Issues with the foundation anchor bolts of the exhaust fan

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This post was last edited by gjn1970 on 2011-6-30 at 14:09. During the installation of the exhaust fan, the civil engineering team made mistakes in the holes for the foundation bolts. The installation requirements specify that there should be a gap of 4–6 MM between the half-coupling of the fan’s bearing box and that of the motor. However, upon inspection, it was found that the gap between the outer wall of the motor-side bolt and the inner wall of the hole where the bolt is inserted is less than 10 MM; in some areas, the bolt is almost in contact with the wall (as the bolt hole is slightly skewed). It is no longer possible to move the bolt any further, as this would prevent the maintenance of the required maximum gap of 6 MM. But a 10MM gap is too small. There are two methods for this purpose: one is to heat the anchor bolts and bend them, with the bent portion located at least 150 MM below the foundation casting hole, and the bending angle being less than 20 degrees ； Another method is to enlarge the wall of the bolt hole on the side with insufficient clearance, using a chisel to do so carefully. However, the latter tends to cause the walls of the anchor bolt holes to become loose, resulting in insufficient bonding strength between the new concrete grout and the original concrete after grouting; moreover, the installation specifications for the former seem to also prohibit it. Since the concrete foundation has already been completed, it is impossible to demolish it and rebuild it. Which of the above methods is the best after making compromises? Are there any other good options?