Greystones Harbour PPP - Civil & Maritime Works - … · 2014-11-12 · period –Design,...

Greystones Harbour –Civil and Maritime Works

Sean Mason, FIEI 2nd May 2013

2 Contents

Contents

1. History2. Bid Stage3. Preferred Bidder

Stage4. Detailed Design

Stage5. Construction Stage

Images from 1996

3

Location

• Design life: 100 years

• MHWS/MLWS: 1.5m / -1.5 m OD Malin

• Climate change: +0.9 m in 100 years

• 100 year return period at 2015

+2.5m OD Malin

. Hmo = 4.7 m

. Tp = 10.7 s

Dublin

Greystones

History

4

Victorian Times

History

5

• Quay Wall Extension

• Kish Base

• Northern Breakwater

History

Developments

6

Coastal Erosion

Coastline

Old Landfill

Harbour Siltation

Storm Damage

Storm Damage1. Siltation of Harbour

2. Damage to

Breakwaters

3. Coastal Erosion

Problems

7

Siltation of Harbour

History

8

• Collapse of Structures

• Cavities within Breakwater

• Remedial Works

History

Damage to Breakwater

9

Coastal Erosion –Railway

• Route Selection – Earl of Meath

• Isombard Kingdom Brunel

• Bray Head – Pre-Cambrian rocks

• Tunnels and Bridges

History

10 History

Coastal Erosion – Railway

11 History

Coastal Erosion – Railway

12

Coastal Erosion – Cliffs

• Dynamic Coastal ‘Cell’• Erosion Process – waves• Erosion Process – rainfall• 0.5m/year average retreat

History

13

Coastal Erosion –Storm Events

• 1929/31 Storms• Houses Lost• Coastal Defences

destroyed

History

[Pictures]

14

The Power of the Sea

[Video Clip]

History

15

The Power of the Sea

History

16

Bid Stage

• 1999 - Greystones (and Delgany) Local Area Plan designated site for new

Harbour/Marina.

make safe and restore existing harbour,

Address coastal erosion, and;

provide new major public amenity.

• 2001 – Wicklow County Council decision to procure through a PPP model.

230 Berth Marina

360 Residential Units

6,000m² Commercial

16 acre public park

Public Harbour, Public Square

Coastal Protection Works

Bid Stage

17

Public Private Procurement (PPP) Model

• 30 year concession period – Design, Construction and Operation

• Award of Preferred Bidder status pre-planning

• EU Public Procurement• WCC provide land,

concessionaire provides public amenities

• Hand-back to WCC all public space

• Significant new facilities for local clubs

Bid Stage

18

Ground Conditions

• Desk Study• Ground Investigations• Ground Model• Made Ground

Bid Stage

Laminated Fluvio-

glacial Sands &

GravelsBeach Shingle

Brown Boulder Clays

Greywacke Bedrock

varies

-6m OD Malin

+10m OD Malin

0m OD Malin

19 Bid Stage

Reference Design and Outline EIS

• Refurbished Harbour• New Marina• Landslide Development• Public Amenities• Coastal Protection

20

Bid Design - Layout

Bid Stage

Coastal protection

02 Marina

03 North breakwater

04 Harbour

05 South breakwater

06 Public slipway

07 Coastguard

08 Yacht clubs

• Minimizing cut and fill • Buildings more protected

21

Bid Design – Harbour Entrance

• Simplify geometry (cost)• Retain dynamic ‘spending’ beach

Bid Stage

Bid design

N

Reference design

Wave disturbance in the harbour

(1-year storm)

23

Bid Design –Breakwaters

• Height and Width constraints

• Structure options: Embankment Sheet-piled

Cofferdam Precast Caisson

(marine access) Precast Block

• Seaward Revetment

Bid Stage

24 Bid Stage

Assumes no interventions to existing coastline

Elevation NTS

Existing cliff top

Existing beach

Perspective View Section 1

Coastal Protection Existing Situation

Scheme Objectives:

• Protect landfill and heritage area

• Preserve coastal cliff walk

• Overall scheme should preserve or

enhance amenity value and minimise

adverse environmental impact

Key Constraint

Avoid increased erosion of coastline to

north of scheme.

25

Coastal Protection Reference Design

• Highly engineered approach to halt

natural process over only part of

north beach

• Significantly increased erosion

forecast over northern section

threatening railway and impacting

on cliff walk

• Complete loss of much of north

beach and replacement with an

unsightly and inaccessible

shoreline, with loss of amenity,

natural cliffs and bird habitat

• Safety issue with regard to access

over and around revetments

• Given uncertainty in future

maritime conditions a highly

engineered approach is not sensible

as there is no flexibility in the

solution

Bid Stage

Perspective View

Section 1

Elevation

New cliff top

Rock Revetment

Engineered slope

26

Coastal Protection Design Development

• Solution is to work with nature rather than against it

• Managed Retreat solution• More sustainable solution for entire

north beach• Landfill protected with revetment

and groynes to create recreational beach area

• Single beach replenishment will supply material to the coastal system, reducing erosion behind berm and to lesser extent to the north by gradual shingle spread

• Existing north beach amenity preserved in its entirety

• Subject to detailed design and modelling off shore ‘reefs’ may be added to further reduce erosion over area protected.

• Reefs may be visually intrusive at low tide and potential safety issue

Bid Stage

Section 1 Showing Beach Replenishment Only Section 1 Showing Optional Reefs

27 Bid Stage

Coastal Protection Design Development

A: Perspective View Showing Beach Replenishment Only A: Elevation Showing Beach Replenishment Only

Existing cliff top

Shingle beach

28

Proposed Coastal Protection strategy

DO

NOTHING

MANAGED

RETREAT

HOLD THE

LINE

Railway

Archaeological

Site

Landfill site

Bid Stage

29

Preferred Bidder Stage

• Preliminary Design and EIA

• Planning Process

• Stakeholder Management

• Contractor Input


30

Preliminary Design and EIA

• Traffic and Access (Batching Plant)

• Protected Views• Ecology (sand-martins

and sea-kale) • Archaeology (St.

Crispin’s Cell and Rathdown Castle)

• Coastal Erosion• Old Landfill• Flooding


31

Planning Process

• WCC application to ABP• CPO included in

application• Foreshore Acquisition

included, Foreshore Lease/License not required

• Dredging and reclamation included in application

• Oral Hearing in March/April 2006

• Request for Further Information in August 2006. Submitted in October 2006

• 2nd Oral Hearing in March/April 2007

• Planning Granted in August 2007


32

Stakeholder Management –Harbour users

• OPW Coastguard Facilities

• Greystones Sailing Club (HUGs)

• Greystones Rowing Club

• Sea Scouts• Ridge Anglers• Diving Club• Moorings Licences• Public (adjoining

residents, local area, wider community)


33

Stakeholder Management

• Harbour residents with real impacts

• Resistance to change –‘Victorian Feel’

• Giving Public Amenity to Private Interests

• GPDA: GreystonesProtection and Development Association

• GUBOH: Give Us Back Our Harbour (twitter @guboh)


34

Contractor Input

• Construction Methodology (by land)

• Programme• Participation in

Planning Process• Value Engineering


35

Borrow Pit

• Materials Balance• Economics of

handling/processing• Granted as part of the

planning permission


36

Detailed Design

• Planning permission granted August 2007

• Concession Agreement signed December 2007

• Detailed Design:

Breakwater Structures

Harbour & Marina

Detailed Design Stage

1. Limited modelling for reference design

2. Hand calculations & limited modelling for

bid design

3. Numerical modelling completed

4. Physical modelling (in progress when

application made)

5. Hand calculations for revised layout

Design risk:

Planning

stage

Detailed

design stage

Bid stage

38

Detailed Design

• Sispar appointed Sisk – Lagan JV for ‘Civil and Marine Works Contract’• Fixed Price D&B Contract (largely designed already)• Arup both Employer’s (Sispar) Representative and Contractor (SLJV) designer!


39

Breakwaters - Stability

• Design for sliding, overturning, settlement

• Granular (porous) base – Goda Equations

• ‘Free standing’ Stacks to take out differential settlements

• Grout ‘socks’ with in-situ slab


40

Breakwaters – Physical Modelling

• DHI Copenhagen


41

Flume Tests on Breakwater and Revetment


42 Detailed Design Stage

Design Wave Conditions

43

Scale Model Testing


44

Harbour Entrance

• Reflected waves – turbulence and water depth

• ‘Porous’ roundheads

• Uplift pressures – anchor piles


Wave disturbance in the harbour: A solid vs a porous harbour entrance

Difference compared to original design

45

Harbour/Marina Wave Climate• Seiching (reflected standing wave) within Marina

• Sloped revetments around Marina under boardwalk


46

Breakwater – Design Development

• Breakwater crest height

• Curved seaward – facing wave-wall

• Wider base blocks (with voids to manage weight)

• Antifer sizes and underlying rock fill sizes


47

Breakwater Layout


48

Civil & Marine Works Contract

• Contract signed between Sispar and SLJV

Construction Stage

49

Construction Stage

• Demolitions

• Batching Plant

• Breakwater Construction

• Dredging and Reclamation

• Piling Works

• Old Landfill

• Beaches and Erosion Protection

• Value Engineering

• Statistics

Construction Stage

50

Demolitions

• Pier, Kish base, north breakwater

• Gap Bridge (cut-stone retained)

Construction Stage

51

Batching Plant (S.M. Morris)

• Agreed early and part of planning as Contractor on-board

• Flexibility in materials (concrete) delivery to site

• Tolerance on 5m x 3m x 1m blocks of 1mm

• Maximised design using pre-cast elements

• Continuous environmental monitoring

Construction Stage

52

Breakwater Construction Plan

• General Approach –land based operation

• Temporary Causeway to allow breakwater construction on 3 fronts

• Bed preparation using frames (minimize divers required)

• Work out with block stacks, return with slab

Construction Stage

53

Breakwater Settlement

Construction Stage

54

Breakwater Construction - Reality• Issue with leading edge of Temporary Causeway

• Bed preparation – levelling frame and divers

• Vulnerability of ‘free-standing’ stacks

Construction Stage

55

Storm Damage

• September 2008• Gusting Force 9 gale• Significant damage

over 9 rows of blocks• Temporary support to

stacks inadequate• Scour protection

around base inadequate

Construction Stage

56 Construction Stage

North breakwater… the day after


South Breakwater

58

Storm Protection

• Timber spacer blocks• End-frame• Levelling Frame for 6

stacks• Scour protection slabs• Revetment as close as

deemed safe behind

Construction Stage

59

Breakwater Tolerances

• Diver checked

formations

• Precise levelling of bed

• Diver assisted crane

placement of blocks

• Very tight tolerances on

block placement

• Visual impact (client and

architect)

60

Dredging

• Need for floating plant• Temporary load-out

quay• Hopper barges for

transfer• Machine excavation of

boulder clay (GPS on bucket)

Construction Stage

61

Reclamation

• Granular below MHWL, cohesive (boulder clays) above

Construction Stage

62

Borrow Pit

63

Landside Earthworks

• Marine Works delay impact on sequencing

• Compaction of fill• Use of lime on wet• boulder clays

Construction Stage

64

Piling Works

• Tubular Steel Piles• Driven to set (+

minimum penetration)• Hydraulic Hammer• Anticipate Driven

Precast Piles for buildings

Construction Stage


Piling Works

66

Old Landfill

• No CH4, traces CO2, granular curtain

• Above water table with porous capping –all mobile containments long-since leached to sea

• Risk Assessment to leave in-situ as parkland

• Approved by WCC and ABP

Construction Stage


Old Landfill

68

Beaches and Erosion

• Where reclaimed, shingle removed for re-use

• 10,000m3 imported shingle at start of construction

• Predicted movement pattern

Construction Stage

69

Beaches and Erosion

• Observed pattern during construction

• 6,000m3 accreted shingle relocated in 2009

• 4,500m3 accreted shingle relocated in 2012

Construction Stage

71

Value Engineering Porous Roundheads

Construction Stage


Value Engineering Porous

Roundheads

73

Precast Recurve Wall

Construction Stage


March 2009

75

22 January 2010

Construction Stage

76

26 March 2010

Construction Stage

77

13 May 2010

Construction Stage

78

13 May 2010

Construction Stage


23 July 2010

80

22 September 2010

Construction Stage

81

22 September 2010

Construction Stage

82

18 January 2011

Construction Stage

83

Statistics

• Concrete Volume 125,000 cu meters, greater than Dundrum SC

• 5,100 breakwater blocks

• 3,900 antifers

• 90,000 tons of 3-6 ton imported rock armour

• 115,000 cu metres dredging /excavation

• 203,000 cu metres reclamation fill

• Contract Value approx. €50m, €1m over tender

• Total spend on development to date circa €70million

Construction Stage

84

ConstructionCompletion

Civil & MarineWorks contractStarted March 2008Completed Feb 2011

Construction Stage

85

Acknowledgements

• Wicklow County Council – Sean Quirke

• Employer’s Rep Jacobs (now Leigh Fisher)

• Sispar – John Sisks & Park Developments

• Sisk Lagan JV (and subcontractors)

• Design Team (OMP, Broadway Malyan, Terry Durney)

• Subconsultants (COWI, DHI)

• Arup Staff (office and site)

• Greystones Public Representatives

• Greystones people

• Jimmy Quinn photography and Derek Paine books

Acknowledgements

86 Thank You

Thank You

Greystones Harbour PPP - Civil & Maritime Works - … · 2014-11-12 · period –Design,...

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