机械连接接头单向拉伸性能检测数据

接头单向拉伸性能检测，对判断接头性能的是否符合要求具有重要意义，有利于保障机械连接接头的质量，提升建筑工程结构安全性。依据GB 50010《混凝土结构设计规范》，钢材牌号为HRB400公称直径在6~50mm间的Ⅱ级接头极限抗拉强度标准值为540MPa。根据JGJ107-2016《钢筋机械连接技术规程》，检测机械连接接头单向拉伸性能，使用液压式万能试验机WE-l000A仪器测得3个试件在钢筋拉断状态下的极限荷载值，计算得出三次极限抗拉强度实测值，计算公式为：极限抗拉强度实测值=极限荷载值/（3.14*（公称直径/2）^2）。比较极限抗拉强度实测值与极限抗拉强度标准值，若三次极限抗拉强度实测值均大于等于极限抗拉强度标准值，则接头单向拉伸性能符合要求；反之，若有任意一次极限抗拉强度实测值小于极限抗拉强度标准值，则须再抽区6个试件进行复检。判定公式如下：F(x)=IF(AND(极限抗拉强度实测值1>极限抗拉强度标准值,极限抗拉强度实测值2>极限抗拉强度标准值,极限抗拉强度实测值3>极限抗拉强度标准值),"合格",须复检)。

Uniaxial tensile performance test of mechanical connection joints is of great significance for verifying whether the joint performance meets the specified requirements, which helps ensure the quality of mechanical connection joints and improve the structural safety of construction engineering. According to GB 50010 *Code for Design of Concrete Structures*, the characteristic ultimate tensile strength of Grade Ⅱ joints made of HRB400 steel bars with nominal diameters ranging from 6 mm to 50 mm is 540 MPa.

According to JGJ107-2016 *Technical Specification for Mechanical Connection of Reinforcing Bars*, when conducting the uniaxial tensile performance test of mechanical connection joints, three specimens are tested until the reinforcing bars fracture using a hydraulic universal testing machine model WE-1000A. Three measured ultimate tensile strength values are calculated via the following formula:
$$ ext{Measured Ultimate Tensile Strength} = frac{ ext{Ultimate Load Value}}{3.14 imes ( ext{Nominal Diameter}/2)^2}$$

Compare the three measured ultimate tensile strength values with the characteristic ultimate tensile strength. If all three measured values are greater than or equal to the characteristic value, the uniaxial tensile performance of the joint meets the requirements. Otherwise, if any one of the measured values is lower than the characteristic value, an additional 6 specimens shall be sampled for retest. The judgment formula is as follows:
$$F(x) = ext{IF(AND(Measured Ultimate Tensile Strength 1} geq ext{Characteristic Ultimate Tensile Strength}, ext{Measured Ultimate Tensile Strength 2} geq ext{Characteristic Ultimate Tensile Strength}, ext{Measured Ultimate Tensile Strength 3} geq ext{Characteristic Ultimate Tensile Strength}), "Qualified", "Re-test Required")}$$