A case study on Coastal protection structure failure. Quay failure in Port of Barcelona. The presentation describes the failure of harbour walls which occurred at Barcelona on 1st January 2007, associated with an inadequate consideration of the ground conditions in the light of the marine environment. At Barcelona, the construction of the quay wall proceeded at a faster rate than the breakwater. In this case the wharf backfill was placed rapidly on the soft muds, progressing from the inland side. The paper discusses the importance of an overview including the ground investigation, engineering design, construction method and speed of construction. KeywordsBearing capacity–Caissons–Shallow foundations–Failure modes–Study cases

1. Presented By,
FAISAL RAHMAN P (OET-2021-31-04)
M. Tech CHE, KUFOS
QUAY FAILURE
IN BARCELONA
HARBOUR
1

2. TABLE
OF
CONTENTS
What Happened?
03
Introduction
01
Project Overview
02
WHY?
04
Conclusions
05
2

3. INTRODUCTION
● The Port of Barcelona Southern expansion project aimed at doubling of it’s capacity, in both
quantitative terms (wharves, breakwaters, cranes, accesses) and qualitatively (new shipping
lines, more services and more connections).
● The southern breakwater, already completed, is 4.8 km long and divided into three sections.
● The extension of the eastern breakwater, also completed, reaches a length of 2.1 km.
● At the El Prat wharf, a wharf is being built measuring 1.5 km in length, with a depth of 16.50
m, generating a surface area of 100 hectares.
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4. Barcelona Harbour Extension Projects, 2005-15
(/Researchgate)
The main actions for the southern
expansion of the Port are;
a. The construction of the
southern breakwater
a. The extension of the
eastern breakwater and
a. The construction of the El
Prat wharf.
PROJECT OVERVIEW
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5. A 1,500m long prat quay was constructed in two phases;
● Phase 1:
○ Prat I was built after mud dredging from 16 to 25 m bsl and the placement of a 9 m thick
rock fill blanket.
○ The wall itself consisted of four caissons on granular foundations.
○ Phase 1 act as a breakwater.
● Phase 2:
○ Phase 2 was protected by the extension to the sloping breakwater.
○ Following dredging to 24 m bsl, the 11.5 m wide caisson was placed on a 8 m thick rock
blanket at a level of 16.5 m bsl.
○ Since the second phase was protected by the breakwater and hence was designed as a
gravity structure.
5

6. On 1 January 2007,
the quay collapsed, and
the caisson slid.
WHAT HAPPENED?
State of Prat Quay after the collapse(/Researchgate)
6

7. WHY?
State of Prat Quay after the collapse(/Researchgate)
7

8. 1
The first phase was to act as a breakwater while the
second phase was protected by the breakwater and
hence was designed as a gravity structure.
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9. 2
The phases and the transformation from breakwater
to quay, filling, consolidation and paving were put
out to tender separately, with a slight time lag.
The caisson and fill works were undertaken by different
companies and there were different site managers.
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10. 3
The nature of the hydraulically placed fill was not
adequately studied and it was placed very quickly to
meet operational requirements.
10

11. 4
The fills were placed commencing at the landward
side, such that a lake was created inside the new
structure.
Drain spillways were not provided.
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12. 5
In the initial phase, when the structure was built as
a breakwater, there was no rear rubble mound,
consequently the loading on the monolithic
structure was greater than anticipated in the design.
12

13. 6
The caisson acted as a dam, hence the pressures
were higher than anticipated at design stage.
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14. 7
The tidal environment, as well as the variable
pressure imposed on the structure by waves, was
difficult to model.
The balance of effective and neutral stresses may
cause ground liquefaction and siphoning.
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15. With these limitations, the quay was prone to sliding as
a consequence of only a slight environmental, geotechnical or
structural disturbance and it collapsed on 1 January 2007.
After debris removal, blasting and caisson refloating,
repair works were undertaken during 2008 and 2009
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16. State of the caissons after the quay slid(/Researchgate)
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17. ● Before using gravity structures in this marine environment, the ground requires improvement or
consolidation to ensure adequate geotechnical parameters.
● The soft material should be removed by dredging and replaced with adequately compacted
material.
● Care must be taken if rapid construction is undertaken as loading too quickly may cause short
term stability problems. The construction works should not be compromised by the client’s desire
to utilise the facility at the earliest possible date.
● Where gravity walls are used, a rear rubble mound of granular material should be constructed with
a slope angle < 37.
CONCLUSIONS
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18. ● An inner construction is interdependent with the linear structure. The
containment wall and yard fills cannot be addressed separately.
● Provision should be made for the removal of water as the fill operation
takes place.
● Analyses should be made not only prior to construction but during all
phases of the works.
CONCLUSIONS
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19. Jose ́ Marı ́a del Campo, Vicente Negro, 2010, “Failures of harbour walls at Malaga and
Barcelona”, Bull Eng Geol Environ (2011) 70:1–6 DOI 10.1007/s10064-010-0313-z
REFERENCE
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20. THANK YOU…
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