7.3　Foundation Marking

7.3.1　Two mutually perpendicular center lines shall be marked on the absorber foundation based on the orientation as shown on the plan，with the deviation of the center point no greater than 10mm.

7.3.2　The equally dividing points on the foundation perimeter shall be clearly marked，including 0°，45°，90°，135°，180°，225°and 270°，with the foundation center as reference.

7.3.3　The center lines of the backing plates or sectional steel members beneath base plate of butt welds shall be marked，with the position deviation of the center lines no greater than 1.5mm.