4 Effective repair methods
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Statutory Documents - IMO Publications and Documents - Circulars - Maritime Safety Committee - MSC/Circular.1055 – Guidelines on the Sampling Method of Thickness Measurements for Longitudinal Strength Evaluation and Repair Methods in Accordance with Annex 12 to Annex B to Resolution A.744(18), as Amended – (Adopted on 23 December 2002) - Annex - Guidelines on the Sampling Method of Thickness Measurements for Longitudinal Strength Evaluation and Repair Methods in Accordance with Annex 12 To Annex B to Resolution A.744(18), as Amended - 4 Effective repair methods

4 Effective repair methods

  4.1 The extent of renewal or reinforcement carried out to comply with annex 12 to Annex B to resolution A.744(18), as amended, should be in accordance with 3.2.

  4.2 The minimum continuous length of a renewed or reinforced structural member should be not less than twice the spacing of the primary members in way. In addition, the thickness diminution in way of the butt joint of each joining member forward and aft of the replaced member (plates, stiffeners, girder webs and flanges, etc.) should not be within the substantial corrosion range (75% of the allowable diminution associated with each particular member). Where differences in thickness at the butt joint exceed 15% of the lower thickness, a transition taper is to be provided.

  4.3 Alternative repair methods involving the fitting of straps or structural member modification should be subject to special consideration. In considering the fitting of straps, it should be limited to the following conditions:

  • .1 to restore and/or increase longitudinal strength;

  • .2 the thickness diminution of the deck or bottom plating to be reinforced should not be within the substantial corrosion range (75% of the allowable diminution associated with the deck plating);

  • .3 the alignment and arrangement, including the termination of the straps, is in accordance with a standard recognized by the Administration;

  • .4 the straps are continuous over the entire 0.5L amidships length; and

  • .5 use of continuous fillet welding and full penetration welds at butt welding and, depending on the width of the strap, slot welds. The welding procedures applied should be approved by the Administration.

  4.4 The existing structure adjacent to replacement areas and in conjunction with the fitted straps, etc., should be capable of withstanding the applied loads taking into account the buckling resistance and the condition of welds between the longitudinal members and hull envelope plating.

Parent topic: Annex - Guidelines on the Sampling Method of Thickness Measurements for Longitudinal Strength Evaluation and Repair Methods in Accordance with Annex 12 To Annex B to Resolution A.744(18), as Amended
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