3 Shear capacity of the double-bottom structure in way of the foremost cargo hold
Clasification Society 2024 - Version 9.40
Statutory Documents - IMO Publications and Documents - International Conferences - SOLAS/CONF.4 - Resolutions of the Conference of Contracting Governments to the International Convention for the Safety of Life at Sea, 1974 – (November 1997) - Resolution 4 - Standards for the evaluation of scantlings and for the evaluation of allowable hold loading of the foremost cargo hold – (Adopted on 27 November 1997) - Annex 2 - Standards for the evaluation of allowable hold loading of the foremost cargo hold - 3 Shear capacity of the double-bottom structure in way of the foremost cargo hold

3 Shear capacity of the double-bottom structure in way of the foremost cargo hold

 The shear capacity C of the double-bottom structure in way of the foremost cargo hold is defined as the sum of the shear strength at each end of:

  • all floors adjacent to both hoppers, less one half of the strength of the two floors adjacent to each stool, or transverse bulkhead if no stool is fitted (see figure 2); and
  • all double-bottom girders adjacent to both stools, or transverse bulkheads if no stool is fitted.

The strength of girders or floors which run out and are not directly attached to the boundary stool or hopper girder is to be evaluated for the one end only.

Note that the floors and girders to be considered are those inside the hold boundaries formed by the hoppers and stools (or transverse bulkheads if no stool is fitted). The hopper side girders and the floors directly below the connection of the bulkhead stools (or transverse bulkheads if no stool is fitted) to the liner bottom are not to be included.

When the geometry and/or the structural arrangement of the double bottom are such as to make the above assumptions inadequate, to the discretion of the Administration or of an organization recognized by the Administration in accordance with the provisions of SOLAS regulation XI/1 (hereinafter referred to as "the Administration"), the shear capacity C of the double bottom is to be calculated according to the criteria laid down by the Administration.

In calculating the shear strength, the net thickness of floors and girders are to be used. The net thickness t net, in mm, is given by:

where:
t = as-built thickness, in mm, of floors and girders
t c = corrosion diminution, equal to 2 mm, in general; a lower value of t c, may be adopted, provided that measures are taken to the satisfaction of the Administration to justify the assumption made.
Parent topic: Annex 2 - Standards for the evaluation of allowable hold loading of the foremost cargo hold

3.1 Floor shear strength

 The floor shear strength in way of the floor panel adjacent to hoppers S f1, in kN, and the floor shear strength in way of the openings in the "outermost" bay (i.e., that bay which is closest to hopper) S f2, in kN, are given by the following expressions:

where:
A f = sectional area, in mm2, of the floor panel adjacent to hoppers
A f,h = net sectional area, in mm2, of the floor panels in way of the openings in the "outermost" bay (i.e., that bay which is closest to hopper)
τ a = allowable shear stress, in N/mm2, to be taken equal to
σ F = minimum upper yield stress, in N/mm2, of the material
η 1 = 1.10
η 2 = 1.20
= η 2 may be reduced, at the discretion of the Administration, down to 1.10 where appropriate reinforcements are fitted to the satisfaction of the Administration.

3.2 Girder shear strength

 The girder shear strength in way of the girder panel adjacent to stools (or transverse bulkheads, if no stool is fitted) S g1, in kN, and the girder shear strength in way of the largest opening in the "outermost" bay (i.e., that bay which is closest to stool, or transverse bulkhead, if no stool is fitted) S g2, in kN, are given by the following expressions:

where:
A g = minimum sectional area, in mm2, of the girder panel adjacent to stools (or transverse bulkheads, if no stool is fitted)
A g,h = net sectional area, in mm2, of the girder panel in way of the largest opening in the "outermost" bay (i.e., that bay which is closest to stool, or transverse bulkhead, if no stool is fitted)
τ a = allowable shear stress, in N/mm2, as given in 3.1
η 1 = 1.10
η 2 = 1.15
= η 2 may be reduced, at the discretion of the Administration, down to 1.10 where appropriate reinforcements are fitted to the satisfaction of the Administration.
Copyright 2022 Clasifications Register Group Limited, International Maritime Organization, International Labour Organization or Maritime and Coastguard Agency. All rights reserved. Clasifications Register Group Limited, its affiliates and subsidiaries and their respective officers, employees or agents are, individually and collectively, referred to in this clause as 'Clasifications Register'. Clasifications Register assumes no responsibility and shall not be liable to any person for any loss, damage or expense caused by reliance on the information or advice in this document or howsoever provided, unless that person has signed a contract with the relevant Clasifications Register entity for the provision of this information or advice and in that case any responsibility or liability is exclusively on the terms and conditions set out in that contract.