1.什么是高強(qiáng)螺栓
1. What is high-strength bolt
高強(qiáng)螺栓，施工中所說的高強(qiáng)螺栓是高強(qiáng)度摩擦預(yù)緊螺栓的簡(jiǎn)稱。在日常溝通中，僅僅是簡(jiǎn)略了“摩擦(Friction)”“預(yù)緊(Grip)”兩個(gè)詞，卻造成了許多工程技術(shù)人員對(duì)高強(qiáng)螺栓基本定義的理解，產(chǎn)生了誤區(qū)。
High strength bolts, referred to in construction as high-strength bolts, are short for high-strength friction pre tensioned bolts. In daily communication, simply abbreviating the words "friction" and "Grip" has caused many engineering and technical personnel to misunderstand the basic definition of high-strength bolts.
高強(qiáng)螺栓.jpg
High strength bolts.jpg
顛覆一：
Disruption 1:
誤區(qū)：材料等級(jí)超過8.8級(jí)的螺栓，就是”高強(qiáng)螺栓“。
Misunderstanding: Bolts with a material grade exceeding 8.8 are considered "high-strength bolts".
高強(qiáng)螺栓和普通螺栓的核心區(qū)別并不在于使用材料的強(qiáng)度，而是受力的形式。本質(zhì)是是否施加預(yù)緊力，并利用靜摩擦力抗剪。(1)*實(shí)際上在英標(biāo)規(guī)范，美標(biāo)規(guī)范中提到的高強(qiáng)螺栓(HSFG BOLT)只有8.8級(jí)和10.9級(jí)兩種(BS EN 14399 / ASTM-A325&ASTM-490)，而普通螺栓卻有包含有4.6，5.6，8.8，10.9，12.9等(BS 3692 11款表2);由此可見，材料強(qiáng)度高低并不是區(qū)別高強(qiáng)螺栓與普通螺栓的關(guān)鍵。
The core difference between high-strength bolts and ordinary bolts is not the strength of the materials used, but the form of force applied. The essence is whether to apply preload and use static friction to resist shear. (1) In fact, in the British standard specifications, the American standard specifications only mention two types of high-strength bolts (HSFG BOLT): grade 8.8 and grade 10.9 (BS EN 14399/ASTM-A325&ASTM-490), while ordinary bolts include 4.6, 5.6, 8.8, 10.9, 12.9, etc. (Table 2 of BS 3692 Clause 11); It can be seen that the strength of the material is not the key to distinguishing high-strength bolts from ordinary bolts.
2.正確理解“高強(qiáng)”，強(qiáng)在何處
2. Correctly understand "high strength" and where it lies
按照GB50017，計(jì)算單個(gè)普通螺栓(B類)8.8級(jí)和高強(qiáng)螺栓8.8級(jí)抗拉及抗剪強(qiáng)度。
According to GB50017, calculate the tensile and shear strength of individual ordinary bolts (Class B) with grade 8.8 and high-strength bolts with grade 8.8.
通過計(jì)算我們可以看到，相同等級(jí)的情況下，普通螺栓的抗拉強(qiáng)度和抗剪強(qiáng)度的設(shè)計(jì)值都要高于高強(qiáng)螺栓。那么高強(qiáng)螺栓，“強(qiáng)”在哪里?
Through calculation, we can see that under the same grade, the design values of tensile strength and shear strength of ordinary bolts are higher than those of high-strength bolts. So where is the strength of high-strength bolts?
為回答這一個(gè)問題，必須從兩種螺栓的設(shè)計(jì)工作狀態(tài)入手，研究其彈塑性變形的規(guī)律，并理解到設(shè)計(jì)破壞時(shí)的極限狀態(tài)。
To answer this question, it is necessary to start with the design working states of the two types of bolts, study their elastic-plastic deformation laws, and understand the limit state at the time of design failure.
普通螺栓和高強(qiáng)螺栓工作狀態(tài)下應(yīng)力應(yīng)變曲線
Stress-strain curves of ordinary bolts and high-strength bolts under working conditions
設(shè)計(jì)破壞時(shí)的極限狀態(tài)
Ultimate state at design failure
普通螺栓：螺桿本身發(fā)生超過設(shè)計(jì)允許的塑性變形，螺桿被剪壞。
Ordinary bolt: The screw itself undergoes plastic deformation that exceeds the design tolerance, resulting in the screw being sheared out.
普通螺栓連接，開始承受剪力前連接板間就會(huì)發(fā)生相對(duì)滑移，繼而螺栓桿和連接板接觸，發(fā)生彈塑性形變，承受剪力。
For ordinary bolted connections, relative slip occurs between the connecting plates before they begin to bear shear force, and then the bolt rod contacts the connecting plate, causing elastic-plastic deformation and bearing shear force.
高強(qiáng)螺栓：有效摩擦面間的靜摩擦力被攻克，兩塊鋼板發(fā)生相對(duì)位移，設(shè)計(jì)考量上即為破壞。
High strength bolt: The static friction force between the effective friction surfaces is overcome, and the two steel plates undergo relative displacement, which is considered as failure in design considerations.
高強(qiáng)螺栓連接，摩擦力承受剪力，當(dāng)荷載增大到摩擦力不足以抵抗剪力，靜摩擦力被攻克，連接板發(fā)生相對(duì)滑移(極限狀態(tài))。但此時(shí)雖然破壞，但螺栓桿與連接板發(fā)生接觸，依然可以利用其本身的彈塑性形變，承受剪力。
In high-strength bolt connections, the frictional force first bears the shear force. When the load increases to a point where the frictional force is insufficient to resist the shear force, the static frictional force is overcome, and the connecting plate undergoes relative slip (ultimate state). But although it is damaged at this time, the bolt rod can still use its own elastic-plastic deformation to withstand shear force when in contact with the connecting plate.
(3)顛覆二：
(3) Subversion 2:
誤區(qū)：高強(qiáng)螺栓的承載能力高于普通螺栓，是為”高強(qiáng)“。
Myth: High strength bolts have a higher load-bearing capacity than ordinary bolts and are considered "high strength".
由單個(gè)螺栓的計(jì)算可知，高強(qiáng)螺栓抗拉和抗剪的設(shè)計(jì)強(qiáng)度均低于普通螺栓。其高強(qiáng)實(shí)質(zhì)是：正常工作時(shí)，節(jié)點(diǎn)不允許發(fā)生任何相對(duì)滑移，即：彈塑性變形小，節(jié)點(diǎn)剛度大。
According to the calculation of a single bolt, the design strength of high-strength bolts in terms of tensile and shear strength is lower than that of ordinary bolts. The essence of its high strength is that during normal operation, nodes are not allowed to experience any relative slip, that is, small elastic-plastic deformation and high node stiffness.
可見：在給定設(shè)計(jì)節(jié)點(diǎn)荷載的情況下，用高強(qiáng)螺栓設(shè)計(jì)的節(jié)點(diǎn)并不一定能節(jié)省螺栓使用數(shù)量，但是其變形小，剛度大，儲(chǔ)備高。適合用主梁，等要求節(jié)點(diǎn)剛度較大的位置，符合“強(qiáng)節(jié)點(diǎn)，弱桿件”的基本抗震設(shè)計(jì)原理。
It can be seen that under a given design node load, nodes designed with high-strength bolts may not necessarily save on the number of bolts used, but they have small deformation, high stiffness, and high safety reserves. Suitable for using main beams and other locations that require high node stiffness, in accordance with the basic seismic design principle of "strong nodes, weak members".
高強(qiáng)螺栓之強(qiáng)，并非在于其本身的承載能力設(shè)計(jì)值，而是表現(xiàn)于其設(shè)計(jì)節(jié)點(diǎn)的剛度大，性能高，抗破壞的能力強(qiáng)。
The strength of high-strength bolts is not determined by their designed load-bearing capacity, but by the high stiffness, high safety performance, and strong resistance to failure of the designed nodes.
3.高強(qiáng)螺栓的對(duì)比
3. Comparison of high-strength bolts
普通螺栓和高強(qiáng)螺栓由于其設(shè)計(jì)的受力原理不同，其在施工檢驗(yàn)方法上有極大的區(qū)別。
Ordinary bolts and high-strength bolts have significant differences in construction inspection methods due to their different design stress principles.
同等級(jí)普通螺栓各項(xiàng)機(jī)械性能要求均比高強(qiáng)螺栓略高，但高強(qiáng)螺栓較普通螺栓多一項(xiàng)沖擊功的驗(yàn)收要求。
The mechanical performance requirements of ordinary bolts of the same grade are slightly higher than those of high-strength bolts, but high-strength bolts have an additional acceptance requirement for impact energy compared to ordinary bolts.
標(biāo)識(shí)樣式對(duì)比
Comparison of logo styles
普通螺栓和高強(qiáng)螺栓的標(biāo)示是對(duì)同等級(jí)螺栓現(xiàn)場(chǎng)識(shí)別的基本方法。由于英美標(biāo)準(zhǔn)中對(duì)于高強(qiáng)螺栓扭矩值計(jì)算的取值并不相同，所以識(shí)別兩種標(biāo)準(zhǔn)的螺栓也有必要。
The identification of ordinary bolts and high-strength bolts is the basic method for on-site identification of bolts of the same grade. Due to the different values for calculating the torque value of high-strength bolts in British and American standards, it is also necessary to identify bolts from both standards.
對(duì)比
Price comparison
高強(qiáng)螺栓：(M24，L60，8.8級(jí))
High strength bolts: (M24, L60, Grade 8.8)
普通螺栓：(M24，L60，8.8級(jí))
Ordinary bolt: (M24, L60, Grade 8.8)
可見普通螺栓大約為高強(qiáng)螺栓的70%，結(jié)合其驗(yàn)收要求的對(duì)比，可以得出，其溢價(jià)部分就應(yīng)該是為了保證材料的沖擊功(韌性)性能。
It can be seen that ordinary bolts are about 70% of the price of high-strength bolts. Based on the comparison of their acceptance requirements, it can be concluded that the premium part should be to ensure the impact energy (toughness) performance of the material.
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