ad 2000-mb - s3-0 -11-2007

AD 2000-Merkblatt

Supersedes October 2000 edition; I = Amendments to previous edition

AD 2000-Merkblätter are protected by copyright. The rights of use, particularly of any translation, reproduction, extract of figures, transmission byphotomechanical means and storage in data retrieval systems, even of extracts, are reserved to the author. Beuth Verlag has taken all reasonablemeasures to ensure the accuracy of this translation but regrets that no responsibility can be accepted for any error, omission or inaccuracy. In cases ofdoubt or dispute, the latest edition of the German text only is valid.

ICS 23.020.30 November 2007 edition

The AD 2000-Merkblätter are prepared by the seven associations listed below who together form the “Arbeitsgemeinschaft Druckbehälter”(AD). The structure and the application of the AD 2000 body of regulations and the procedural guidelines are covered by AD 2000-Merkblatt G 1.

The AD 2000-Merkblätter contain safety requirements to be met under normal operating conditions. If above-normal loadings are to beexpected during the operation of the pressure vessel, this shall be taken into account by meeting special requirements.

If there are any divergences from the requirements of this AD 2000-Merkblatt, it shall be possible to prove that the standard of safety ofthis body of regulations has been maintained by other means, e.g. by materials testing, tests, stress analysis, operating experience.

Fachverband Dampfkessel-, Behälter-und Rohrleitungsbau e.V. (FDBR), DüsseldorfHauptverband der gewerblichen Berufsgenossenschaften e.V., Sankt AugustinVerband der Chemischen Industrie e.V. (VCI), Frankfurt/MainVerband Deutscher Maschinen- und Anlagenbau e.V. (VDMA), Fachgemeinschaft Verfahrenstechnische Maschinenund Apparate, Frankfurt/MainStahlinstitut VDEh, DüsseldorfVGB PowerTech e.V., EssenVerband der TÜV e.V. (VdTÜV), Berlin

The above associations continuously update the AD 2000-Merkblätter in line with technical progress. Please address any proposals forthis to the publisher:

Verband der TÜV e.V., Friedrichstraße 136, 10117 Berlin.____________

Special casesGeneral verification of stability

for pressure vessels

Basic principlesAD 2000-Merkblatt

S 3/0

Contents

0 ForewordThe AD 2000 body of regulations can be applied to satisfythe basic safety requirements of the Pressure EquipmentDirective, principally for the conformity assessment inaccordance with Modules “G” and “B + F”.

The AD 2000 body of regulations is structured along thelines of a self-contained concept. If other technical rules areused in accordance with the state of the art to solve relatedproblems, it is assumed that the overall concept has beentaken into account.

The AD 2000 body of regulations can be used as appropriatefor other modules of the Pressure Equipment Directive or fordifferent sectors of the law. Responsibility for testing is asspecified in the provisions of the relevant sector of the law.

1 ScopeThe S 3 series of the AD 2000-Merkblätter provides informa-tion on allowing for the additional forces in pressure vesselwalls; see also 4.5 of AD 2000-Merkblatt B 0. They also pro-vide information for those cases where the verification of thestability is also to include the effects on the retaining and

supporting structures, as well as on those components ofthe pressure vessel itself which are subject to pressurestresses. The procedures for these are regulated in thisAD 2000-Merkblatt. Possible solutions for some of thestructural shapes which frequently occur are also given.

2 General2.1 The S 3 series of the AD 2000-Merkblätter shall beused only in conjunction with AD 2000-Merkblatt B 0.

2.2 The S 3 series of the AD 2000-Merkblätter include thefollowing parts:

S 3/.. – General verification of stability for pressure vesselsS 3/0 –, Basic principlesS 3/1 –, Vessels on skirt supportsS 3/2 –, Horizontal vessels on saddle supportsS 3/3 –, Vessels with domed ends on feetS 3/4 –, Vessels with support bracketsS 3/5 –, Vessels with ring supportsS 3/6 –, Vessels with nozzles subject to additional loadingsS 3/7 –, Allowing for of thermal stresses in heat exchang-

ers with solid headers

0 Foreword1 Scope2 General3 Symbols and units

4 Specifications for a strength verification withthe inclusion of stability

5 LiteratureAppendix 1: Specimen of a certificate in accordance

with 2.7

BA75E3EC9238321DFDAD9E8AEA77DB4BB3DF8BFFFF8CE3D73A9D38EFA8

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2.3 If requirements regarding strength and stability verifica-tion in addition to the verifications in accordance with theB series of the AD 2000-Merkblätter are specified for a ves-sel, the following procedures can be used. The possible solu-tions given in AD 2000-Merkblätter S 3/1 to S 3/7 take intoaccount these specifications.

2.4 4.1 of this AD 2000-Merkblatt contains the loadingsessential for stability verification together with information ondetermining the load variables. The appropriate loads for theparticular application case can be determined from these.The corresponding, jointly-acting loads are summarisedunder load cases in accordance with 4.2, allowing for theirsignificance for the pressure vessel. The level of the permis-sible stress during the strength verification then dependsupon the type of load. 4.3 contains information on strengthverifications including the specifications necessary for thepermissible stresses where these exceed those in AD 2000-Merkblatt B 0.

2.5 If there are standards which give specific dimensions,connecting geometries and details of permissible loads(for example bracket supports to DIN 28083-1 and -2) forpressure vessels or parts of pressure vessels, no additionalstrength verifications are necessary. It is then sufficient tocompare the loads which occur with those which are per-missible.

2.6 The connecting parts of supporting elements on frame-works, platforms etc. shall be designed such that it is possiblefor the force to be introduced without slippage, tilting or lifting.If platforms are fitted which do not comply with DIN 28017,the stability of these shall be separately verified.

2.7 The verifications in accordance with the S 3 series of theAD 2000-Merkblätter do not include steel or solid structureswhich serve to transfer the load. To describe the commoninterface it is necessary to document the maximum loads andanchor forces as well as the number, quantity and quality ofanchor bolts and the maximum compressive stress exertedby concrete used in the calculation, for each type of load (see4.2.1) in a separate certificate, e.g. in accordance withAppendix 1.

2.8 When using materials in accordance with the W seriesof the AD 2000-Merkblätter for the manufacture of supportingand attaching elements, the certification in accordance with2.2 of DIN EN 10204 can be used for the verification of thematerial.

Materials of identical type are to be used for parts that arewelded to the pressure vessel wall. If materials are usedwhich are not of identical type, approval for the deviations isto be certified.

2.9 The B and S series of the AD 2000-Merkblätter can beused for the verification of stability in accordance withregional building regulations for the vessel itself as well asfor the supporting and attaching elements.

3 Symbols and unitsThe following apply in addition to, as a deviation from, thespecifications of AD 2000-Merkblatt B 0.

a Factor for coefficient of safety in accordance with4.3.4.1 (3) or (4) –

cf Coefficient of wind force –

cf korr Corrected coefficient of wind force –

d Diameter of vessel including insulation mm

dF Reference diameter of supporting elements mm

e The wall thickness to be used asa basis for the calculation aftersubstraction of the wall thicknessallowances c1, c2, ... mm

eZ Wall thickness of skirt supports mm

f Permissible calculation stress inaccordance with 4.3.4 N/mm2

fP Permissible calculation stress forthe test case N/mm2

fM Permissible calculation stress forthe installation case N/mm2

fS Permissible calculation stress forspecial cases N/mm2

n Number of supporting elements –

w Clearance between vessels and/orbetween vessels and building mm

A Number of platforms –

An Projected area mm2

B Live load deduction %

C Total live load to be taken into account %

D Diameter of vessel mm

Gd Maximum possible total weight oft thevessels in service in the section planeunder consideration N

Gz Minimum possible total weight of vesselin service in the section plane underconsideration N

H Height of vessel above ground mm

M Total moment of the supporting elementsin the section plane under consideration,resulting from external loads Nmm

NFd Compressive force on supporting elements N

NFz Maximum tensile force on supporting elements N

SM Coefficient of safety for installation cases –

SS Coefficient of safety for special cases –

4 Specifications for a strength verification with the inclusion of stability

4.1 Loads

4.1.1 Loads means the influences acting on the pressurevessel and its attaching and supporting structures whichcause stress in the vessel.

4.1.2 When determining the loads, constraining forces andmoments due to restrictions on deformation (for example dueto supporting structures, components fitted on and inside aswell as pipe connections) shall be taken into account.

4.1.3 The specified number of load reversals shall be takeninto account for load cases which are to be included in thefatigue analysis.

4.1.4 For each load case, it shall be checked whether thefollowing loads occur and whether yet further loads also oc-cur. Examples of such loads are as follows.


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4.1.4.1 Dead load

This includes the dead load of the pressure vessel and of thecomponents attached to it, the charge of the pressure vesseland other loads which are constantly present.

4.1.4.2 Pressures

This includes pressures related to place and time includinglocal pressure application (for example when closing andopening valves).

4.1.4.3 Temperatures

This includes temperature patterns which vary with locationand time including temperature fields limited to specific areas(e.g. during charging and discharging processes) as well astemperature gradients in the component cross section. Theeffect of thermal insulation shall be allowed for.

4.1.4.4 Static and dynamic loads from components fitted onand inside as well as from pipes (e.g. due to pressure surges,thermal expansion) and charging loads.

4.1.4.5 Live loads

Live loads can act on platforms or components fitted on orinside. The loads for components fitted on or inside are deter-mined in accordance with DIN 1055-3, and for platforms andwalkways in accordance with DIN 4133.

If more than three platforms are fitted to one vessel, the liveloads for the global stability verification can be reduced inaccordance with 9 of DIN 1055-3 in accordance with the fol-lowing rules: The live loads of the three platforms (walk-ways) which most frequently place a load on the componentare calculated using the full amount. Live loads of other plat-forms (walkways) may, where there are uneven loads, bereduced according to the loads in descending order by anamount increasing in steps of 20 %. The reduction of theoverall live load shall, however, not exceed 40 %. The fol-lowing deductions and overall platform loads result wherethe platform live loads are the same.

The individual verification for single platforms (walkways) aswell as the local introduction of the load into the pressurevessel wall is carried out in each case using the total liveload associated with the platform.

4.1.4.6 Wind loads

The wind loads shall be determined in accordance with DIN1055-4, or where there are tall slender vessels with a height(H > 20 m above ground, H/D > 10) such as for columns inaccordance with DIN 4133. The projected area (vertical tothe direction of the wind) of the particular part under consid-eration is used for assessment. For vessels with a height todiameter ratio < 4,0, the wind roof load shall be taken intoaccount. The magnitude and line of effect can be deter-mined in accordance with DIN 4119.

For adjacent vessels or vessels close to buildings the co-efficient of wind force cf shall be chosen relative to theclearance of the vessels in accordance with DIN 1055-4.For simplification, the following can be used in accord-ance with DIN 18914 Supplement 1 (9/85) where theclearances are d + w � 2d:

(1)

When determining wind loads, access ladders, platformsand connected pipelines etc. may be taken into account inone lot using an allowance. Unless otherwise specified andthe additional projected area is < 15 % of the vessel project-ed area, the increase in wind load in accordance with 5.2.2of DIN 1055-4 can be calculated by an overall increase of25 % in the static pressure.

As an alternative to the aforementioned calculation, the windloads of access ladders, platforms and connected pipelinescan be determined in accordance with the following.

(1) The coefficient of wind force cf, is

cf = 0,7 for cylindrical vessels and the pipes runningparallel to them, provided the average clearancebetween the pipeline and cylinder is ≥ 1,2 timesits diameter, including the insulation.

cf = 1,5 for the adjacent pipes provided the averageclearance between the pipeline/cylinder is < 1,2times its diameter including insulation

cf = 1,2 for steel structures such as ladders and tubu-lar framework

cf = 1,4 for steel structures such as platform andwalkways.

(2) The following projected areas An are to be used

– Round solid platforms (angle at circumference360°):Platform external diameter × 0,5 m. For columns theplatform external diameter where there is an effectiveplatform width of 1000 mm (standard width in accord-ance with DIN 28017-1) is the diameter of the co-lumn with its insulation + 2,4 m.

– Platforms round, with an angle at the circumference> 100°:as for solid round platforms

– Platforms round, with an angle at the circumference≤ 100°:(vessel diameter with insulation + single width ofplatform) × 0,5 m

– Platforms, polygonal:Diagonal dimension × 0,5 m

– Walkways:Length × 0,5 m

– Ladders with safety fittings:Vertical height of ladder × 0,33 m

A detailed determination of the wind loads in accordance withDIN 1055-4 can be used instead of the simplified determina-tion of the wind loads using the foregoing parameters.

4.1.4.7 Vibrations resulting from wind load

In the case of vessels with a natural oscillation period ofT � 1 sec, account shall be taken of vibrations in the winddirection resulting from the dynamic effects of gusts of wind,eg. in accordance with [1] or [2]. This is generally the casewith very tall or very slender vessels. Fatigue analysis neednot be carried out for this type of loading.

Vibrations transverse to the wind direction as a result ofeddy shedding are not to be expected even in the case of tallslender vessels, e.g. columns, if platforms, ladders, parallelpipework, lateral manhole nozzles etc. are distributed overthe full height. Internal fittings such as fluid distributor endsor filler packings in particular, if they are located in the upperpart of the column, also counteract transverse vibrations.

A 1–3 4 5 6 7 8 9 � 10B 0 20 40 60 80 80 80 40

C 0 95 88 80 71,4 65 60 60

cf korr 1 7

100 1 wd----+⎝ ⎠

⎛ ⎞ 90,2–

-----------------------------------------------+

⎝ ⎠⎜ ⎟⎜ ⎟⎜ ⎟⎛ ⎞

cf⋅=


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In the case of very slender and tall chimney-like vessels with-out any significant fittings outside or inside, if transversevibrations are to be expected, fatigue analysis shall becarried out for this loading. This can also apply to columnsbeing assembled depending on the type of assembly andstate of manufacture where other temporary or permanentdesign measures to prevent transverse vibrations are pos-sible. These measures may also be required if transversevibrations are observed during operational stoppages(column with no fluid charges, fillers internals etc.).

In cases of doubt, the possibility of transverse vibrationsoccurring can be determined in accordance with [1] or [2].For information oh this, see also [3].

4.1.4.8 Snow loads

Snow loads are determined in accordance with DIN 1055-5.As a rule, the projected area at right angles to the verticalis used as a basis for the loaded area. For platforms andwalkways the snow loads can be allowed for in accordancewith DIN 4133.

4.1.4.9 Other dynamic loads (for example, earthquakes,processes with rapid pressure rises).

Details of the tracing point excitation during earthquakes canbe obtained from DIN 4149. Information from the operator isnecessary regarding possible processes involving rapidpressure rises and associated stresses.

4.2 Load cases

The load cases to be taken into account are the states in thepressure vessel and/or in the system which includes thepressure vessel. They are to be given regardless of the instal-lation point, the process conditions and, if necessary, regard-less of the legal and regulatory basis applicable to therequirements and to be classified in accordance with thedetails in this subclause.

The load cases in this case represent a combination of simul-taneously-acting loads or corresponding load patterns. Theindividual loads shall be determined in accordance with thedetails in accordance with 4.1 and combined to form loadcases in accordance with the example in Table 1. In doing soonly those loads which occur jointly with respect to time needto be combined. In special cases the loads acting jointly shallbe combined in each case with only one special load.

For all load combinations the superposition shall always bechosen which determines the maximum possible internalforce in this combination.

All the stresses and load cases to be taken into accountshall be given.

4.2.1 Types of load cases

Load cases can be:

– Operating cases (OC)

– Test cases (TC)

– Installation cases (IC)

– Special cases (SC)

4.2.1.1 Operating cases (OC)

Operating cases are those load cases for which the plantwith the system in a functional state (undisturbed state) isdesigned and suitable. Other operating cases are load caseswhich occur during malfunction of parts of the plant or sys-tems (disturbed state) provided this does not stand in the wayof continued operation for safety reasons.

4.2.1.2 Test cases (TC)Test cases are pressure and tightness testing. This includestests in the manufacturing works or by the operator afterinstallation, and also recurrent tests, taking account of theparticular supports and locally occurring pressure.

4.2.1.3 Installation cases (IC)The stresses which occur during installation, transport anderection (for example inertia forces, wind loads) are to betaken account of as installation cases for the particular instal-lation condition.

4.2.1.4 Special cases (SC)Special cases are events during the occurrence of which theplant cannot be continued to be operated for safety reasons,but which shall be kept in check when they occur.

4.3 Verifications of strength an stability

4.3.1 GeneralThe type and scope of the necessary strength verificationsdepend on the type of component for which the verificationis to be carried out and the loads to be taken into account(see 4.1) and/or the stresses caused by these.

For the load cases given in 4.2, the strength verifications con-tained in the B and S series of the AD 2000-Merkblätter shallnormally be used, taking into account the permissible calcu-lation stresses contained in 4.3.4. Verifications going beyondthis shall be carried out in accordance with AD 2000-Merk-blatt G 1 (4.2 and 4.3).

The stresses found during the stress analyses are assessedin accordance with AD 2000-Merkblatt S 4.

4.3.2 Type of component4.3.2.1 Pressure-stressed componentsThe B and S Series of the AD 2000-Merkblätter apply (asapplicable) to all pressure parts and to all parts firmly con-nected to the pressure vessel. For welded support structures,the part which is integrally joined to the pressure vessel shallbe calculated in accordance with the B and S (where appli-cable) series of the AD 2000-Merkblätter. The boundarybetween the integral retaining part and the support structureis decided using the condition over the run-out length, forexample for skirt supports (Fig. 1) where

(2)

Fig. 1.

4.3.2.2 Supporting elementsSupporting elements can be verified in accordance with theS 3 series of the AD 2000-Merkblätter.

4.3.2.3 Anchor boltsThe minor diameter area of the bolt (Ad3 in accordance withDIN 13-28) is the determining factor for dimensioning.

x Da ez⋅≥


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Table 1. Example of assignment of loads and load cases to the stress stages and permissble design stress

4.3.3 Type of load

4.3.3.1 Components subject to compressive load

For components subject to compressive load the stresseswhich occur during individual loads (see 4.1) shall be deter-mined separately according to membrane and bendingstresses, in addition to the dimensioning in accordance withthe B series of the AD 2000-Merkblätter, particularly for areaswhere forces are applied as well as for the essential loadbearing cross sections. The stresses determined for the in-dividual loads are then totalled according to the signs, sep-arately according to membrane and bending stresses, inaccordance with the defined load cases (see 4.2) for eachlocation under consideration and are then compared withthe permissible calculation stresses in accordance with4.3.4. In this case, the global membrane stresses resultingfrom mechanical loads shall not exceed the stress limitsspecified in 4.3.4. The higher stress limits may be used forsuperposed stresses resulting from mechanical and thermalloads. For membrane stresses in severely restricted localareas, such as points where loads are applied, and for thetotal stresses resulting from membrane and bending stress-es, the permissible calculation stresses can be increasedcorresponding to the details in AD 2000-Merkblatt S 4.

If compressive membrane stresses occur for the stressesdetermined outside local points, the stability shall also beverified for this load case. Stability verification in accordance

with DIN 18800 is a possibility in these circumstances, inaddition to the B series of the AD 2000-Merkblätter.

4.3.3.2 Supporting elements

For supporting elements of shell-shaped components theconstructions for components subject to compressive loadin 4.3.3.1 apply in principle.

For supporting elements of rod-shaped components thestresses (tensile, compressive, bending and their combina-tions) shall be determined for the individual combinations,starting from the load combination, and shall be limited tothe permissible calculation stresses in accordance with4.3.4 depending on the load case and load combination. Ifcompressive or bending stresses occur in these compo-nents under the individual load combinations, these shall belimited in accordance with DIN 4114.

If verifications are made either completely or partially in ac-cordance with standards for steel construction, the mainload H load case corresponds to operating case OC and themain load and additional load HZ case corresponds to theinstallation and test case and the main and special loadcase HS corresponds to the special cases.

4.3.4 Permissible design stress

The permissible design stresses depend on the load caseand type of component. They are included in Table 1 by wayof example. The following bases are used.

Load

cas

e1)

in a

ccor

danc

e w

ith 4

.2

Load in accordance with Permissible design stress in

accordance4.1.4.1 4.1.4.2 4.1.4.3 4.1.4.4 4.1.4.5 4.1.4.6 4.1.4.8 4.1.4.9In

here

nt lo

ad

Inte

rnal

pre

ssur

e

Vac

uum

or

exte

rnal

pres

sure

Loca

l pre

ssur

ebu

ild-u

p

Tem

pera

ture

2)

Ext

erna

l loa

ds a

ndlo

ad m

omen

ts(s

tatic

, dyn

amic

)

Live

load

s

Win

d lo

ads3

)

Sno

w lo

ads3

)

Dyn

amic

load

s3) ,

eart

hqua

kes

Pre

ssur

eve

ssel

Sup

port

igel

emen

ts

OC 1 × × × × × × ×

f fOC 2 × × × × × × × ×

...

TC 1 × × ×

fP 1,1 · fTC 2 × × ×

...

IC 1 × × ×

fM 1,1 · fIC 2 × × ×

...

SC 1 × × × ×

fS 1,5 · fSC 2 × × × ×

...

1) The load cases given here are examples of allocations and are to be accordingly given for the particular application case.2) The associated temperature is generally decisive for determining the permissible stresses. Additional thermal stresses shall be allowed for the load cases

shown with a cross in this column.3) The details for load superposition contained in the relevant DIN standards can be taken into account.


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4.3.4.1 Pressure vessels

(1) The permissible design stress f is determined from the-material characteristic value K and the coefficient ofsafety S in accordance with AD 2000-Merkblatt B 0 or inaccordance with the corresponding calculation sheets toobtainf = K/S.

(2) For the test cases, the coefficient of safety S' is used, in-stead of (1) to determine the permissible design stressfP = K/S'.

(3) For installation cases, a distinction is made betweeninstallation loads which act for short periods (e.g. settingdown during transportation) and longer-acting installa-tion loads.

The permissible design stressesfM = K/SM

are in this case derived from the coefficients for theoperating case and test case by adapting the coefficientof safety in accordance with AD 2000-Merkblatt B 0 toobtain

SM = S – a · (S – S' ), (3)

wherea = 1,0 for short-term stress anda = 0,5 for long-term stress.

(4) For special cases the permissible design stressfS = K/SS

is established as for installation case taking a = 1,25. Inthis case, however, SS shall be not less than 1,0.

4.3.4.2 Supporting elements

(1) The permissible design stress for operating casesf = K/S

the strength characteristic value K with the coefficient ofsafety for the design case in accordance with AD 2000-Merkblatt B 0 can be used as a basis for materials givenin the W series in the AD 2000-Merkblätter.

(2) The coefficient of safety may be reduced by a factor of1,1 for the installation and test cases.

(3) For special cases the coefficient of safety can be reducedby a factor of 1,5.

(4) The required safety with respect to stability depends onthe type of verification on which it is based, whereby areduction in the necessary coefficients of safety inaccordance with the specifications for supporting ele-ments under (1) to (3) can be taken into account asnecessary.

If stability verifications are carried out in accordance withDIN 4114, the v values for all tough (ductile) materials inaccordance with the W series of the AD 2000-Merk-blätter, whose tensile yield strength Rp02 at room tem-perature is � 240 N/mm2 can be used. For such materi-als with a tensile yield strength at room temperature ofbetween 240 and 360 N/mm2 the v values for St 52can be used.

(5) As a deviation from AD 2000-Merkblatt B 0, the ambienttemperature can be used for parts of the supporting ele-ment if these are outside the thermal insulation of thevessel.

If steels contained in DIN 4133 are used for supporting ele-ments, the K values contained in it can be used as the designtemperature.

4.3.4.3 Anchor boltsFor anchor bolts for strength classes 4.6 and 5.6 and alsoanchor bolts made of 1.0038 and 1.0570 materials, thestrength characteristic value K for the operating load casesat ambient temperature is the yield strength given in DIN28082-2. For higher temperatures the characteristic val-ues given in AD 2000-Merkblatt W 13 for these materialsapply.

In the operating load cases the coefficient of safety S is 2,2with respect to the yield strength. Furthermore, the appro-priate regulations in 4.3.4.2 (2), (3) and (5) apply.

4.3.5 Checking the stability verificationA prerequisite for checking the stability verification is check-ing the dimensioning of the pressure-containing vessel com-ponents (cf. 4.2.1 and 4.2.2 of AD 2000-Merkblatt HP 511).

A description of the complete static system, the necessarydesign drawings and the required calculations including cal-culation against internal pressure shall be submitted forchecking the stability verification.

A test report shall be prepared on conclusion of a successfulcheck and the evidence checked shall be given a check note.

4.4 Load distribution where there are severalsupporting points

If a vessel is supported on several feet or lugs equallyspaced, then, where the division is equal, the maximum com-pressive force at each individual element can be calculatedas follows:

. (4)

An anchorage against lifting is necessary where

(5)

The following shall be used as the maximum tensile force fordetermining the anchor bolt forces.

(6)

for n � 4.

For n = 3 columns, the maximum tensile force is given by

(7)

The individual anchor bolt forces are determined as a func-tion of the structural relationships in the point of the foot (see6.2 of AD 2000-Merkblatt S 3/3).

Where an even load distribution cannot be guaranteed byensuring a uniform support, the maximum value of n that canbe used for the calculation is 3. Where two support points areused a stable supporting state is not generally guaranteed.Account is to be taken of this if necessary by using additionalsupports in the horizontal direction.

The rotational axis through the centre of the vessel shouldbe used when determining the bolt force components due tothe instantaneous loading.

The calculation bolt forces shall be increased by 10 % toallow for bolt pretensioning.

4.5 Taking into account longitudinal forcesAs part of the stability verification, the longitudinal forces inthe pressure vessel wall due to external loads and gravitatio-nal loads shall be checked to determine whether these lead

NFd1n--- 4M

dF-------- Gd+⎝ ⎠

⎛ ⎞=

4MdF-------- 0,7Gz>

NFz1n--- 4M

dF-------- 0,9 Gz⋅–⎝ ⎠

⎛ ⎞=

NFz13--- 6M

dF-------- Gz–⎝ ⎠

⎛ ⎞=


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to an increase in the overall stress and therefore require anincrease in the wall thickness. If in this case compressiveforces occur in the longitudinal direction in the vessel wall,a stability verification, e.g. in accordance with DIN 18800, isalso necessary.

It should be noted that for austenitic materials above element(402) in DIN 18800-1, reduced material numbers accordingto technical standards (e.g. DIN 4133) shall be used.

4.6 Assessment of welds on supporting elements

The formation of welds shall be in accordance with DIN 8558.Fillet welds need not be verified if the weld thickness is atleast 0,7 times the smallest wall thickness of the weldedplates and the weld is formed on both sides. The weld thick-ness g and a weld factor v = 0,6 shall be used as a basis forthe calculation of fillet welds welded on one side. Butt weldswelded on one side shall be assessed using v = 0,7 wherethere are tensile membrane stresses.

For butt welds welded on both sides v = 0,85 shall be used forassessment where there are tensile membrane stresses.

The weld factors v shall only be taken into account whenverifying membrane stresses.

5 Literature

[1] DIN 4133 Steel stacks, November 1991 edition

[2] Eurocode 1: Basis of design and actions on structures –Part 2-4: Actions on structures – Wind actions (currentlyENV 1991-2-4)

[3] Richtlinienkatalog Festigkeit RFK (Catalogue of StrengthGuidelines): Part 3: BR-K1 (No. 5.2 Transverse vibra-tions), 3rd edition 1981, VEB Komplette ChemieanlagenDresden (now Linde-KCA-Dresden GmbH)


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Specimen of a certificate in accordance with 2.7

Appendix 1 to AD 2000-Merkblatt S 3/0

Connecting loads of vessel, relative to system axis and[ ] lower edge of skirt support/ring support, level of bracket support[ ] lower edge of profile/tubular supports[ ] lower edge of saddle supportin kN and kNm:

Operating loads V H M

z x y x y z

Empty weight

Operating weight

Test weight

Supporting loads

External loads V H M

z x y x y z

Live

Wind

Snow

Loads per support– max V

V H M

z x y x y z

Operating

Live

Wind

Snow

– min V

Operating

Live

Wind

Snow

Maximum anchorage force [kN]

Maximum surface pressure [N/mm2]

Publisher: Source of supply:

Beuth Verlag GmbH10772 BerlinTel. 030/26 01-22 60Fax 030/26 01-12 [email protected]

Verband der TÜV e.V.

E-Mail: [email protected]://www.vdtuev.de


AD

200

0 C

od

e -

Issu

e 20

11-0

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ad 2000-mb - s3-0 -11-2007

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