Analysis of the advantages and characteristics of steel truss floor bearing plate

At present, steel truss floor bearing

plate has been widely used in various large-scale construction projects at home and abroad, with the more mature technology, combined with its own advantages, so that steel truss floor bearing plate has a wide application prospect in multi-high-rise buildings.

Overview of rebar truss floor slabs

Steel truss floor

bearing plate is also known as steel truss formwork, its production and installation is carried out separately, first the main stressed steel bar in the floor slab in the factory using special equipment to process into steel truss, and then the steel truss and galvanized steel plate welded into one to form a combined structural system. In the construction stage of the structural floor, the system replaces the construction template with galvanized steel sheet, and bears the self-weight and construction load of the floor concrete together with the truss structure formed by the welding of steel bars in the structure. After pouring concrete, a reinforced truss concrete floor slab is formed, which bears the use load during the use phase.

Force

characteristics of rebar truss floor slabs

Ordinary reinforced concrete floor slabs have almost no deflection due to the formwork at the bottom of the construction stage, but when the concrete setting hardening reaches a certain strength to remove the formwork, the floor slab will generate tensile stress at the bottom of the slab under its own weight, thereby pulling the concrete. Compared with ordinary cast-in-place reinforced concrete floor slabs, the stress characteristics of reinforced truss floor bearing slabs are superior. When there is no temporary support, before the concrete hardens, the strength and stiffness of the floor slab is the strength and stiffness of the steel truss, and the concrete hardening is carried out under the deformation of the steel truss formwork, so the self-weight of the floor will not cause tensile stress on the concrete at the bottom of the slab. However, under the permanent load and floor live load, the floor deforms the slab, and tensile stress is generated at the bottom of the slab, so that the slab will crack, and the cracking delay is obvious compared with the ordinary concrete slab, and the stiffness of the floor slab is much greater than that of the ordinary concrete floor slab. In the use stage, the steel bars in the rebar truss floor bearing slab bear the load together with the concrete, and the bearing capacity of the tensile steel bar is the same as that in the ordinary reinforced concrete floor slab.

Analysis of the advantages and characteristics of rebar truss floor slabs

Faster construction schedule

Construction processThe construction process of steel truss floor bearing plate is: transportation →unloading→ lifting → on-site stacking→ support angle steel setting at the edge of the column→ on-site laying→ vertical support steel bar welding→ bolt welding→ side formwork welding→ on-site pipeline laying→ on-site additional rebar lashing → pouring concrete → pouring completed.

The traditional cast-in-place concrete floor slab construction is cumbersome, requiring scaffolding, timber support molds, lashing steel bars, wood demolition molds and scaffolding, and pouring concrete can only be carried out in a single layer, and the construction speed is slow, which affects the construction period. For the characteristics of rapid construction of steel structures, especially high-rise steel structures, the floor slab should be selected without support molds, less steel bar binding, and can significantly accelerate the progress of steel truss floor bearing plate or profiled steel plate composite floor. Most of the steel bar tasks of the steel truss floor bearing plate are completed in the factory, and the overall construction speed of the floor slab is fast, while the cast-in-place floor slab also needs to tie a large number of additional steel bars on site, and the overall construction speed is slow.

Multi-layer floor slab laying and pouring concrete at the same time Steel truss floor bearing plate itself can bear the construction load, which can provide a spacious working platform for various types of work, so pouring concrete and other types of work can be multi-layer three-dimensional operation, greatly accelerating the construction speed and shortening the construction period. Due to the limitation that the traditional cast-in-situ floor slab can only be constructed on a single floor, the overall construction progress of the steel structure is greatly limited by the construction progress of the floor slab, and the speed advantage of the core tube and the advanced construction technology of the steel structure cannot be fully displayed, resulting in waste of resources, which is of obvious significance for large-scale high-rise and super-high-rise buildings.

More reliable construction quality The quality and speed of on-site rebar lashing are determined by the operation of on-site workers, weather conditions, etc., while the quality and supply of rebar truss floor bearing plates are guaranteed by automated mechanical equipment. The thickness of the protective layer of the floor and the spacing of the steel bars can fully meet the design requirements, which improves the forming quality of the floor slab. The minimum lap length in the truss direction is 50mm and the minimum lap length in the distribution bar direction is 30mm to ensure that the support is reasonable and the concrete is poured without leakage to ensure the quality of concrete pouring and forming.

The stress mode of the rebar truss floor slab is more reasonable, and the calculation of the

rebar truss concrete floor slab is equivalent to the design theory of ordinary cast-in-place concrete, while the stress mode of the rebar truss is more reasonable, which can provide greater stiffness, and the rigidity in both directions is consistent, and has good seismic performance. The steel formwork at the bottom of the steel truss floor bearing plate is flat, the rigidity of both directions is similar, and the steel truss web bar bar improves the stress performance of the floor slab and has the best seismic performance. Moreover, the steel truss floor bearing plate can be designed as a two-way slab, the lower surface of the steel truss floor bearing plate is flat, the truss space is large, and the floor slab can easily construct the lower steel bar without increasing the thickness of the floor structure layer.

Steel truss floor slab

has good fire and anti-corrosion performance For the use of steel truss floor bearing slab in the floor slab, its stressed steel bar is completely wrapped by concrete, the thickness of the concrete protective layer is uniform and consistent, and the repair of the floor slab after fire is equal to or better than the traditional cast-in-place reinforced concrete floor slab, while the traditional cast-in-place reinforced concrete floor slab is more experienced and easier to repair in the problem of fire repair. The galvanized steel plate at the bottom of the steel truss floor bearing plate itself has anti-corrosion function, and it is only used as a formwork in the construction stage, and does not participate in the force in the use stage, so the anti-corrosion age does not need to consider the requirements of the design life of the building.

Practical application and development prospect of rebar truss floor slab

The steel truss floor bearing plate has the characteristics of superior force characteristics, fast and convenient construction, reliable safety measures, good fire and corrosion resistance, and high comprehensive cost and efficiency, and has a good development and application prospect in multi-high-rise buildings. At present, it has been widely used in the following fields: used in prefabricated floor slabs, high-speed railway prefabricated sleepers; It is used in multi-high-rise and super-high-rise steel structure buildings; It is used in the LOFT mezzanine structure in the building; It is used in complex stressed and special-shaped structural buildings; Used in cast-in-place concrete (RC) construction; It is used in sloped roof structure buildings; It is used in down-plate structure buildings. This product has been successfully used in PetroChina, Sinopec, China Nuclear Power, Foxconn, Changan Ford, FAW Toyota, FAW-Volkswagen, Beijing Hyundai Motor, Peugeot-Citroen Automobile, Geely Automobile, Jianghuai Automobile, Hankook Tire, Dongfang Electric, Dongfang Steam Turbine, Erzhong, Dongfang Boiler, Chengguan Express Railway, Chengmian Lehigh-speed Railway, Chengdu Second Ring Road Bridge, GLP, Shanghai Baosteel, Lafarge Cement, Chengdu Military Region, Lutianhua, Chuantianhua, Chengdu Museum, Chengdu Aquarium, Global Center, Western China International Expo City, BMW 4S, Mercedes-Benz 4S, Audi 4S, BYD 4S, PUSH Group, Wuliangye, Jiangsu Yurun, Midea Air Conditioning, Gree Electric Appliances, Philips Appliances, Siemens Appliances, Suning Electric Appliances, Chengdu Customs, Chengdu Pressure Plant, China Tobacco, Honghua Petroleum, Chuanrun Co., Ltd., Sichuan Petrochemical, Quanti Steel City, Wanteng Metal, Yujiang Heavy Machinery, Long March Automobile, Zhengxing Group, Southwest People's Yuan, Xinston GMP Technology Transformation Project, Dujiangyan 6914 Project, Meihe Cable, Nanchong Airport, Chengdu Muwei precision abrasive, Chengdu Construction Engineering, Western China Building Materials Industrial Park and other projects; He has participated in the construction of national key projects for many times, and has been applied in dozens of projects such as China State Construction, China Railway, China Metallurgical Energy, China Nuclear Corporation, China Water, China Energy, Yangtze River Precision Industry, Hangxiao Steel Structure, China Shipbuilding Heavy Industry, Wushuan Heavy Industry, China Machinery, State Electric Power, etc., which has created conditions for the reform and improvement of China's floor construction technology.