Dapeng Town Industrial Park, Tongshan District, Xuzhou City, Jiangsu Province, China
In the past steel structure construction, usually used in the form of a combination of floor steel and concrete, the main reason for this situation is that this structure does not need to build a template project, in addition, the overall construction speed is faster than other methods, the construction of steel structure can reflect a very obvious cyclical characteristics, but today’s construction of construction projects, The construction personnel should ensure the bidirectional stiffness of the structure, and in addition, it can withstand more unidirectional forces, so this structural form can reflect a very significant advantage.
Steel truss floor bearing plate is originally the form of steel bars, after processing, it has the characteristics of steel bars truss, after the truss to carry out steel welding work, and then press it into a pressed steel plate, and then to effectively connect the truss and steel plate. However, in today’s engineering construction work, because the construction conditions have changed greatly, in addition, the construction material also has a very obvious difference, in the actual work, we need to use a variety of types of steel truss, in general, the number of triangular steel truss is 3, truss spacing must be between 180mm. Even if the structure of the truss has been confirmed, but the position and height of the truss head and the thickness of the truss need to be properly changed according to the requirements of the project, in the calculation, the calculation value should be removed from the thickness of the floor, so that the calculated results are more accurate.
In the construction of the project, the steel truss floor plate should be connected with each other, after the laying of steel bars, in addition to carrying out welding work. In addition, it should be treated according to the specific characteristics of the construction of the steel structure, which can be carried out at the same time as the concrete pouring, so as to ensure the performance of the structure.
This floor form can effectively control the manual workload in the process of engineering construction, in addition, it also enhances the efficiency of construction. The thickness of this floor is smaller, so the indoor space is significantly enhanced. In addition, the thickness of the steel plate also meets the needs of construction. Therefore, it also provides convenience for welding work. The flat surface of this structure is very strong, in addition, the appearance is also very beautiful, this structure will not crack the problem. Its fire resistance is relatively good, in the case of long-term construction will not produce durability decline, the overall seismic capacity of the building has also been significantly improved.
There are two main forms of steel truss, the first is to set a temporary type of support structure, such a form and ordinary concrete in essence is no different. The second is not to set up temporary support. Its strength and stiffness levels are very high, the floor adopts this way to deal with the problem of deformation, in addition, its own load bearing capacity is also very good, the concrete tension of the bottom of the plate is large, so this structure is better than ordinary concrete structure. In the process of use, the steel truss upper and lower string steel and concrete work together to play a role, this floor and reinforced concrete laminated floor has the same mechanical performance, although the hand tensile steel stress is larger, but its bearing capacity and ordinary reinforced concrete no difference.
The construction of reinforced truss concrete pouring slab shall comply with the following operating procedures: drawing up the construction plan, entering the first floor bearing plate, lifting the first floor bearing plate installation – additional reinforcement lashing and pipeline laying – stud welding side mold installation – concealed engineering acceptance – concrete pouring.
In order to satisfy the force and ensure no leakage when concrete is poured, the length of the steel truss floor plate extending into the flange edge of the steel beam must meet the design requirements. In any case, the shelving length of the steel truss on the steel beam should not be less than 5d (d is the diameter of the steel bar at the bottom of the steel truss and the larger value of the two); The length of the galvanized steel plate extending into the flange edge of the steel beam should not be less than 30mm.
After the steel truss floor plate is in place, the vertical steel bars at its end should be spot-welded with the steel beam immediately; The bottom die is spot-welded with the steel beam along the width of the plate. The welding is done by manual arc welding, and the spacing is not more than 300mm. After laying a certain area, the bottom bar of the plate must be tied in time to prevent the lateral instability of the steel bar frame; At the same time, temporary support must be set up in time according to the design requirements, and ensure that the support is stable and reliable.
Avoid excessive concentrated loads on the steel truss floor plates. It is forbidden to cut any bar member on the steel truss at will. At the opening of the floor, reinforcement bars and side molds must be set up according to the design requirements, and the steel bars of the steel truss can be cut off when the concrete of the floor reaches the design strength. When the plane shape changes, the end of the steel bar truss can be cut, and the end of the support bar can be repaired and then installed. When the pipeline is laid in the plate, the rigid pipeline can be used when it is passing through, and the material with better flexibility should be used when it is passing through diagonally due to the influence of the steel truss. Due to the limited spacing of steel bar trusses, pipelines with smaller diameters should be used as far as possible to disperse perforated embedments, and multiple pipelines should be avoided. The side formwork is a key component to prevent concrete leakage. The side formwork is pressed close to the steel beam surface, and the lower end of the side formwork is spot-welded with the steel beam surface every 300 ~ spacing. The upper end of the edge formwork must be welded with steel bars and bolts.
As a new type of floor slab, the joint connection of steel truss floor bearing plate should be treated according to the corresponding structure. The diameter and spacing of additional bars are determined by design. During the construction process, the installation sequence should be strictly implemented, and the quality and safety inspection should be carried out step by step. Including the following: ① the type of steel truss floor bearing plate; ② Whether the vertical bar and the plate edge of the support are welded with the steel beam; (3) Additional steel bar length and arrangement spacing; ④ Stud welding quality, quantity and spacing; ⑤ whether the edge of the plate has the possibility of leakage; ⑥ Whether the temporary support meets the design requirements.
The engineering practice has proved that the bottom mold of the steel truss floor plate can be removed after the concrete reaches the design strength, so the steel truss floor plate can be applied to the buildings without suspended ceilings (such as residential buildings). After the bottom die is removed, anti-rust treatment should be done on the bare ribs of the steel bar truss at the bottom of the plate. The bottom of the floor should be plastered after treatment.
The construction technology of steel truss floor bearing plate has obvious advantages, and it has the characteristics of high production efficiency, small negative effect on the environment, convenient installation and low cost input in the application process, so it also provides a new development direction for the construction of steel structure building floor engineering in China.
