South Breakwater Berths, Port of Fujairah, United Arab Emirates

Project Description

ESC was asked to look into the alternative for a design that proposed using an H Pile and sheet pile system from Europe for the construction of this vital part of the Port of Fujairah.
Working closely with Athena SA, ESC proposed the ESC H Pile system which eventually won the award from the Port of Fujairah and their Engineers Mott MacDonald of the United Kingdom. During the course of the design stage of the project ESC held site meetings in the UAE and video conferencing calls with Mott MacDonald’s geotechnical and structural team in London, England. ESC ensured that all facets required by the Client and their Engineers were able to be met.

Figure 1 Concept Drawing of the Project

ESC not only worked with the owners but the contractor Athena SA had constant site visits and communication from ESC both during the design stage and the implementation stage of the project. Designs of the wall system took into account the preferred method of construction detailed by Athena SA and were adapted accordingly whilst at the same time ensuring the stringent safety factors of the Clients Engineers were followed in terms of the seismic and structural conditions.
The Port of Fujairah proposed to construct a new quay wall and associated works at the existing facility. The type of wall to be used will be an embedded sheet pile wall, restrained by tierods to buried sheet pile anchor wall. The scope of works covered the following structures;

STRUCTURE 1: South Breakwater Berth Quay Wall
STRUCTURE 2: West Port Craft Dock
STRUCTURE 3: Tugs Jetty

Figure 2 Port of Fujairah inspecting production in ESC’s China factory

Figure 3 H Pile products ready to be shipped after completed painting works and protective wrapping put in place

The scope of the design covered;
i) Evaluation of geological data and existing site conditions to determine a range of geotechnical parameters for use in the designs.
ii) Analysis of the retaining wall and restraint system given the geotechnical parameters, site requirements and loading considerations, including seismic design.
iii) Specification and design of necessary sheet pile and tie rod components to withstand the calculated geotechnical and imposed loads
iv) Evaluation of the corrosion conditions, and design of the sheet pile system components to accommodate these conditions, including specification of protective coatings.

Figure 4 Tugs Jetty barge based installation begins using the ESC designed driving guide

Figure 5 Tugs Jetty Sheet Pile and Tie Rods complete

The British Standards were used as the basis for the design, unless specifically stated otherwise by the Engineer. These standards will include, but not be limited to the following;

Other publications that were referred to were;
PIANC – “Seismic Design Guidelines for Port Structures”
Global Seismic Hazard Assessment Program – Global Seismic Hazard Map 1999

The specific design software that was employed to assist with the Design included;
i) PLAXIS 2D – V8 Professional
Plaxis is a finite element package intended for 2D analysis of deformation, stability and groundwater flow in geotechnical engineering. Using the Plaxis package, earth and retaining wall structures can be constructed in a stage by stage approach, similar to the actual construction method.
ii) REWARD version 2.5
The REWARD program was developed in the UK by Geocentrix Ltd in association with British Steel. It is a program that uses standard earth pressure theories to calculate overturning versus restoring moments and hence determine pile lengths, bending moments and anchor loads.
iii) STRAND7
The STRAND software is a general purpose 3D finite element package, with both linear and non linear capabilities. Designed by Strand7 Pty Ltd in Australia, the software allows the accurate modelling of intricate and detailed components, with complex load applications.

Figure 6 West Port Craft Dock sheet pile installation

Evaluation of Geological Data
The purpose of this report was to evaluate the data from the soil investigations and laboratory tests and from this, determine an accurate soil profile across the project site, including the assignment of soil parameters.
The soil investigation was carried out after the commencement of the works. This soil investigation consisted of 12 boreholes specifically targeted to the zones where the works are to be carried out. The results from these boreholes were the primary source of geological information, however in the case of this project an older set of logs was available and will still be maintained and used as a reference if required.
In addition to the drilling, tests were carried out on the sand and rock fill materials to determine bulk properties.
The results of the soil tests allowed the assignment of soil parameters to the various soil types and strata. These parameters used as measured values, and were referred to as representative Soil parameters.
In certain layers, the soil parameters had to be based on experience or precedence as direct tests could not be carried out or were non representative. In this case, the recommendations of BS8002 for soil properties were followed where possible.

A considerable depth of sediment has accumulated along the coastal fringe since the Hajar Mountains were formed. With the close proximity of the sediment source and variable depositional processes, substantial lateral variation in the sediment faces is prevalent over quite short distances. In addition, there have been a number of periods of both higher and lower sea levels throughout the depositional history. Sediments have been exposed to leeching, cementation and weathering processes as well as further inundation and deposition that uncomfortably overlie the weathered surfaces.

The resulting sedimentary pile is highly variable in grain size, extent of cementation and degree of consolidation in both vertical and horizontal directions.

Figure 7 Installation at the West Port Craft Dock begins

Figure 8 West Port Craft Dock in progress

Seismic Evaluation and Considerations
Seismic design was in accordance with the PIANC document “Seismic Design Guidelines for Port Structures”, using peak ground accelarations (10% probability of exceedance in 50 years) for Fujairah in accordance with the Global Seismic Hazard Map 1999 produced by the Global Seismic Hazard Assessment Program.

Retaining Wall Design Calculations
The local stability calculations of the retaining wall were performed in accordance with the requirements of BS8002. This shall include the following criteria;
i) Determination of Design Soil Parameters
Design soil parameters are defined as the representative parameters obtained in R03 divided by a mobilization factor. This shall be applied as follows;
Design tan f’ = representative tan f’max
M
Design c’ = representative c’
M
Design cu = representative cu
M
Where M is considered the mobilization factor and will be taken as 1.2 for effective stress designs and 1.5 for total stress designs.
ii) Wall friction was taken as 2/3 of the representative f’
iii) Coefficients for active and passive earth pressures (ka and kp) were determined after Caquot and Kerisel, as given in BS8002.
iv) The standard calls for a minimum surcharge of 10kPa was applied, however the project requirements for all structures exceeded this value. Hence, the surcharge as specified by the project requirements will be followed.
v) An overdredge allowance of 300mm below the scour protection mattress was allowed.
vi) Load cases were determined to consider the combined effect of geotechnical loads, surcharge loads, live loads and seismic loads.
vii) Tidal lag was taken as the differential of MSL in the retained soil, and MLWS in front of the quay wall, in accordance with section 51.5 BS6349-1.
Analysis was performed for a variety of load cases, considering stage by stage construction and the resulting cumulative effects. Effective and total stress designs will be performed as appropriate to consider short and long term performance.

Figure 9 Capping Beam Installation begins at West Port Craft Dock

Corrosion Evaluation and Design
The corrosion rates on the sheet pile structures were taken as the upper limits in Table 25, BS6349-1. Corrosion of tierods was as per BS8002 clause 4.5.2.2.6 on the exposed lengths of rod only. Corrosion is not expected to occur in the threaded section within the couplers and turnbuckles on the tierods.
Design of all components were considered post corrosion loss. Protective coatings were applied to the sheet pile structures and the tie rods as per the requirements of the tender documents.

Figure 10 Main wall installation using a hydraulic drop hammer for the final installation to refusal

Structural Specifications for Sheet Piles

The specifications for the proposed Main Wall and the Anchor Wall piles are as follows:

Material tonnages used in the project were:

Coating Requirements

The specified coating for the sheet piles is for shot blasting followed by 2 layers of 250 micron Jotamastic 87. The coating is to be applied to the top 5.5m front and back surface for main wall; while for anchor wall , the coating is applied to whole length both sides of piles.

Figure 11 Typical Section Details for Main Wall

Design of Retaining Wall Components
The design of the sheet pile system was performed in accordance with the requirements of BS5950-1. The loads obtained from the local stability analysis (R 04) were used in the sheet pile calculations and these are considered worst case soil loads. Design structural loads were then determined by the application of a partial load factor of 1.2.
In determining required structural capacity, the full yield strength of the material was utilized. For example, the calculation for required modulus was;
Zreq = Mo . glf
fy
Where:
Zreq = modulus of section
Mo = Bending Moment from geotechnical analysis
fy = material yield strength
glf = partial load factor = 1.2
All calculations for structural capacity of the sheet pile systems were performed post corrosion loss.
The tierod system was designed based on the loads calculated in R 05. Design loads for the tie rod calculations were taken as the working loads with a factor of 2.0, or the seismic loads with a factor of 1.0, whichever is greater. All components of the tie rod system including connections and waling were designed to have to have at least the same capacity of the tierod itself. All calculations were performed post corrosion loss to the tie rod system and its components.

Figure 12 Main wall and deadman wall installation complete. Awaiting the tierods installation.

Figure 13 Tie rod installation begins

Figure 14 Now for the filling between the rods and the back fill compaction to begin in earnest

Figure 15 Sacrificial Anode for added corrosion protection

Figure 16 Final touches at South Breakwater Berths and its ready for use

Figure 17 Completed West Port Craft Dock ready to start work

Figure 18 Full length of the 1.3km main quay wall