Section 3 Secondary member end connections

3.1.1 Secondary members, that is longitudinals, beams, frames and bulkhead stiffeners forming part of the hull structure, are generally to be connected at their ends in accordance with the requirements of this Section.

3.1.2 Where end connections are fitted in accordance with these requirements, they may be taken into account in determining the effective span of the member. For determination of span point,see Pt 3, Ch 3, 3.3 Determination of span point.

3.2.1 The symbols used in this Section are defined as follows:

3.3.1 Scantlings of bracket connections are based on the following criteria:

1. Where a bracket is connecting a stiffener to a primary member, the bracket is to be based on the modulus of the stiffener;

2. Where a main transverse frame terminates, the bracket at the head of the frame is to be based on the modulus of the frame;

3. Where, in the midship region, a longitudinal strength member is cut at a transverse supporting member and the continuity of strength is provided by brackets, the bracket is to be based on the cross-sectional area and the modulus of the longitudinal member. Care is to be taken to ensure correct alignment of the brackets on each side of the primary member;

4. Elsewhere, the lesser modulus of the members being connected by the bracket.

3.4.1 The lengths, a and b, of the arms are to be measured in accordance with Figure 10.3.1 Diagrammatic arrangements of stiffener end brackets and are to be such that:

1. a + b ≥ 2,0l

2. a ≥ 0,8l

3. b ≥ 0,8l

where

l is the length of a bracket as required by Table 10.3.1 Bracket scantlings.

3.4.2 Bracket scantlings are to comply with the requirements of Table 10.3.1 Bracket scantlings.

3.4.3 Where the bracket is lapped on to the stiffening member, the length and width of overlap is to be adequate to provide for the required area of welding, but the length of overlap should be not less than the depth of the stiffener.

3.4.4 For the purpose of these Rules, bracket connections not complying with these minimum requirements are considered as bracketless connections.

3.5.1 The modulus of the bracket through the throat is to be not less than that of the smaller stiffening member to be connected.

3.5.2 The design of end connections and their supporting structure is to be such as to provide adequate resistance to rotation and displacement of the joint.

3.5.3 The toes of brackets should not land on unstiffened panels of plating. Special care should be taken to avoid notch effects at the toes of brackets.

3.6.1 For the purpose of these Rules, bracketless connections are divided into two types as follows:

3.6.2 Type 2 connections may only be adopted at watertight bulkhead stiffeners, wash bulkhead stiffeners and at stiffeners on centreline division bulkheads (non-tight) in tanks. Type 2 connections are not allowed for the secondary member end connections in way of the deep tank boundary or the shell boundary.

3.7.1 Where a stiffening member is fitted with end brackets complying with, or in excess of the requirements of Pt 3, Ch 10, 3.4 Scantlings of end brackets, the modulus of the member need not be corrected.

3.7.2 The modulus of bracketless stiffeners is to be increased as follows:

3.8.1 The constraint of the end connection is to be assured by the positioning of floors and/or carlings or a corrugated bulkhead in line with the corrugated bulkhead under consideration. This type of connection is considered as a bracketless Type 1 connection, see also Figure 10.3.3 End connections of corrugated bulkheads. Where the bulkhead corrugations are not supported, the connection is considered as a Type 2 connection, see also Figure 10.3.3 End connections of corrugated bulkheads.

3.8.2 The yield stress of floors and/or carlings in line with the corrugated bulkhead is not to be less than the yield stress of the corrugated bulkhead.