Project Cost Control In The Design Stage Of Steel Structure Building

Engineering cost control in material selection

As my country's steel production continues to increase year by year, steel varieties tend to diversify. Various new building materials, such as lightweight thermal insulation wall panels, color-coated profiled steel plates, floor decks, etc., have been continuously developed and promoted. Building steel structures have more room for material selection in the design stage. The choice of materials is different, the direct cost of the project is different, and the total cost is different. Reasonable selection of building materials in the design stage and control of the unit price of materials or engineering quantities are effective ways to control the project cost.

 

 

Many, high-rise steel structure building (roof) floor deck: in design, according to the role in the building (roof) structure system, the floor deck can take two forms, namely

① the floor deck is only permanent The formwork generally adopts ordinary galvanized profiled steel plate, which has lower requirements for minimum galvanizing amount and fire resistance time, and is relatively cheap;

②As a formwork during construction, it replaces the tensioned steel bars in the use stage, that is, composite floor slabs. Since the floor deck is considered as a tension bar in the design, its service life must be consistent with the service life of the main steel structure, so its minimum galvanizing amount and fire resistance time are relatively high, and the unilateral price is relatively high.

 

 

Steel specifications and materials: Due to the increase in steel varieties, there are more types of components available for structural design. For example, frame columns can adopt hot-rolled H-beams, welded H-beams, spiral welded round steel pipes, welded square steel pipes, and combined cross-sections, and steel beams can take forms such as equal cross-sections and variable cross-sections. The material can be Q235 plain carbon steel or Q345 low alloy steel. High-strength materials should be used as much as possible in the design. For example, the use of Q345 steel can save 15%-25% of steel than the use of Q235 steel, and the saving ratio for tensile or bending components is larger. When designing, choose economical cross-section steel, such as hot-rolled H-section steel, T-section steel, etc. In some cases, the use of hot-rolled H-section steel columns and beams may use slightly more steel than the use of welded H-section steel. However, considering the processing cost and construction schedule, the cost may be more advantageous.

 

 

Engineering cost control in structural system

Different structural systems, peace, and facade layout have obvious effects on the project cost. In the design stage, only by determining the reasonable layout and facade layout and structural system according to the functional requirements of the building can the project cost be effectively controlled and economically applicable.

 

The design of the steel structure of the portal frame steel structure also has the economic span and the optimal spacing of the frame. When the process requirements allow, it is more economical to choose a small-span portal frame. Under normal circumstances, the optimal spacing of portal frames is 6m-9m. When large-tonnage cranes are installed, the economical column spacing is generally 7m-9m. It should not exceed 9m. When it exceeds 9m, roof purlins, crane beams and wall frames The amount of steel used in the system will increase accordingly, and the cost is not economical.

 

In the multi- and high-rise steel structures, the engineering volume of the floor structure system occupies a large proportion, which has an important influence on the work performance and cost of the structure. When determining the floor structure plan, the main consideration is to ensure that the floor slab has sufficient plane overall rigidity, which can reduce the weight of the structure and reduce the height of the structure layer, which is conducive to convenient on-site installation and rapid construction, and better fire protection and sound insulation Performance, and easy to lay the pipeline. Common floor slab practices include: profiled steel plate composite floor slab, prefabricated floor slab, laminated floor slab and ordinary cast-in-place reinforced concrete floor slab. At present, the most commonly used methods are profiled steel composite floor slabs and ordinary cast-in-place reinforced concrete slabs. When using these two methods, considering the combination of cast-in-situ slab and steel beam to form a combined beam that bears the common force, the height of the steel beam can be effectively reduced and more steel can be saved.

 

In the high-rise steel structure, the frame column adopts the circular steel tube concrete column, and the beams and slabs adopt the steel-concrete composite structure. The total steel consumption is greatly reduced compared with the ordinary steel structure, which can effectively reduce the project cost.

 

The advantages of steel structure construction determine that it will have strong vitality. In the design stage, technological innovation, material selection, and design optimization are the key stages for controlling construction costs and promoting the industrialization of building steel structures.