gladstone gate office presentation

Recovery of Gladstone Gate

1 Description2 Initial Concept

3 Solution4 Refining Solution5 Design Method6 Fabrication7 Lift8 Lessons Learned9 Questions & Answers

Introduction


• The gate was subsequently recovered & put in temporary storage

• Temporary measures to bring port back into operation

• The gate was damaged & required repairing

• Removal from the dock was required

• Solution for gate removal from the dock to be developed

In January 2004 operations at the Port of Liverpool were

brought to a halt, when, during a storm one of the lock

gates at Gladstone dock was ripped from its hinges.


Height 17 600 mm

Breadth 21 952 mm

Depth 2 400 mm

Weight 393 tonnes

Details of Gate`


Gladstone Dock GateLondon Bus


Initial Concept

Initial feasibility undertaken by MDHC

Options considered

•Conventional repair using dry dock

•Conventional lift of gate using crane

•Tipping cradle


Conventional repair using dry dock

• Condition of gate below water line unknown

• Availability of dry dock


Conventional lift using cranes

• Weight & size of gate would require a tandem lift using two 1000 tonne cranes

• Availability of space to accommodate the footprint


Tipping Cradle


Tipping Cradle• Distinct advantages to MDHC

• Mersey Mammoth floating crane could be used (250 t capacity)

• Wholly owned by MDHC

• Another 5 gates require refurbishment

• cradle could be reused


400

t

250 t

184 t BuoyancyTotal Lift

400-184=216 t max


Initial Option

Use of Mersey Mammoth to rotate gate and pull it onto quay side

230 tonne of kentledge required

Requirement to rotate gate from bottom


What to do when gate is horizontal Two options considered

• Slide gate onto quay side

• Provide vertical support at end of cradle

• Enter the Camel


What is “The Camel” • Floating barge Used to salvage vessels

• Built circa 1958

• Length 104’ (42.67m)

• Beam 35’ (10.67 m)

• Owned by MDHC

• Laid-Up for 3-4 years

• Therefore no cost on project & ideal for use


Problems With Using Camel• Floating vessel

• Age – Unknown condition

• No access to inside for condition survey

• Fuel on board – No possibility of welding to deck


Problems With Using Camel• Floating vessel

Design calculations

• Age – Unknown condition

Lloyds survey

• No access to inside for condition survey

Lloyds survey

• Fuel on board – No possibility of welding to deck

Clamped connection to bollards


Details of Camel Bollard Clamp


Preferred solution

• Use tipping cradle to recover gate

• Mersey Mammoth used to lift cradle

• Camel used to support gate during repairs


Tipping Cradle


Design Method

• Very good drawings of gate available

• Strength an condition of dock wall uncertain

• Good Guide to gate weights & CoG’s

• Uncertainty on gate conditionAmount of leakageAmount of entrained silt

• Trial lift required


Trial Lift

• Trial lift undertaken May 2005

• Results inconclusive – Gate appears heavier than drawing weight

• Further investigation revealed gate was not emptied of all water for trial.

• Gate reported as being clear of silt

• 2nd trial lift not possible during design

• Uncertainty as to reason for excess weight


Design Brief

• To cater for uncertainty of gate weight 50 tonne allowance

• 60% / 40% split in load to cater for1.Uneven distribution in load 2. Incorrect position of gate in cradle

• Upper & lower bound load cases defined

• Upper bound – Used for member design & lifting loads

• Lower bound – Used for lifting loads

• Stability and strength of dock wall by assessment

• Lateral load resisted by shear key in foundations


Gate Prior to Rotation Gate in Final Position


171 te

83 te72 te 75 te

100 te

74 te

329 te

201 te

230 te

195 te

168 te

142 te

0 te

50 te

100 te

150 te

200 te

250 te

300 te

350 te

400 te

450 te

0 10 20 30 40 50 60 70 80 90 100

Angle of Rotation

Mam

mot

h Lo

ad

Upper Bound Vertical Mammoth Load

Lower Bound Vertical Mammoth Load

High Predicted load on Mammoth not includingBuoyancy

Low Predicted load on Mammoth includingBuoyancy


Design Brief

• 250 tonne capacity of Mammoth not sufficient to rotate gate from vertical

• Additional lifting capacity required

• Additional capacity should provide horizontal pull

• Use of tugs to start lift

• Mammoth to complete lift

• Foundations provided remote from quay edge to take lateral loads


Method of Analysis

Simple 2D STAAD Pro models for various configurations

Vertical, 10°,22.5°, 33.75°, 45°, 67.5, 90°

Various configurations

•Gate against wall

•Gate supported on Mammoth

•Gate supported on tug

•Gate supported on Camel (final condition)


Testing Requirements

• Two types of testing

• NDT of welds

• Load testing of critical items


Testing RequirementsNDT of welds

• Many full penetration weld in highly loaded areas

• No redundant load path in these areas

• All full pen welds 100% MPI & 100% UT


Main Pin Detail

No positive connection to coping


Main Pin Detail


Testing RequirementsLOLER Requirements

REGULATION 9 -THOROUGH EXAMINATION AND INSPECTIONLoad testing to confirm the build quality and structural load bearing capability of the lifting equipmentFunctional and operational envelope tests to verify the satisfactory working range of the lifting equipment.Testing of lifting equipment should be undertaken at the discretion of the competent person

.


Testing RequirementsLoad test of critical items

Discussions with HSE

• Main pin assembly

• Tug lifting eye

• Mammoth lifting eye


Testing RequirementsLoad test of critical items

Programme & cost implications

•Test main pin assemblies only

•Full NDT of all components of Lifting Eyes

•Measures taken to ensure no person under the shadow of the lift

•For design of lift items FoS = 2.0

•For load test proof load = 1.5


Testing Frame for Main Pin


Lifting of Gate


Lessons Learned


Test requirements and impact

Tightening of clamp assemblies

Use of Camel

Lessons Learned


Questions & Answers

gladstone gate office presentation

Documents