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In structural design, vertical components such as concrete walls and columns often account for a very important proportion.
Combined with some problems encountered in the process of design and drawing review in common basic specifications, the editor summarizes some contents that may be ignored in the requirements of structural structure, hoping to be helpful to you.
Several commonly used structural codes are as follows: Code for design of concrete structures gb50010-2010 (2015 Edition) (hereinafter referred to as “concrete code”), code for seismic design of buildings gb50011-2010 (2016 Edition) (hereinafter referred to as “code for resistance”), technical specification for concrete structures of high-rise buildings jgj3-2010 (hereinafter referred to as “high code”) and technical specification for concrete special-shaped column structures jgj149-2017 (hereinafter referred to as “different regulations”) Building Code: Code for fire protection design of buildings gb-50016-2014 (2018 Edition) (hereinafter referred to as “code for fire protection”) 01 one of the structural requirements for stirrups of frame columns, which is specified in 9.3.2-1 of the mixed code: This article is specified in the code for resistance and the high code It is not specifically mentioned in the, if the design only looks at the last two specifications, it is easy to be ignored.
This article is often easily omitted in the design of frame structures with grade IV earthquake resistance, The minimum diameter of stirrup required for grade IV earthquake resistance is 6 (column root 8), but when the longitudinal reinforcement diameter of the column is 25 and above, the stirrup diameter should be 8 and above.
02 it is specified in 9.3.2-5 of the code for resistance and the code for design of height in the second part of the structural requirements for stirrups of frame columns It is not specifically mentioned in.
This one is also easy to be omitted in the design of grade IV seismic frame structure, The minimum diameter of stirrup required for grade IV earthquake 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 hook straight section of stirrup for columns with large reinforcement ratio (greater than 3%): and the longitudinal reinforcement should be hooked.
03 code for concrete design of frame column stirrup structure (III) 11.4.
12-2 stipulates that for short columns with shear span ratio not greater than 2, if the longitudinal reinforcement diameter is 16, it should be noted that the maximum spacing of stirrups in the densified area should be ≤ 96 rather than 100 (generally, the longitudinal reinforcement diameter of frame columns is large, which is not a problem).
This article of the mixed regulations is better than 6.3 of the anti regulations Article 3) of 7-2 specifies that the stirrup spacing of frame column and short column shall not be greater than 6D (the provisions of the code for resistance are as follows).
This article of the mixed code specifies that the stirrup spacing of short column with shear span ratio not greater than 2 shall not be greater than 6D than article 3) of 6.4.3-2 of the high code (the high code) The provisions are as follows).
For short columns, people sometimes forget to check in the design, We sorted out the following situations for use: short columns caused by staggered floors (formed due to staggered floors in the building) sandwich short columns (formed due to interlayer in the building) short columns filled in the whole process (formed due to large column section) (this one is easily ignored due to the setting of strip windows in the building) the diameter of the vertical distribution reinforcement of the 04 shear wall at the indoor and outdoor height difference of the first floor of the short column formed by the setting of beams on the half platform in the staircase (formed outdoors due to the covering soil > 600 height) is specified in 11.7.15 of the code for concrete design: this one is consistent with 6.4.4-3 of the code for resistance (as follows) it is required that the minimum diameter of the vertical distribution reinforcement of the shear wall should not be less than 10.
And the height specification is 7.2.18 (as follows) this point is not mentioned.
For this article, because some owners require cost saving and some drawing review requires strict compliance with specifications, we often adopt a compromise method in the design, that is, D8 / D10 spacing is used to meet the requirements of all parties.05 the diameter of horizontal and vertical distribution reinforcement of frame shear wall structure is in the code for resistance 6.5.
2: it can be seen from this article that higher requirements are put forward for the shear wall in the frame shear wall, and the diameter of horizontal and vertical distributed reinforcement should not be less than 10.
This point of this article is not mentioned in the mixed regulations and the high regulations.
06 requirements for horizontal and vertical distributed reinforcement at some positions of high-rise shear wall structure 7.2 of the code for design of tall buildings 19 stipulates that this article is only available in the high code.
During the design of high-rise shear wall structure, attention shall be paid to the requirements for the reinforcement ratio of horizontal and vertical distributed reinforcement in the wall at the above position in case of grade IV earthquake resistance, and the spacing requirements of horizontal and vertical distributed reinforcement in the wall at the above position in case of all earthquake resistance grades.
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 greater than those of general frame columns, the following points need special attention: A.
one of the key points to note is that the limb end refers to the column limb with a range of one limb thickness along the limb height direction, as shown in Figure 6.2 of the special regulations 15 (see the figure below).
B.
key points 2.
C.
key points 3.
D.
key points 4.
E.
key points 5.
08 requirements for section structure of vertical members of shear wall with class I fire protection in common building code code for fire protection design of buildings gb-50016-2014 (2018 Edition), for buildings with class I fire protection (please confirm the fire rating and position of the project with the building) pay attention to the section size of structural walls and columns.
Article 5.1.2 of the code for fire protection has the following requirements for vertical components of concrete structures: Code for fire protection The section of various structural members is specified in Appendix 1 of the article description: it can be seen that the concrete wall 180 meets the class I fire protection requirements.
Generally, our wall thickness is 200 or more, which is no problem.
The concrete column shall meet the section size of class I fire prevention.
There is no problem with general frame columns.
The points to be noted are: 1 Staircase column.
Limited by the building wall, the ladder column can only be 200 wide, so the length must be 500 to meet the requirements.
2.
The columns at the part of the accessible roof shall meet the above requirements.
The above articles are the summary of some structural problems of concrete vertical members encountered by the editor in the design process, hoping to be helpful to the students who are new to the field of structural design.
When designing, you can’t just look at the anti-seismic design code, and only look at the high-rise design code.
You think it’s always stricter than the mixed code.
In fact, it’s not necessarily.
As mentioned above, some basic terms are only reflected in the mixed code, so you must combine them.
When designing, we should not only look at the structural specifications, but also understand the relevant specifications of buildings.
Only in this way can we do the structural design, do the right structural design and do the structural design well.
References: Code for design of concrete structures gb50010-2010 (2015 Edition), code for seismic design of buildings gb50011-2010 (2016 Edition), technical specification for concrete structures of high rise buildings jgj3-2010, technical specification for concrete special-shaped column structures jgj149-2017, code for fire protection design of buildings gb-50016-2014 (2018 Edition) Pay attention now! ◆ structural design of Zhulong ◆ micro signal: zhulongjg ◆ architectural design of Zhulong ◆ micro signal: zhulongjz ◆ rock and soil of Zhulong ◆ micro signal: zhulongyt stamp the original text below for more material!..
