Substructure Design & Intro Exercise TU delft

Thursday, 13 November 2014 MSc Offshore & Dredging Engineering Faculty CEG, Department Hydraulic Engineering Faculty 3mE, Department Maritime & Transport Technology

Basis for Structural Design

2

Lecture overview 1. Over Overvi view ew lectures on structural design and analysis 2. Subs Substr truc uctu ture re Design: Geometry and Configuration  Jacket versus Tower  Space frames  Elevations and Framing  Substructure Configuration  Preliminary Member Sizing

3. Intro Introdu duct ctio ion n to the exercise 

Aim of the of the Exercise

 Project Scope  Workshop on Substructure Configuration  Phase 1: Preliminary Design & Environmental Loads  Phase 2: Structural Analysis


3

Overview Lectures: Structural Design and Analysis Substructure:  Today:

Substructure Design: Geometry and Configuration

 Lecture 5: Envi Environ ronme ment ntal al Loads

Tue 18/11, 10:45‐12:30, 3mE‐D

of Towers  Lecture 6: Quasi‐Static behaviour of T

Thu 20/11, 10:45‐12:30, 3mE‐D

 Lecture 7: Quasi‐Static behaviour of J of Jackets

Tue 25/11, 10:45‐12:30, 3mE‐D

Tubular Joints 1  Lecture 10: Tubular

Mon 01/12, 13:45‐15:30, 3mE‐D

 Lecture 11: Tubular Tubular Joints 2

Tue 02/12, 10:45‐12:30, 3mE‐D

Foundation and Topsides: Foundatio tion n Design in Practice  Lecture 13: Founda

Mon 08/12, 13:45‐15:30, 3mE‐D

 Lecture 14: 14: Theor Theory y of Foundation of Foundation Design, and

Topsides Design In between: Lectures on Dynamics and Fatigue

Tue 09/12, 10:45‐12:30, 3mE‐D


4

Substructure versus Foundation: Tower or Jacket? Definition of a Jacket type substructure: A substructure, made of a tubular space frame, providing support for a superstructure with all or some of the foundation piles inserted through the legs and connected to the legs at the top ‐

Definition of a Tower type substructure: A substructure, made of a tubular space frame, providing support for a superstructure with all or a number of the foundation piles inserted through and connected to sleeves around the legs at the base of the structure ‐

Additional for both: So called skirt piles may be inserted through and connected to sleeves at the base of the structure between the legs ‐


5

Jacket Substructure


6

Leg‐Pile Connection for a Jacket Substructure Main Leg-Pile Connection above WaterLevel

Pile Shim Plates

Slot Seal Rod

Leg Brace


7

Tower Substructure


8

Tower Substructure – Pile Sleeve


9

Leg‐Pile Connection for a Tower Substructure Grouted Sleeve Connections Pile

Sleeve

Main Leg‐Pile connection at sea floor

Grout Annulus

Packer

Mudline Mud Wiper


10

Design requirements for the substructure The substructure dimensions are determined by:  Dimensions topside  Water depth  Dimensions base of structure (foundation requirements)  Elevation of top horizontal bracing / air gap Substructure

Additional aspects are:  Number & position of the legs  Number & position of piles  Number & position of well conductors, and  Number & position of work in the water (risers, caissons, sumps)

Based on the above we can design a fixed steel structure:

3D Steel Space Frame


11

Square versus Triangular Framing •

A hinged square frame is statically indeterminate

•

A portal frame needs to be designed for moments

•

A hinged triangular frame is statically determinate  a 3D space frame is usually a set of triangular frames!


12

Plane and space frames Plane frame:

Space frame:

Minimum # of members needed:

Minimum # of members needed:

M min  2 N  3

M min  3 N  6


13

Types of substructure brace patterns

All these structures are made up of triangles


14

3D Steel Tubular Space Frames 3D Steel Tubular Space Frames are very effective as they provide: 

3D‐strength and 3D‐stiffness,

 Transparency,  Adaptability / Flexibility

We do however have to consider:  Maintenance  Corrosion:

Coating or Sacrificial anodes? In handbook and during lectures:  Simplified – 2D analysis 

All loads are considered to be in‐plane of frame and applied at frame nodes



All joints are assumed to be hinged

 Consequently, only axial forces in the members


15

Deck elevation


16

Deck elevation


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Water Depths and Deck elevation Water depths may be given as:  MSL: Mean Sea Level  LAT: Lowest Astronomical Tide  HAT: Highest Astronomical Tide

Relation:

LAT  MSL 

tide 2

 HAT  tide

Maximum water depth: Dmax  MSL 

tide 2

air gap

 surge  subs.  settl.

Dmax

HAT MSL LAT

Subsidence is often mixed up with settlement: Subsidence: Lowering of the sea floor due to the extraction of hydrocarbons from a reservoir Settlement: Lowering of the sea floor due to soil compression under weight of the structure

wave crest settlement subsidence storm surge 1 2

tide

1 2

tide


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Water Depths and Deck elevation Water depths may be given as:  MSL: Mean Sea Level  LAT: Lowest Astronomical Tide  HAT: Highest Astronomical Tide

Relation:

LAT  MSL 

tide 2

 HAT  tide

Maximum water depth: Dmax  MSL 

tide 2

 surge  subs.  settl.

air gap

Dmax

HAT MSL LAT

 Subsidence is due to reservoir compaction.  Settlement is due to soil compaction  Generally, we find the wave crest as 55 to

60% of the 100 yr wave height (Hmax ). 

An air gap is added as a safety margin and is commonly chosen as 1,5 m.

wave crest settlement subsidence storm surge 1 2

tide

1 2

tide


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Terminology: Broadside and End‐on

End‐on loading

Broadside loading

Broadside frame

End‐on Broadside

Diagonal

Diagonal loading

End‐on frame

Diagonal


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True Batter Angle Suppose a:  1:10 batter angle in broadside direction, and  1:10 batter angle in end‐on direction

The 3D‐ or true batter must then have a ratio: Thus, the true batter angle is then found as:

2:10

1:

10 2

Max: 1:6

= 1: 7,1

M p

√

1:10

1 1

Broadside

G

End‐on

Note that, the batter angle should not exceed 1:6 so as not to exceed the allowable the foundation piles during installation


21

Framing When submerged the top horizontal framing develops buoyancy forces working against its own weight. The resulting fluctuating vertical bending moment during the passage of a wave crest causes fatigue loads. 

To minimize fatigue issues, the elevation of the top horizontal frame is chosen above the top of the waves in normal operational weather conditions. Consequently, the minimum elevation of the top horizontal framing should at least be equal to the wave crest;

Southern North Sea 6.0 m

 Northern North Sea: 8 m above MSL  Southern North Sea: 6 m above MSL 

The maximum elevation of the uppermost submerged horizontal frame is chosen such that it is always flooded. Thus, for example at: LAT wave trough surge. Generally of no concern, as in most cases the optimal framing leads to a larger elevation distance from MSL. ‐



‐

The bottom horizontal frame should be sufficiently elevated above mudline to allow for settlements.

MSL ???


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Selection of of bay bay dimensions For fabrication purposes, the bays (or panels) are often chosen geometrically equal: dim i 1  m  dim i

 Each bay i has dimensions:

1



 b N  N Consequently, we can find m as: m     b0 



h

The bay heights are found as: N



N 1

hi  h1  mh1  ...  m

i 1

h  h1

N

m

i 1

m 1 N

 h1

i 1

m 1

tan  odd   Brace angles:

tan  even 

 m 1  h h    1 N m 1  

h1 

hi bi  hi tan  1 hi bi  hi tan  2

1   2  even  odd ,thus if  1   2   even  odd


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Bay dimensions: Example

Q1: What is the ratio m? Q2: What is the height of the of the upper bay?


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Bracing Patterns Non‐ optimal

Diagonal Bracing

X‐Bracing

Better

Best 40‐50°


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Horizontal framing Next to configuring the broadside and end‐on frames, we also need to properly configure the Horizontal framing. Horizontal frames generally have 2 functions:  Provide support for the infrastructure

between topsides and sea floor  Provide structural stability and integrity

Infrastructure between topsides and sea floor:  Provide space for a conductor frame  Include framing for risers, sumps & caissons

Structural stability and integrity:  Horizontal frame should always be statically determinate: so use triangles as a

basic shape for the member bracings 

If Broadside, End‐on and Horizontal frames are in turn statically determinate, the whole structure is statically determinate…


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Rules of Thumb for Preliminary Member Sizing Once the configuration of the substructure space frame is known, we can determine the centre‐to‐centre lengths of all members in the space frame. Using Rules of Thumb, we can use this length L to determine:  Initial member diameters D, Do, Di  Initial wall thicknesses t

Generally, due to stability requirements: Stiffness > Strength. Consequently, diameter selection is generally based on slenderness.

Slenderness:

 

KL r g

L : Member length  , with K : Effective Buckling Length Coefficient r : Radius of Gyration g

Slenderness is an empirical value:  Horizontal bracing members:

  100

 Diagonal, X‐ and K‐braces:

  80


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Effective Buckling Length The effective buckling length is generally described through the coefficient K . The coefficient K describes the ratio between the effective buckling length of a structural element and the actual length of that structural element.

K 

Leff b

Lb

eff

1 eff 2 b

L

L

L

eff

Leff b

Leff b

Lb

L

 1,0

K 

L

L

 0,5

K 

L

 2,0

Values for the effective buckling length coefficient:  Horizontal, diagonal and K‐braces:

K  0,8 (slightly conservative: 0,7‐0,75)



K  0,5

X‐braces:

 Jacket/Tower‐Legs:

K  1,0


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Radius of Gyration The Radius of Gyration, or Gyradius, is used to describe the distribution of cross‐ sectional area in a column around its centre of gravity. r g 

Radius of Gyration:

I

, with

A

I : 2nd moment of area   A : cross‐sectional area

For tubular members, we find:  Cross‐sectional area: 

2nd

moment of inertia:

A 



I



D  4

64

 Di 2   A   Dt

2 o

D

4 o

D

4 i



Consequently we find the radius of gyration as:

Do

Di

 t 2   3  I  D t 1  2   D t 8  D  8 

r g 

3

I A

D  Do  t  Di  t



 D 3t 8  Dt



D 2 2


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Rules of Thumb for Initial Member diameters Combining the obtained values and equations for slenderness, buckling coefficient and radius of gyration, we find the following rules of thumb for the different type of tubular space frame members

KL

 

r g

K L r g r g 

D 2 2

Horizontal

Diagonal, K

X

100

80

80

0,8

0,8

0,5

125

100

160

D  0,023L

D  0,029L

D  0,018L

Note that although D is the average of Do and Di , the factors in these rules of thumb are rounded up and may therefore be used for Do as well.


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Rules of Thumb for Initial Wall Thicknesses To determine the initial wall thicknesses t of the members in the space frame, we use rules of thumb that compare the wall thicknesses with member diameters D. 

To allow for cold rolling steel plates into tubulars:



The practical upper limit is approx. found as:

D t D t

 24  60

 Members in the top of the structure are generally required to be relatively

thick due to significant wave loading (fatigue), collisions and corrosion. Therefore, members near sea level:

D t

 2530

 Members that are always below sea level, are generally subject to lower loads

and therefore require less thick walls. Therefore, members below sea level: 

For Jacket and Tower legs:

D t D t

 40  60


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Neutrally Buoyant Members As substructure space frames are generally fabricated in an onshore fabrication yard, their bracing members are internally dry and water tight (closed welds). Consequently, submerged bracing members are subject to:  Gravity loads from their own weight, and  Buoyancy loads due to the displaced water

A bracing member is neutrally buoyant when:  Weight:  Buoyancy:

Fg   sg



Fb  w g

The exact solution yields:

D  4

2 o

 4

 Di2    sg Dt

Do2   w g

D t



Weight = Buoyancy



4

4 2

D  t 

2  s  w  2  s   s   w 

By approximation, we can derive: In terms of outer diameter, we find:

 w D t Do

4 

 s  w

2  4

D t



D

7850 1025

 s  w

2





 D  t  Dt

D t

2

 s  7850  D

t D

 28,60   w  1025 t

 2  28,63

 1  29,6



Thursday, 13 November 2014 MSc Offshore & Dredging Engineering Faculty CEG, Department Hydraulic Engineering Faculty 3mE, Department Maritime & Transport Technology

J.S. Hoving


Introduction to the exercise ‐ Overview Introduction to the Exercise: 

Aim of the Exercise

 Project Scope  Phase 0: Workshop on Substructure Configuration  Phase 1: Structural Design & Environmental Loads  Phase 2: Structural Analysis  Deadlines & Deliverables


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Introduction to the exercise Part of the course OE4651 Bottom Founded Structures consists of an exercise regarding the design and analysis of a Bottom Founded Offshore Structure. 

The exercise counts for 25% of your final grade; However note that, to pass the course, you need to at least pass the exercise. In other words: you will only get a final grade for this course, if you are awarded a 6 or higher for the exercise.



The exercise is performed in teams of 3 students; Naturally, we expect more from a group of 3 students than we expect from groups of 2 students.

 Between group members the exercise grade will not

be differentiated. It is therefore extremely important to work well together as a team!


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Aim of the exercise Of course, there is software available to design and analyse bottom founded offshore structures. But...  What data will we use as input for the software? 

How do we know whether the resulting design is optimal?

Software is generally suitable to optimize your design, for example using structural analysis software such as SACS/USFOS. However, the preliminary design is performed (mostly) by hand. Additionally, performing this exercise will:  Provide understanding of the structural mechanics of bottom founded structures  Give insight in the influence of environment loading to the design of bottom

founded offshore structures  Allow you to quickly check numerical results by simplified hand calculations  Allow you to point out possible issues in the design and ask the right questions.  Make it much easier to pass the exam (!)


38

Project Scope Shell has newly discovered a big gas field in the southern part of the North Sea! In order to analyse whether the develop‐ ment of this gas field is feasible, you are asked to develop the preliminary design of an offshore structure for this location. At the gas field location, the mean sea level is 31.6 m, which makes this location very suitable for a steel space frame structure, with a piled foundation; in this case a jacket.

Your tasks in this project comprise:  Global configuration of the jacket structure;

Workshop (Phase 0)

 Leading up to the preliminary design,

Phase 1

including horizontal framing;  Calculation of the environmental loading;  Structural analysis: member & foundation check.

Phase 2


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MetOcean data Shell’s MetOcean department has done some preliminary research and supplied you with the following MetOcean data for the location of the field:  Water depth = 31.6 m (assume a flat seabed)  Design wave height = 9.6 m (100 year wave)  Wave period = 14.2 s  Tidal range = 3.0 m  Storm surge = 1.2 m (+) / 0.2 m (‐)  Surface current velocity = 2.2 m/s  Marine growth = 36 mm  Subsidence = 0.4 m (at end of production life)

Subsidence is often mixed up with settlement, however Subsidence:

The lowering of the sea floor due to the extraction of hydrocarbons from its reservoir

Settlement:

The lowering of the structure due to soil com‐ pression under the weight of the structure


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Functional requirements 6 Conductors: 

We will require 6 production wells to produce the field, therefore our jacket needs to accommodate 6 conductors with an outer diameter of D=32″ and a wall thickness of t=1″.

 This type of conductor requires a 96” ctc‐spacing.

2 Risers: 

To export the gas, there will be an 16″ export riser.

 Addionally, another 14″ riser ties into our

platform from another field. 2 Caissons: 

a 24″ caisson to pump up fire water with its tip at 12 m below MSL, and



a 24″ caisson as a sump, with its tip at 26 m below MSL.


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Jack‐up drilling 

All wells will be drilled by a jack‐up rig, so there will be no derrick on the jacket.

 Additionally, the layout of your structure will

depend on the required clearance and the maximum outreach of the jack‐up derrick!


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Topsides layout 

For the design of our substructure, we consider the topsides as a closed box with a length of 30 m, a width of 15 m and a height of 20 m.

 According to the topsides manufacturer, the diameter of the deck legs are 36”

and the end‐on deck and broadside leg spacing are respectively 10 m and 20 m.  There will be a 25x25m helideck and a platform crane, but no boat‐landing. 

The operational mass of the complete topsides is estimated at 1700 mt.


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Considerations for the Substructure Geometry 

To allow sufficient space for the shimmed connection between the foundation piles and the jacket legs, the connection between piles and topsides deck legs is located 2,5 m above the uppermost horizontal framing



The distance that the topsides deck legs extend below the topsides deck bottom depends on deck level and the level of the uppermost horizontal framing



To avoid fatigue problems in the uppermost horizontal framing due to waves and buoyancy, its minimum elevation should at least be 6 m above MSL at all times.

 Accordingly, the minimum elevation of the uppermost

submerged horizontal framing should be chosen such that the frame remains flooded at all times. 

The pile batter should never exceed 1:6 to avoid operational problems during pile driving. Thus, a batter of 1:7 is allowed, a batter of 1:5 is not.

2.5 m


44

Phase 0: Workshop on Substructure Configuration Purpose of the workshop:

To help you establish the global configuration and layout of your jacket structure as soon as possible. The workshop involves:  Registration of the teams  First sketches and ideas of a global jacket structure configuration based on the

functional requirements  Discussion and Q&A regarding your jacket design per team  Establish a sound global design for your jacket structure


45

Getting started with the Substructure Design What do we have to take into account when establishing our substructure design? 1. Determine minimum and maximum water depths. 2. Determine the elevation of the topsides deck bottom, based on the water depth, MetOcean data and the subsidence. 3. Determine the elevation of the top horizontal frame, based on the substructure geometry considerations. (Do not forget to take subsidence into account!) 4. Determine the pile and leg batter, bay heights and thus the remaining framing levels, based on the given functional requirements and substructure geometry considerations. 5. Determine the position and orientation of all substructure members, in both broadside and end‐on frames, optimizing its structural integrity, i.e. focusing on redundancy and strength, while taking the weldability of joints into account;

Note that: optimal welds are achieved at an angle of approx. 45⁰, nevertheless due to equipment size the angles may never be smaller than 30⁰! This is the point where we want you to be after the workshop!


46

Sizing of the jacket piles, legs and members  Initially we assume the foundation piles to have a diameter of 42″; The pile

capacities are given in the table in section 2.3 for several pile diameters.  Generally, the diameter of a jacket leg has to be about 4‐6” larger than the pile

diameter to allow for:  leg wall thickness,  excess joint can wall thickness, and  spacer plate thickness 

The member diameters are initially determined using thumbs of rule:  Diagonal members:  Horizontal members:

KL/r g ≈ 80

D = 0,029L

KL/r g ≈ 100

D = 0,023L

 Wall thicknesses of jacket legs and members follow from D/t ‐ratio’s:  For the legs:

D/t 60

 For the members:

D/t 40

≈

≈

 Note that for commercially available steel tubulars:  Diameters go up in steps of 2”  Wall thicknesses

in steps of 0,125”


47

Horizontal framing Considerations:  Conductor bracings  Determine position of conductors, risers & caissons  Triangulation of bracings  Weldability:  Preferred angles are between 40‐50⁰  Nevertheless angles must be > 30⁰  Rules of thumb:  Member diameters (KL/r g ≈ 80):

D = 0,029L

 Member wall thickness:

D/t 40 ≈

Use common sense to check yourselves: 

A member‐diameter should always be smaller than the diameter of the member or leg to which that member is to be connected, to make sure that a sensible welding configuration is achieved


48

Loads on a substructure Now:

The substructure configuration is complete, and the size (L,D,t ) of all substructure elements is known

Thus:

We can now determine the loading on the platform for the ULS‐case, i.e. for extreme environmental conditions with a 100‐year return period

Loads to be considered are:  Wind, waves & currents  Permanent topsides loads (Weight)  Variable topsides loads (Operations)  Weight and buoyancy of the substructure

Lecture 5: Environmental loads & Morison equation ‐ Tue 18/11 The design wind loads are given as: 

End‐on wind load = 0,5 MN

 Broadside wind load = 0,8 MN


49

Environmental loads MetOcean Data

Wave theory (Airy) Wave approach angle & phase + current

Water particle velocities & accelerations

Platform Configuration

Don’t forget Marine Growth!

Stick Model (Equivalent diameters for drag & inertia) Lecture 5: Environmental loads Morison Equation

Environmental loading


50

The Stick‐model & Morison equation The Stick‐Model: Consider the structure as a cylinder, with its diameter alternating over height: 1. We determine different equivalent diameters for drag and inertia 2. Use the Morison equation to determine the corresponding load

Morison equation for a cylinder with diameter D: u : water particle velocity F   4 C M  D2u  21 C D  Du u     F I

F D

  : water density   C M : Inertia coefficient C : Drag coefficient


51

Directional spreading Environmental conditions are multi‐directional and random. To account for this, we use the directional wave spreading factor:  Unidirectional:

ϕws = 1

 Omnidirectional:

ϕws = 0,707 (= 2 ) ϕws = 0,906

 Most situations:

The wave spreading factor is to be applied to velocities and accelerations.


52

Current Blockage The Morison equation considers hydrodynamic loads to a single body;  Often, we have multiple bodies to consider simultaneously  Especially current is influenced by the presence of multiple bodies  Current blockage factors should always be multiplied by the current profile


53

Phase 1: Preliminary design & environmental loads Next steps: 

Use rules of thumb to determine pile, leg and member sizing

 Sizing of the interior of the horizontal frames  Determine environmental loading  Determine permanent and variable loads  Determine overturning moment and base shear

Phase I Deliverables: (also see chapter 5 of the hand‐out)  Initial diameter and wall thickness of all structure components  Drawings of the broadside, end‐on and horizontal frame plans  Determine the weight in air and as installed buoyancy  Calculate equivalent diameters for drag and inertia and

drawings of the resulting stick‐model for your structure  Determine the hydrodynamic loads at reference levels in

broad‐side, end‐on and diagonal directions  Give the resulting overturning moments and base shear

Deadli

Mo 01/12, 13:00, E mail & Blue Box @ CEG 2.91


54

Phase 1 summary sheet As a part of your phase 1 report, please summarize your phase 1 results using the phase 1 summary sheet given in appendix F of the exercise description.


55

Structural Integrity Next up: check the platform’s structural integrity under design conditions. From Phase 1, we know the loads on the jacket structure; 1. Determine whether these loads are:  Permanent Loads,  Variable Loads, or  Environmental Loads

2. Combine loads into design actions using LRFD; we will here only consider the Ultimate Limit State (ULS) Partial load factors

γm

γG

γQ

γ E

Permanent and variable actions only

1,18

1,3

1,5

0

Extreme conditions; action effects due to permanent and variable actions are additive

1,18

1,1

1,1

1,35

Extreme conditions; action effects due to permanent and variable actions oppose

1,18

0,9

0,8

1,35


56

Support reactions Consider the 2‐dimensional problem, i.e. one pile on either side: • symmetric vertical loads • anti‐symmetric vertical loads • horizontal loads • overturning moments

The forces on the piles are considered in the local pile co‐ordinate system:



Pa

: axial

Pt

:

Pm

: moments

transverse


57

Foundation Check We initially assumed a pile diameter of 42”, is this enough? 

For the axial pile check use a resistance factor: 1.25

(ISO19902)



For the lateral pile check use resistance factor: 1.0

(ISO19902)

If so:

We have chosen the correct foundation pile

If not:

We have to change the pile diameter

Pile diameter (“)

30”

36”

42”

48"

54"

60”

72”

Wall thickness (“)

1,0”

1,0”

1,75”

2,0"

2,25"

2,5”

2,75”

Ultimate compression (MN)

15,9

18,5

22,1

25,1

28,1

31,1

37,3

Ultimate tension (MN)

5,6

6,6

7,7

8,9

9,9

11,0

13,2

Ultimate lateral loading (MN)

1,5

2,5

3,5

4,5

5,3

6,9

9,4

Q: What is the influence of changing the pile diameter?


58

Member Check Determine:  Axial forces in the members

Leg‐pile connection

 Moments in the members

Frame Analysis:  Moments and Shear along the structure  Section method

Lecture 5: Quasi‐static behaviour of Towers – Thu 20/11 Lecture 6: Quasi‐static behaviour of Jackets – Tue 25/11 Resistance factors to be used: (ISO19902)  Member axial tension, bending or shear check: 1.05  Member axial compression check: 1.18  Member buckling check: 1.25

For more info on this: see Appendix D of the exercise description

Guides


59

Punching shear check of a joint N 1

For the punching shear criterion, it is assumed that during the ULS, the punching shear yields stress v p is uniformly distributed over the punching shear area A p around the brace perimeter: v p 

f y 0 3

A p   d1t 0

d 1 q1

1  sin  1

v p

2sin  1

The governing load for punching shear is the vertical component of the tensile force N 1: N1 sin 1  A p v p

t 1

 N1  0,58 f y 0 d1t 0

1  sin  1 2

2sin  1

Check all braces of a joint for punching shear that is: 1. Located between leg and diagonal at mudline 2. Located between leg and diagonal at top horizontal frame Lecture 10: Tubular Joints 1 – Mon 01/12 Lecture 11: Tubular Joints 2 – Tue 02/12

d 0

t 0


60

Phase 2: Structural analysis Next steps:  Determine the support reactions of the jacket  Perform the foundation check  Perform the member check  Perform a joint check for a single joint

Phase 2 Deliverables: (also see chapter 7 of the hand‐out)  Give the Jacket support reactions due to combined loads  Calculations of the axial, lateral and bending loads on the piles  Check the foundation pile diameter and wall thickness  Change foundation pile if necessary and recalculate (!)  Member check for the braces in broadside and end‐on faces  Punching shear check of a joint of your choice:  Between leg and diagonal at mudline  Between leg and diagonal at top horizontal frame


61

Phase 2 summary sheet As a part of your final report, please summarize your final results using the phase 2 summary sheet given in appendix G of the exercise description.


62

Deadlines and deliverables Important dates and times for the exercise are: 

Mon 17/11

13:45‐15:30

Workshop Jacket Configuration



Mon 01/12

13:00

Deadline deliverables Phase 1



Mon 05/01

13:00

Deadline deliverables Phase 2

All deliverables are to be submitted in digital format as well as hardcopy.  Submit the digital version of your exercise‐reports by e‐mail to both:  [email protected], and  [email protected].  Submit 1 hardcopy of your exercise‐reports to the blue box outside

room 2.91 on the 2nd floor of the Faculty of Civil Engineering and Geosciences, which can be easily recognized by this picture If, at

time,

realise that

wont be able to make the deadline;

63


Substructure Design & Intro Exercise TU delft

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