Welded I-beam is a steel plate structure with dimensions and profile similar to those of an identical hot rolled beam (according to ГОСТ 26020-83 or СТО АСЧМ 20-93 standard). The use of welding while manufacturing of welded beams allows combination of horizontal sheets dimensions (or chords) with vertical walls dimensions.
Welded beam advantages:
- The use of welding allows using several different grades of steel in one beam (hybrid beam). In this case some beam sections that are exposed to maximal stress are made of extra hard steel. Sections exposed to minimal stress are made of low carbon steel. This allows reducing steel beam costs up to 5 %
- Welded beam manufacturing process allows manufacturing of beams with holes, grooves and punching. Welded beam is the best solution in case when structure and load capability and hardness requirements exceed the rolled section capabilities
- There is an opportunity to select composite section for welded beam that can reduce its weight up to ten percent
- It is possible to manufacture variable cross-section welded beams
- Manufacturing of welded beams of the required length instead of standard length allows reduction of costs for manufacturing wastes up to fifteen percent
Metal structures with welded beams ensure noticeable economic benefit when erecting buildings and structures of different types. The use of welded beams in metal frame structures allows to considerably lightweight the components of such structures with increased safety coefficient. Besides, the use of welded beams allows creation of economic bearing support shapes. And this, in turn, reduces the weight of the entire metal structure.
The main purpose of welded beams is their application in metal building structures such as building frames for industrial purposes, residential buildings, public and agricultural buildings.
Box beams have a set of advantages in comparison with open beams.
These advantages include:
- higher load-bearing capacity of structures or their components with bending behaviour in two planes and twist behaviour. the material in closed sections is generally located at perimeter zones with respect to the centre of gravity. This provides an inertia moment and resistance increase relative to Y axis (from component plane) and twist inertia moment
- in view of considerable increase (in tens of times) in the twist inertia moment in components with closed sections, flexure torsion buckling is generally eliminated
- components with closed sections are more stable during installation and less susceptible to mechanical damage during transportation and installation
Structural solutions. Closed, in particular box-shaped cross sections are used, if necessary, for beam hardening in transverse direction, provided that cross links are absent, bending is performed in two planes, and torque is available, with limited structure height and large transversal forces. Similarly to force action, these design limitations are applied to beam structures of bridges, strength elements of industrial buildings, cranes etc.
The availability of two walls makes it particularly urgent to reduce its thickness while ensuring local stability. Structurally, it is achieved by the curvature of wall or by creation of different types of links between the walls in the form of diaphragms, tie bolts, etc.
Our company offers manufacturing of structures with the use of Nelson anchoring stops.
Nelson flexible anchors are ideal for connecting steel structures with concrete components. The main advantage is their ability to withstand high loads, even under pulling out forces.
So-called flexible stops are used to join reinforced concrete plate and metal beams. They are metal rods with upset head, with butt welded to the upper sheet beam. It is assumed that stops are connected with the beam with the help of semiautomatic arc contact welding.
Stop welding process consists of several phases and is performed in automatic mode that eliminates the possibility of human factor influence on the quality of welding. The weld pool is formed by a ceramic ring which acts as a flux. Welding process of a single stop lasts 0.2…0.8 seconds depending on its diameter. Welding technology is so perfected that in case of proper use we can talk about almost 100 % guarantee of welding joint quality , which is confirmed by multiple tests.
Stops are manufactured according to ISO 13918.
The process of pin welding by Nelson technology includes the same basic metallurgical principles as any other kind of arc welding technology: arc is used to fuse the end of the bolt (pin) or the electrode with the part of metal workpiece of basic structure. Nelson welding system includes: lightweight welding gun, control power system, and DC power supply.
Bolt (pin) and ceramic O-ring are inserted into the welding gun, then the end of the pin is placed directly to the workpiece and gun trigger is pushed. Electric arc: arc discharge between pin and main workpiece creates connection between melted (liquid) metal limited by ceramic guide ring that helps insert the pin into the whole automatically. The result is high-quality fusion welding which ensures metal hardening in a split second, and, what is also important, the weld joint becomes much stronger than the pin. Due to its inherent advantages – weld joint with equal strength as the one of the base metal, one-sided fastening without holes drilling or punching.
In modern practice it is often required to use corrugated deck as a permanent timbering for concreting. In this case pin is welded through the corrugated deck to the steel beam.
Nelson pins can be welded through usual timbering and through hot galvanized corrugated deck 1.5 mm thick.
For composite structures, the pin under shear strength is one of the most common techniques used in the construction of new bridges. Nelson pins, like in the case of buildings, are welded onto the surface of a steel beam that ensures equal distribution of transverse forces in all directions and eliminate deformations that may occur as a result of manual welding, and also allows obtaining sufficient compression of concrete around the dowel.
Manual welding of anchor devices to door frame edge plate or flat monolithic frame is a very expensive and slow operation. Instead, deformed reinforcement anchor devices made by Nelson technology ensure reliability of connection and the same workforce productivity both in factory and construction conditions due to the high speed.
In the process of pin welding any possibility of welded components deformation is eliminated.
Anchor bolts made by Nelson technology are approved by the Nuclear Regulatory Commission for hardened steel joints to concrete tank containment of a nuclear reactor and other structures of nuclear power plants. Besides, they are used in any concrete structures where embedded parts are required.
Pin welding technology provides many advantages such as lower production costs. It also holds connected components together with the concrete diaphragm and ensures high quality of components connection.
In comparison with manual welding of rebar welding, deformed reinforcement welding suggests better control of chemical and physical properties, high quality of welded components.
As all benefits of Nelson technology are well known, it can be used for manufacturing of column base and many other steel components covered with concrete. Estimated data for screw bolts can be found in Nelson literature or in the literature of Manual Welding Institute, as well as in the sources on pre-stressed precast reinforced structures.
Embedded parts with welded Nelson flexible anchors are ideal for connection of steel structures with concrete components. The main advantage of the embedded parts with flexible anchors is their ability to withstand high loads, even under pulling out forces.
Steel components with welded Nelson anchors are approved for use in accordance with European Technical Approval ЕТА-03/0039 (for structural steel) and ЕТА-03/0040 (for stainless steel).