Since the reform and opening up, high-rise buildings have risen more and more on the ground of China. Super high-rise and long-span building structures generally use steel. Low-alloy special steel has been widely accepted by the domestic construction industry. Steel has appeared in developed countries as early as the 1960s. Structure high-rise residential. These houses have reasonable structure, flexible space division, easy factory production, short construction period, convenient renovation, small site used during construction, less pollution to the surrounding environment, and low construction cost. The traditional brick-concrete structure and reinforced concrete structure are rejected by the economic and durable ideas. They are also affected by the relatively expensive steel prices, the matching of new light-weight insulation and high-strength wall materials that do not meet international standards, and the low technical level of the construction team. Poor quality, inadequate professional engineering support, and inability to adapt to steel structure construction, so that there are many obstacles to the promotion of new high-rise steel structure residences. 1. The structural system and design of high-rise light steel structure residences In the past, the residential system has always followed the old model of "Qin brick and Han tile" In order to break through the tradition, people in the industry have conducted extensive explorations, such as large slab buildings, lattice buildings, unit hoisting and concrete frames, etc., but these models are still relatively old and the construction environment is difficult to guarantee. The steel structure house is based on the factory-produced steel beam and steel column as the skeleton, and is equipped with a new type of light-weight insulation and high-strength wall materials as the envelope structure, which overcomes the shortcomings of many traditional models 1.1 structural scheme 1.2 floor system is a strong structure For lateral stiffness, the floor of high-rise light steel residential buildings must have sufficient bearing capacity, stiffness, and overall structure. Currently, reinforced concrete composite floor slabs are commonly used: the steel beams are covered with aluminum plated steel plates, and the upper layer is poured with 100mm ~ 150mm thick Concrete, profiled plates and steel beams are connected by studs. In addition, prestressed thin plates and cast-in-place concrete layers, ordinary reinforced concrete light steel multi-ribbed beams and cast-in-place reinforced concrete composite floors, etc. can be used, but the floor and steel beams should be guaranteed. Reliable connection between steel beams and concrete floor slabs can significantly improve the bearing capacity and overall stability of the beams, and effectively reduce the height of the beams. The connection between the main beam and the secondary beam is generally a simple-supported equal-height connection. Sometimes Unequal height connections are also used. For example, when combined floor slabs are used, in order to facilitate the laying of profiled steel plates, the top surface of the primary and secondary beams should be different from the thickness of the profiled steel plates (see). At the same time, the net height of the building can be large.
Practice has proved that the form of reinforced concrete composite floor can meet the basic requirements of the structural structure of the floor, but the technical measures for roof insulation and thermal insulation on the roof (such as placing satellite antennas) have been further improved. If a sloped roof is adopted, not only beautify the facade of the high-rise building, but also increase the space used, but also bring about improvements in roof insulation and rainwater leakage, but how to design the floor of the high-rise light steel structure residence on the slope roof, The lateral rigidity of the strong monolithic structure has yet to be explored. 1. 3 Supporting systems In order to strengthen the lateral rigidity of high-rise light-weight steel residential buildings and resist horizontal loads and earthquakes, ordinary steel or thin-walled square steel is usually used to arrange vertical support systems in the wall plane. According to the requirements, it can be arranged in one direction or two directions along the vertical and horizontal directions, and the support is hinged with the frame, designed according to the tension rod or the pressure rod. Taking into account the layout of doors and windows, X-shaped, single diagonal bar, herringbone, inverted herringbone, W, inverted W, door, etc. can be used without affecting the function of the building, the support on the plane should be uniform Arrangement, for the last five supports, the additional bending moment caused by the supporting axial force on the beam should be checked, and the eccentric support can also be used (see). The advantage of the eccentric support is that it has sufficient stiffness under small or medium horizontal loads. It has good ductility under severe overload (such as a large earthquake) and is a good shear support.
1.4 Enclosure structure In order to reduce the self-weight of the steel structure of high-rise buildings, the enclosure structure mostly uses lightweight filling materials, such as hollow blocks, aerated concrete blocks, etc., sometimes composite walls composed of profiled steel plates and light insulation layers There are also many light and beautiful glass curtain wall structures on the exterior walls of houses. The inner wall can be made of light-weight filled walls such as hollow blocks, aerated concrete, or light steel keel gypsum board. At present, there are also aluminum alloy frame glass partitions.
Practical materials for envelope structure such as "YTONG" aerated concrete, etc. The material uses quartz sand as aggregate, cement and lime as binder, gypsum as hardener, and aluminum powder as foaming agent to form lightweight concrete (AUTOCLAVEDLINGTWEIGHTCONCETE, ALC for short). , In terms of compressive strength, bulk weight, moisture content shrinkage, frost resistance, impermeability, sound insulation and fire resistance, all meet and exceed national standards, making its product performance show excellent heat insulation, simple and reasonable use, and wide application Sexuality and fierceness. This kind of caA said that the combination of raw materials and ^ shaped steel f is a better way to solve the envelope structure. For flat steel buildings, most of the roofs are made of coiled material for waterproofing and lightweight insulation materials, such as QN boards. , Polyethylene concrete blocks, etc., to ensure the quality of roof waterproof and thermal insulation.
1.5 Foundation form The foundation of high-rise light steel structure houses is commonly used under column independent foundation, strip foundation, cross type foundation, and sometimes raft foundation can also be used. When independent foundation under column is adopted, it should be noted that the relative uneven settlement of each foundation on the superstructure influences. Foundation beams are usually cast-in-place or prefabricated reinforced concrete structures, sometimes steel foundation beams can also be used according to requirements, but the column feet and steel beams buried under the ground are usually wrapped with concrete to solve the anti-corrosion problem. 1.6 node structure steel structure columns of high-rise buildings Welding I-shaped or box-shaped sections are mostly used. Due to the thin section web, the connection between the weak axis direction and the beam is mostly hinged, and the strong axis direction is rigidly connected. When the rigid connection is adopted, its mechanical characteristics are more complicated, and more accurate results are often obtained through experiments. Design data. At the same time, the steel structure of the high-rise building is relatively thin, and the weld joint on the construction site should be avoided as much as possible. In order to strengthen the overall rigidity of the structure, the secondary beam is sometimes made into a continuous beam. 1.7 Fire prevention and anti-corrosion measures China's steel structure waterproofing mainly uses waterproof coatings , Foam fireproof paint and external fireproof board. For exposed steel structure components, such as stairs and other parts, multi-purpose paint or fire-resistant paint is used. The thickness of the paint is 10mm ~ 40mm, and the fire resistance limit can reach 1.5h ~ 3h. The hidden fire resistance time of the foam paint is generally 0.5h. , Perlite and vermiculite fireproof spraying or fireproof board is a cost-effective method. 3Qnm ~ 40mm thick perlite and vermiculite fireproof spraying can achieve a fire resistance limit of 1.5h, and also has a certain anti-corrosion ability. The exposed steel components are generally anti-corrosive with anti-corrosion paint or fire-proof paint composed of primer and top coat.
2 Design examples of light steel residences through inspections, and comprehensive analysis and comparison of relevant data collected at home and abroad. From the current situation, it is reasonable to position the steel structure residences in small high-rise buildings around 11 floors. The reasons are mainly in the following aspects : (1) After analysis, small high-rise residential buildings can fully utilize the high-strength steel material strength, and the mechanical properties of steel materials are fully utilized; (2) Compared with high-rise buildings, small high-rise buildings improve the land use coefficient and comprehensive economic benefits Good; (3) The investment of small high-rises in auxiliary facilities such as fire protection will be greatly reduced, the comprehensive investment is relatively moderate, and has strong vitality.
21 Project Overview The small high-rise light steel structure in this research plan is designed to be 42m long, 12m wide, and 12 floors in total. The staircase space is 27m, and the rest are 3.6m; all storeys are 3m high, and the total construction area is 5990m2. Leaping floor layout, one indoor staircase, staircases and elevators at each end of the house. To save investment, the elevator has a stop every other floor, and another long aisle connects the stairs at both ends. 22 The structural form of the structural system is supported by a steel frame. The composition of the structural system is: the vertical system is composed of floor slabs and frame beams and columns; the lateral system is a vertical through steel support as the main anti-side force member, which is The columns together form a 23-floor system. The floor of this scheme uses light steel concrete composite slabs. The floor slab structure is divided into three layers. The bottom layer is cold-rolled thin-walled rectangular square tube secondary beams with a spacing of 900mm. The vertical direction is reinforced and the spacing is about 1m. With wire mesh.
24 The support structure of the outer wall and the sub-wall of the enclosure system is a steel bracket of cold-rolled thin-walled steel keel, which not only serves as the support structure of the enclosure wall, but also serves as the lateral support of the frame, and each layer is a closed body, strong structure The overall rigidity wall in the horizontal direction of the body is made of lightweight composite wall. The main wall materials are straw board and Yitong board. The exterior wall decoration is a special external wall insulation and waterproof decoration product.
The selection principles of 25-node connection node: (1) safe and reliable, the connection point should be selected at various places with small stress as much as possible; (2) less steel is used, economical, welding is preferred; (3) construction is convenient, fast and convenient Operation, reducing on-site assembly work.
26 Fireproof and anticorrosive treatment of structural members Rattan-frame beam and column adopt STU fireproof coating as the waterproof layer of beam. The anti-corrosion and fire-proof design of the components should be considered. When et fire-resistant steel is used, the coating and anti-corrosion issues of the components should also be considered. Reliable, easy construction, flexible space division, easier to meet the requirements of architecture and other obvious advantages, has a large potential market demand, can drive the development of related industries. With the development of China's metallurgical business, the variety and quality of structural steel There will be great development in the new century. When China and the developed countries can use low-alloy high-strength structural steel in residential construction, the steel consumption and cost of high-rise light steel residential buildings will be greatly reduced, thus It can usher in a mature period for the development of high-rise civil light steel residential buildings.
If you can use machine room-less elevators, such as Finland's "KONE", etc., the twelve-story light steel structure small high-rise housing has more comprehensive comparative economic advantages, and home buyers have a higher rate of housing, making the light steel structure Housing has a stronger market vitality.
According to the requirements of the Ministry of Construction, the organization of professional specifications and specifications in design, construction and materials is an important work link to promote the design and application of light-weight steel structure houses.