【Haichuan Chemical Construction Technology】-- For bolt-weld hybrid joints, should tightening be done first followed by welding, or welding first followed by final tightening? See what the specifications say! !

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Understand construction techniques to build chemical engineering projects well. 【HaiChuan Chemical Construction Techniques】 – Regularly updated summary posts: https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=5719396 -------------------------------------------------------------------------------- GB 50755-2012 Code for Construction of Steel Structure Projects, 7.4.9: For connection joints that use both high-strength bolts and welding, when there are no specific provisions in the design documents, it is advisable to follow a construction sequence in which the bolts are tightened first and then welding is carried out. JGJ 82-2011 Technical Code for High-Strength Bolt Connections in Steel Structures 5.4.2 2 The construction sequence should be such that the flanges are welded after the initial tightening of the high-strength bolts, followed by the final tightening of those bolts ； 3 When the construction sequence of tightening bolts first and then welding the flanges is adopted, it is advisable to take supplementary tightening measures for the high-strength bolts used to join the web members, or increase the number of bolts by 10%. JTGT 3650-2020 Technical Specifications for the Construction of Road Bridges and Culverts 8.12.23 When the bridge’s steel structure is connected using a combination of welding and high-strength bolts, the bolted connections should have their high-strength bolts tightened finally only after the welds have been inspected and found to be satisfactory. The three sets of guidelines are basically consistent. To prevent welding deformation from preventing the bolt from being inserted, first insert the bolt and give it a preliminary twist. Weld again to relieve welding deformation, then perform the final tightening. Avoid frictional sliding of the mating surfaces that may result from welding deformation, as this can affect the preload force.