Course project - Arrangement of pit and monolithic pit

Contents

Introduction

Preparatory work

Earthworks

Calculation of excavation volume during pit installation

Selection of a set of machines for pit development

Backfilling and soil compaction

Safety in earthworks

3. Job Instruction for Foundation Arrangement

3.1 Scope of Job Instruction Application

3.2 Procedure and organization of works performance

3.2.1 Selection of a set of machines according to the arrangement of monolithic pedestal

Technology of winter concreting by method of thermoactive (heating) formwork

3.3 Quality control and acceptance of works

3.4 Calculation of labor and machine time

3.5 Logistical resources

3.6 Safety precautions

3.7 Technical and economic parameters of Job Instruction

3.8 Occupational safety

List of literature

Introduction

In this course work, the technology for digging the pit and the device of the monolithic pile pile are designed. Works are performed in the following sequence: preparatory work, ditch device, grillage device. By the beginning of piling works excavation works shall be completed and accepted. The technology and acceptance of earthworks is performed according to the design and JV.

After the piles are submerged, concrete works are performed on the structure of the pile pile. The pedestal is made of concrete in order to transfer the load from the building structure to individual piles.

The design of the works should be carried out taking into account the maximum mechanization of labor-intensive processes and taking into account the best practices of the region, federation, including foreign experience.

Objectives and objectives of the course project.

The purpose of the course project is to obtain theoretical knowledge and skills of independent technological design, compile technical and economic measures to perform works and cycles within the established time frame with minimum costs not exceeding the estimated cost, ensure safe methods of performing works, perform works taking into account the requirements of the project and standards for the quality of works.

When developing the task list, it is necessary to take into account the achieved construction experience, taking into account the maximum mechanization of labor-intensive processes and ensuring labor safety.

Preparatory work

One of the important stages of the construction of buildings and structures is the preparation of the construction site for the start of construction and installation work, which is carried out, as a rule, before the start of construction and in some cases reaches about 30% of the total construction duration.

The contracting organization, after concluding an agreement with the customer-developer and obtaining permission to carry out work, must perform a complex of off-site and on-site preparatory work, for which a work project is necessarily being developed.

Off-site preparatory work includes the construction of access roads, power lines, water supply networks, sewage collectors with treatment facilities, residential settlements for builders, as well as the creation (if necessary) of a production base of construction and installation organizations.

The on-site preparatory works include: engineering and geological surveys, the creation of a geodetic basis for construction, the clearing of the territory for construction and installation work, the demolition of buildings, the planning of the territory, the removal of surface groundwater and artificial lowering of the ground water level, the shifting of existing and laying new engineering networks, the arrangement of temporary roads, providing the site with temporary fencing, lighting, fire water supply and necessary equipment.

Job Instruction for Foundation Arrangement

3.1 Scope of Job Instruction Application

The Job Instruction contains requirements for the pile pile arrangement. The pit is 2.85 m deep, the type of soil is sandy. Piles are clogged before device of pile pile. The thickness of the sand preparation should be taken as 100 mm. Concrete preparation 100 mm thick class B7.5. Cast-in-situ pedestals are made of reinforced concrete using concrete of class B30 and hot-rolled reinforcement of class AIII. Mating of the pedestal with piles is provided as rigid .

Instructions on the technology and organization of work performance, quality control, safety, labor protection are given, calculation of labor costs and machine time, technical and economic indicators are given.

The map is intended for manufacturers of works, craftsmen and foremen, as well as employees of technical supervision of the customer and engineering and technical workers.

The process sheet is made in accordance with the requirements of SP 70.13330.2012 "Load-bearing and enclosing structures," SNiP 12032001 "Safety in construction" Ch.1 "General requirements" and SNiP 12042002 "Safety in construction" Ch.2 "Construction production," industrial safety standards and PPB - 01 - 93 "Fire Safety Regulations of the Russian.

3.3 Technology of winter concreting by method of thermoactive (heating) formwork

During winter concreting use thermoactive formwork of "Antey" brand. Thermoactive (heating) formwork is called multilayer shields, which are equipped with heating elements and insulated. Thermoactive formwork operates from electric current with voltage 40... 121 and 220 V, estimated electric power consumption per 1 m3 of heated concrete 100... 160 kWh.

When using thermoactive formwork, the temperature of the concrete mixture at the time of laying should not be lower than + 5С. Heating is carried out depending on surface modulus at 35... 60C with temperature rise rate 5... 10C/h.

To reduce heat loss and create a steaming mode in the heated zone, it is recommended to cover concreted sections of structures during heating with polyethylene film, tarpaulin or ruberoid. The same is recommended after the removal of the thermoactive formwork, which eliminates the sharp cooling of concrete and the occurrence of cracks as a result of temperature stresses.

Heat is transferred through the deck of the board to the surface layer of concrete, and then spreads throughout its thickness. Concrete heating in this way does not depend on the ambient temperature. The heating formwork is used in the construction of thin-walled and medium-massive structures, as well as in the soaking of joints and seams at ambient air temperature up to - 40 ° C.

The structures of the heating formwork are manifold. The main requirement for them is the uniformity of the temperature distribution along the formwork of the shield.

The heating elements are tubular electric heaters (TENs), heating wires and cables, flexible fabric tapes, as well as heaters made of nichrome wire, compositions of polymer materials with graphite (carbon tape heaters) and conductive elements, etc.

Tubular electric heaters consist of tubes (steel, copper, brass) with a diameter of 9... 18 mm, inside of which there is a nichrome spiral. Space between spiral and tube walls is filled with crystalline magnesium oxide. The heating temperature of the TENs 300... 600 ° С, so they should not contact the surface of the formwork adjacent to the concrete, but be located from it at a distance of 15... 20 mm.

Wire heating elements are made of nichrome wire with a diameter of 0.8... 3 mm, which is wound on a frame of insulating material and insulated with asbestos. Such heaters are less reliable, as they are subject to deformation during loading and unloading operations, so they require a careful ratio.

As heating cables, cables of the type PSTN or KVMS are used. They consist of a constant wire with a diameter of 0.7... 0.8 mm, placed in a heat-resistant insulation. The insulation surface is protected from mechanical damage by a metal protective stockade.

Heaters are placed on the formwork panel depending on heating modes and power: heating wires and cables are installed close to the deck, TENs - at a short distance from it.

In a plywood heating formwork, heating cables and wires are pressed into protective coatings consisting of a stack of thin polymer films.

Carbon tape heaters are glued with special adhesives to the deck of the shield. In order to ensure strong contact with the switching wires, the ends of the belts are meditated.

TENs are attached to the inside of the deck of the boards using special retainers and pressure plates, and heating wires (cables) - using sheet plates of asbestos. The insulation shall be protected against damage by a protective casing. To connect the formwork boards to each other, recesses are left in the protective casing in accordance with the position of the fixing holes. Fork connectors are used to connect the boards.

Before installation of thermoactive panel formwork, the integrity of insulation and electrical wiring shall be checked by inspection. Formwork is installed in concreting unit by separate boards manually or by enlarged panels by means of cranes. Shields and panels are attached in the same way as in summer conditions. After attachment, boards and panels are connected to the electrical network. Installations for power supply of thermoactive formwork and control of concrete heating mode consist of a torus step-down transformer, a wiring system, a control panel and a room for an electrician or operator on duty. The plant provides power to the 100... 150 m formwork.

The formwork is connected to special terminal boxes, which are located above the surface of the formwork not lower than 0.5 m. When heating the frame elements (columns, girders, beams), the terminal boxes are suspended from extendable tubing installed at a distance of 50... 70 cm from the heated element.

Before concreting, reinforcement and previously laid concrete are heated. For this purpose thermoactive formwork is switched on for a short time, preliminary covering the concreting unit with tarpaulin or polyethylene film from above.

Minimum temperature of laid concrete mixture is 5 ° С. It is laid by conventional methods, while ensuring that the electric cable is not damaged and the insulation is not moistened. At wind speed more than 12 m/s, formwork forms are covered with tarpaulin or polymer film.

Observance of the process heating mode allows to obtain concrete of the required physical and mechanical characteristics. Controlled heating parameters are concrete heating speed, temperature on the board deck and heating duration.

Shields are transported and stored in vertical position in cassettes or stacks. When stored in stacks, wooden gaskets are installed so as not to damage the electrical connectors.

Staple glass fiber with foil shielding layer is used for heat insulation. The coating should have good waterproofing as its surface is in contact with the liquid phase of the concrete. The working layer of rubber is generally reinforced with fiberglass. Cotton fabric parts are impregnated with fire-retardant compositions.

Holes 9 are provided for passing the strap or clamps to attach the coatings to each other. Coatings can be placed on vertical, horizontal and inclined structures. Power supply of TAGP is carried out from step-down transformers with voltage 36... 120 V. Like the panels of the thermal formwork, TAGP is equipped with temperature sensors with output of indicators to the control panel. This allows you to quickly monitor the warm-up mode.

At the end of the work, it is rolled up and placed in a special two-section cabinet. In one section there is transformer with control board, and in the other - compartments for coating storage. Special mobile stations equipped with transformers, compartments for storing cable wiring and TAGP set are used.

Before works start, state and operability of heating equipment and temperature control automation are checked. The general layout of the coating on the concreted structure, its switching and warm-up modes should be given in the work design. In order to comply with the process mode of concrete heating, the concrete temperature should be measured at least after 1 hour and the outside air temperature should be measured at least once.

Movement of people on heated structures is allowed with concrete strength of at least 2.5 MPa. Concrete should be warmed up for at least 30 hours.

Requirements for concrete works at negative temperatures:

1. At average daily ambient air temperature below 5 ° С and minimum daily temperature below 0 ° С it is necessary to take special measures to maintain laid concrete in structures and structures.

2. Transportation methods and means shall ensure prevention of concrete mixture temperature decrease below the design required during its laying in the structure.

3. The condition of the base on which the concrete mixture is laid, as well as the temperature of the base and the method of laying, should exclude the possibility of freezing of the concrete mixture in the contact zone with the base. When holding concrete in the structure by the method of thermos, during preliminary heating of the concrete mixture, as well as when using concrete with anti-frost additives, it is allowed to lay the mixture on an uncoated non-granular base or old concrete, if, according to the calculation, it does not freeze in the contact area during the design period of concrete holding. At air temperature below minus 10 ° С, concreting of densely reinforced structures with reinforcement of diameter more than 24 mm, reinforcement from rigid rolling profiles or with large metal embedded parts should be carried out with preliminary heating of the metal to a positive temperature or local vibration of the mixture in the armature and formwork zones, with the exception of laying of pre-heated concrete mixtures (at mixture temperature more than 45 ° С).

4. Before the concrete mixture is laid, cavities after installation of reinforcement and formwork must be covered with tarpaulin or some other material from snow, rain and foreign objects. If cavities are not closed and ice is formed on the reinforcement and formwork, it should be removed before laying the concrete mixture by blowing with hot air. Steam is not allowed for this purpose.

5. Contact heating of laid concrete in thermoactive formwork should be used when concreting structures with surface module 6 or more. After compaction, the exposed concrete surfaces and adjacent sections of thermoactive formwork panels shall be protected against concrete loss of moisture and heat.

6. If the ambient temperature is negative, the structure shall be waterproofed or heated. Thickness of heat insulation is assigned taking into account ambient air temperature. When heating concrete with anti-frost additive, the possibility of local heating of surface layers of concrete above 25 ° С shall be excluded. To protect against moisture freezing, the exposed surfaces of freshly laid concrete together with the adjacent surfaces of the formwork must be safely covered.

7. Open surfaces of laid concrete in monolithic joints shall be reliably protected against moisture freezing. In case of cracks in joints it is necessary to expand them only at stable positive air temperature.

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