Recently, many friends said that when measuring the thread steel, they encountered some minor problems, so I would like to ask what methods of measuring the diameter of the thread steel are.

　　螺纹钢直径测量方法

　　Measuring Method of Thread Steel Diameter

　　废话不多说，施工现场常釆用下面的螺纹钢直径测量方法：

　　The following methods of measuring the diameter of threaded steel are often used in the construction site.

　　1、以前老标准用重量法算面积：面积=长度*重量/7.85；

　　1. The old standard used to calculate area by gravimetric method: area = length * weight / 7.85;

　　即用称称得的单位长度的钢筋重量，除以钢的容重7.85，得到断面积，再折算出“直径”。

　　That is to say, the section area is obtained by dividing the weight of steel bars per unit length by the volume weight of steel 7.85, and then the "diameter" is calculated.

　　面积(s)=圆周率π(3.14)*半径(r)的平方

　　Area (s) = the square of PI (3.14) * radius (r)

　　直径=半径*2

　　Diameter = radius*2

　　2、在现场也常用游标卡尺直接量直径：一侧卡肋，一侧卡光面，量三个截面计算平均直径，折减5%即可的办法。

　　2. Vernier calipers are also commonly used in the field to measure the diameter directly: one side of the caliper, one side of the caliper smooth surface, measuring three sections to calculate the average diameter, which can be reduced by 5%.

　　3、用卡尺直接测量内径（不含肋），对照五金手册相应钢筋的内径尺寸即可。按GB1499.2的规定，应测量钢筋内径d1，不能测肋的尺寸。如公称直径12、14、16、18的，其内径d1分别为11.5、13.4、15.4、17.3，允许偏差±0.4。再如公称直径20、22、25的，d1分别为19.3、21.3、24.2，允许偏差±0.5。

　　3. Measure the inner diameter (without ribs) directly with calipers, and compare the inner diameter of the steel bar in the hardware manual. According to GB1499.2, the inner diameter of reinforcing bar D1 should be measured, but the size of ribs can not be measured. If the nominal diameters are 12, 14, 16 and 18, their inner diameters D1 are 11.5, 13.4, 15.4 and 17.3, respectively, with an allowable deviation of <0.4. If the nominal diameter is 20, 22 and 25, D1 is 19.3, 21.3 and 24.2, respectively, and the allowable deviation is (+0.5).

　　带肋钢筋横肋设计原则应符合下列规定：

　　The design principles of ribbed bar transverse ribs shall comply with the following provisions:

　　横肋与钢筋轴线的夹角β不应小于45度，当该夹角不大于70度时，钢筋相对两面上横肋的方向应相反；

　　The angle beta between the transverse rib and the axis of the steel bar should not be less than 45 degrees. When the angle is less than 70 degrees, the direction of the steel bar relative to the transverse rib on both sides should be opposite.

　　横肋公称间距l不得大于钢筋公称直径的0.7倍；

　　The nominal spacing of transverse ribs shall not be greater than 0.7 times the nominal diameter of reinforcing bars.

　　横肋侧面与钢筋表面的夹角α不得小于45度；

　　The angle alpha between the side of the transverse rib and the surface of the reinforcing bar shall not be less than 45 degrees.

　　钢筋相邻两面上横肋末端之间的间隙(包括纵肋宽度)总和不应大于钢筋公称周长的20%；

　　The total clearance (including longitudinal rib width) between the ends of the transverse ribs on the adjacent two sides of the reinforcing bar should not be greater than 20% of the nominal circumference of the reinforcing bar.

　　当钢筋公称直径不大于12mm时，相对肋面积不应小于0.055；公称直径为14mm和16mm时，相对肋面积不应小于0.060；公称直径大于16mm时，相对肋面积不应小于0.065。

　　When the nominal diameter of reinforcing bar is less than 12 mm, the relative rib area should not be less than 0.055; when the nominal diameter is 14 mm and 16 mm, the relative rib area should not be less than 0.060; when the nominal diameter is greater than 16 mm, the relative rib area should not be less than 0.065.

　　关于螺纹钢直接测量方法，就是这样的了。如果大家还想要了解更多钢材方面的小知识，就多多关注我们吧：http://www.jzqgc.com/

　　关于螺纹钢直接测量方法，就是这样的了。 If you want to know more about steel, pay more attention to us: http://www.jzqgc.com/