High strength bolts can be easily distinguished into large hexagonal bolts in terms of shape. The nuts of large hexagonal bolts are regular hexagonal, which can be inferred to be convenient for fixing with a wrench. This is the type of high-strength bolts used for the first time.

扭剪型高强螺栓其端部端部有梅花卡头，并且螺栓的螺帽一般是圆形(不需要使用扳手固定);是日本人在HSFG的基础上开发研制的改进型产品。

Torsional shear type high-strength bolt has a box head at the end and the nut of the bolt is generally round (no need to use a wrench to fix it); It is an improved product developed by Japanese on the basis of HSFG.

01外观对比分析

01 Comparative analysis of appearance

大六角型：

Large hexagon:

六角头螺栓使用定扭矩扳手施工，由于其施拧时并不握裹螺杆，在旋转螺母的同时可能会带动螺杆进行“同转”，无谓消耗扭矩值，造成无法拧紧。故将螺杆头设计成大六角，在发生同转的情况时，可以用普通扳手予以临时固定，避免同转现象。

The hexagon head bolt is constructed with a constant torque wrench. Since it does not wrap the screw when screwing, it may drive the screw to "turn at the same time" while rotating the nut, which is unnecessary to consume torque value, resulting in failure to tighten. Therefore, the screw head is designed as a large hexagon. In case of simultaneous rotation, it can be temporarily fixed with an ordinary wrench to avoid simultaneous rotation.

定扭矩扳手伸出来的支撑杆主要是为了提供支点以确定其施加的扭矩，故如无可靠支点，扳手无法施工。

The support rod extended by the constant torque wrench is mainly used to provide a fulcrum to determine the torque applied. Therefore, if there is no reliable fulcrum, the wrench cannot be constructed.

扭剪型：(梅花头)

Torsional shear type: (plum blossom head)

扭剪型螺栓使用扭剪型扳手施工，其根部使用正反向扭杆直接通过“梅花头”夹紧螺杆本身，故施拧时不会发生同转现象。其产品设计的思路是：利用螺杆达到预拉力值时，材料所能承受对应的剪力，来设计削弱梅花头的根部截面，达到剪断的目的。

Torsional shear type bolts are constructed with torsional shear type wrenches, and the screw itself is clamped directly through the "quincunx head" with forward and reverse torsion bars at the root, so the phenomenon of simultaneous rotation will not occur during tightening. The idea of product design is to use the corresponding shear force that the material can bear when the screw reaches the pre tension value to design the root section of the weakened plum blossom head to achieve the purpose of shearing.

02

02

原理对比分析

Principle comparison and analysis

首先必须理解：同一型号的大六角和扭剪型螺栓在正确的施工方法下可以达到的预拉力设计值是同样的。

First of all, it must be understood that the design value of pretension that can be achieved by the same type of large hexagon bolts and torsional shear bolts under the correct construction method is the same.

大六角头高强螺栓（HSFG）施拧过程：(理解“扭矩系数”）

Tightening process of large hexagon high strength bolt (HSFG): (understand "torque coefficient")

“541” 原则

"541" principle

“541”原则，是日本人在工程实践的基础上反复实验总结出的关于扭矩值和预紧力之间的对应关系。英国钢结构教科书中对此进行了引用和阐述，其给出了扭矩损耗的因素。国内进行钢结构教育中，很少提及“541”原则，而是直接反应成为我们理解的“扭矩系数”：

The "541" principle is the corresponding relationship between torque value and preload summarized by Japanese repeated experiments on the basis of engineering practice. This is quoted and elaborated in British steel structure textbooks, which gives the factors of torque loss. In domestic steel structure education, the "541" principle is rarely mentioned, but it directly reflects our understanding of "torque coefficient":

的夹紧力 / 输出总力矩 = 扭矩系数 （0.11~0.14）

Clamping force/total output torque=torque coefficient (0.11~0.14)

故“扭矩系数”是大六角高强螺栓HSFG施工的重要参数，为了保障大六角螺栓施工质量，必须对扭矩系数进行测定检验。

Therefore, "torque coefficient" is an important parameter for HSFG construction of large hexagon high-strength bolts. In order to ensure the construction quality of large hexagon bolts, the torque coefficient must be measured and inspected.

扭剪型高强螺栓（TCB）施拧过程：（理解“紧固轴力”）

Tightening process of torsional shear high-strength bolt (TCB): (understand "fastening axial force")

削弱截面的剪断过程

Shear process of weakened section

在施加扭矩聚集材料内拉应力达到设计值(“紧固轴力”)的同时，其材料的对应抗剪强度恰好能使梅花头削弱截面拧断。

When the applied torque gathers the internal tensile stress of the material to reach the design value ("fastening axial force"), the corresponding shear strength of the material can just make the weakened section of the quincunx head twist off.

分析可知即便是扭剪型螺栓，也不是直接反馈螺杆中的预拉力值，而是利用抗剪能力进行了代换，其检验项仍然不是直接项，存在代换的误差。

It can be seen from the analysis that even for torsional shear type bolts, the pre tension value in the screw is not directly fed back, but is replaced by using the shear resistance. The inspection items are still not direct items, and there are replacement errors.

故为了保障扭剪型螺栓的施工质量，必须对其剪断时对应代表的“紧固轴力”进行测定。其值应当符合预紧力设计值。

Therefore, in order to ensure the construction quality of the torsional shear bolt, the corresponding "fastening axial force" must be measured when it is cut. The value shall conform to the design value of preload.

03扭剪型和大六角的对比

03 Comparison between torsional shear type and large hexagon

连接副组成对比

Composition comparison of connecting pairs

基于国标JGJ-82 6.1.1规定，高强螺栓连接副中，大六角螺栓需要两垫一母，扭剪型高强螺栓则要一垫一母。

According to the national standard JGJ-82 6.1.1, in the connection pairs of high-strength bolts, two gaskets and one nut are required for large hexagon bolts, and one gasket and one nut are required for torsional shear type high-strength bolts.

验收方式对比

Comparison of acceptance methods

大六角螺栓HSFG在施工之后，使用定扭矩扳手检验。在验收扭剪型TCB时，关注梅花头被拧断即合格。

The large hexagon bolt HSFG shall be inspected with a constant torque wrench after construction. During the acceptance of torsional shear TCB, the quincunx head shall be regarded as qualified if it is broken.