How To Calculate Steel Structure Building
Mar 28, 2026
Due to the advantages and extensive use of steel structures, engineering quantity calculation and software operation of steel structures have become one of the necessary knowledge and skills for general engineers. In order to let everyone understand steel structure calculation formulas, rules and software more quickly, the article lists and summarizes the basic knowledge of steel structure calculation. Let's take a look at it.
Steel structure calculation rules
1) Steel roof truss, steel mesh frame
Calculate the weight of the steel according to the size shown in the design, without deducting the weight of the holes, trimming and cutting limbs, and the weight of welding rods, rivets, bolts, etc. will not be added.
For irregular or polygonal steel plates, the area of the circumscribed regular rectangle is calculated.
The steel grid should distinguish the connection forms such as spherical joints and steel plate joints.
2) Steel bracket, steel truss
·According to the size shown in the design, it is calculated by the weight of the steel. The weight of holes, trimmed edges, and cut limbs shall not be deducted, and the weight of welding rods, rivets, bolts, etc. shall not be added.
·Irregular or polygonal steel plate, calculated by its circumscribed rectangular area.
·The unit of measurement is t.
3) Steel column, steel beam
·According to the size shown in the design, it is calculated by the weight of the steel. The weight of holes, trimmed edges, and cut limbs shall not be deducted, and the weight of welding rods, rivets, bolts, etc. shall not be added.
·Irregular or polygonal steel plate, calculated by its circumscribed rectangular area.
·Including solid web columns, empty web columns, steel tube columns, steel beams and steel crane beams, etc. The unit of measurement is t.
·Corbels, etc. Attached to the steel column are incorporated into the steel column engineering quantity.
·The gusset plate, reinforcement ring, inner lining pipe, corbel, etc. on the steel pipe column are incorporated into the steel pipe column engineering quantity.
·When the design stipulates that steel brake beams, steel brake trusses and car blocks are set up, their engineering quantities should be incorporated into the steel crane beams.
4) Profiled steel floor, wall panels
Profiled steel plate floor: Calculated according to the size of the design drawing and the horizontal projected area of laying, and the area of columns, stacks and holes within 0.3 square meters is not deducted. The unit of measurement is square meters.
Profiled steel wall panel: Calculated according to the size of the design drawing and the hanging area. The area of holes within 0.3 square meters will not be deducted, and the area of corners, edges, and window sill flashing will not be calculated separately. The unit of measurement is square meters. The profiled steel plate floor slab is poured with reinforced concrete, and the concrete and reinforcement are calculated according to the relevant regulations in concrete and reinforced concrete.
5) Steel components
The general calculation rules for steel members are as follows:
Calculate the weight of the steel according to the size shown in the design. Such as steel supports, steel purlins, steel skylight frames, steel wall frames (including columns, beams and connecting rods), steel platforms, steel walkways, steel railings, steel funnels, steel brackets, sporadic steel components, etc. The weight of holes, trimmed edges and cut limbs will not be deducted, and the weight of welding rods, rivets, bolts, etc. will not be added.
For irregular or polygonal steel plates, the area of the circumscribed rectangle is calculated. The unit of measurement is t.
6) Metal mesh
Calculate the area according to the size of the design diagram, including production, transportation, installation, painting, etc.
Steel structure calculation formula
Basic parameters of theoretical weight of steel bars
Weight per meter (Kg) = 0.00617 × diameter of steel bar (mm) × diameter of steel bar (mm), that is, the weight of steel bar is proportional to the square of the diameter. At the same time, the theoretical weight of the steel bar (Kg) ≈ 0.00785 × cross-sectional area [Π* steel bar radius (mm) * steel bar radius (mm)]
The weight of ordinary steel bars commonly used in construction projects:
Φ4=0.099Kg
Φ5=0.154Kg
Φ6=0.222Kg
Φ6.5=0.26Kg
Φ8=0.395Kg
Φ10=0.617Kg
Φ12=0.888Kg
Φ14=1.21Kg
Φ16=1.58Kg
Φ18=2.0Kg
Φ20=2.47Kg
Φ22=2.98Kg
Φ25=3.85Kg
Φ28=4.83kg
Φ30=5.549kg
Φ32=6.31kg
Φ36=7.99kg
Φ38=8.903kg
Φ40=9.87kg
Φ50=15.42kg
Calculation formula
Flat steel, steel plate, steel strip W=0.00785×width×thickness
Square steel W=0.00785×side length
Round steel, wire rod, steel wire W=0.00617×diameter
Steel pipe W=0.02466×wall thickness (outer diameter-inner diameter)
Equilateral angle steel W=0.00785×edge thickness (2 edge width-edge thickness)
Unequal angle steel W=0.00785×edge thickness (long edge width+ short edge width-edge thickness)
I-beam W=0.00785×waist thickness [height+ f (leg width-waist thickness)]
Channel steel W=0.00785×waist thickness [height+ e (leg width-waist thickness)]
Remark
1. The exact calculation formulas of angle steel, I-beam and channel steel are cumbersome, and the simplified table formula is used to calculate approximate values.
2. f value: 3.34 for general models and with a, 2.65 for b, and 2.26 for c.
3. e value: 3.26 for general models and those with a, 2.44 for those with b, and 2.24 for those with c.
4. All lengths are in millimeters.