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1、ABS T I T L E GISCSSDSEMT 95 065LL02 DOL0793 9T5 FOUNDED :862 - AMERICAN BUREAU OF SHIPPING such as locations at the bracket toes, cut-outs, terminations of heavily loaded members, the connection of flexible elements with much stiffer members, the ends of unbalanced structural members, just to name
2、a few. For ship structures designed with relatively low working stresses and high safety margins, the 1 Copyright American Bureau of Shipping Provided by IHS under license with ABS Licensee=Boeing Co/5910770001 Not for Resale, 08/07/2008 20:38:39 MDTNo reproduction or networking permitted without li
3、cense from IHS -,-,- ABS T%TL,E GISCSSDSEMT 95 Ob5LL02 0030777 5 Y O detrimental effects of such stress concentrations may not be readily apparent. On the other hand, for structures designed with relatively high working stresses and low safety margins, damaging effects of such stress concentrations
4、could appear sooner than the anticipated period of time. Appropriate stress concentration factors (SCFs) obtained from either experimental data or structural analyses are required to evaluate the design of structural details. 2.3 Weld Effects and Fatigue Strength Another important factor to be consi
5、dered is the effects of welding on the properties of material (heating effects) and on structural continuity (profile of the weld deposit and under- cuts). This factor which highly depends on the welding methods, processes and workmanship is vital for assessing the fatigue strength of the joint. To
6、date, the welding effects on the fatigue strength are primarily determined by experimental data presented in the form of S-N curves and characteristics of the test specimens, as shown in the Appendix 52AA of the Rules. 3.0 CONSIDERATIONS FOR DESIGN OF STRUCTURAL DETAILS In light of the discussions g
7、iven in Y2A5.4, it is apparent that the necessary criterion for the design of structural details is simply to offer a well balanced joint which is compatible with the anticipated working stresses. To this end, the solution is to be tailored to a specific location of a specific design. In addition, t
8、here is no unique solution to the problem. Many alternatives may exist. The designerdbuilders would have to exercise their judgment based on their fabrication facilities, techniques and experience. The information offered below is provided for reference. 3.1 Structural Configuration and Arrangement
9、of Brackets When selecting the structural configurations and sizing the brackets connecting primary supporting members, due consideration is to be given to the bad transmission and the 2 Copyright American Bureau of Shipping Provided by IHS under license with ABS Licensee=Boeing Co/5910770001 Not fo
10、r Resale, 08/07/2008 20:38:39 MDTNo reproduction or networking permitted without license from IHS -,-,- AR5 TITLE GISCSSDSEMT 95 Ob51102 OOL0798 487 W 3 . 2 relative stiffnesses of the members to be connected. A smooth pattern of load transmission is essential. The connecting bracket is to be of suf
11、ficient size to withstand the highly concentrated loads and to shift the critical spots (bracket toes) to the lower stressed regions. An appropriate stiffening system is also required for large brackets to prevent local structure instability and tripping. Sample illustrations are shown in Fig. 1 and
12、 Fig. 2 for damages experienced in existing tankers with recornmended modfications. Installation of Brackets and Collar Plate To prevent local distortions and to minimize the magnifying effects of structural notches, consideration is to be given to additional brackets and collar plates (or lugs) at
13、the criitical joints and cut-outs, respectively. Sample illustrations are shown in Fig. 3 for local damages recorded and the recommended modifications. Alternatively, different stiffening systems may be considered to minimize the critical spots in highly stressed regions. For example, utilization of
14、 the horizontal stiffeners with appropriate tripping brackets for floors in the double bottom, instead of vertical stiffeners would eliminate the critical spots at the face bar toes on the flange of longitudinal as shown in Fig. 3 4 2 . 3 . 3 Softening Hard Spots To minimize the stress concentration
15、 at hard spots, such as bracket toes, tapered face plate, and welded connections of the face plate of transverses and bulkhead plating, the welded joints may be softened by providing a large radius at bracket toes or a cope hole with proper reinforcement of the surrounding panel to prevent local ins
16、tability. Some sample illustrations are shown in Fig. 4. To minimize the detrimental effects of knuckles in structural elements, sample illustrations are shown in Fig. 5. 3 Copyright American Bureau of Shipping Provided by IHS under license with ABS Licensee=Boeing Co/5910770001 Not for Resale, 08/0
17、7/2008 20:38:39 MDTNo reproduction or networking permitted without license from IHS -,-,- ABS TITLE GISCSSDSEMT 95 = Ob51102 0010799 313 3.4 Improvement of Fatigue Strength At crkal structural joints, the fatigue strength can be improved, as discussed in the previous paragraphs, by reducing the magn
18、itudes of nominal stresses (working stresses) andor minimizing the stress concentrations. In addition, it may also be advisable to consider the following improvements on the fatigue strength: 1) Utilizing better contour shapes for cut-outs, such as the cope holes shown in Fig. 6. 2) Having bracket t
19、oe and the surrounding weld deposit ground smooth with an appropriate radius as shown in Fig. 7. 4.0 SAMPLE STR UCTURAL DETAIL S These examples are divided into the following five groups: Figure 1 - Examples for Bracket Enlargement a) Connection of Bottom Girder and Vertical Web b) Bottom Girder End
20、 Bracket c) Bottom Transverse End Bracket d) Reinforcement at Connection of Bottom Girder and Oil Tight Bulkhead Figure 2 - Examples for Bracket Modification a) Connection of Centerline Girder and Oil Tight Transverse Bulkhead b) Connection of Horizontal Girder and Side Longitudinal c) Longitudinal
21、End Bracket Figure 3 - Examples for Additional Brackets and Collar Plate a) Connection of Bottom Girder and Swash Bulkhead b) Tripping Bracket on Transverse Web c) Connection of Longitudinal to Floor in Double Bottom d) Connection of Longitudinal to Transverse Web Figure 4 - Examples for Hard Spot E
22、ffects a) Tapered Face Plate of Horizontal Girder b) Connection of Transverse Face Plate and Bulkhead Plating c) Bracket Toe on Bottom Transverse d) Bracket Toe on Longitudinal e) Sniped Tripping Bracket on Horizontal Girder Figure 5 - Examples for Knuckle Effects 4 Copyright American Bureau of Ship
23、ping Provided by IHS under license with ABS Licensee=Boeing Co/5910770001 Not for Resale, 08/07/2008 20:38:39 MDTNo reproduction or networking permitted without license from IHS -,-,- Modification I I ! ! ! i Existing Figure l(a) Connection of Bottom Girder and Vertical Web 5 Copyright American Bure
24、au of Shipping Provided by IHS under license with ABS Licensee=Boeing Co/5910770001 Not for Resale, 08/07/2008 20:38:39 MDTNo reproduction or networking permitted without license from IHS -,-,- ABS T I T L E GISCSSDSEMT 95 Ob5LL02 OOLOBOL BTL I Modification I& WAY Existing /- Figure l(b) Bottom Gird
25、er End Bracket 6 Copyright American Bureau of Shipping Provided by IHS under license with ABS Licensee=Boeing Co/5910770001 Not for Resale, 08/07/2008 20:38:39 MDTNo reproduction or networking permitted without license from IHS -,-,- ARS T I T L E GISCSSDSEMT 95 m Ob5LL02 OOLO802 738 Modification PE
26、NETRATION SERTED PLATE ITH INCREASED THICKNESS * LUGS Existing - .- LONGITUD I NAL BULKHEAD II Figure l(c) Bottom Transverse End Bracket 7 Copyright American Bureau of Shipping Provided by IHS under license with ABS Licensee=Boeing Co/5910770001 Not for Resale, 08/07/2008 20:38:39 MDTNo reproduction
27、 or networking permitted without license from IHS -,-,- ABS T I T L E GISCSSDSEMT 95 Ob51102 0010803 674 = Modification Existing Figure l(d) Reinforcement at Connection of Bottom Girder and Oil tight Bulkhead 8 Copyright American Bureau of Shipping Provided by IHS under license with ABS Licensee=Boe
28、ing Co/5910770001 Not for Resale, 08/07/2008 20:38:39 MDTNo reproduction or networking permitted without license from IHS -,-,- ABS TITLE GISCSSDSEMT 95 m Ob51102 0010804 500 H Modification Existing 0.T. BULKHEAD BOTTOM TRANSVERSE I - , FRACTURE y BOTOM - SHELL FRACTURE 7 V I W A - A Figure 2(a) Con
29、nection of Centerline Girder and Oil tight Trans Bulkhead 9 Copyright American Bureau of Shipping Provided by IHS under license with ABS Licensee=Boeing Co/5910770001 Not for Resale, 08/07/2008 20:38:39 MDTNo reproduction or networking permitted without license from IHS -,-,- ABS TITLE GISCSSDSEMT 9
30、5 m Ob5LL02 OOL0805 447 m Modification Existing TRANSVERSE BULKHEAD FRACTURE - f SIDE SHELL Figure 2(b) Connection of Horizontal Girder and Side Longitudinal 10 Copyright American Bureau of Shipping Provided by IHS under license with ABS Licensee=Boeing Co/5910770001 Not for Resale, 08/07/2008 20:38
31、:39 MDTNo reproduction or networking permitted without license from IHS -,-,- ABS TITLE GISCSSDSEMT 95 Ob51102 OOL080b 383 Modification Existing t I Figure 2(c) Longitudinal End Bracket 11 Copyright American Bureau of Shipping Provided by IHS under license with ABS Licensee=Boeing Co/5910770001 Not
32、for Resale, 08/07/2008 20:38:39 MDTNo reproduction or networking permitted without license from IHS -,-,- ABX T I T L E GISCSSDSEMT 95 = Ob51102 0010807 21T Modification Existing I i l Figure 3(a) Connection o f Bottom Girder and Swash Bulkhead 12 Copyright American Bureau of Shipping Provided by IH
33、S under license with ABS Licensee=Boeing Co/5910770001 Not for Resale, 08/07/2008 20:38:39 MDTNo reproduction or networking permitted without license from IHS -,-,- ABS T I T L E GISCSSDSEMT 95 m Ob51102 OOLOBOB 156 = Modification e l - TRANS. CUTOUT il I /I Figure 3(b) Tripping Bracket on Trans. We
34、b 13 Copyright American Bureau of Shipping Provided by IHS under license with ABS Licensee=Boeing Co/5910770001 Not for Resale, 08/07/2008 20:38:39 MDTNo reproduction or networking permitted without license from IHS -,-,- ABS T I T L E GISCSSDSEMT 95 = Ob51102 0010809 O92 W Modification ect Existing
35、 f“ -7 V I E W A - A Figure 3(c) Connection of Longitudinal to Floor in D.B. 14 Copyright American Bureau of Shipping Provided by IHS under license with ABS Licensee=Boeing Co/5910770001 Not for Resale, 08/07/2008 20:38:39 MDTNo reproduction or networking permitted without license from IHS -,-,- ABS
36、 TITLE GISCSSDSEMT 75 m OIALLOZ OOLOBLO 804 m Modification Existing VICW A -A t a+- I Figure 3(d) Connection of Longitudinal to Trans. Web 15 Copyright American Bureau of Shipping Provided by IHS under license with ABS Licensee=Boeing Co/5910770001 Not for Resale, 08/07/2008 20:38:39 MDTNo reproduct
37、ion or networking permitted without license from IHS -,-,- ABS T I T L E GISCSSDSEMT 75 Ob51102 00108LL 740 H Modification - I irr Figure 4(a) Tapered Face Existing i 1 Plate of Horizontal Girder 16 Copyright American Bureau of Shipping Provided by IHS under license with ABS Licensee=Boeing Co/59107
38、70001 Not for Resale, 08/07/2008 20:38:39 MDTNo reproduction or networking permitted without license from IHS -,-,- Modification Existing LONGITUCINAL BULKHE D Figure 4(b) Connection of Transverse Face Plate and Bhd Plating 17 Copyright American Bureau of Shipping Provided by IHS under license with
39、ABS Licensee=Boeing Co/5910770001 Not for Resale, 08/07/2008 20:38:39 MDTNo reproduction or networking permitted without license from IHS -,-,- ABS T I T L E GISCSSDSEMT 95 m Ob5LL02 OOLOBL3 513 m Modification Existing BOlTOM TRANSVERSE Figure 4(c) Bracket Toe on Bottom Transverse 18 Copyright Ameri
40、can Bureau of Shipping Provided by IHS under license with ABS Licensee=Boeing Co/5910770001 Not for Resale, 08/07/2008 20:38:39 MDTNo reproduction or networking permitted without license from IHS -,-,- AS TITLE GISCSSDSEMT 95 ObSLL02 OOLOBL4 45T H Modification Existing Figure 4(d) Bracket Toe on Lon
41、gitudinal 19 Copyright American Bureau of Shipping Provided by IHS under license with ABS Licensee=Boeing Co/5910770001 Not for Resale, 08/07/2008 20:38:39 MDTNo reproduction or networking permitted without license from IHS -,-,- ABS T I T L E GISCSSDSEMT 95 9 Ob51102 OOLOB1S 39b Modification Existi
42、ng Figure 4(e) Sniped Tripping Bracket on Horizontal Girder 20 Copyright American Bureau of Shipping Provided by IHS under license with ABS Licensee=Boeing Co/5910770001 Not for Resale, 08/07/2008 20:38:39 MDTNo reproduction or networking permitted without license from IHS -,-,- ABS T I T L E GISCSS
43、DSEMT 95 = 0652202 OOLDBLb 222 9 Modification * i-? VIE& A-A H IS Existing i i 5 Figure 5 Examples for Knuckle Effects 21 Copyright American Bureau of Shipping Provided by IHS under license with ABS Licensee=Boeing Co/5910770001 Not for Resale, 08/07/2008 20:38:39 MDTNo reproduction or networking pe
44、rmitted without license from IHS -,-,- ABS TITLE GISCSSDSEMT 95 m Ob51102 DOL0817 Lb9 m Gpe hole ground back I Il t - * 1 Figure 6 Improved Cope Hole Details 22 Copyright American Bureau of Shipping Provided by IHS under license with ABS Licensee=Boeing Co/5910770001 Not for Resale, 08/07/2008 20:38
45、:39 MDTNo reproduction or networking permitted without license from IHS -,-,- ABS T I T L E GISCSSDSEMT 95 m 0651102 0010818 OT5 W i Ground back welds 2 7 5 m Longitudinal Figure 7 Improved Brackets Toes 23 Copyright American Bureau of Shipping Provided by IHS under license with ABS Licensee=Boeing
46、Co/5910770001 Not for Resale, 08/07/2008 20:38:39 MDTNo reproduction or networking permitted without license from IHS -,-,- ABS T I T L E GISCSSDSEMT 95 m Ob5LL02 OOLOBL T3L m 1995 TECHNICAL PUBLICATION ORDER FORM AMERICAN BUREAU OF SHIPPING &AFFILIATED COMPANIES Corporate Publications Dept.: Two World Trade Center, 106th Floor New York, NY USA 10048 Tel: (21 2) 839-501 6 FAX: (21 2) 839-5208 MERICAN BURE