The variety of structural solutions for buildings and structures requires the use of various methods and techniques for their installation. The choice of the method of building a building depends on its design and technological features, the degree of enlargement of elements, the material of the structures, the means of mechanization and other factors.
Methods of installation of structural elements are directly dependent on the degree of enlargement of mounting elements, the sequence of assembly of prefabricated elements, the method of installation of structures in the design position, means of alignment and temporary fixing of elements and other signs.
Installation methods according to the degree of integration of elements. Depending on the degree of enlargement of structures, installation is divided into small-element, element-wise, large-block, complete-block and installation of structures in finished form.
Small-scale installation of individual structural elements is characterized by considerable labor-intensiveness, incomplete workload of mounting mechanisms due to the large difference in the masses of the various mounted elements, a large number of lifts, and the embedding of numerous joints. Often there is a need for a scaffolding device for fixing individual elements and pre-assembly directly in the structure. The method is not very effective and is used extremely rarely.
The element- wise installation of individual structural elements (columns, girders, floor panels, etc.) requires a minimum of the cost of preparatory work. It is widely used in the construction of civil and industrial buildings, their installation from an on-site warehouse and from vehicles.
Large-scale installation of geometrically immutable flat or spatial blocks, pre-assembled from individual elements. The mass of blocks is adjusted, if possible, to the maximum carrying capacity of the assembly mechanisms. This reduces the number of installation lifts, eliminates the implementation at the height of the majority of installation operations. Examples of a flat block are the frame of a high-rise building frame, a covering shell block; spatial elements - blocks covering single-storey industrial buildings of the size of a cell, including trusses, connections, and coating structures.
Complete-block installation implies a full degree of factory readiness of large blocks of size per cell, including already mounted communications - sanitary, electrical, ventilation, located between the belts of farms. In civil engineering, the method includes the installation of block rooms and block apartments. The erected building is divided into large-sized, but transportable structurally finished, fully finished (painted, finished, floors) and equipment-equipped mounting blocks that deliver to the place of installation and carry out the assembly of buildings. The mass of such assembly units can reach 100 tons.
Installation of structures in finished form involves the construction of the structure completely at ground level with the final connection and fixing of all nodes with the subsequent installation of the structure in the design position. Apply the method for the installation of supports of power lines, radio towers, shells, factory pipes, etc.
Methods of targeting mounting elements on supports. Depending on the method of installation in the design position the following types of installation are distinguished.
Free installation , in which the mounted element without any restrictions set in the design position with its free movement. The method requires constant control of the position of the element in space during its installation, the need to perform alignment, mounting and other operations at height. The disadvantages of the method is the increased complexity and high complexity of the work.
Restricted-free installation is characterized by the fact that the mounted structure is installed in guide stops, latches and other devices, which partially restrict the freedom of movement of the structure, but which leads to a decrease in labor costs for temporary fastening and alignment. The method improves the performance of crane equipment by reducing the time of the installation cycle.
Forced assembly of a structure is based on the use of conductors, manipulators, indicators, and other means ensuring the total or specified restriction of the structure's movements from the action of its own mass and external influences. The method provides improved accuracy of installation, leads to a significant reduction in labor costs.
Installation methods according to the sequence of installation of elements. When assembling structures of buildings and structures, it is necessary to observe the following requirements:
■ the assembly sequence should ensure stability and geometric unchangeability of the mounted parts of the building at all stages of installation;
■ installation of structures on each building site should allow for further work on the installed site;
■ safety of installation, general construction and special works at the facility, taking into account their implementation on a combined schedule.
Depending on the adopted sequence, the installation of structural elements is carried out by the following methods: differentiated (separate), complex and mixed (combined).
Differentiated or separate method is characterized by the installation of similar structural elements, including their temporary and final consolidation. For single-storey industrial buildings, all columns are first installed, then all crane beams, and wall elements are hung at the last penetration of the erection crane. In multi-storey residential buildings wall panels, partitions, sanitary ware cabins and other elements are successively mounted. Work is completed on the floor laying panels.
The complex method provides for the sequential installation, temporary and final consolidation of various structural elements that make up the skeleton of a single cell of the building. The installation of the elements of another cell begins after the design consolidation of the structures of the previous cell. The advantage of this scheme is the possibility to proceed to the subsequent finishing works and the installation of process equipment in the cells, completed with the installation. The method is used in the installation of multi-storey frame and frameless buildings, single-storey industrial buildings with a metal frame.
Mixed or combined method is a combination of separate and complex methods. Installation by a mixed method is most often used for single-storey industrial buildings from precast concrete. In the first assembly flow, all columns are installed, in the second flow, crane girders, roof trusses and coating panels are mounted in the cells, wall panels are hung in the third flow. The method is effective when it is possible to provide each installation stream with independent installation means. Installation with the required time shift can be provided by all three mounting mechanisms, which leads to a significant reduction in the installation time.
Что бы оставить комментарий войдите
Комментарии (0)