by In structural design, vertical components such as concrete walls and columns often account for a very important proportion.
The compiler, in combination with some problems encountered in the design and drawing review process of common basic specifications, summarized some contents that may be ignored in the structural requirements, hoping to help you.
Several commonly used structural codes are as follows: Code for Design of Concrete Structures GB50010-2010 (2015 Edition) (hereinafter referred to as “the Code”), Code for Seismic Design of Buildings GB50011-2010 (2016 Edition) (hereinafter referred to as “the Code”), Technical Code for Concrete Structures of Tall Buildings JGJ3-2010 (hereinafter referred to as “the Code”), Technical Code for Concrete Specially Shaped Column Structures JGJ149-2017 (hereinafter referred to as “the Code”), building codes: The Code for Fire Protection Design of Buildings GB-50016-2014 (2018 Edition) (hereinafter referred to as the Code for Fire Protection), one of the structural requirements of frame column stirrups, stipulates in 9.3.2-1 of the Code for Concrete Structures that this article is not specifically mentioned in the Code for Resistance to Fire and the Code for Concrete Structures, and it is easy to be ignored if the design only looks at the latter two codes.
However, this item is often omitted in the design of the frame structure with Level 4 seismic resistance.
The minimum diameter of the stirrup required for Level 4 seismic resistance is 6 (column root 8), but when the longitudinal reinforcement diameter of the column is 25 or more, the stirrup diameter should be 8 or more.
02 The second part of the structural requirements for the stirrups of frame columns, 9.3.2-5 of the Concrete Code, stipulates that this article is not specifically mentioned in the Code of Resistance and the Code of Height.
This one is also easy to be omitted in the design of the frame structure with Grade IV seismic resistance.
The minimum diameter of the stirrup required for Grade IV seismic resistance is 6 (column root 8), but when the longitudinal reinforcement of the column is greater than 3%, the stirrup should be 8 or more.
It can also be seen from the above that the 2015 revision also puts forward stricter requirements for the straight section of the hook of the stirrup for the column with large reinforcement ratio (more than 3%): and the longitudinal reinforcement should be hooked.
03 The third structural requirement for stirrups of frame columns, 11.4.12-2 of the Concrete Code, stipulates that for short columns with a shear-span ratio of no more than 2, if the diameter of longitudinal reinforcement is 16, it should be noted that the maximum spacing of stirrups in the densified area should be ≤ 96 and not 100 (generally, the diameter of longitudinal reinforcement of frame columns is larger, which is not a problem).
This article of the Code of Concrete Design has more requirements than that of article 3) of 6.3.7-2 of the Code of Resistance for the spacing of stirrups between frame columns and short columns not greater than 6d (the provisions of the Code of Resistance are as follows).
This article of the Code for Concrete Structures has more requirements than article 3) of 6.4.3-2 of the Code for Concrete Structures for short columns with a shear span ratio of not more than 2, and the stirrup spacing is not more than 6d (the provisions of the Code for Concrete Structures are as follows).
For short columns, people sometimes forget to check in the design, We have sorted out the following situations for use: short columns caused by staggered floors (formed due to the staggered floors of the building) sandwich short columns (formed due to the interlayer of the building) filled with short columns (formed due to the large section of the column) filled with short columns (formed due to the installation of strip windows in the building, which is easy to be ignored) short columns formed at the first floor of the staircase due to the installation of beams on the half-platform (The diameter of the vertical distribution reinforcement of the 04 shear wall is formed due to the covering soil>600 high outdoors).
According to 11.7.15 of the Code for Concrete Design, this article and 6.4.4-3 of the Code for Concrete Design (as follows) require that the minimum diameter of the vertical distribution reinforcement of the shear wall should not be less than 10.
However, Gao Gui 7.2.18 (below) does not mention this point.
For this item, because some owners require cost savings and some drawings require strict deduction of specifications, we often use a compromise method in design, that is, d8/d10 spacing to meet the requirements of all parties.
05 The diameter of horizontal and vertical distribution reinforcement in frame-shear wall structure is specified in 6.5.2 of the Code of Resistance to Seismic Design: from this point, it can be seen that higher requirements are put forward for the shear wall in frame-shear wall, and the diameter of horizontal and vertical distribution reinforcement should not be less than 10.
This point of this article is not mentioned in the Mixed Rules and the High Rules.
06 Requirements for horizontal and vertical distribution reinforcement in some locations of high-rise shear wall structures are specified in 7.2.19 of the High Specification: this is only provided in the High Specification.
When designing high-rise shear wall structures, attention should be paid to the requirements for the reinforcement ratio of horizontal and vertical distribution reinforcement in the wall at the above locations and the spacing requirements for horizontal and vertical distribution reinforcement in the wall at the above locations at all seismic levels.
07 The requirements of special-shaped columns are higher than those of general frame columns.
The definition of special-shaped columns is as follows: in addition to the requirements for axial compression ratio and minimum reinforcement ratio of special-shaped columns are higher than those of general frame columns, the following points need to be paid special attention to: a.
One of the key points of attention is that the limb end refers to the column limb with a range of one time the limb thickness along the limb height direction a, as shown in Figure 6.2.15 of the Code (the figure below).
B.
Key points for attention 2.
Key points for attention 3 d.
Key points for attention 4.
Key points for attention 5.
08 The section structure requirements of vertical members of shear wall with Class I fire protection are listed in the common building code Code for Fire Protection Design of Buildings GB-50016-2014 (2018).
For buildings with Class I fire protection (please confirm the fire protection grade and position of the project with the building), attention should be paid to the section size of structural wall column.
Article 5.1.2 of the Code for Fire Protection has the following requirements for the vertical members of concrete structures: the section of various structural members is specified in Appendix 1 of the provisions of the Code for Fire Protection: it can be seen that the concrete wall 180 meets the Class I fire protection requirements.
Generally, the wall thickness is 200 and above, and there is no problem.
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