Installation technology of prefabricated reinforced concrete structures of industrial buildings

Contents

Introduction

1 Space planning solution

2 Determination of erection quantities

2.1 Layout of the building in layout axes

2.2 Specification of prefabricated elements of building structures

3 Selection of small mechanization tools for erection of building structures

3.1 Load grippers

3.2 Devices for adjustment and temporary fixation of structures

3.3 Accessories providing the workstation of the installer

3.4 Calculation of four-branch sling

3.5 Tools and equipment for installation

4 Calculation of technical parameters of installation of rafters and selection of crane for building erection

4.1 Installation of columns

4.2 Installation of adjustment trusses

4.3 Installation of rafter trusses

4.4 Installation of coating plates

4.5 Installation of wall panels

5 Organizational methods and calculation of installation works productivity

5.1 Selection of vehicles for the delivery of structures

5.2 Calculation of vehicle performance

5.3 Sizing the installation area

5.4 Calculation of installation works productivity

6 Technical and economic evaluation of assembly according to planned calculation indicators

7 Construction structure installation technology and work schedule

7.1 Installation technology of reinforced concrete structures

7.2 Safety precautions

7.3 Quality Control

7.4 Calculation of labor costs

7 Construction structure installation technology and work schedule

Introduction

Installation of building structures is a complex-mechanized process of in-line assembly of buildings and structures from elements and structural units of factory manufacture. All works of the underground part of the building shall be performed prior to the start of installation works.

During installation, the invariability and stability of each mounted structure or cell of the structure shall be ensured. The installation sequence should provide for the possibility of delivery of individual areas of the structure for finishing or installation of equipment in a given time frame.

Erection of building structures consists of preparatory and basic processes.

Preparatory processes include transportation, warehousing and pre-assembly.

The main processes are preparation for lifting and lifting of structures, alignment and temporary fixation, grouting of joints and seams, as well as corrosion protection of structures.

Installation of building structures is performed according to the process design of installation works - PMTCT. Process design is designed to develop optimal technological solutions and determine the main organizational conditions for the implementation of construction processes, works, construction of a building or structure as a whole. The purpose of the design of the work is to choose the technology and organization of their execution, which will allow to carry out the construction of the facility in the required time, with the proper quality and reduce the cost of work. The optimal solution can be achieved on the basis of the typification of the project, the industrialization of the construction of the building framework and the entire cycle of finishing work, the use of complex mechanization and advanced electrified manual tools.

Space Planning Solution

Dimensions in the axes of the building: 216x96 m.

Temperature block size: 72 m.

Building height: 10.800 m.

Overall height of the building: 14.400 m.

Structural diagram of the building: frame.

Wall enclosing structures: single-layer reinforced concrete panel.

Roof: rolling, roll, with organized drainage.

Selection of Work Options

2.1 Work Execution Options

1. For arrangement of elements supply for installation

From vehicles.

2. By the degree of enlargement of structures

Element-by-element. Installation of structural elements in the design position.

3. According to the method of bringing the structure to the design position

Free installation (with vertical expansion).

Installation diagram.

1. According to the sequence of installation of structures in the design position.

Complex

2. By location of installation cranes.

Longitudinal within the outline of the building.

Selection of small mechanization tools for erection of building structures

4.1. Load grippers

For the process diagrams adopted for the design of the building erection, we select load gripping and slinging devices, devices for temporary fastening of structures in the design position, as well as means for organizing workplaces.

When erecting objects from prefabricated elements, various mounting devices are used. A special place is occupied by cargo grips, which include slings, grips and crossarms of various structures and assignments.

The load gripping devices are designed for reliable connection (suspension) of the lifting element to the crane hook and its release after temporary fixation. They are also necessary for the share of removal of structural elements from vehicles during storage or delivery from the acquired warehouse to the place of installation.

Main principles of load-gripping devices operation:

engagement of structures using flexible slings and crossbars;

gripping by means of tick-borne devices;

clamp using friction grips;

suction with vacuum grips.

Selection of gripping devices will be made for each structural element of the building

The lifting of prefabricated reinforced concrete elements is mainly carried out by loops laid in concrete during the manufacture of products. The disadvantage of this method lies in the need for a reinforcement steel cost per loop arrangement. Saving steel and increasing labor productivity is achieved by using loopless grips.

For the installation of columns with special holes in the body, crossarms are used. Grippers of two metal cheeks are used as load-gripping devices, which, embracing the mounted elements, hold them with the help of rod put in them.

To ensure the safety of long prefabricated reinforced concrete structures, rigid crossbeams are used, which consist of a metal beam with slings attached to it to capture the mounted elements. Load gripping devices for trusses are selected depending on their weight and length, as well as the presence of mounting holes or various protrusions in the element.

Four-branch slings are used to lift the coating plates.

Wall panels and partitions, which are in vertical position, are installed using a two-branch sling, selected taking into account the weight, length and material of the mounted structures.

Installation technology of building structures

12.1 Installation of columns

Before installation of columns it is necessary to check their dimensions, the error of which should be not more than 1 mm; Apply hairlines that facilitate the installation of columns in the foundation sleeves or on the headers of the sub-columns. The columns are previously delivered to the installation zone and laid out with tops facing the foundation. If necessary, bottom of foundation cup is leveled with layer of cement mortar. Columns are installed in the foundation only after the strength of the solution has reached 70% of the design strength. Installation of columns is performed by method of free or limited-free installation. In the first case, various systems of wedges and inventory wedge inserts are used for temporary fastening and reconciliation, in the second - single conductors. If the height of the columns is more than 8 m and the mass exceeds 5 t, temporary fasteners in the form of braces attached to adjacent foundations or special anchors (for extreme columns) are used. Column is installed in shell of foundation, centered till hairlines coincide with hairlines on upper plane of foundation. Temporary fixation and reconciliation of the column is carried out by inventory screw wedges while holding it on the crane hook. At the same time installers with theodolites check the column verticality in two planes. At their command, installers using screw wedges correct minor deviations of the column from the vertical. In case of significant deviations, vertical reconciliation is carried out using clearing. After reconciliation and temporary fixation, the lower ends of the braces are fixed to slinging loops on neighboring foundations or to inventory anchors installed in the ground.

12.2 Installation of rafters and adjustment trusses

Unloading of trusses and beams on the site, laying and installation of elements is carried out usually by an automobile crane in the area of ​ ​ the crane. Installation of these structures can be carried out with pre-laying of elements or directly from vehicles. The trusses and beams are laid out in such a way that the crane from the installation parking lot can set them in the design position without changing the boom departure. To ensure the stability of the mounted elements on the ground, they are stored in special cassettes. When delivering structures to the object in significant quantities, temporary storage in group cassettes without laying out in the installation area is allowed.

For truss slinging, crossarms equipped with grips with remote automatic or semi-automatic disassembly shall be used.

Trusses and roof beams should be installed in the design position, combining axial hairlines at their ends with hairlines on the supporting surfaces of the underlying ones. Elements are secured by conductors pre-installed on column heads. Disassembly is performed after installation of spacers and welding of bonds to upper belts.

After lifting, installation and alignment, the first truss is braced with braces, which are fixed to rearranged inventory anchors or pre-installed and frozen columns, the following are connected to each other by special struts having a rigid size of 6 or 12 m in axes. After installation of the first pair of trusses, 8 coating plates are laid on them to create an initial rigid system. Then all temporary fasteners are removed, i.e. all inventory spacers and braces are removed as the coating plates are laid and welded. At the same time, all permanent connections provided for by the project should be established with the farms.

12.3 Installation of coating plates

The coating plates are pre-stored in the area of the installation crane. Installation begins after complete fixation of the girders. The bonding plates are laid on the girders shelves after the girders are welded to the column consoles. In multi-storey columns, first, bond plates of the lower and then upper floors of the tier are laid.

Slinging of slabs is performed by traverse. The row slabs of the first floor and then the next floors are laid on a layer of mortar or cement paste. If necessary, preliminary level of support surfaces is leveled with layer of cement mortar. Panels are lifted by loops.

The installation of the coating plates begins with the laying of the extreme plate, the laid plate is immediately welded. After laying of all row plates of cell embedded parts of plates are welded to embedded parts of girders. Laid plates are fixed to each other by means of steel straps on welding, and to external walls they are connected by means of anchors. Seams between slabs are sealed with cement sand mortar on fast-hardening cement or fine-grained concrete mixture.

Once all frame elements have been secured to one floor, the next floor elements are installed.

During installation and fixation of the plate, the installers prepare the next plate for lifting. When installing the extreme plate, the installers rise to the coating and install a temporary fence.

After the plates are installed, the joints are frozen. Installation is most often carried out by a separate flow immediately after concrete has gained the necessary strength in the joints between the columns and foundations.

12.4 Installation of wall panels

Wall panels are mounted between columns to the entire height of the building. Slinging of panels with length of 6 m is performed with two-branch slings.

When installing external panels, the accuracy of mounting is of particular importance for the panels to perform not only enclosing, but also aesthetic functions. Therefore, it is necessary to observe the dimensions of the joints, the proper quality of their finishing, the preservation of the faces of the face surfaces.

During geodetic check of accuracy of works execution it is controlled: for panels of the first row - alignment of the bottom face of the panel with risks of laying axes; Aligning faces of adjacent or overlapping panels verticality of faces of installed row of wall panels.

To uncover horizontal seams or apply sealing mastic from the outside, to seal vertical seams between panels, scaffolds or lifting cradles are used, which are located on the outside of the span after moving the installation crane to the next parking lot.