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.

扭剪型高強(qiáng)螺栓其端部端部有梅花卡頭，并且螺栓的螺帽一般是圓形(不需要使用扳手固定);是日本人在HSFG的基礎(chǔ)上開發(fā)研制的改進(jìn)型產(chǎn)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外觀對比分析

01 Comparative analysis of appearance

大六角型：

Large hexagon:

六角頭螺栓使用定扭矩扳手施工，由于其施擰時(shí)并不握裹螺桿，在旋轉(zhuǎn)螺母的同時(shí)可能會(huì)帶動(dòng)螺桿進(jìn)行“同轉(zhuǎn)”，無謂消耗扭矩值，造成無法擰緊。故將螺桿頭設(shè)計(jì)成大六角，在發(fā)生同轉(zhuǎn)的情況時(shí)，可以用普通扳手予以臨時(shí)固定，避免同轉(zhuǎn)現(xiàn)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.

定扭矩扳手伸出來的支撐桿主要是為了提供支點(diǎn)以確定其施加的扭矩，故如無可靠支點(diǎn)，扳手無法施工。

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：(梅花頭)

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桿直接通過“梅花頭”夾緊螺桿本身，故施擰時(shí)不會(huì)發(fā)生同轉(zhuǎn)現(xiàn)象。其產(chǎn)品設(shè)計(jì)的思路是：利用螺桿達(dá)到預(yù)拉力值時(shí)，材料所能承受對應(yīng)的剪力，來設(shè)計(jì)削弱梅花頭的根部截面，達(dá)到剪斷的目的。

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

原理對比分析

Principle comparison and analysis

必須理解：同一型號的大六角和扭剪型螺栓在正確的施工方法下可以達(dá)到的預(yù)拉力設(shè)計(jì)值是同樣的。

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.

大六角頭高強(qiáng)螺栓（HSFG）施擰過程：(理解“扭矩系數(shù)”）

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

“541” 原則

"541" principle

“541”原則，是日本人在工程實(shí)踐的基礎(chǔ)上反復(fù)實(shí)驗(yàn)總結(jié)出的關(guān)于扭矩值和預(yù)緊力之間的對應(yīng)關(guān)系。英國鋼結(jié)構(gòu)教科書中對此進(jìn)行了引用和闡述，其給出了扭矩?fù)p耗的因素。國內(nèi)進(jìn)行鋼結(jié)構(gòu)教育中，很少提及“541”原則，而是直接反應(yīng)成為我們理解的“扭矩系數(shù)”：

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":

的夾緊力 / 輸出總力矩 = 扭矩系數(shù) （0.11~0.14）

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

故“扭矩系數(shù)”是大六角高強(qiáng)螺栓HSFG施工的重要參數(shù)，為了保障大六角螺栓施工質(zhì)量，必須對扭矩系數(shù)進(jìn)行測定檢驗(yàn)。

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.

扭剪型高強(qiáng)螺栓（TCB）施擰過程：（理解“緊固軸力”）

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

削弱截面的剪斷過程

Shear process of weakened section

在施加扭矩聚集材料內(nèi)拉應(yīng)力達(dá)到設(shè)計(jì)值(“緊固軸力”)的同時(shí)，其材料的對應(yīng)抗剪強(qiáng)度恰好能使梅花頭削弱截面擰斷。

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，也不是直接反饋螺桿中的預(yù)拉力值，而是利用抗剪能力進(jìn)行了代換，其檢驗(yàn)項(xiàng)仍然不是直接項(xiàng)，存在代換的誤差。

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.

故為了保障扭剪型螺栓的施工質(zhì)量，必須對其剪斷時(shí)對應(yīng)代表的“緊固軸力”進(jìn)行測定。其值應(yīng)當(dāng)符合預(yù)緊力設(shè)計(jì)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扭剪型和大六角的對比

03 Comparison between torsional shear type and large hexagon

連接副組成對比

Composition comparison of connecting pairs

基于國標(biāo)JGJ-82 6.1.1規(guī)定，高強(qiáng)螺栓連接副中，大六角螺栓需要兩墊一母，扭剪型高強(qiáng)螺栓則要一墊一母。

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.

驗(yàn)收方式對比

Comparison of acceptance methods

大六角螺栓HSFG在施工之后，使用定扭矩扳手檢驗(yàn)。在驗(yàn)收扭剪型TCB時(shí)，關(guān)注梅花頭被擰斷即合格。

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.