Structural design experience collection
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1. When designing a sloping roof, after the beams are reinforced, the net height must be calculated from the bottom elevation of the beam to see if it meets the requirements, especially at entrances such as stairs. 4 S8 d8 2. When designing a sloping roof, the beams at the ridge (sun corners and back corners) can be appropriately reduced. When the span of the slab is small, no beams are needed. Otherwise, the use may be affected and the clear height will be insufficient. Furthermore, it will also affect the appearance. 3. The stair column (where the middle platform functions) should be encrypted throughout because it is a short column. 3 A0 ` * j# ] 4. For concrete walls with a protective layer of 50mm on the front surface, Φ8#150 double-layered two-way steel mesh should be added within 50mm to reduce shrinkage cracks in the concrete. 5. For the value of beam height, the needs of building space should be considered, and the net height requirements should be negotiated with the building. 3 a& o6 o. a) G) ^ * v! P 6. For 8m span beams in office buildings, shopping malls, etc., it is not good to choose 300x800 beams. You should choose 350x700. For some long-span public keys, the beam width should be appropriately increased and should be more than 300. It is better to choose 350 or 400, because: + W1 H- L( a5 n% Q$ L- a6 P" B- F8 z# t! y ① The beam width is widened, which is beneficial to shear resistance and conforms to the principle of "strong shear and weak bending". 6 n8 N3 { * G% M5 t: s$ \ ②For 350-wide beams, the diameter of the stirrups can be reduced by using limb hoops. + |4 Z$ V8 b+ p4 c. J# p" ] 1 R ③The main beam is widened to facilitate the anchoring of the secondary beam steel bars. 7. The size of the columns should be controlled according to the axial pressure ratio as much as possible. The difference in the axial pressure ratio should not be greater than 0.2. When the building has requirements, this issue should be negotiated with the building. ; i+ T1 G1 , J. N1 ] 1 n:o * v" ~ 9. When reinforcing beams, the anchorage length of the beam should be fully considered, especially the secondary beams, which should try to meet the requirements of the atlas. . @. q: 10. When reinforcing the plate, you should pay attention to the difference between grade I and grade II steel (whether there are hooks), and when the plate thickness is different, be careful not to pull the steel bars through. 2 K9 M- T8 @& k 11. When drawing a large-scale drawing, be sure to compare it with the architectural large-scale drawing and elevation drawing to meet the internal requirements of the building. 12. When reinforcing beams, attention should be paid to the setting of waist bars. The waist bars on one side should be greater than 0.1% bhw. ( o( ?/ |7 R& B1 a; n * d' T2 a 13. When reinforcing columns, the requirements for reinforcement ratio, stirrups, main bars, angle bars, and minimum volume reinforcement ratio should be met at the same time. 14. The post-cast belt should be strengthened according to the new specifications. 15. In high-rise buildings, after large holes are opened in the floor slabs, they should be strengthened in accordance with Article 4.3.8 of JGJ3-2002. 16. The cross-section height of the shear wall limbs should not be greater than 8m, otherwise structural holes should be opened. 1 f+ t+ e" s- \2 r0 F2 y8 p; L 17 Construction camber: Find the short-term deflection (1\2 long-term) and then bring it into the specification to find the camber value/ B6 r X9 a( |5 S3 18 The exposed and ceiling panels need to be considered for anti-seepage and anti-cracking. According to the elastic method, the first-level 8 spacing of 200 is generally used, and the rest is added by calculation; the smaller and denser the anti-cracking reinforcements, the better, and stool reinforcements can be added artificially to increase the stiffness. 19 Cantilever beams must pay attention to the reinforcement of the reinforcement, the full length of the stirrups is dense, and the deflection is checked, especially those with a length greater than 1 meter.$ E/ v1 ?2 T4 d8 mj 20 Over-limit problem of coupling beams: The stiffness of coupling beams will be reduced if the coupling beams are too short. You can directly subtract the beam height to simulate the stiffness reduction, and use the calculated internal force of the beam to place it on the original high beam for reinforcement verification + K4 F, h$ _,
Discussion on experience in steel structure design (data comes from the Internet for educational purposes only)* Purpose) (1) Determine whether the structure is suitable for steel structures. Steel structures are usually used for high-rise, long-span, complex structures, large loads or crane lifting capacity, large vibrations, high-temperature workshops, high sealing requirements, structures that require mobility or frequent assembly and disassembly. Intuitively speaking: Buildings, stadiums, opera houses, bridges, TV towers, warehouses, factories, residences and temporary buildings, etc. This is consistent with the characteristics of the steel structure itself. (2) Structural selection and layout are only briefly introduced here. Please refer to relevant professional books for details. Since structural selection involves a wide range of factors, structural selection and layout should be carried out under the guidance of experienced engineers. What should be emphasized in the entire process of steel structure design is "conceptual design", which is especially important in the structure selection and layout stage. For some problems that are difficult to make precise rational analysis or are not specified in the specifications, the layout and detailed measures of the control structure can be determined from an overall perspective based on the design ideas obtained from the mechanical relationship between the overall structural system and sub-systems, failure mechanisms, earthquake damage, test phenomena and engineering experience. Conceptual design can be used to conceive, compare and select quickly and effectively at an early stage. The resulting structural scheme is often easy to calculate by hand, has clear concepts, is qualitatively correct, and can avoid unnecessary cumbersome operations in the structural analysis stage. At the same time, it is also the main basis for judging whether the output data of computer internal force analysis is reliable or not. Steel structures usually include frames, plane (wooden row) frames, grids (shells), cable membranes, light steel, tower masts and other structural types. Most of its theories and techniques are mature. There are also some problems that have not been solved, or there are no simple and practical design methods, such as the stability of the lattice shell. When selecting structures, their different characteristics should be considered. In light steel industrial plants, when there are large suspended loads or moving loads, you can consider abandoning the portal frame and using a grid frame. In areas with basically heavy snow pressure, the roof curve should be conducive to the sliding of snow (snow load needs to be considered within 50 degrees of the tangent). For example, the limestone warehouse shed of Yadong Cement Plant uses a three-center circular lattice shell. Nearly half of the total snow load was released. Similar considerations apply to areas with heavy rainfall. When the building allows it, it is more economical to arrange bracing in the frame than a simple frame with rigid joints. For buildings with larger roof coverage spans, you can choose a suspension or cable-membrane structure system with tension-based components. In the design of high-rise steel structures, steel-concrete composite structures are often used. In high-rise buildings with high seismic intensity or irregularities, the core tube plus outer frame form, which is unfavorable to earthquake resistance, should not be chosen purely for economic reasons. It is advisable to choose a structural system with surrounding giant SRC columns and a supporting frame as the core. More than half of such senior executives in our country are the former. Unfavorable for earthquake resistance. The layout of the structure should be comprehensively considered based on system characteristics, load distribution and properties. Generally speaking, the stiffness should be uniform. The mechanical model should be clear. Limit the influence range of large loads or moving loads as much as possible, so that they can be transmitted to the foundation in the most direct route. The distribution of lateral supports between columns should be uniform. Its centroid should be as close as possible to the line of action of lateral force (wind earthquake). Otherwise, the torsion of the structure should be considered. There should be multiple lines of defense on the side of the structure. For example, if there is a supported frame structure, the columns should be able to withstand at least 1/4 of the total horizontal force alone. The layout of the secondary beams on the floor level of the frame structure can sometimes be adjusted in its load transfer direction to meet different requirements. Usually, secondary beams are arranged in the short direction in order to reduce the cross-section, but this will increase the cross-section of the main beam, reduce the clear height of the floor, and sometimes the side columns on the top floor will be too much. At this time, supporting the secondary beams on shorter main beams can sacrifice the secondary beams to save the main beams and columns. (3) Estimated cross-section After the structural layout is completed, a preliminary estimate of the component cross-section is required. Mainly the assumptions of the cross-sectional shape and size of beams, columns, supports, etc. Steel beams can be selected from channel steel, rolled or welded H-shaped steel sections, etc. According to the load and support conditions, the cross-sectional height is usually selected between 1/20 and 1/50 of the span. When the flange width is determined according to the l/b limit based on the spacing of the lateral supports between the beams, the complex calculation of the overall stability of the steel beam can be avoided. This method is very popular. After determining the section height and flange width, the plate thickness can be estimated according to the locally stable construction provisions in the specification. The column section is estimated based on the slenderness ratio. Usually 50
Although I am not a civil engineering major, my design work involves some knowledge related to civil engineering. I often come here and gain a lot. study * Yes, thank you!
That's awesome. I'm a mechanical major, and I occasionally come across the design of steel structures. It seems like I need to learn from the experts.* There are too many things