides for the construction of a single-point prefabricated reinforced concrete pipe with a diameter of 1 m, length 26.28 m for a road (with an embankment height from 4 to 7 m).
The design of the pipe was adopted according to the "Standard design (501 Zh-5) of prefabricated unified concrete culverts for railways and highways" of the Glavtransproekt, approved by the order of the Ministry of Railways and the Ministry of Transport Construction dated July 8, 1966 No., inv. No. 101/1.
The pipe is assembled from precast concrete elements:
foundation - from curved blocks, laid on crushed stone preparation;
pipe body - of links 1 length m;
heads with flaps - from separate blocks.
Strengthening the channel at the heads is not provided for in the technological map.
In all cases of application of the technological map, it is necessary to link it to the local conditions of the work.
II. PRODUCTION TECHNOLOGY INSTRUCTIONS
The construction of the pipe includes:
preparation of the construction site;
center works;
reception and placement of equipment, materials and structures at the construction site;
installation of a pit for the foundation of the pipe and head;
crushed stone preparation device;
installation, foundation blocks, heads and pipe links;
filling the pit sinuses with soil;
concreting of trays within the heads;
waterproofing works;
backfilling the pipe with soil.
Site preparation
Site in the pipe construction zone (at a distance of at least 10 m on each side of the pipe axis) are planned with a bulldozer with slopes that provide water flow from the pipe.
At the exit head, the natural channel is cleared, and at the entrance head at a distance of at least 1.5 m from the contour of the pit, they block the channel with soil and arrange a bypass ditch or embankment of the construction site. These measures must ensure complete drainage of surface water from the pit.
For the delivery of equipment, concrete blocks and materials by a bulldozer, access roads are cleared and planned to provide free passage in a circular traffic pattern.
Breakout work
The position of the pipe is determined by the road design. The design organization must fix in nature and hand over the point of intersection of the road axis with the longitudinal axis of the pipe, the longitudinal axis of the pipe, fixed by four outrigger stakes (Fig.), And the height benchmark according to the act to the work producers.
Measurements along the pipe axis outline the contour of the pit and mark it with pegs.
At a distance of 1 m from the boundaries of the pit, they arrange a cast-off of boards or beams (Fig.) and indicate on it the longitudinal axis of the pipe and the position of the heads, flaps, and sections of the foundation.
Whenever possible, the strip should be buried in the ground to protect it from damage by a bulldozer or excavator.
Sequence of installation of blocks and pipe links
|
Crane parking |
Mounting number |
Marne element (block no.) |
Block weight, T |
Maximum reach of an arrow, m |
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Installation of exit head blocks (portal and openers) |
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The device of gravel-sand preparation under the exit head |
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Laying the curved foundation block |
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Installation of tapered link and pipe links |
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Laying of curved foundation blocks |
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Installation of pipe links |
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Laying curved blocks |
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Installation of pipe links |
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Installation of blocks of an entrance head |
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The device of gravel-sand preparation under the entrance head |
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Installation of curved foundation blocks |
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Mounting pipe links and tapered link |
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Installers 4 bit - 1 and 3 bits - 1 take blocks and links and install them with guy wires and crowbars to the design position.
Installer 3 bit examines and cleans blocks and links, sling them for feeding into the pit. Installer 2 bit fills the vertical seams of the curved foundation blocks with sand-cement mortar before installing the links. After installing and unfastening the head blocks, the entire unit performs work to fill the space behind the portal block and the base for the trays with a gravel-sand mixture.
Before installing the last links of the pipe, the installer 2 dig. proceeds to grout grout under the pipe links using a flat funnel (see. rice.). He finishes work immediately after the installation of the last links of the pipe. Then it goes to another pipe.
The workers of the insulators, working two at each head, concreted the trays at the exit and entrance heads. The concrete mixture is delivered by dump trucks and unloaded onto the sand and gravel preparation, spread with shovels in an even layer and compacted with a surface vibrator. The surface of freshly laid concrete is smoothed with floats and covered with sand. Immediately after the installation of the trays, the workers of the link fall asleep simultaneously from both sides of the cavity of the excavation. The soil is pushed on with the D-271 bulldozer, in hard-to-reach places, it is thrown by hand, and then, with shovels, it is distributed in an even layer in the sinuses of the excavation and compacted with C-690 electric rammers. A link of insulators also performs work on sealing seams between links and head blocks, installing gluing and coating waterproofing of the pipe, as well as backfilling the pipe with soil to a height of 0.5 m.
Two waterproofers 3 and 2 bits. make tows from tow, dip them in bitumen and seal the seams between the links. Then they proceed to caulking the seams from the inside with cement mortar with jointing. They work from the middle of the pipe to the edges, installing light portable circles under the upper part of each seam (see Fig.), supporting the solution in the seam.
They were followed by two waterproofers 4 and 2 dig. arrange the gluing of the seams. To do this, one cuts the panels of bituminized fabric into strips 25 cm, at this time, another worker brings mastic, pours hot bituminous mastic onto the joint with a thin stream from a scoop with a drain device, and both stick the bituminous cloth.
The same link arranges the coating insulation using a spray unit or an auto aspirator.
The entire link is backfilled with soil using an E-302 excavator equipped with a grab. Workers compact the soil layer by layer with C-690 electric rammers.
Machine operators are obliged at the beginning of the shift (or at the beginning of work with a small amount of work) to check the readiness of the machines for work, eliminate minor malfunctions, refuel the machine with fuel and water, drive the machine during work, and at the end of the shift (or work) clean the machine and inform mechanic about the deficiencies noticed. The crane operator is obliged to check and test the rigging and installation equipment before starting work.
V. CALCULATION OF LABOR COSTS FOR THE CONSTRUCTION OF A DISTRIBUTED WATER PIPE WITH A HOLE OF 1 m, LENGTH OF 26.28 m
|
Code of norms and prices |
Description of work |
Link composition |
unit of measurement |
Scope of work |
Time rate, man-h |
Price, RUB-kopeck |
Standard time for the full scope of work, man-h |
The cost of labor costs for the full scope of work, RUB-kop. |
|
|
A. Preparatory work |
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|
ENiR, 2-1-24, No. 6a |
Site planning with a bulldozer in 3 passes on one track |
Driver 5 bit - 1 |
100m 2 |
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By the time |
Layout of a structure with an axis leader and a cast-off device |
2 bit - 1 |
man-h |
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Reception of tools, fixtures and equipment and their installation, construction site lighting device |
Structural installers: 3 bits. - 1 1 bit - 1 |
man-h |
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ENiR, 4-4-92, No. 1 |
Unloading and sorting head blocks |
Crane operator 6 bit - 1 Structural assemblers: 4 bit. - 1 3 bit - 1 |
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ENiR, 4-4-92, No. 3 |
Unloading and sorting of curved blocks |
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ENiR, 4-4-92, No. 6 |
Unloading and sorting pipe links |
Crane operator 6 bit - 1 Structural assemblers: 4 bit. - 1 3 bit - 1 |
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Total |
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B. Earthworks a) Digging a pit |
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ENiR, 2-1-15, tab. 2, no. 56 + d |
Development of soil of the II group with the D-271 bulldozer (when moving it up to 20 m) |
Driver 5 bit - 1 |
100m 3 |
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ENiR, 2-1-10A, tab. 3, No. 3z |
Development of soil of the II group with the E-302 excavator |
Driver 4 bit - 1 |
100m 3 |
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ENiR, 2-1-15, tab. 2, no. 56 + d, approx. 3, K = 0.85 |
Moving the soil of the II group by the D-271 bulldozer at a distance of 20 m |
Driver 5 bit - 1 |
100m 3 |
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ENiR, 2-1-31, tab. 2, no. 1e, approx. 3a, K = 1.2 |
Modification of the soil of the II group in the pit manually after its development by an excavator and a bulldozer |
Excavator 2 dig. - 1 |
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ENiR, 2-1-46, No. 26, K = 1.2 at 2-1-31, approx. 3b |
Cleaning the bottom of the pit in group II soils manually with cutting irregularities, filling in depressions with soil compaction, checking the planned surface according to a template |
Excavator 2 dig. - 1 |
100m 2 |
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b) Backfilling the sinuses of the pit and pipe |
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ENiR, 2-1-15, tab. 2, no. 56 + d, approx. 3, K = 0.85 |
Moving the soil of the II group by the D-271 bulldozer at a distance of 20 m |
Driver 5 bit - 1 |
100 m 3 |
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ENiR, 2-1-44, tab. 1, no. 26 |
Filling the pit sinuses with soil manually with ramming |
Excavators: 2 dig. - 1 1 bit - 1 |
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For ENiR, 2-1-45, tab. 3, No. 2a, K = 1.2 |
Tamping the soil of the II group with electric rammers after backfilling in layers of 15 cm |
Excavator 3 dig. - 1 |
100m 2 |
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ENiR, 2-1-12, tab. 3, no. 1c |
Backfilling the pipe with soil to a height of 0.5 m excavator E-302, equipped with a grab bucket |
Excavator driver 5 digits - 1 |
100m 3 |
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For ENiR, 2-1-45, tab. 3, No. 1a, K = 1.2 |
Tamping the soil with electric rammers when filling the pipe with 20 layers cm (66m 3 : 0,2m = 330m 2) |
Excavator 3 dig. - 1 |
100m 2 |
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Total |
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Total for earthworks |
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B. Arrangement of two heads |
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ENiR, 4-4-88, No. 56 |
Arrangement of gravel-sand preparation for bevels and head trays in layers of 15 cm (11,8: 0,15 = 79m 2) |
3 bit - 1 2 bit - 1 |
100m 2 |
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ENiR, 4-4-88, No. 4A |
Crushed stone preparation device 0.1 thick m(1,2: 0,1 = 12m 2) |
100m 2 |
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ENiR, 4-4-91, tab. 2, no. 1b |
Crane installation of pattern blocks No. 24 weighing 1.5 tons |
Crane operator 6 bit - 1 Structural assemblers: 4 bit. - 1 3 bit - 2 |
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ENiR, 4-4-94, No. 2b |
Installation by crane of conical links No. 27 weighing 1.3 t |
Crane operator 6 bit - 1 3 bit - 2 |
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ENiR, 4-4-93, No. 1 |
Crane installation of block No. 35 of the portal wall weighing 3 tons |
Crane operator 6 bit - 1 Structural assemblers: 4 bit. - 2 3 bit - 2 |
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ENiR, 4-4-93, No. 5 |
Crane installation of blocks No. 39p, l of slope wings weighing 3.1 t |
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ENiR, 4-4-99, No. 1 |
Caulking of seams of links with portal walls of tow impregnated with bitumen |
Structural assemblers: 4 bit. - 1 3 bit - 1 |
1m seam |
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ENiR, 4-4-99, No. 3 |
Joint isolation device |
3 bit - 1 |
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ENiR, 4-4-99, No. 2 |
Sealing the joints between the tapered link and the portal wall of the head with cement mortar |
Structural assemblers: 4 bit. - 1 |
1m seam |
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ENiR, 4-4-97, No. 2 |
Caulking of vertical seams between the blocks of the portal wall and the sloping wings of the head |
1m seam |
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ENiR, 4-4-97, No. 4 |
Filling vertical joints between head blocks with cement mortar |
Structural assemblers: 4 digits - 1 3 bit - 1 |
1m seam |
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ENiR, 4-4-97, No. 7 |
Sewing seams between head blocks |
Structural assemblers: 4 bit. - 1 3 bit - 1 |
1m seam |
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ENiR, 4-4-101, No. 1 |
Coating insulation device |
Waterproofing devices: 3 bores. - 2 |
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Total for 2 heads |
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D. Installation of links and pipes and construction of foundations |
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a) Section 2.01 m long |
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ENiR, 4-4-88, No. 4a |
Crushed stone preparation device with a layer thickness of 0.1 m |
Road workers: 4 digits - 1 3 bit - 1 2 bit - 1 |
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ENiR, 4-4-91, No. 1b, tab. 2 |
Laying by crane of the curved block No. 4 of the foundation of the pipe body weighing 1.9 t |
Crane operator 6 bit - 1 Structural assemblers: 4 bit. - 1 3 bit - 2 |
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ENiR, 4-4-94, No. 2b |
Installation of pipe links with a weight of 1.1 t by a crane |
Crane operator 6 bit - 1 Structural assemblers: 4 bit. - 2 3 bit - 2 |
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ENiR, 4-4-99 No. 1 |
Structural assemblers: 4 bit. - 1 3 bit - 1 |
1m seam |
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ENiR, 4-4-99, No. 3 |
Papered joint insulation device |
Waterproofing devices: 4 bits. - 1 3 bit - 1 |
1m seam |
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ENiR, 4-4-101, No. 1 |
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ENiR, 4-4-99, No. 2 |
1m seam |
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Total per section |
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Only 2 sections |
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b) Section 3.02 m long |
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ENiR, 4-4-88, No. 4a |
Crushed stone preparation device with a layer thickness of 0.1 m |
Road workers: 4 digits - 1 3 bit - 1 2 bit - 1 |
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ENiR, 4-4-91, tab. 2, No. 16 |
Laying by crane of the curved block No. 5 of the foundation of the pipe body weighing 1.4 T |
Crane operator 6 bit - 1 Structural assemblers: 4 bit. - 1 3 bit - 2 |
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ENiR, 4-4-94, No. 26 |
Crane-laying pipe links weighing 1.1 T |
Crane operator 6 bit - 1 Structural assemblers: 4 bit. - 2 3 bit - 2 |
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ENiR, 4-4-99, No. 3 |
The device of gluing the insulation of the joint |
Waterproofing devices: 4 bits. - 1 3 bit - 1 |
1m seam |
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ENiR, 4-4-99, No. 1 |
Caulking of seams of pipe links with tow impregnated with bitumen |
Structural assemblers: 4 bit. - 1 3 bit - 1 |
1m seam |
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ENiR, 4-4-101, No. 1 |
Coating waterproofing device |
Waterproofing devices 3 sizes - 2 |
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ENiR, 4-4-99, No. 2 |
Sealing joints with cement mortar |
Assembler of structures 4 bit. - 1 |
1m seam |
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Total |
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Just 5 sections |
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Total for 7 pipe sections |
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E. Arrangement of trays at the heads |
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ENiR, 4-4-98 |
Concreting of trays at the inlet and outlet heads with a thickness of 20 cm |
Concreters: 4 digits - 1 3 bit - 2 |
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ENiR, 17-31, No. 1 + 3 |
Fresh concrete care |
Road worker 1 size - 1 |
100m 2 |
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Total |
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Total per pipe |
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Including: for the work of the link number 1 (I cycle) №№ 1 - 10, 17; 29; 36 |
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Tapered links No. 27 |
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Round links No. 13 |
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Portal wall blocks No. 35 |
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Slope wall blocks No. 39l and No. 39p |
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Concrete mix M-150 |
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Cement mortar M-150 |
Backhoe and grab-equipped excavator |
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Bulldozer |
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Mobile power plant |
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Mobile spray unit |
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Surface vibrator |
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Electric rammers |
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Digging shovels LKO-1 |
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Collecting shovels LP-1 |
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Carpentry axes |
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Portable circled |
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Transverse saw |
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Level 1 m |
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Roulette RS-20 |
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Steel skins |
TsNIIS of the Ministry of Transport |
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Flat funnels |
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Steel caulking |
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Water tank |
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Container for bitumen varnish |
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Leveling slats |
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Trowels (trowels) |
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TYPICAL TECHNOLOGICAL CARD (TTK)
PRODUCTION OF WORKS ON CONSTRUCTION OF A COLLECTIVE WATER PIPE WITH A HOLE 3.0x2.0 m WITH MONOLITHIC HEADS
I. SCOPE
I. SCOPE
1.1. A typical technological map (hereinafter TTC) is a complex regulatory document that establishes, according to a certain specified technology, the organization of work processes for the construction of a structure using the most modern means of mechanization, progressive structures and methods of performing work. TTK is designed for some average working conditions. TTK is intended for use in the development of Projects for the production of work (PPR), other organizational and technological documentation, as well as for the purpose of familiarizing (training) workers and engineering and technical workers with the rules for the construction of reinforced concrete, prefabricated culverts with a hole 3.0x2.0 m with monolithic heads under the road embankment.
1.2. This map provides instructions on the construction of a culvert by rational means of mechanization, data on quality control and acceptance of work, industrial safety and labor protection requirements during the production of work.
1.3. The regulatory framework for the development of a technological map are: SNiP, SN, SP, GESN-2001 ENiR, production rates of material consumption, local progressive rates and prices, labor costs, rates of consumption of material and technical resources.
1.4. The purpose of the creation of the TC is to describe solutions for the organization and technology of construction work in order to ensure their high quality, as well as:
- reducing the cost of work;
- reduction of construction time;
- ensuring the safety of the work performed;
- organization of rhythmic work;
- unification of technological solutions.
1.5. On the basis of the TTK, as part of the PPR (as mandatory components of the Project for the production of works), Working flow charts (RTK) are developed for the performance of certain types of work on the construction of a culvert. Working flow charts are developed for the specific conditions of a given construction organization, taking into account its design materials, natural conditions, the available fleet of machines and building materials tied to local conditions. Working flow charts regulate the means of technological support and the rules for the implementation of technological processes in the production of work. The design features for the construction of the culvert are decided on a case-by-case basis by the Working Project. The composition and level of detail of the materials developed in the RTK are established by the relevant contractor construction organization, based on the specifics and volume of work performed.
Working flow charts are considered and approved as part of the PPR by the head of the General Contractor for the construction organization, in agreement with the Customer's organization, the Customer's Technical Supervision.
1.6. The technological map is intended for work managers, foremen and foremen performing construction work, as well as employees of technical supervision of the Customer and is designed for specific conditions of work in the III temperature zone.
II. GENERAL PROVISIONS
2.1. The technological map has been developed for the complex of works on the construction of the culvert.
2.2. Work on the construction of the culvert is carried out in one shift, the duration of the working time during the shift is:
Where 0.828 is the utilization rate of mechanisms in time during the shift (the time associated with preparing for work and carrying out the ETO - 15 minutes, breaks associated with the organization and technology of the production process and the driver's rest - 10 minutes every hour of work).
2.3. The scope of work that is consistently performed during the construction of the culvert includes:
- preparatory work;
- center works;
- excavation;
- installation work (installation of the outlet head, installation of the foundation for the pipe body, installation of pipe links, installation of the inlet head);
- waterproofing works;
- strengthening work.
2.4. The technological map provides for the performance of work by a complex mechanized unit with automobile jib crane KS-4561A(see fig. 1 and fig. 2) with a lifting capacity of 25.0 t as a driving gear.
Fig. 1. General view of the KS-4561A truck crane
Fig. 2. Altitude and cargo characteristics of the KS-4561A crane
2.5. Work should be carried out in accordance with the requirements of the following regulatory documents:
- SP 48.13330.2011. Organization of construction;
- SNiP 3.01.03-84. Geodetic works in construction;
- SNiP 3.02.01-87. Earthen structures, foundations and foundations;
- SNiP 3.06.04-91. Bridges and pipes;
- SNiP 3.03.01-87. Bearing and enclosing structures;
- SNiP 3.04.01-87. Insulating and finishing coatings;
- SNiP 3.04.03-85. Protection of building structures from corrosion;
- Benefit to SNiP 3.02.01-83 *. Manual for the production of work in the construction of foundations and foundations;
- VSN 32-81. Waterproofing bridges and pipes;
- SNiP 12-03-2001. Labor safety in construction. Part 1. General requirements;
- SNiP 12-04-2002. Labor safety in construction. Part 2. Construction production;
- RD 11-02-2006. Requirements for the composition and procedure for maintaining as-built documentation during construction, reconstruction, overhaul of capital construction facilities and requirements for certificates of inspection of works, structures, sections of engineering and technical support networks;
- RD 11-05-2007. The procedure for maintaining a general and (or) a special journal of accounting for the performance of work during construction, reconstruction, overhaul of capital construction objects.
III. ORGANIZATION AND TECHNOLOGY OF WORK PERFORMANCE
3.1. In accordance with SP 48.13330.2011 "Organization of construction", prior to the commencement of construction and installation work at the facility, the Contractor is obliged to obtain from the Customer the design documentation and permission to perform construction and installation work in accordance with the established procedure. Carrying out work without permission is prohibited.
3.2. Before starting the construction of the culvert, it is necessary to carry out a set of preparatory work and organizational and technical measures, including:
- to appoint persons responsible for the high-quality and safe performance of work;
- instruct the members of the team on safety measures;
- to place the necessary machines, mechanisms and inventory in the work area;
- arrange temporary driveways and entrances to the place of work;
- to provide communication for the operational dispatch control of the production of work;
- to establish temporary inventory household premises for storing building materials, tools, inventory, heating workers, eating, drying and storing work clothes, bathrooms, etc .;
- provide working tools and personal protective equipment;
- prepare places for storing materials, inventory and other necessary equipment;
- to fence off the construction site and put up warning signs illuminated at night;
- provide the construction site with fire-fighting equipment and signaling means;
- draw up an act on the readiness of the facility for the production of work;
- obtain permits for the production of work from the technical supervision of the Customer.
3.3. Before starting the construction of the pipe, the following activities and works must be performed:
- accepted from the customer a construction site prepared for the production of works;
- construction materials, necessary equipment, tools, reinforced concrete pipe sections were delivered and stored;
- entrances and exits from the site are arranged;
- water drainage from the place of work is provided;
- made a geodetic breakdown of the contour of the pit.
3.4. Reinforced concrete structures delivered to the construction site (see Fig. 3) are unloaded from vehicles with a KS-55713-4 truck crane.
Fig. 3. Construction site plan
1 - fittings; 2, 3 - lumber warehouse; 4 - the path of the crane; 5 - warehouse block of pipe links; 6 - container with cement; 7 - concrete mixer; 8 - water tank; 9 - power plant; 10 - crushed stone warehouse; 11 - sand warehouse
The pipe links delivered to the construction site are stacked in one tier on a sand cushion. Dropping pipe links from vehicles or into a pit is prohibited. The pipes are laid along the pipe pit, in accordance with the technological sequence of installation, leaving a berm with a width of at least 4.0 m for the crane entrance.
Mounting loops on the links of the pipe body are cut by electric welding flush with the concrete surface before installing the pipe cutting the loops with a chisel or bending them is not allowed.
To ensure the drainage of water from the work site, the existing watercourse is directed bypassing the installation site - a pit for the pipe body.
3.5. Geodetic alignment works
3.5.1. The geodetic breakdown of the pit is to mark it on the ground. The breakdown is carried out in two planes: horizontal and vertical. With a horizontal breakdown, the position of the axes is determined and fixed on the ground, and with a vertical breakdown, the calculated depth of pipe laying.
3.5.2. The breakdown of the pit for the pipe begins with finding and fixing the longitudinal axis of the pipe, performing the following steps:
- restore the axis of the road;
- measure with a steel tape (twice) the distance from the PC to the longitudinal axis of the pipe along the axis of the road;
- a steel nail 100-120 mm long is hammered at the point obtained;
- center the theodolite over the nail and transfer to nature the angle between the pipe axis and the road axis;
- fix the obtained longitudinal axis of the pipe with four control posts, two on each side, installed at least 3 m from the boundaries of the pit;
- the mark of the nearest benchmark, as well as the marks of the pipe inlet and outlet trays, are transferred to the control posts;
- check the compliance of the future channel of the drainage ditch with the project;
- break the outlines of the pit according to the breakout drawing with the fixing of its contours. To do this, castoffs are installed parallel to the pit axes at a distance of 2-3 m from its border (see Fig. 4), the position of which is recorded in the alignment drawing. On the rags, the main axes of the pipe are marked with a tape measure, fixing them with risks and appropriate inscriptions.
Fig. 4. Inventory cast-off
2 - a string of steel wire; 3 - plumb line
3.5.3. The surveyor, using the theodolite, transfers the axes to the upper edge of the castoff and fixes them with risks. The breakdown of the places where the marks are applied is made by the method of leading notches from the axes X and Y center grid available in the working drawings. For a relative mark 0,000
adopted the elevation of the top of the pipe corresponding to the absolute elevation available on the master plan. The position of the centerline axes of the pipe is fixed with steel wire strings tensioned on the castor. Then they are transferred to the surface of the platform with the help of plumb lines lowered from the stretched strings and this point is fixed with metal pins. The accuracy of the planned breakdown of the pit should be within 5 cm. Anchor marks (pegs with marks) are retained until the pipe is handed over to the customer. The stake points damaged in the course of work must be restored immediately.
The accuracy of the alignment work must comply with the requirements of SNiP 3.01.03-84 and SNiP 3.02.01-87. The diagram of the production of a geodetic breakdown of the pit is shown in Fig. 5.
Fig. 5. Scheme of production of geodetic pipe staking
3.6. Development of a pit
3.6.1. The development of the pit for the pipe body and the head is carried out single-bucket excavator ET-16(see Fig. 6), a special swamp modification, the pressure of which on the ground does not exceed 20-25 kPa, with a widened and lengthened caterpillar track. The discovered underground water outlets into the foundation pit (springs, springs, etc.) are drowned out with a clay plug.
Fig. 6. Excavator ET-16
The cleaning and leveling of the pit bottom to the design marks (by 5-10 cm) is carried out manually, under the rail, taking into account the design slope and the specified building rise equal to 1/50 of the embankment height, directly in front of the foundation.
The soil developed by the excavator is placed in a dump, followed by removal outside the construction site. The bottom of the pit is compacted vibrating plate LF-70, up to 0.95.
A break between the end of the excavation and the construction of the foundation for the pipe body, as a rule, is not allowed.
If the foundation is delayed, it is necessary to develop the foundation pit with an undershoot to the design mark, and cover the foundation pit with heat-insulating material. When using peat (0.16-0.18 g / cm), the layout, layout and compaction is done manually. Insulating blocks made of aerated concrete, foam, etc. laid with an automobile crane. The completed work is presented to the Customer for signing on the construction of the pit, in accordance with Appendix 3, RD-11-02-2006.
3.7. Installation of a monolithic concrete foundation slab for the pipe body
3.7.1. For prefabricated reinforced concrete pipe links, it is necessary to build a foundation in the form of a monolithic slab of concrete class B20, W6, F150 0.20 m thick by layer crushed stone M 800, fraction 20-40 mm 0.10 m thick.
Crushed stone is brought up front loader VOLVO L-45B(bucket capacity 1.2-2.5 m), leveled by hand, compact vibrating plate LF-70D up to not less than 0.95.
The completed work is presented to the Customer for signing the certificates of inspection of the hidden work on the "pillow" device, in accordance with Appendix 3, RD-11-02-2006.
3.7.2. For the installation of monolithic concrete slabs, a collapsible formwork with a height of 20 cm is installed on the finished "pillow". The marking of the places of installation of the formwork is made by the method of alignment notches from the axial points of the pipe. Anchor points are fixed on a cast-off located outside the work area. For a relative mark 0,000
the elevation of the top of the pipe is accepted, corresponding to the absolute elevation indicated on the master plan. The formwork is assembled from edged softwood lumber VI p. with a thickness of 40-50 mm and bars of 40x40 (50x50) mm. On the inside, the boards are fixed to the required size with spacers, and with outer stakes driven into the ground close to the boards, which, just like boards, perceive the lateral pressure of the concrete mixture.
3.7.3. Wooden "beacons" 30 mm high are installed on the compacted crushed stone "cushion" and on them, to give strength to the monolithic foundation, meshes made of reinforcing steel A-III, grade 35GS, 12 mm in diameter, with a cell pitch of 100x100 mm, are laid. The grids are laid with an overlap of at least 25-30 reinforcement. The nets are connected by bandaging the joint in three places (in the middle and at the ends) with a knitting, steel wire with a diameter of 0.8 ... 1.0 mm using special hooks.
Reinforcement meshes are supplied to the work area by an automobile crane. Manual installation is allowed only with a mass of reinforcing elements up to 20 kg.
3.7.4. The process of placing concrete mix consists of working operations associated with feeding it into the formwork and compaction. Before placing the concrete mixture in the formwork, it is necessary to check:
- formwork fastening elements;
- the quality of cleaning the formwork from debris and dirt;
- the quality of cleaning the reinforcement from rust deposits;
- the extension of the axes of the structure (paint) on the reinforcing cage;
- close up large formwork gaps with slats or tow;
- cover the inner surfaces of the formwork with plastic wrap to reduce the strength of adhesion of concrete to boards;
- present the finished formwork and the installed reinforcing mesh with the outlets to the Customer for inspection and signing the Act for hidden work on the formwork and installation of the reinforcing cage, in accordance with Appendix 3, RD-11-02-2006.
3.7.5. The concrete mix is delivered to the object concrete mixer trucks SB-049A(4.0 m) and unloaded into rotary buckets with a capacity of 0.8 m located within the radius of the crane, after which the bucket is placed in a vertical position with a truck crane, transported to the place of laying and unloaded into the formwork.
3.7.6. When laying concrete mix, you must follow the basic rules:
- adding water when laying the concrete mixture is not allowed;
- cold water separated from the mixture must be removed;
- the height of the free throwing of the concrete mixture should not exceed 1.0 m.
During the laying of the concrete mixture, it is necessary to provide for the protection of the manufactured structure from atmospheric precipitation with plastic wrap.
Stripping of a concrete structure and loading it with pipe links is allowed when the concrete reaches a strength equal to at least 75% of the design strength.
3.8. Monolithic head device
3.8.1. Operations for the construction of cast-in-place concrete heads are performed in the following order:
- a pit is being developed for the portal wall and sloping wings;
- the formwork of the portal wall is installed with the adjustment of the shields and their fastening;
- the formwork of the left sloping wing is installed with a plumb line and fastening;
- install the formwork of the right slope wing;
- take the concrete mix from the bucket served by the truck crane;
- the concrete mixture is placed in the formwork and compacted with a vibrator;
- smooth the open surface of the freshly laid mixture;
- take care of concrete.
3.8.2. The development of the pit under the head is carried out single-bucket excavator ET-16... The cleaning and leveling of the bottom of the pit to the design marks (by 5-10 cm) is carried out manually. The soil developed by the excavator is placed in a dump, followed by removal outside the construction site. The bottom of the pit is compacted vibrating plate LF-70, up to 0.95. Crushed stone is poured into the pit under the head with a design layer, taking into account the safety factor for compaction equal to 1.25, leveled and compacted with a vibrating plate.
3.9. Installation of collapsible formwork under the tops
3.9.1. The formwork is used to give the required shape, geometric dimensions and position in space of the erected heads (portal wall and sloping wings) by placing the concrete mixture in the volume limited by the formwork.
3.9.3. Formwork panels are made from edged lumber 50 mm thick, 100 mm wide and wooden blocks 50x50 mm. The front parts of the boards in contact with concrete are sheathed with waterproof, bakelite, plywood 16 mm thick (FBS-16), fixed to the boards with self-tapping screws.
3.9.4. For concreting the heads, a collapsible formwork is used. The collapsible formwork is assembled from ready-made elements - shields. The assembly of the formwork panels is carried out at the assembly site in a certain sequence:
- the boards are laid with the working surface down, in the places where the mounting and working fasteners are installed, wooden slats are placed;
- the overall dimensions of the shields are verified, wooden limiter bars are nailed along their contours;
- shields are connected with each other by wooden plates;
- holes with a diameter of 18-20 mm are drilled in wooden slats in the places where the screeds pass;
- wooden fights are laid on top of the shields;
- fights with shields are connected with nails or staples;
- stiffness ties are placed on top of the contractions perpendicular to them, for which the same contractions are used;
- struts are attached to the lower tiers of the scrum or stiffening ties, which ensure the stability of the panels in a vertical position.
3.9.5. The installation of the formwork panels in the design position is carried out according to the risks applied to the crushed stone preparation according to the alignment axes fixed on the cast-in, with the simultaneous verification of the verticality of the panels along the alignment axes with theodolites.
The place of installation of the formwork is cleaned of chips, debris, snow, ice. When installing shields, you need to monitor the density of their abutment to each other. When installing the formwork, it is necessary to ensure its stability with the help of racks, resting them on a solid foundation and fastening them with clefts.
