How should foundation bolts be set?

The question is too general, making it difficult to provide a targeted answer. It is suggested that the original poster describe the issue in more detail

I don’t know what the original poster is asking Installation or design? Still, for verification, take a look at this article: Handling Common Problems with Foot Bolts. The quality of the installation of foot bolts has a direct impact on the quality of equipment installation. Some equipment has strict requirements regarding the accuracy of elevation and position, especially those with a high degree of automation, where such requirements are even stricter. Therefore, after the anchor bolts are installed and before the equipment is mounted, they must be inspected and adjusted. When deviations occur, actions should be taken based on the actual conditions of the equipment, using different methods for correction. The common methods include the following: 　　(1) Correction of centering deviation in foot bolts 　　When the diameter of the foot bolt is 30 mm or less and the offset of its centerline is within 30 mm, the bolt can first be heated red using oxygen-acetylene welding, after which it can be bent using a sledgehammer (or a jack). Once corrected, it must be welded firmly with steel plates to prevent it from returning to its original shape when the bolts are tightened. If the bolt spacing is incorrect, it can be bent using an oxy-acetylene flame to heat it up, then a steel plate can be welded in place to reinforce it; this plate can be filled with grout later to secure it in place. 　　In the case of large bolts (with a diameter of over 30 mm) that experience significant deflection, the bolt should first be cut, and a steel plate should be welded in the middle of the bolt. If the strength of the bolt is insufficient, two reinforcing steel plates can be welded to either side of the bolt; their length should be at least 3 to 4 times the diameter of the bolt. 　　(II) Handling of elevation deviations in foundation bolts 1. When the bolt is too high, the excess part must be cut off before threading it. When threading, it is necessary to prevent oils from dripping onto the concrete foundation, as this could cause corrosion and affect the quality of the foundation. 　　2. When the bolt is low and the deviation is not large (within 15 mm), the bolt can be heated red using oxy-acetylene, and then stretched. The method of elongation involves using two layers of shims as supports, then placing a steel plate with a hole in the middle on top of them over the anchor bolts; this plate is tightened with nuts, and the force generated by tightening the nuts is used to elongate the parts of the bolts that have been heated. 2 to 3 steel plates must be welded on at the thinned area of the bolt diameter for reinforcement. If the equipment is already placed on a base and moving it is difficult, and provided that the strength of the frame flange is sufficient, the nuts can be tightened directly on the base to stretch the bolts. Once the appropriate length has been reached, the nut must be loosened to prevent excessive tension once the bolt cools down, which could even crack the base flange. 　　If the bolt is too low (15 mm below the required height) and cannot be lengthened by heating, a deep pit can be dug around the bolt; the bolt should be cut at a distance of about 100 mm from the bottom of the pit, and a newly fabricated bolt should be welded in place, ensuring that its elevation meets the requirements. Afterwards, it should be reinforced with round steel. The length of the reinforcing round steel is generally 4 to 5 times the diameter of the bolt. 　　(III) Handling of loose foundation bolts When tightening the foundation bolts, it is possible for them to become loose; in such cases, the bolts should first be adjusted back to their original positions, and enough soil around the bolts should be removed. Then, U-shaped steel bars should be welded to both the vertical and horizontal directions around the bolts. The area inside the hole should be cleaned thoroughly with water and filled with grout, and the nuts should be tightened only after the concrete has reached its designed strength. 　　(IV) Handling of deviations in adjustable foot bolts The method for dealing with deviations in adjustable foot bolts is roughly the same as that for fixed foot bolts; the only difference is that the foot bolt can be pulled out for adjustment. If the bolt is too long, a section can be cut off on a machine tool before threading it ； If the bolt is too short, it can be lengthened using hot forging ； If the position is incorrect, correct it using the bending method. 　　V. Precautions for tightening foot bolts 1. When tightening the foot bolts, a washer should be placed under the nut. 2. When tightening the bolts, start from the middle of the equipment and then work towards the sides in a cross-diagonal pattern, applying even force throughout. It is strictly prohibited to tighten one side before tightening the other, and the level of equipment installation should be checked again after the nuts are tightened. 3. When tightening bolts, standard-length wrenches should be used; only bolts of M30 or larger allow the use of extensions to increase the length of the wrench. During operation, it is necessary to ensure proper tightening while also preventing excessive force that could damage the threads.

The article on the 5th floor is not advisable. Such as: (1) Handling of the centering deviation of foundation bolts ； Foundation bolts transmit forces vertically from the equipment to the foundation; if they bend, they will stretch and thus become loose. If necessary, first cut the bolt in half and weld a steel plate in the middle of it; if the strength of the bolt is insufficient, two additional reinforcing steel plates can be welded to either side of the bolt, with their length being no less than 3–4 times the diameter of the bolt. ”It serves the same purpose as the embedded iron and does not function to secure equipment ； (II) Handling of the elevation deviation of foundation bolts ； The length of the anchor bolts is designed according to specific requirements; if the length is reduced, the anchoring strength decreases, and it will not be possible to meet the design specifications, which can lead to problems. In particular, approach (II)--2 is difficult to understand: using the hot-drawing process to lengthen the anchor bolts damages their internal metal structure, resulting in a decrease in their tensile strength ； Another approach is even less acceptable – it would require cutting the anchor bolts of the structure; can welding in this way meet the strength requirements? There are strict regulations for manufacturing anchor bolts. Regarding (3), (4), and the same above, it is also difficult to understand ； As for (5), it falls under the category of mechanical installation; you simply need to provide the civil engineering conditions required for such installation. Leveling and alignment of the equipment do not involve using bolts in a diagonal pattern as mentioned in the text – it depends on specific requirements. . . . . . I have managed projects several times, and I’m extremely angry at the views expressed in such articles; to put it bluntly, they are complete nonsense. In my personal opinion, it is recommended that such irresponsible articles be removed as soon as possible to avoid future problems. (With all due respect)

Hehe, the suggestions put forward by the person on floor 6 are quite valid. So we can discuss whether the measures mentioned above are feasible in the event that the foundation bolts deviate from their proper position I. If it is a central deviation, how should it be handled? If it can’t be bent, are there any other options besides replacement? II. If it is a level deviation, how should it be handled? If it is too high, how can the equipment be installed without cutting the threads? If it is too low, how can it be installed without extending it? Note that it’s not just a matter of increasing the length; there are also certain reinforcement measures in place to counteract issues related to bolt deformation and changes in strength. The design is indeed sound, but problems can arise during installation. To add more, regarding the issue of cutting off bolts, this has indeed been done in the past; however, with proper precautions and reinforcements in place, no tests were carried out on-site. Still, based on experience, such practices were continued. Feel free to offer your feedback.

To apply the ideas from the 7th floor in practice, relevant supporting conditions are needed; otherwise, it’s unclear how you will handle the role of supervisor, and you are likely to have to pay a price for it.

It is divided into installed and pre-embedded types. During the foundation installation phase, the bolts are already installed; embedding involves first creating holes and then using secondary grouting to secure the bolts in place. Generally, embedding is done for accurate positioning, but the planted ones often have significant deviations.

The quantity and length of the anchor bolts are determined by the equipment specialists; the civil engineering team only needs to construct according to the foundation drawings and leave the required holes.

If the bolt is too short, it can be lengthened using hot forging； If the position is incorrect, correct it using the bending method. Such a method definitely won’t work; the thread pitch changes after it is stretched, so how can nuts be installed? Correction by bending is also not good, as it reduces strength. Ultimately, it’s best to avoid it at the source!

What is mentioned in #5 are all methods that have been used in practical engineering applications. As asked in #12, \"When the thread pitch changes after stretching, how can nuts be installed?\" ”Only the bare shaft part is stretched, not the threaded section.