RULES FOR CLASSIFICATION Inland navigation vessels. Part 3 Structures, equipment Chapter 2 Design load principles. Edition December 2015 DNV GL AS

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1 RULES FOR CLASSIFICATION Inland navigation vessels Edition December 2015 Part 3 Structures, equipment Chapter 2 s The content of this service document is the subject of intellectual property rights reserved by ("DNV GL"). The user accepts that it is prohibited by anyone else but DNV GL and/or its licensees to offer and/or perform classification, certification and/or verification services, including the issuance of certificates and/or declarations of conformity, wholly or partly, on the basis of and/or pursuant to this document whether free of charge or chargeable, without DNV GL's prior written consent. DNV GL is not responsible for the consequences arising from any use of this document by others. The electronic pdf version of this document, available free of charge from is the officially binding version.

2 FOREWORD DNV GL rules for classification contain procedural and technical requirements related to obtaining and retaining a class certificate. The rules represent all requirements adopted by the Society as basis for classification. December 2015 Any comments may be sent by to rules@dnvgl.com If any person suffers loss or damage which is proved to have been caused by any negligent act or omission of DNV GL, then DNV GL shall pay compensation to such person for his proved direct loss or damage. However, the compensation shall not exceed an amount equal to ten times the fee charged for the service in question, provided that the maximum compensation shall never exceed USD 2 million. In this provision "DNV GL" shall mean, its direct and indirect owners as well as all its affiliates, subsidiaries, directors, officers, employees, agents and any other acting on behalf of DNV GL.

3 CHANGES CURRENT This is a new document. The rules enter into force 1 July Part 3 Chapter 2 Changes - current Rules for classification: Inland navigation vessels DNVGL-RU-INV-Pt3Ch2. Edition December 2015 Page 3

4 CONTENTS Changes current...3 Section 1 General Definitions Application...5 Section 2 Range of navigation Range of navigation... 6 Section 3 Local loads Symbols General Load definition criteria Vessel motions and accelerations External pressure Internal pressures Testing pressures Part 3 Chapter 2 Contents Section 4 Hull girder loads General Vertical bending moment calculation...19 Rules for classification: Inland navigation vessels DNVGL-RU-INV-Pt3Ch2. Edition December 2015 Page 4

5 SECTION 1 GENERAL 1 Definitions 1.1 Local loads Local loads are pressures and forces which are directly applied to the individual structural members: plating panels, ordinary stiffeners and primary supporting members. 1.2 Hull girder loads Hull girder loads are forces and moments which result as effects of local loads acting on the vessel as a whole when considered as a girder. 1.3 Loading condition A loading condition is a distribution of weights carried in the vessel spaces arranged for their storage. Part 3 Chapter 2 Section 1 2 Application 2.1 Fields of application The design loads defined in these rules shall be used for the determination of the hull girder strength and structural scantlings in the central part of vessels Load direct calculation As an alternative to the formulae in Ch.3 Sec.10, the designer may provide, under his responsibility, the values of hull girder loads. In this case, the justified calculations of these values shall be submitted to the Society. Rules for classification: Inland navigation vessels DNVGL-RU-INV-Pt3Ch2. Edition December 2015 Page 5

6 SECTION 2 RANGE OF NAVIGATION 1 Range of navigation 1.1 General Each vessel is granted a range of navigation according to its scantlings and other constructional arrangements. The ranges of navigation considered in these are defined in Pt.1 Ch.2 Sec.2 [10]. The significant wave heights corresponding to ranges of navigation are listed in Table Navigation coefficient The navigation coefficient to be used for the determination of vessel scantlings is given by the formula: n H = 0.85 H = significant wave height [m] (wave height measured from crest to trough). Part 3 Chapter 2 Section Length-to-depth ratio In principle, the length-to-depth ratio of the vessel shall be withing the following limits: for IN(1.2) to IN(2.0) : L/ D for IN(0.6) : L/ D Vessels having a ratio beyond these limits shall be considered by the Society on a case-by-case basis. 1.4 Ranges of navigation IN(1.2) to IN(2) On vessels assigned the range of navigation IN(1.2) to IN(2), the hatchways shall be fitted with efficient means of closing. The openings of the engine room, if there is an engine room, shall be protected by a superstructure or by a deckhouse. Table 1 Values of significant wave height [m] Range of navigation Wave height, H IN(0) 0 IN(0.6) 0.6 IN(1.2) to IN(2.0) 1.2 to 2.0 Rules for classification: Inland navigation vessels DNVGL-RU-INV-Pt3Ch2. Edition December 2015 Page 6

7 SECTION 3 LOCAL LOADS 1 Symbols L = rule length [m], defined in Ch.1 Sec.1 [1] B = breadth [m], defined in Ch.1 Sec.1 [1] D = depth [m], defined in Ch.1 Sec.1 [1] T = draught [m], defined in Ch.1 Sec.1 [1] C B = block coefficient, defined in Ch.1 Sec.1 [1] P = design pressure [kn/m 2 ] x, y, z = x, y and z co-ordinates [m] of the calculation point with respect to the reference co-ordinate z L z TOP d AP p pv ρ L n a B system defined in Ch.1 Sec.1 [1.4] = z co-ordinate [m] of the highest point of the liquid = z TOP + d AP = z co-ordinate [m] of the highest point of the tank or compartment = distance from the top of the air pipe to the top of the tank [m]. For minimum distance for the top of the air pipe above deck, see Pt.4 Ch.6 Sec.1 [13.1.1] = setting pressure [kn/m 2 ] of safety valves or maximum pressure [kn/m 2 ] in the tank during loading/unloading, which ever is the greater = density [t/m 3 ] of the liquid carried = navigation coefficient defined in Sec H, where H is the significant wave height [m] = motion and acceleration parameter = h W = wave parameter [m] = a SU = surge acceleration [m/s 2 ] defined in [4.2.1] a SW = sway acceleration [m/s 2 ] defined in [4.2.2] a H = heave acceleration [m/s 2 ] defined in [4.2.3] α R = roll acceleration [rad/s 2 ] defined in [4.2.4] α P = pitch acceleration [rad/s 2 ] defined in [4.2.5] α Y = yaw acceleration [rad/s 2 ] defined in [4.2.6] T SW = sway period [s] defined in [4.2.2] T R = roll period [s] defined in [4.2.4] T P = pitch period [s] defined in [4.2.5] A R = roll amplitude [rad] defined in [4.2.4] A P = pitch amplitude [rad] defined in [4.2.5] V = maximum ahead service speed [km/h] Rules for classification: Inland navigation vessels DNVGL-RU-INV-Pt3Ch2. Edition December 2015 Page 7

8 2 General 2.1 Application The following requirements apply for the definition of local loads to be used for the scantling checks of: platings ordinary stiffeners primary supporting members. 2.2 Inertial loads For a range of navigation higher than IN(1.2), inertial local loads induced by vessel relative motions and accelerations shall be taken into account. 3 Load definition criteria 3.1 Cargo and ballast distributions When calculating the local loads for determining the structural scantling of an element which separates two adjacent compartments, these may not be considered simultaneously loaded. The local loads to be used are those obtained considering the two compartments individually loaded. For elements of the outer shell, the local loads shall be calculated considering separately: the external pressures considered as acting alone without any counteraction from the vessel interior the differential pressures (internal pressure minus external pressure) considering the compartment adjacent to the outer shell as being loaded. 3.2 Draught associated with each cargo and ballast distribution Local loads shall be calculated on the basis of the vessel draught T 1 corresponding to the cargo or lightship distribution considered according to the criteria [3.1]. The vessel draught shall be taken as the distance measured vertically on the hull transverse section at the middle of the length from the base line to the waterline in: a) full load condition, when: one or more cargo compartments are considered as being loaded and the ballast tanks are considered as being empty the still water and wave external pressures are considered as acting alone without any counteraction from the vessel s interior b) light ballast condition, when one or more ballast tanks are considered as being loaded and the cargo compartments are considered as being empty. Rules for classification: Inland navigation vessels DNVGL-RU-INV-Pt3Ch2. Edition December 2015 Page 8

9 4 Vessel motions and accelerations 4.1 General Vessels motions and accelerations are defined, with their signs, according to the reference co-ordinate system in Ch.1 Sec.1 [1.4] Vessel motions and accelerations are assumed to be periodic. The motion amplitudes are half of the crest to through amplitudes Trough an alternative to the formulae the Society may accept the values of vessel motions and accelerations derived from direct calculations or obtained from model tests, when justified on the basis of the vessel s characteristics and intended service. 4.2 Vessel absolute motions and accelerations Surge The surge acceleration a SU shall be taken equal to 0.5 m/s Sway The sway period and acceleration are obtained from the formulae in Table 1. Table 1 Sway period and acceleration Period T SW [s] Acceleration a SW [m/s 2 ] 7.6 a B Heave The heave acceleration is obtained [m/s 2 ] from the following formula: α H = 9.81 a B Roll The roll amplitude, period and acceleration are obtained from the formulae in Table Pitch The pitch amplitude, period and acceleration are obtained from the formulae in Table Yaw The yaw acceleration is obtained [rad/s 2 ] from the following formula: Rules for classification: Inland navigation vessels DNVGL-RU-INV-Pt3Ch2. Edition December 2015 Page 9

10 4.3 Vessel relative accelerations Definition At any point, the accelerations in X, Y and Z direction are the acceleration components which result from the vessel motions defined from [4.2.1] to [4.2.6] Vessel conditions Vessel relative motions and accelerations shall be calculated considering the vessel in the following conditions: upright vessel condition: In this condition, the vessel encounters waves which produce vessel motions in the X-Z plane, i.e. surge, heave and pitch. inclined vessel condition: In this condition, the vessel encounters waves which produce vessel motions in the X-Y and Y-Z planes, i.e. sway, roll and yaw Accelerations The reference values of the longitudinal, transverse and vertical accelerations at any point are obtained from the formulae in Table 4 for upright and inclined vessel conditions. Table 2 Roll amplitude, period and acceleration Amplitude A R [rad] Period T R [s] Acceleration α R [rad/s 2 ] without being taken greater than 0.35 E = GM = Distance, in m, from the vessel s centre of gravity to the transverse metacentre, for the loading considered; when GM is not known, the following values may be, in general, assumed: full load: GM = 0.07 B lightship: GM = 0.18 B Table 3 Pitch amplitude, period and acceleration Amplitude A P [rad] Period T P [s] Acceleration α P [rad/s 2 ] Rules for classification: Inland navigation vessels DNVGL-RU-INV-Pt3Ch2. Edition December 2015 Page 10

11 Table 4 Reference values of the accelerations a X, a Y and a Z Direction Upright vessel condition Inclined vessel condition X - Longitudinal a X1 and a X2 [m/s 2 a x2 = 0 ] Y - Transverse a Y1 and a Y2 [m/s 2 a Y1 = 0 ] Z - Vertical a Z1 and a Z2 [m/s 2 ] K X = T 1 = draught [m] defined in [3.2]. 5 External pressure 5.1 Pressure on sides and bottom The external pressure at any point of the hull, in [kn/m 2 ], shall be obtained from the following formulae: for z T: P E = 9.81 (T z n). for z > T: P E = MAX (5.9 n ; 3) + p WD p WD = specific wind pressure [kn/m 2 ] as defined in Table 5. Table 5 Specific wind pressure Navigation Notation Wind pressure p WD [kn/m 2 ] IN(1.2), IN(2) 0.4 n IN(0.6), IN(0) 0.25 Rules for classification: Inland navigation vessels DNVGL-RU-INV-Pt3Ch2. Edition December 2015 Page 11

12 5.2 Pressure on exposed decks On exposed decks, the pressure due to the load carried shall be considered. This pressure shall be defined by the Designer and, in general, it may not be taken less than the values given in Table 6. Table 6 Pressure [kn/m 2 ] on exposed decks Exposed deck location Weather deck 3.75 (n + 0.8) Exposed deck of superstructure or deckhouse: first tier (non public) 2.0 upper tiers (non public) 1.5 public Pressure on watertight bulkheads p E The still water pressure [kn/m 2 ] to be considered as acting on platings and stiffeners of watertight bulkheads of compartments not intended to carry liquids is obtained from the following formula: p WB = 9.81 (z TOP z) 6 Internal pressures 6.1 Liquids General The pressure transmitted to the hull structure [kn/m 2 ] by liquid cargo (p C ) or ballast (p B ) is the combination of the still water pressure p S and the inertial pressure p W Still water pressure Liquid cargo the still water pressure is the greater of the values obtained [kn/m 2 ] from the following formulae: p S = 9.81 ρ L (z L z) p S = 9.81 ρ L (z TOP z) p pv Ballast p S = 9.81 (z L z + 1) Inertial pressure The inertial pressure is obtained from the formulae in Table 7 and shall be taken such that: p S + p W Dry bulk cargoes General The pressure transmitted to the hull structure shall be obtained using the formula: Rules for classification: Inland navigation vessels DNVGL-RU-INV-Pt3Ch2. Edition December 2015 Page 12

13 p 0 z H = mean total pressure on the inner bottom (combination of the mean still water pressure p S defined in [6.2.2] and the mean inertial pressure p W defined in [6.2.3]) = p S + p W 0 If n 1.02: p W = 0 = Z co-ordinate [m] of the inner bottom. Table 7 Liquids - inertial pressure Vessel condition Inertial pressure p W [kn/m 2 ] 1) Upright Inclined 1) p W = 0 if n 1.02 l B = longitudinal distance [m] between the transverse tank boundaries, without taking into account small recesses in the lower part of the tank (see Fig.1) a TY, a TZ = Y and Z components (negative roll angle) [m/s 2 ] of the total acceleration vector defined as follows: a TY = a Y2 a TZ = a Z2 Y H, Z H = Y and Z co-ordinates [m] of the highest point of the tank in the direction of the total acceleration vector. Rules for classification: Inland navigation vessels DNVGL-RU-INV-Pt3Ch2. Edition December 2015 Page 13

14 Figure 1 Distance l B Mean still water pressure on the inner bottom The mean still water pressure on the inner bottom is obtained [kn/m 2 ] from the following formula: L H B 1 m C = length [m] of the hold, to be taken as the longitudinal distance between the transverse bulkheads which form boundaries of the hold considered = breadth [m] of the hold = mass of cargo [t] in the hold considered Mean inertial pressure on the inner bottom The mean inertial pressure on the inner bottom is obtained [kn/m 2 ] from the following formula: where m C, L H and B 1 are defined in [6.2.2]. 6.3 Heavy dry bulk cargoes Pressure on side and bulkhead structure The pressure on side and bulkhead structure shall be determined in compliance with [6.2] Inner bottom design pressure The inner bottom design pressure, p MS [kn/m 2 ] is the combination of the still water pressure p S and the inertial pressure p W determined in compliance with [6.3.3] and [6.3.4] respectively. If n 1.02: p W = Inner bottom still water design pressure The inner bottom still water design pressure p S is obtained [kn/m 2 ] from the following formula: k S = coefficient to be determined using the formula: L H = = length [m] of the hold, to be taken as the longitudinal distance between the transverse bulkheads which form boundaries of the hold considered ρ = cargo density [t/m 3 ] ρ 2.5 φ = angle of repose of the bulk cargo considered Rules for classification: Inland navigation vessels DNVGL-RU-INV-Pt3Ch2. Edition December 2015 Page 14

15 φ Inner bottom inertial design pressure The inner bottom inertial design pressure p W is obtained [kn/m 2 ] from the formula given in [6.3.3], using the following value of k S : 6.4 Dry uniform cargoes General The pressure transmitted to the hull structure, p C [kn/m 2 ] is the combination of the still water pressure p S and the inertial pressure p W Still water pressure The value of the still water pressure p S shall be specified by the designer Inertial pressure The inertial pressure p W is obtained [kn/m 2 ] as specified in Table Dry unit cargoes General The force transmitted to the hull structure is the combination of the still water force F S and the inertial force F W. Account shall be taken of the elastic characteristics of the lashing arrangement and/or the structure which contains the cargo. Table 8 Dry uniform cargoes - Inertial pressures Vessel condition Inertial pressure p W [kn/m 2 ] 1) Upright (positive heave motion) in z direction in y direction Inclined (negative roll angle) in z direction 1) p W = 0 if n 1.02 Rules for classification: Inland navigation vessels DNVGL-RU-INV-Pt3Ch2. Edition December 2015 Page 15

16 6.5.2 Still water force The still water force transmitted to the hull structure shall be determined on the basis of the force obtained [kn] from the following formula: Where m C is the mass [t] of the cargo. F S = 9.81 m c Inertial forces The inertial forces are obtained [kn/m 2 ] as specified in Table 9. Table 9 Dry unit cargoes Inertial forces Vessel condition Inertial force F W [kn] 1) Upright F W,X = m C a X1 in x direction (positive heave motion) F W,Z = m C a Z1 in z direction Inclined F W,Y = m C a Y2 in y direction (negative roll angle) F W,Z = m C a Z2 in z direction 1) F W = 0 if n Wheeled cargoes Tyred vehicles The forces transmitted through the tyres are comparable to pressure uniformly distributed on the tyre print, the dimensions of which shall be indicated by the designer together with information concerning the arrangement of wheels on axles, the load per axle and the tyre pressures. With the exception of dimensioning of plating, such forces may be considered as concentrated in the tyre print centre Non-tyred vehicles The requirements of [6.6.3] also apply to tracked vehicles; in this case the print to be considered is that below each wheel or wheelwork. For vehicles on rails, all the forces transmitted shall be considered as concentrated at the contact area centre Still water force The still water force transmitted to the hull structure by one wheel shall be determined on the basis of the force obtained [kn] from the formula: F s = 9.81 m C m c = Q A /n W Q A n w = axle load [t]. For fork-lift trucks, the value of Q A shall be taken equal to the total mass of the vehicle, including that of the cargo handled, applied to one axle only = number of wheels for the axle considered Rules for classification: Inland navigation vessels DNVGL-RU-INV-Pt3Ch2. Edition December 2015 Page 16

17 6.6.4 Inertial forces The inertial forces are obtained [kn] as specified in Table Accommodation The still water pressures transmitted to the deck structures are obtained [kn/m 2 ] as specified in Table Helicopter loads Landing load The landing load transmitted through one tyre to the deck shall be obtained [kn] from the following formula: W H = maximum weight of the helicopter [t] F CR = 7.36 W H Where the upper deck of a superstructure or deckhouse is used as a helicopter deck and the spaces below are quarters, bridge, control room or other normally manned service spaces, the value of F CR shall be multiplied by Emergency landing load The emergency load resulting from the crash of the helicopter shall be obtained [kn] from the following formula: F CR = W H Helicopter having landing devices other than wheels In the case of a deck intended for the landing of helicopters having landing devices other than wheels (e.g. skates), the landing load and the emergency landing load shall be examined by the Society on a case-bycase basis. Rules for classification: Inland navigation vessels DNVGL-RU-INV-Pt3Ch2. Edition December 2015 Page 17

18 7 Testing pressures 7.1 Still water pressures The still water pressures to be considered as acting on plates and stiffeners subject to tank testing are specified in Ch.3 Sec.3 [3]. Table 10 Wheeled cargoes - inertial forces Vessel condition Inertial force F W [kn] 2) Upright (positive heave motion) Inclined F W,Z = m C a Z1 F W,Y = m C a Y2 in z direction in y direction (negative roll angle) 1) F W,Z = m C a Z2 in z direction 1) This condition shall be considered for the racking analysis of vessels with the type and service Notation Ro/Ro ship or with the additional class Notation Ferry, with m C taken equal to the mass [t] of wheeled loads located on the structural member under consideration. 2) F W = 0 if n 1.02 Table 11 Deck pressure in accommodation compartments Type of accommodation compartment p [kn/m 2 ] Large spaces (such as: restaurants, halls, cinemas, lounges, kitchen, service spaces, games and hobbies rooms, hospitals) 4.0 Cabins 3.0 Other compartments 2.5 Rules for classification: Inland navigation vessels DNVGL-RU-INV-Pt3Ch2. Edition December 2015 Page 18

19 SECTION 4 HULL GIRDER LOADS 1 General 1.1 Definition and convention Definition The hull girder loads are forces and moments which result as effects of local loads acting on the vessel as a whole when considered as a girder Sign convention The vertical bending moment is positive when it induces tensile stresses in the deck (hogging bending moment); it is negative in the opposite case (sagging bending moment). 2 Vertical bending moment calculation 2.1 Still water vertical bending moments Part 3 Chapter 2 Section The design still water vertical bending moments are the maximum still water bending moments calculated, in hogging and sagging conditions at the midship transverse section for the loading conditions specified in [2.1.2] Loading conditions For all vessels, the following loading conditions shall be considered: light ship fully loaded vessel loading and unloading transitory conditions, where applicable The design still water vertical bending moments shall be obtained from formulae given in Ch.3 Sec Additional bending moments For vessels assigned the IN(0.6) or IN(1.2) to IN(2) range of navigation defined in the Pt.1 Ch.2 Sec.2 [10], an additional vertical bending moment, calculated according to Ch.3 Sec.10 [7] shall be added to the still water hogging and sagging bending moments, under both loaded and light conditions, for the determination of the hull girder strength and structural scantlings. Rules for classification: Inland navigation vessels DNVGL-RU-INV-Pt3Ch2. Edition December 2015 Page 19

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