Light metal frame (Lightweight Steel Frame or LSF)
The LSF system is the fastest method in the construction industry, which is based on Canadian and Australian standards. This system is one of the most suitable construction systems used in the world today.
² Design:
In order to properly design the LSF structure, it is necessary to model the structure in three dimensions and with high accuracy with all the details. This work is done by the dedicated FRAME BUILDER software of the genesis company as one of the most advanced structural design software in the world with distinct characteristics. Professional design along with providing executive details in all buildings. The above software provides all the necessary information, maps and solutions to improve the construction operations and also the optimal economic efficiency in the use of frames made of LSF light steel at the disposal of executives, customers and users.
After creating a 3D (virtual) model of the desired building, appropriate framing is done based on calculations and engineering principles, and then plans for the production and installation of panels are prepared, taking into account all the details and engineering considerations.
Maps are divided into different groups as follows
:
1- Map of walls and ceilings and related connections, including the size of structural members, thickness of sheets, distances between members, location of load-bearing and non-load-bearing walls, details of connections and considerations related to regulations.
2- Plan of the roof and trusses (if necessary) and the related connections, including plans for the production of trusses, windproofing of roofs, connections and regulatory points.
² The most important features of the LSF system:
1- The LSF light steel structure system is the most suitable method for adding one or two floors to buildings that have already been built because:
1-1- Due to the lightness of the consumables, no additional load is placed on the underlying structure.
1-2- There are no traditional construction problems and dirt that often cause problems and dissatisfaction of the residents of the lower units.
1-3- The execution time will be very short and fast.
1-4- After the execution of the facade, the facade of the added floor will be completely identical with the other floors below.
1-5- With a beautiful roof, you can give a special glory to the whole building.
1-6- All the requirements of the building standards are met.
2- LSF style steel structures system is the most suitable method for building villas in different areas because:
2-1- The main advantage of this system is the considerable speed in its implementation, so that the duration of the implementation of a finished villa unit is about 60 working days.
2-2- In this system, the structural components are connected with screw joints and form an integrated earthquake-resistant building system.
2-3- By performing the roof with attractive designs and covering with beautiful panels, you can give a special effect to the villa.
2-4- Due to the fact that the material of all the profiles is galvanized, the structure will be very resistant to corrosion and rusting, especially in harsh weather like the northern and southern regions of the country.
5-2- The sound insulation in this system significantly reduces the transmission of environmental sounds inside the building and as a result provides the highest level of peace and comfort in the interior space.
2-6- All materials used in this system have high resistance against fire.
2-7- Due to the use of prefabricated materials and the short installation time and small volume of transportation, it is possible to build a villa in the most distant mountainous and forest places.
3- LSF style steel structures system is an advanced structural system that is used in all kinds of constructions such as villas, residential, office and industrial buildings with one to three floors, hotels and apartment hotels, school and university buildings, restaurants and …. It has application. In this system, the structural components are connected with screw connections and form an integral building system resistant to wind, earthquake, snow, etc.
² Different parts of the light steel structure:
1- Foundation: To transfer the load of a structure to the soil, an intermediate structure is needed to transfer this load to the ground without causing much deformation. In the light steel frame system, due to the low weight of the structure and beams, strip foundations are used, and if the soil is weak, wide foundations are used. The thickness of the foundation in this structure is very small due to its lightness and is considered as the minimum value.
Connecting the light structure to the foundation is done using the following two methods:
*A: Installation of columns (vertical members of the structure) to the foundation, which are directly connected to the foundation through connecting rods.
*B: Connecting the lauk (horizontal members of the structure) to the foundation, in this method, the lauks are first tied to the connecting rods of the foundation and then the columns are connected to the lauks.
2-False floor: This system is used to place the finished floor of the building higher and create an empty space under the structure, and by creating an empty space on the floor of the structure, in addition to natural ventilation under the building, in humid areas and from gathering It prevents moisture and water, and also makes the sewage network simple and prevents the entry of insects and vermin.
3- Floor structure: In this part of the structure, beams are connected to the main beams and form the floor frame. The final covering of the floor structure can be made of concrete or other coverings.
² Components of LSF:
LSF structures are produced as panels and the components of each panel are:
:
:Stud, upright load-bearing members::Track, connecting members of the frame
Joist: Roof bending members: Flat Strap: Lateral load-bearing members
These buildings consist of 3 main components: sections made of cold-rolled steel sheets for the structure, plasterboard plates as the inner layer of heat and sound insulation, and also the connections of this system are in the form of automatic screws and CO2 welding in factory conditions. The sections used in this system are U, C, and Z, which are usually connected to each other with cold connections.
Each wall consists of a number of general C-shaped components (master) at intervals of 40 to 60 cm, which are connected at the top and bottom to the horizontal components of the U or C-shaped gutter (track or runner). If the C-shaped sections are used as a track (runner), it is necessary to make cuts at the installation site of the master.
Studs:
The C-shaped sections that are installed vertically are called Studs, which are used as load-bearing walls and bear the pressure of the incoming load.
It is a gravity-bearing structural system that can be combined with other structural systems, such as structural reinforced concrete walls. It is used as a mixed structural system in short buildings. The use of its various forms has been allowed according to the regulation. Its sections have various dimensions and the range of thickness changes is between 2.5 and 0.6 mm. The connection of LSF to the foundation is formed by a horizontal coil with section c. The vertical components act as a column bearing member in gravity loads, some of these members in the opening of the lateral bracing of the structure, in addition to the gravity load, also bear the forces caused by the lateral load, which are introduced in the system under the name of stud. The roof of these structures consists of cold-rolled metal beams. Beams and beams mainly have sections with c and z shapes. The roof covering with concrete slab can be designed as a metal composite roof if there is a necessary integration between the concrete and the steel profile of the beam. In order to carry the lateral load of the structure along the main orthogonal length, lateral load openings are used (Load Bearing Wall).
Load-bearing openings are created in 4 ways:
1. Bracing opening system with diagonal members
2. Shear wall system with thin steel sheet
3. Bearing wall system with OSB coating
4. Reinforced concrete shear wall system
that bracing with diagonal members is allowed for residential buildings up to 2 stories and the side bearing system of reinforced concrete shear walls up to 4 residential stories is allowed. Low heat transfer makes it difficult for permanent use such as: residential buildings, but its performance is suitable for intermittent use. Is. The sound performance of the built walls and ceilings meets the expectations of the national building regulations if the measures are followed.
LSF forming materials do not have a fire load, but cold rolled profiles have little fire resistance and must be well protected, which is one of the reasons for using plaster as an internal coating to achieve this goal.
Trucks
The U-shaped sections that are installed horizontally in the structure are the runners that are responsible for the integration and connection of the stud parts to each other and the formation of wall panels and strengthening the structure and bear the tension.
Joists
C-shaped sections that are used horizontally in the structure. And they are used for concreting the roof and floor.
² Implementation methods:
1- Assembly at the place of execution: (stick-built) In this method, the steel sections are cut and numbered and transferred to the place of implementation of the plan and are connected to each other with cold connections (bolts and nuts) at the place of execution. A wall can be installed horizontally on the ground and then lifted and installed in its place. This method is highly accurate.
2-Tilt up system: In this method, first the desired part such as wall, frame and facade parts are executed horizontally in the project site and then it is transported to the desired place by a crane and installed in the desired place.
3- Box system: This method is used to build limited and small building spaces such as services or condos. In this method, the light steel frame is assembled as prefabricated boxes after being transported to the workshop and connected to each other. In the next step, the wall and ceiling parts and empty walls are executed.
² Advantages of the LSF system:
1) Benefits for designers
1-1) Modernity of the building system
1-2) The modernity of standards related to building performance
1-3) Diversity in facade materials
1-4) Flexibility in design
2) Benefits for builders
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