Project for the organization of the construction of a multifunctional residential complex at the address Moscow region Istra st. Working. 1-section 25-storey residential building with built-in attached rooms
- Added: 09.07.2014
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2. Short description of construction site, design solutions
3. Main Construction Solutions
4. Organization of the Geodetic and Laboratory Service
5. Equipment supply and construction quality control
6. Construction needs in personnel, energy
resources, basic construction machinery and transport
facilities, temporary buildings and structures
7. Health and safety measures,
conservation of the natural environment
8. Construction Schedule
Applications: Construction Plan
Construction Site Fencing Diagram
The construction organization project (PIC) was developed in accordance with the "Organization of Construction Production" (SNiP 12012004), "Methodological Recommendations for the Development and Design of the Construction Organization Project, Work Execution Project" (MDS 1246.2008) and is the basis for the development of the work execution project.
When developing the anti-icing system, the requirements of existing regulatory acts and documents for design and construction are taken into account.
The initial data for PIC development are:
- object design task;
- engineering survey materials,
- PIC was developed taking into account the increase in labor productivity, elimination of counter haul transportation, maximum use of the work front, combining construction processes and ensuring their continuity and flow in accordance with the technological sequence.
PIC provides for:
- Use of small mechanization tools;
- reduction of the number of areas and warehouses on the construction site due to installation of structures directly from vehicles;
- Compliance with environmental protection requirements.
Construction structures, parts, materials and equipment shall be delivered within the timeframe ensuring timely entry of the facility.
PIC is designed in accordance with the current norms and regulations and provides for measures to ensure explosion safety and fire safety during construction and operation.
The project provides for the construction of buildings, structures and engineering systems, a complete list of which is presented in the design estimates. Construction and structural characteristics of the designed structures are given in the architectural and construction part of this project.
It is planned to provide construction with construction materials, structures and parts from local plants of the construction industry of the Moscow region and from other regions of Russia under direct contracts.
The adopted scheme allows to ensure the execution of construction and installation works as soon as possible with the organization of work in two shifts.
Prior to commencement of construction the following shall be performed by the customer:
- withdrawal of land for construction in kind has been formalized;
- excavation of the soil quarry for backfilling and the place of landfill of excess soil;
- a geodetic basis has been created and technical documentation for it and for the points and signs of this base fixed on the site, including points of the construction grid, axes that determine the position and dimensions of buildings and structures in the plan along the boundaries and inside the built-up area;
points have been identified and technical specifications have been handed over to the contractor for connection to the networks of temporary (for the construction period) power supply networks.
3.1 Organization of construction in winter.
1. Concrete works in winter conditions
During concrete works under conditions of negative temperatures, cement and concrete aggregates practically do not change, and water freezes in the concrete mixture, which disrupts the connection of aggregates with cement, that is, the hydration process stops. Established ,
that reduced adhesion of concrete to reinforcement is especially important for the operation of structures under load.
Optimum concrete holding temperature 20 ° С .
Concrete works in winter conditions are carried out at average daily outdoor temperature below 5 ° С and minimum daily temperature below 0 ° С. Winterization works shall be carried out according to the work execution projects and process charts.
When performing concrete works, it is necessary to monitor the temperature of the concrete mixture, which by the beginning of concrete holding or heating according to the "thermos" method should not be lower than the value established by the calculation; to the beginning of artificial heating of the concreted structure - not lower than + 5 ° С. Places of unloading of concrete mixture coming to the site shall be protected from wind.
The terms of decompression and loading of concrete structures are established in accordance with the actual temperature conditions specified in the Job Instructions, or after testing of concrete by non-destructive methods. Removal of formwork and heat protection from structures aged by thermos method is performed not earlier than concrete cooling in external layers
up to 0 ° С, during electric heat treatment - after concrete cooling to the temperature stipulated by the calculation, when using anti-frost additives to the temperature for which the amount of additives is calculated, - 30, 25, 20% of the design strength at the grade of 200, 300, 400, respectively.
Temperature measurement results are recorded in the temperature control list. After removing the formwork, the structures should be covered with heat-shielding mats if the temperature difference between the surface layer of concrete and the outside air exceeds 20 ° C for structures with a concrete surface module from 2 to 5 and 30 ° C for structures with a surface module of 5 and above.
In accordance with the requirements of SNiP IIIB.2-62, the choice of the method of holding concrete at negative temperatures should be made under the following conditions. Concrete mixture is laid in insulated formwork (thermos method ),
designed for slow cooling of concrete until design strength is obtained. Heating of concrete with electric current or steam should be used in concreting of thin structures, as well as in cases when it is impossible to apply the thermos method, including chemical additives (hardening accelerators).
The concrete mixture to be laid must be movable. The degree of mobility of the concrete mixture depends on the size of the structures and their purpose, the density of the reinforcement and is determined by the technical viscosimeter. Table 1 shows the concrete mixture mobility during concreting of various structures.
Electric heating and heating of the concrete mixture with the help of electric current is widely used in construction practice. During electrical heating of concrete, all electrical starting equipment must be serviceable and reliably grounded. Heating zones are usually enclosed, and signal bulbs are hung on the fences in the dark. During the entire warm-up period
electric current of concrete must be assigned to the duty electrician provided with protective means (dielectric gloves, tools with insulating handles, voltage indicators, dielectric mats).
The consumption of electrical energy depends on a number of factors: the duration of electrical heating, the volume of heated concrete (structure), the temperature difference of the outside air and the laid concrete mixture .
To calculate the mode of concrete mixture heating, the following is determined:
power capacity for heating 1 m2 of formwork;
power capacity for heating the entire formwork;
specific electric power consumption for the entire volume of heated concrete;
duration of concrete cooling.
Preparation, transportation and laying of concrete mixture in winter conditions .
Concrete mixture shall be prepared in heated concrete mixing rooms (units). It is recommended to use heated water, thawed or heated aggregates. When preparing a concrete mixture only on heated water, it is necessary to load coarse aggregate simultaneously with the bay of about half of the water and load all other components (sand, water and cement) after several revolutions of the drum. Duration of mixing is determined by
the degree of thawing of aggregates or their heating, and in the absence of these indicators, the duration of mixing
should be increased by at least 25% against the summer norm. When transporting the concrete mixture, measures should be provided to prevent its cooling (shelter, insulation of containers, pipelines, as well as places of unloading), while avoiding excessive overloading of the mixture.
When controlling the quality of work, it is necessary to ensure that the base for laying concrete, as well as the laying method, exclude the possibility of freezing the concrete mixture at the junction with the base; The heaving soils were heated to a positive temperature before the concrete mixture was laid; formwork and fittings were cleared of snow; fittings with a diameter of more than 25 mm and
large embedded parts (parts) at air temperature below 10 ° С were heated to positive temperature; the temperature of the laid concrete mixture in the formwork by the beginning of holding or heating was different depending on the applied
methods: when holding concrete under "thermos" conditions (temperature is determined and maintained according to calculation); when using anti-frost additives, it must be 5 ° C higher than the freezing temperature of the solution; when using potash as an anti-frost additive, the concrete temperature in the initial hardening period should be negative; during electrical heating both before the start of preliminary heating of the concrete mixture, and at forcing heating of laid concrete in structures, the temperature should not be lower than 0 ° C in the most cooled places, and when using other treatment methods - not lower than 2 ° C;
concrete maintenance shall be performed in accordance with design provisions, cover immediately upon completion of concreting with hydro and heat-insulating materials unpaved surfaces of concrete and reinforced concrete structures.
Concrete and reinforced concrete works carried out in winter conditions shall be under strict control. The quality of the materials and products used should be systematically checked; water heating temperature; aggregate and concrete
mixture at unloading from concrete mixer (every 2 hours); dosing anti-frost additives; implementation of measures for
shelter, insulation and heating of containers during transportation and acceptance of concrete at the construction site with inspection of at least
once per shift; compliance of the formwork thermal insulation with the requirements of Job Instructions, and, if necessary, heating
joined surfaces and soil base; temperature of laid concrete when using methods of "thermos," preliminary electrical heating of concrete mixture, with steam heating in heaters - every 2 hours in the first day, at least twice a shift in the next three days and once a day in the rest of the holding time; when using concrete with anti-frost additives - three times a day before acquiring its design strength; during electrical heat treatment of concrete during the period of temperature rise at a rate of up to 10 ° С per hour - in 2 hours, further - at least twice per shift; temperature
outdoor air at the end of concrete holding and smelting - 1 times per shift; strength, frost resistance (external
structures), waterproof and other qualities of concrete; correct arrangement of seams, placement of holes, openings and
projections, installation of embedded parts; thickness of protective layer, compliance with its regulatory requirements.
During concreting of the structure, the following additives are added to the concrete mixture, which reduce the freezing temperature of water in the concrete:
sodium nitrite (LV) NaNO2 (GOST 1990674);
calcium chloride (CC) CaCl2 (GOST 45077) + sodium chloride (CN) KaCl (GOST 1383068);
calcium chloride (CA) + sodium nitrite (LH);
calcium nitrate (NK) Ca (NO3) 2 (GOST 414277) + urea (M) CO (NH2) 2 (GOST 208175E);
Preliminary electrical heating of concrete mixtures is carried out in specially equipped portable silos or
directly in the bodies of car dump trucks; if the mixture is discharged directly into the formwork, then by means of electrodes ,
immersed in concrete mixture.
Distance between electrodes, m, is determined by formula, where - distance between adjacent electrodes, m; - voltage per
electrodes, B (220 or 380 V); - design specific electrical resistance of heated mixture, Ohm (determined with
using an electric discosimeter or can be taken approximately 8 ohm); - specific power, kW/m3.
The heating time of the mixture is on average 5... 10 min. Temperature of heated concrete mixture shall not exceed 80 ° С.
The mixture is laid during 20 minutes after its heating.
Infrared heating is used for heat treatment of concrete in thin-walled structures with a large surface modulus (walls erected in sliding formwork, slabs, beams), as well as monolithic joints.
The source of infrared radiation is TENs of the HVSV or NVA type or rod carbord emitters of diameter
6... 50 mm, length 0.3... 1 m. TEN power by 1 m of length ranges from 0.6 to 1.2 kW, the temperature of the radiating surfaces from 300 to 600 ° С. Infrared emitters are released at 127, 220 and 380 V. Carborundum emitters have a power of up to 10
kWh and operating temperature 1300... 1500 ° С.
Concrete hardening occurs as a result of its peripheral heating (Fig. 5.1). The optimal distance between the emitters and the heated surface 1... 1.2 m.
It is possible to heat both open surfaces of concrete and through formwork. For better absorption of infrared radiation, the formwork surface is coated with black matte varnish. Open surfaces of concrete are closed to avoid drying
polymer film, pergamine or ruberoid. The temperature on the concrete surface shall not exceed 80... 90 ° С.
For heat treatment of linearly extended densely reinforced structures (columns, beams, pipes, channels), induction heating is used, as a result of which steel reinforcement or formwork is heated in an alternating magnetic field, which is created by passing alternating current through the winding of a spiral or flat inductor.
To supply inductors, an alternating current of industrial frequency of reduced or network voltage is used. Energy consumption 120... 150 kWh/m3.
During the first 2... 3 h after laying, the concrete mixture is kept at a temperature of 5... 8 ° C, which is achieved by periodically turning on the inductor for 5...... 10 min every hour. Then the concrete temperature is increased at a rate of 5... 15 ° C. After concrete reaches the design temperature, the stress is either switched off and the concrete is held by the thermos method or switched to the inductor pulse mode of operation.
Induction heating has a number of advantages: it ensures uniformity of heating in section and length of structures, eliminates metal consumption on electrodes.
Steam heating of concrete is carried out by saturated steam.
For this purpose heat is arranged, structure is covered with several layers of tarpaulin or heat jackets are arranged around formwork. Outside the box is insulated. Steam under the tarpaulin or into the boxes is delivered using rubber sleeves through 1.5... 2 m. The steam heating mode is standard.
It is recommended to conduct steam heating of concrete up to the set of design strength or values close to it. Steam heating in heaters is used to withstand concrete of foundations, shoes and foundation slabs.
Steam jackets are arranged during concreting of columns, girders, beams and slabs of intermediate floors with = 10... 20 m-1.
During electric heating current is passed directly through mass of laid concrete with the help of electrodes. The electrodes can be internal (rod and string) and surface (sewing, stripe and floating).
Heating with electrodes is carried out at voltage within 50... 100 V using transformers. Application
120... 220 V is possible only with electrical heating of concrete and slightly reinforced (not more than 50 kg of reinforcement
on 1 m3 of concrete) structures; 380 V is possible only if the electrodes are connected with a zero wire so that the working voltage in concrete does not exceed 220 V. Electrical heating at a voltage in the network above 380 V is prohibited.
To connect the electrodes to the wires, soffits are used, which are wooden boards (length 3... 4 m, width 16... 20 cm, thickness 2.5...... 4 cm) with rollers, to which three insulated wires with unseals from wires with a section area of 1.5 mm2 are attached. The taps are connected to the electrodes, and the wires are connected to the network. Electrodes, regardless of type, are connected to
different phases singly or in groups.
Concrete temperature rise rate shall be not more than 5 ° С/h for structures with = 2... 4 m1; 8 ° С/h s = 4... 6 m1; 10 ° С with = 6 m1; 15 ° С/h - for frame and thin-walled structures with a length of 6 m; 20 ° С/h - for joints.
Concrete cooling speed at the end of heating shall not exceed 8 ° С/h. Concrete warm-up temperature - not more than 80 ° С for
instructions from < 10 m1, 60 ° С with = 10... 15 m1, 40 ° С with = 15... 20 m-1.
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