During the construction of pipelines, the reinforced concrete head performs several important functions. It ensures uniform movement of fluid through the pipeline due to a uniform slope, supports slopes and protects gaps from falling asleep with soil.
Reinforced concrete head of a pipe at our enterprise will be able to get in wide assortment. We offer several sizes and guarantee excellent quality. The head of the culvert contributes to an increase in the durability of pipelines and ensures their long-term trouble-free operation. We offer reinforced concrete products with a number of advantages:
- High strength. It allows the product to withstand high mechanical loads.
- Resistant to temperature extremes and minimal water absorption. These factors will make it possible to withstand destructive environmental factors for a long time.
- Any reinforced concrete head undergoes multi-stage control, so we guarantee the absence of defects and maximum reliability.
The price of a reinforced concrete head of any size will be profitable, you can get the necessary information by calling our phones. We offer to place an order with delivery of products to the regions, please contact us!
We offer to buy exhaust gas heads
In the construction of culverts, reinforced concrete exhaust gas heads are indispensable products. They are classified as reinforced concrete products for reclamation purposes, since they are designed to protect the road from atmospheric phenomena affecting it. Reinforced concrete OG heads are L-shaped elements that can be of different sizes.
Exhaust gas pipe heads are a necessary element for strengthening the side of the roadway and preventing destruction. Our precast concrete plant offers high-quality exhaust gas caps made of heavy concrete with excellent strength characteristics.
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The construction of pipes is prohibited if there are ice and ice drifts. On streams and rivers that have fish spawning grounds, the installation of pipes is possible only with the permission of the fish inspection.
The elevation of the edge of the soil sheets at the approach to the pipe above the calculated level of the water base is taken to be not less than 0.5 ma, and for a pipe with a pressure or semi-pressure mode, not less than 1 ma.
The pipe heads are constructed from portal walls and a pair of sloping wings, which are buried in the soil base below the freezing depth by 25 cm and are installed on a base of crushed stone materials with a thickness of 0.1 mA.
The natural earth below the freezing depth is replaced with a mixture of sand and gravel.
Pipes are divided into 3 groups according to their bearing capacity: the calculated height of the soil backfill is 2 m, 4 m, 6 m.
It is permissible for certain conditions to build pipelines using pipes with other design heights and soil backfills.
Pipe grades consist of alphanumeric groups separated by hyphens. In this case, the first group contains designations of types, and the second - diameters in centimes and useful length in decims, as well as numbers of groups according to bearing capacity.
The construction of pipes takes place in accordance with GOST 26633 from heavy concrete mixes, where the compressive strength class B 25 is established. The concrete water resistance of the pipe must comply with W4.
Pipes TS, TB, TSP and TBP are supplied to consumers complete with sealing rings made of rubber material. Cracks on pipe surfaces are unacceptable, with the exception of a shrinkage width of not more than 0.05 mm.
Pipe heads with openings of 0.5 ... 0.75 m are constructed from portal walls that are buried in the ground below the freezing depth by 25 cm.
Slope wings can be made of a B15 grade monolith without reinforcement and taking into account the formwork size of the precast concrete block.
The length of the pipes (Ltr) is determined using the formula:
Ltr \u003d in + 2 (n-s-d) xm,
where in is the width of the earth in max;
n is the bulk height in max;
c is the wall thickness in max;
d - pipe opening in max;
m - coefficient of sloping foundations.
Construction technology of reinforced concrete pipes (reinforced concrete culvert pipes)
Before installation, it is necessary to carefully check the pipes for permissible deviations in accordance with GOST.
- Check pipe elements for permissible deviation according to GOST (link length is 0-1 cm, wall thickness is 0.5-1 cm, other measurements are approximately + 1 cm).
- Remove sags, concrete splashes on the connecting link elements.
- Select all pipe elements by brand according to the project decision.
- Store pipe elements in one place.
Preparatory work on site:
- Select and prepare a site for construction. Uproot the shrub and plan it with the necessary equipment.
- Accept and place material, equipment and structures in specific locations.
- Break the axis of the pipe and the excavated contour.
Geodetic work that is carried out in the construction process usually includes:
- arrangement of the structure in plans, taking into account the main axes and contours of the pit;
- altitude breakdown;
- leveling of longitudinal profiles of pipe trays.
The device in the plans occurs with the fixing of visible signs in place, by which it is possible to accurately determine the location of the pipe and its constituent elements. Fastening usually takes place with the help of two pillars, which are installed along the longitudinal axes of the pipes, in order to ensure their safety for the entire construction period, and pegs driven along the bulk axes in the necessary places.
In some cases, at a distance of 150-200 cm from the border of the pit, cast-off boards are built horizontally, on which characteristic foundation points are marked. The boards themselves are nailed to poles that are fixed to the ground.
With a planned breakdown, a strict exposure of the alignment position is needed, which is located along the axes of the embankments.
If any unfavorable soil or other factors are identified at the locations of pipes and heads, their displacement in the required direction is required. All differences from the existing project must be agreed with the design organizations and the customer, as a result of which the most appropriate technology will be selected.
High-rise technology is to determine the surface marks at the locations of the pipes and the depth of cutting the earth or, conversely, its filling under the pipes. Soil work related to digging a foundation pit and arranging a foundation is carried out in the presence of instrumental control.
With the help of a level, the compliance with the project of the actual mark of the excavated bottom to the pillow top is checked. In a similar way, the height positions of the foundation are controlled, and later on, the installation of pipes and heads.
The longitudinal profiles of the pipe are leveled immediately before backfilling and backfilling of the bulk layer to the project marks. Necessary, periodic and continuous further observations are established in accordance with the required standards.
This technology is produced with binding to benchmarks, which are located near the pipes.
Execution work
The pit is obtained using an excavator.
Excavator digging and manual cleaning of pits.
The device (if necessary) of the excavated bottom with stone material by pressing with the help of drowning tools.
The pit for the foundation, where the culverts will be located, is developed mainly without fences (fasteners). Only in water-saturated soil, with significant inflows of water and the impossibility of ensuring the stability of the walls of the pit, the earth is developed taking into account the fixing protection. Strengthening the pits is applicable if there are operated structures nearby. This technology ensures their stability.
Pit outlines and the technology of their development depend on the construction of pipes and their foundations, on the types and conditions of the earth. The steepness of the slopes of the pit is assigned taking into account the depth of the pit and the characteristics of the developed land.
If the design provides for waterproofing or other work is performed that is associated with the presence of people here, then the distance between the side surfaces of the foundation and the vertical walls of the pit is applied at least 70 cm. When there are no such works, these pairs can be reduced to 10 cm.
In case of foundation concreting without formwork, the excavated size is taken equal to the size of this foundation.
When excavating pits with slopes, the gap between the foundation and the bottom of the slope must be at least 30 cm. When digging a pit, measures are taken to prevent filling them with surface or ground water. For these purposes, earthen ridges are poured along the pit contours. When constructing pipes on permanent watercourses, it is necessary to make a dam or divert the channel to the side with a ditch.
If water nevertheless got into the pit, it must be removed or a descent into the ditch should be arranged below. This is usually possible during the construction of a slope water supply system or mechanized drainage. In these cases, enclosed pits are made at the bottom of the pit, from which water is pumped out using a pump. Such pits are located behind the foundation contour. They provide drainage during work with the foundation, up to the backfill.
As the pit deepens, the pit fence must be lowered. Soils of non-rocky rocks are developed by earth-moving machines without disturbing the natural composition of soils in the foundations. The shortfall is 10-20 cm. The final cleaning of the pit takes place before laying the foundation.
To date, of the various earth-moving machines, bulldozers and excavators are the most widely used in the construction of water pipelines on roads and railways.
The bulldozer is most popular when arranging pits.
Pit construction by bulldozers is most appropriate when laying the pipes themselves and heads at the same level or if there are minor differences.
For a pit that is not fenced, an excavator is used that has a backhoe or dragline. The advantage of this mechanism is the ability to develop soil at different depths, which helps to ensure the construction of pits under the middle parts of pipes and heads, the foundation soles of which are laid at considerable depths.
When developing a fenced pit, it is advisable to use grabs.
In all situations, the excavated soil is placed outside the excavation at distances that can ensure the stability of the walls or fences. Heaps of earth should not interfere with the construction, installation and water flow.
The device and construction of the foundation
There is a small-clastic and large-block foundation.
When mounting the foundation using prefabricated elements, you first need to lay the head blocks to the sole level. Then, the sinuses of the foundation heads are filled to the same level. Subsequently, from three sides they are covered with local soil, and in places where foundations of different depths are mated, with sand-gravel or sand-gravel mixtures, which must be compacted in layers and poured with cement mortar.
Then the foundation masonry and heads must be carried out taking into account the sectional. Consistent construction is required, from the output heads to the input ones. Multi-row masonry is performed using suture dressing. For the installation of a monolithic foundation, you need:
- fabricate and install formwork;
- deliver ready-mixed concrete or prepare it on site;
- lay the mixture
- provide the necessary care, remove the formwork, fill the sinuses.
The simplicity of the outlines of the foundation allows you to make formwork in the form of an inventory board, which is used at many construction sites. The surfaces of such shields must be smooth. Before concreting, they are recommended to be lubricated with grease. This will later help to more easily separate the shields from the concrete structure.
In order to load the concrete mixture into the sectional formwork, it is necessary to use inventory trays or buckets, which are loaded on site or delivered from the concrete mixing unit. Compaction of concrete occurs with the help of deep or surface vibrators.
The device of a prefabricated monolithic foundation occurs in the following sequence: it is required to install the formwork between the sections on the prepared base or pillow, pour the concrete mixture into the available space.
The requirements for the production of concrete work are the same as for the installation of a monolithic foundation. Mechanisms and equipment for foundation devices must be selected taking into account all technological processes for the construction of pipes.
An approximate list of equipment is: a crane, a mortar mixer, a concrete mixer, a vibrator, an electric rammer, a welding unit, a mobile power plant.
It is possible to increase efficiency in the installation of pipes if you organize the processes of manufacturing, delivery of structures and installation of pipes on the site, observing a single integrated schedule.
A prerequisite for these events is good entrances and developed building bases. The foundation and the number of pipe heads in this situation are mounted "from wheels". The necessary elements are removed from the vehicle by a crane and placed in the structure.
The device of the pile foundation is very common where weak soil is present. Piles are driven mainly by units, which include pile driving equipment based on tractors, truck cranes or excavators.
Culvert reinforced concrete pipes: installation
Prefabricated heads and pipe bodies begin to be mounted after the foundation device and axillary backfill.
Before installation, the foundation and head blocks, links must be cleaned of dirt, and in winter conditions - of ice and snow.
A link or blocks that have a flat surface of the lower faces must be installed on a cement mortar. Cylindrical links are required to be installed on wooden linings in compliance with the required clearances between them and the foundation. Subsequently, a concrete mixture is pressed under the links, thereby ensuring full contact of the links over the entire distance.
The solution must be poured from one side, while controlling its appearance from the other. Then the missing solution is replenished from the opposite side. This ensures complete alignment and filling of the seams. Solution is necessary such where mobility makes about 12 centimes.
By filling vertical and horizontal joints, it is possible to provide a continuous and monolithic pipe structure in the area where expansion joints are present.
Docking seams on links or sections of pipes are characterized by caulking on all sides with tow, which is impregnated with a bituminous mixture. From the inside, the seams must be sealed by 0.03 m with cement mortar.
The entire installation process is carried out in compliance with the design gaps between the links and blocks in order to maintain the sectional size and prevent overlapping of the expansion joint.
Waterproofing and piping
The main type of insulation is reinforced concrete and today occurs with the help of bituminous mastic.
Coatings are arranged unreinforced (coated) and reinforced (pasted). Coating waterproofing is two layers of bituminous mastic, each having a thickness of 1.5-3 mm over the ground layer.
Reinforced waterproofing consists of material layers between a three-layer bituminous mastic over a primer layer.
The surfaces of elements of reinforced concrete pipes and their elements (links, floor slabs, nozzles, and others) are usually protected by glued insulation.
Waterproofing: work sequence
- surface preparation;
- proper waterproofing;
- protective layers.
During surface preparation, when working with a structure, it is necessary to clean it from dirt, dry it, and in some situations it is necessary to level it with a cement mortar.
It is necessary to apply a preparatory layer from a cement mortar where internal corners are formed, for example, on the ceilings of pipes and heads in front of cordon stones, for a drain device in a multipoint pipe, etc.
The first technological operation is waterproofing, that is, it is necessary to apply bituminous varnish to the insulated surfaces, which acts as a primer, in order to fill small cracks and pores. In addition, it improves the adhesion of bituminous mastic and concrete surfaces.
There are also non-mechanized methods of priming devices using brushes.
Non-reinforced waterproofing is arranged after the primer has dried, but not less than 24 hours after application.
Hot mastic is applied in layers with a thickness of 1.5-3 millimeters, moreover, the next layer after the first one has cooled down. For these purposes, hand tools (spatula, etc.) are used. It is possible to improve the quality of work and reduce labor costs if mechanized methods are used, mainly using pneumatic spraying.
Reinforced waterproofing is arranged in this way: first, one layer of hot bitumen is applied and a layer of one of the rolled materials is glued. The same is repeated for subsequent layers. The layer that will be the last must be covered with mastic 1.5-3 mm thick and leveled using a manual electric roller, if necessary, supplement the places where the waterproofing was insufficient.
Individual canvases are overlapped with a 10 centime overlap. The first and second joint should not be one above the other. Subsequent joints are made with a shift of at least 0.3 m relative to the joints of previously laid layers.
The rolled material is pasted without the formation of bubbles, while a snug fit of the material on all surfaces is required. Waterproofing is smoothed out with the help of electric irons, electric rollers.
The device of protective layers is necessary so that the waterproofing is not subjected to mechanical damage during backfilling, given that it is one of the important elements during many years of operation and normal operation of pipes.
Backfill
Reinforced concrete culverts must be covered with soil after all construction work has been completed and the appropriate acceptance certificate has been issued.
For these purposes, the same land from which the embankment was erected is suitable.
Bulk construction over culverts is divided into two stages:
- Fill with soil the sinuses between the foundation and the walls of the pit.
- Fill pipes at link height.
The soil is laid simultaneously on all sides of the pipe to an equal height and compacted by special soil-compacting vibro-impact machines, and in their absence, pneumatic rollers are used. The soil prism is backfilled with the help of inclined layers, the thickness of which is assigned taking into account the current standards.
When moving along a separate soil layer along the pipes, the machine should start working from a remote area, gradually approaching the pipes themselves. It is possible to compact the soil directly at the pipes themselves, if on the opposite side there is already a backfilled layer of earth of the same level along the entire length of the pipes. In this case, special attention is paid to soil compaction at the pipe walls. Here, a manual electric rammer should be located no closer than 0.05 mA from the wall.
Over the middle parts of the pipes, it is forbidden to re-compact the soil in order to avoid structural overloads in the future. With significant bulk heights of more than 10 m above the pipes, it is recommended to leave a zone where the density is reduced. Next, level the ground with a bulldozer without seals.
If, during construction, the equipment that moves over or near the backfilled structures is heavier than the live loads, then additional backfilling is required to avoid damage to the pipe.
The degree of soil compaction within the prism limits of the backfill is assessed using the coefficient K, which determines the ratio of the density that has been achieved to the standard maximum (determined by the standard compaction method). The latter is given in the production working draft, which includes data from geological and engineering surveys. The current instruction requires that a compaction factor of at least 0.95 be ensured. Density control is carried out with a Kovalev moisture meter-density meter. It should be said that in the processes of backfilling pipes, deviations from K, which is equal to 0.95, to the smallest side are prohibited. After all, with a decrease in the density of the earth, the deformation modulus and the bearing capacity of the pipes are significantly reduced.
Safety (TB)
Only those workers who have passed the necessary medical commission and introductory (general) safety briefing and safety briefing directly at the place of work can be hired for this job.
In addition, employees are required to learn a safe method of work according to a program lasting 6-10 hours within three months from the start of work. After graduating from training, you should pass an exam in a permanent commission, the results of which will draw up an act that needs to be invested in the employee's personal file.
The construction site must have permanent or temporary sanitary facilities: latrines, washrooms, changing rooms, clothes dryers, eating areas, showers, first-aid posts or first-aid kits. Workers must be provided with drinking water.
The construction administration must provide workers with overalls, footwear and personal protective equipment in accordance with current regulations.
Builders need:
- carry out the correct and safe conduct of construction and installation works;
- control the condition of scaffolding and scaffolding, protection devices, foundation pits, etc.;
- check the cleanliness and order at work places, on access roads and aisles,
- to ensure the illumination of workplaces, to check the correct operation of underhead and crane roads;
- instruct employees on safety at the workplace in the workplace;
- control the use and proper use of personal protective equipment and overalls by employees;
- monitor compliance with the norms of carrying gravity, provide workplaces with posters and inscriptions.
Head blocks are important components of culverts that close its body. These devices, regardless of the geometric shape, perform a number of identical functions. Firstly, they contribute to the uniform inflow and outflow of waters of various origins. Secondly, they have a strengthening function, supporting the slopes of embankments. An important task is to protect the entrance and exit clearance of the structure from clogging with soil.
Heads determine the mode of hydraulic operation of the pipeline: pressure, semi-pressure and non-pressure. There is an inlet section, located on the upper side of the embankment, and an outlet section, located on the downstream side. By design, the head parts are classified into: portal, corridor, socket, collar, streamlined.
Portal heads have the simplest structure. They are presented in the form of a retaining block necessary to maintain the slope of the road embankment. With respect to the longitudinal axis of the pipe, the wall is installed perpendicularly. This design is suitable for low flow rates and low flow rates.
A feature of the corridor head is parallel blocks deployed at their beginning, the height of which is constant.
The socket head includes a portal wall block and sloping wings. Such a structure improves the conditions for the flow of fluid. The device is designed to operate pipes in non-pressure and pressure modes. Socket heads in combination with elevated links are installed in rectangular pipes, and in combination with conical ones - for round ones.
Collar heads are elliptical end links located in the plane of the slope of the embankment.
In the form of a truncated pyramid, a streamlined head is made. Its complex design allows the pipeline to function effectively in floods with a full cross section. These heads are suitable for the installation of round pressure pipes.
Standard designs provide for pipe designs for operation in different modes, as well as for areas of permafrost, ice formation and on slopes. Based on the calculations of the strength of the water flow, its width, frequency, as well as on the characteristics of the soil, a suitable head shape is chosen. The width of the tip, corresponding to the watercourse, captures the flow of water and prevents erosion of a significant part of the road embankment.
The ZHBI MARKET plant successfully carries out sale of reinforced concrete heads. The production of head blocks is based on various standard projects. It is possible to manufacture reinforced concrete products according to the working documentation provided by customers. You can buy products from the manufacturer for equipping road facilities in St. Petersburg and other regions at affordable prices.
TYPICAL TECHNOLOGICAL CHART (TTK)
PERFORMANCE OF WORKS ON THE CONSTRUCTION OF A PREfabricated Culvert With A Hole Of 3.0x2.0 M With Monolithic Heads
I. SCOPE
I. SCOPE
1.1. A typical technological map (hereinafter referred to as TTK) is a comprehensive regulatory document that establishes, according to a specific technology, the organization of work processes for the construction of a structure using the most modern means of mechanization, progressive designs and methods of performing work. TTK is designed for some average conditions for the production of work. The TTK is intended for use in the development of Projects for the production of works (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 production of work on the construction of a reinforced concrete, prefabricated culvert with an opening of 3.0x2.0 m with monolithic heads for the embankment of the road.
1.2. This map contains instructions for the construction of a culvert using rational means of mechanization, data on quality control and acceptance of work, industrial safety and labor protection requirements in the course of work.
1.3. The regulatory framework for the development of a technological map is: SNiP, SN, SP, GESN-2001 ENiR, production norms for the consumption of materials, local progressive norms and prices, labor costs, norms for the consumption of material and technical resources.
1.4. The purpose of creating the TC is to describe solutions for the organization and technology of construction work in order to ensure their high quality, as well as:
- cost reduction of works;
- reduction of construction time;
- ensuring the safety of work performed;
- organization of rhythmic work;
- unification of technological solutions.
1.5. On the basis of the TTK, as part of the WEP (as mandatory components of the Works Project), Working Technological Maps (RTK) are developed for the performance of certain types of work on the construction of a culvert. Working technological maps 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 technological maps regulate the means of technological support and the rules for the implementation of technological processes in the production of work. Structural features for the construction of a culvert are decided in each case by the Working Design. The composition and level of detail of materials developed in the RTK are established by the relevant contracting construction organization, based on the specifics and scope of work performed.
Working technological maps are considered and approved as part of the PPR by the head of the General Contracting Construction Organization, in agreement with the Customer's organization, the Customer's Technical Supervision.
1.6. The technological map is intended for the foremen of work, foremen and foremen performing construction work, as well as employees of the technical supervision of the Customer and is designed for specific conditions for the performance of work in the III temperature zone.
II. GENERAL PROVISIONS
2.1. The technological map has been developed for a complex of works on the construction of a culvert.
2.2. Culvert construction work is carried out in one shift, the working hours during the shift are:
Where 0.828 is the coefficient of use of mechanisms in time during the shift (the time associated with preparing for work and conducting 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 sequentially performed during the construction of a culvert includes:
- preparatory work;
- marking works;
- excavation;
- installation works (installation of the outlet head, installation of the foundation for the pipe body, installation of pipe sections, installation of the inlet head);
- waterproofing works;
- fortification works.
2.4. The technological map provides for the performance of work by an integrated mechanized link with truck jib crane KS-4561A(see fig. 1 and fig. 2) with a lifting capacity of 25.0 t as a driving mechanism.
Fig.1. General view of the truck crane KS-4561A
Fig.2. Altitude and load characteristics of the crane KS-4561A
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. Earthworks, 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 against corrosion;
- Manual to SNiP 3.02.01-83*. Manual for the production of work in the construction of foundations and foundations;
- VSN 32-81. Waterproofing of 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 the requirements for certificates of examination of work, structures, sections of engineering and technical support networks;
- RD 11-05-2007. The procedure for maintaining a general and (or) special journal for recording the performance of work during the construction, reconstruction, overhaul of capital construction projects.
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 works at the facility, the Contractor is obliged to obtain from the Customer project documentation and permission to perform construction and installation works in the prescribed manner. Work without permission is prohibited.
3.2. Prior to the commencement of work on the construction of a culvert, it is necessary to carry out a set of preparatory work and organizational and technical measures, including:
- appoint persons responsible for the quality and safe performance of work;
- briefing the members of the safety team;
- place the necessary machines, mechanisms and inventory in the work area;
- arrange temporary passages and entrances to the place of work;
- provide communication for operational and dispatching control of the production of works;
- establish temporary inventory household premises for storing building materials, tools, inventory, heating workers, eating, drying and storing work clothes, bathrooms, etc.;
- provide workers with tools and personal protective equipment;
- prepare places for storing materials, inventory and other necessary equipment;
- fence the construction site and put up warning signs illuminated at night;
- provide the construction site with fire-fighting equipment and signaling equipment;
- draw up an act on the readiness of the object for the production of work;
- obtain permits for the performance of work from the technical supervision of the Customer.
3.3. Prior to the construction of the pipe, the following activities and works must be performed:
- the construction site prepared for the production of works was accepted from the customer;
- construction materials, necessary equipment, tools, reinforced concrete pipe sections were delivered and stored;
- Arranged entrances and exits from the site;
- ensured water drainage from the place of work;
- a geodetic breakdown of the contour of the pit was made.
3.4. Reinforced concrete structures brought to the construction site (see Fig. 3) are unloaded from vehicles by a truck crane KS-55713-4.
Fig.3. 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 sections delivered to the construction site are laid in one tier on a sand cushion. Dropping pipe sections from vehicles or into the 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 access.
Mounting loops on the links of the pipe body are cut flush with the surface of the concrete by electric welding before the pipe is installed. cutting 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 around the installation site - a pit under the pipe body.
3.5. Geodetic marking works
3.5.1. The geodetic breakdown of the pit is to designate 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 estimated depth of the 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 obtained point;
- the theodolite is centered over the nail and the angle between the axis of the pipe and the axis of the road is transferred to nature;
- fix the resulting longitudinal axis of the pipe with four control posts, two on each side, installed no closer than 3 m from the boundaries of the pit;
- transfer to the control posts the mark of the nearest benchmark, as well as the marks of the inlet and outlet trays of the pipe;
- check the compliance of the future channel of the drainage ditch with the project;
- break the outlines of the pit according to the layout drawing with fixing its contours. To do this, cast-offs are installed parallel to the axes of the pit at a distance of 2-3 m from its border (see Fig. 4), the position of which is fixed in the layout drawing. On cast-offs, 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 - steel wire string; 3 - plumb
3.5.3. The surveyor, using a theodolite, transfers the alignments of the axes to the upper edge of the cast-off and fixes them with risks. The breakdown of the places of drawing risks is carried out by the method of alignment serifs from the axes X and Y center grid available in the working drawings. For a relative mark 0,000
the mark of the top of the pipe was adopted corresponding to the absolute mark available on the general plan. The position of the center axes of the pipe is fixed with steel wire strings stretched on a cast-off. Then they are transferred to the surface of the site with the help of plumb lines lowered from the stretched strings and this point is fixed with metal pins. The accuracy of the planned laying out of the pit should be within 5 cm. The fixing marks (pegs with marks) are kept until the pipe is put into operation by the customer. Stakeout points damaged in the course of work must be immediately restored.
The accuracy of the layout work must comply with the requirements of SNiP 3.01.03-84 and SNiP 3.02.01-87. The scheme for the production of geodetic breakdown of the pit is shown in Fig.5.
Fig.5. Scheme of production of geodetic breakdown of the pipe
3.6. Pit development
3.6.1. The development of a pit for the pipe body and heads 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, which has a broadened and elongated caterpillar track. Detected underground outlets of water into the pit (keys, springs, etc.) are drowned out with a clay plug.
Fig.6. 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, under the rail, taking into account the design slope and the specified building lift equal to 1/50 of the height of the embankment, directly in front of the foundation.
The soil developed by the excavator is placed in a dump, with subsequent removal outside the construction site. The bottom of the pit is sealed vibrating plate LF-70, up to 0.95.
A break between the end of the development of the pit 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 a shortfall to the design mark, and cover the pit with heat-insulating material. When using peat (0.16-0.18 g / cm 3), the layout, layout and compaction are done manually. Insulating blocks made of aerated concrete, polystyrene, etc. installed with a truck 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. Under the prefabricated reinforced concrete sections of the pipe, 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.
Rubble is brought up wheel loader VOLVO L-45B(bucket capacity 1.2-2.5 m), leveled by hand, compacted vibrating plate LF-70D up to at least 0.95.
The completed work is presented to the Customer for signing of certificates of examination of hidden work on the installation of a "cushion", in accordance with Appendix 3, RD-11-02-2006.
3.7.2. For the installation of a monolithic concrete slab, a collapsible formwork 20 cm high is installed on the finished "cushion". Anchor points are fixed on a cast-off located outside the work area. For a relative mark 0,000
the mark of the top of the pipe was adopted, corresponding to the absolute mark indicated on the general plan. The formwork is assembled from edged softwood lumber VI c. 40-50 mm thick and bars 40x40 (50x50) mm. On the inside, the boards are fixed to the desired size with spacers, and on the outside with stakes driven into the ground close to the boards, which, 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 "pillow" and on them, to give strength to the monolithic foundation, grids of reinforcing steel A-III, grade 35GS with a diameter of 12 mm, with a cell pitch of 100x100 mm are laid. Grids are laid with an overlap of at least 25-30 reinforcement. The meshes are connected by tying 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.
The supply of reinforcing meshes to the work area is carried out by a truck crane. Manual installation is allowed only with a mass of reinforcing elements up to 20 kg.
3.7.4. The process of laying the concrete mixture consists of work operations associated with its supply to the formwork and compaction. Prior to placing the concrete mixture in the formwork, it is necessary to check:
- formwork fastening elements;
- the quality of formwork cleaning from debris and dirt;
- quality of rebar cleaning from rust deposits;
- drawing out the axes of the structure (with paint) on the reinforcing cage;
- with slats or tow, close up large cracks in the formwork;
- cover the internal surfaces of the formwork with a plastic film to reduce the adhesive force of concrete with boards;
- present the finished formwork and the installed reinforcing mesh with outlets to the Customer for examination and signing of the Act for covert work on the formwork and installation of the reinforcing cage, in accordance with Appendix 3, RD-11-02-2006.
3.7.5. The concrete mixture is delivered to the site truck mixers SB-049A(4.0 m) and unloaded into swivel buckets with a capacity of 0.8 m located within the radius of the crane, after which the bucket is set in a vertical position by a truck crane, transported to the place of laying and unloaded into the formwork.
3.7.6. When laying the concrete mix, the following basic rules must be observed:
- adding water when laying the concrete mixture is not allowed;
- cold water separated from the mixture must be removed;
- the height of the free dropping 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 a polyethylene film.
The stripping of the concreted structure and its loading with pipe sections 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 device of heads from monolithic concrete are performed in the following order:
- a pit is being developed for the portal wall and sloping wings;
- install the formwork of the portal wall with the adjustment of the shields and their fastening;
- install the formwork of the left sloping wing with alignment and fixing;
- install the formwork of the right sloping wing;
- take the concrete mixture from the tub, filed by a truck crane;
- lay the concrete mixture in the formwork and compact it with a vibrator;
- smooth the open surface of the freshly laid mixture;
- Maintain concrete.
3.8.2. The development of a pit for heads is carried out single-bucket excavator ET-16. The cleaning and planning 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, with subsequent removal outside the construction site. The bottom of the pit is sealed 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 for heads
3.9.1. The formwork serves to give the required shape, geometric dimensions and position in space of the erected heads (portal wall and sloping wings) by laying the concrete mixture in the volume limited by the formwork.
3.9.3. Formwork panels are made of edged lumber 50 mm thick 100 mm wide and wooden bars 50x50 mm. The front parts of the shields in contact with concrete are sheathed with waterproof, bakelite, plywood 16 mm thick (FBS-16), fixed to the shields with self-tapping screws.
3.9.4. For concreting the heads, a collapsible formwork is used. Collapsible formwork is assembled from ready-made elements - shields. Formwork panels are assembled at the assembly site in a certain sequence:
- the boards are laid with the working surface down, wooden slats are placed at the installation sites of the mounting and working fasteners;
- verify the overall dimensions of the shields, along their contour, wooden blocks-limiters are nailed;
- shields are interconnected with wooden plates;
- holes with a diameter of 18-20 mm are drilled in wooden slats in places where screeds are passed;
- wooden fights are laid out on top of the shields;
- fights with shields are connected with nails or staples;
- rigidity ties are laid on top of the contractions perpendicular to them, for which the same contractions are used;
- struts are attached to the lower tiers of the bouts or stiffeners, ensuring the stability of the panels in a vertical position.
3.9.5. The formwork shields are installed in the design position according to the risks applied to the crushed stone preparation according to the marking axes fixed on the cast-off, with the simultaneous alignment of the verticality of the shields along the marking axes with theodolites.
The place of installation of the formwork is cleaned of wood chips, debris, snow, ice. When installing shields, you need to monitor the density of their adjoining 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 unfastening them with girders.
