The Port of Miami (POM, Seaport) is currently partnering with the US Army Corp of Engineers to widen anddeepen its harbor. As such, the Port is working with consultants to strengthen its existing container wharves to accommodate wider and deeper vessels. The futuredredge depth of -50′ MLW is eight feet deeper than the design dredge elevation of the existing wharves. These facilities need to be made compatible with future conditions. As the Cruise Capital of the World and Cargo Gateway of the Americas, POM is a vital contributor to the local, state and national economies. The Port has a total economic impact of more than USD17 billion a year and generates more than 176,000 jobs. The Port serves approximately 20 shipping lines that call on more than 100 countries and 250 ports across the world, serving the markets of Asia, the Caribbean, Central America, Europe, the Middle East, North America and South America. 2009 saw Miami handling over 800,000 TEU (twenty-foot equivalent units), ranking eleventh among US ports. In order to maintain this position and grow market share the Port continues to implement and revise its 25-year master plan. POM astutely recognises that the global trend for growth in container shipping, combined with the Panama Canal enlargement project, will bring growth opportunities to whichever eastern US ports are ready to receive the larger canal vessels and to throughput the higher container volume. POM is therefore taking the necessary measures to remain aggressive in the marketplace and to win a proportional market share of the potential post canal enlargement traffic. There are ongoing and planned projects for enhancing the intermodal transport of cargo from the Port and into the highway and rail infrastructure. Additionally, there are terminal specific and wharf-side limitations which must also be addressed to ready the port for the future traffic; these may be defined primarily in three interrelated elements:
Infrastructure challenges
Container handling equipment (i.e. ship-to-shore cranes) must be of sufficient size and speed to economically interact with the various classes of container ships that call on the port, and the physical infrastructure on which the cranes reside must be adequate to meet the high demands due to these large mechanical structures. Wharf front structures must have sufficient capacity to resist mooring forces imposed by various classes of container ships and harbor traffic. The structural systems themselves must resist environmental loads and provide the required service life (i.e. corrosion protection and structural durability). Shipping channel and berthing areas must have sufficient width and depth to accommodate the largest container ships anticipated to call on the port in the future. To address the last of those limitations, Phase II of the Port of Miami Harbor Dredging Project was completed in June 2006. It involved the deepening of the South Channel and the Central Turning Basin from -34-ft to -42-ft NGVD 29 (hereafter also referred to as NGVD) and included maintenance dredging of all berthing areas. Phase III of the Port of Miami Harbor Dredging Project, scheduled to commence in Spring 2012, involves deepening Fisherman’s Channel and the Central Turning Basin to -50-ft MLLW (approximately -52.74 NGVD), the Entrance Channel and Government Cut to -52-ft, and widening the South Channel by 100 feet, inclusive of expanding the berthing area from 106-ft to 160-ft. Beginning in spring 2012, the US Army Corps of Engineers will begin a dredging project to deepen the approaches and harbor at the Port. At Cargo Wharves I-VII, the alongside channel (Fisherman’s Channel) will be deepened to 50 feet with an additional 2 feet of over-dredge allowance. The existing structures vary in age, condition, and detail, and were designed to accommodate various alongside depths ranging from 42 feet to 46 feet. HDR was tasked with evaluating and strengthening the existing structures for the future dredge. Preparation of construction contract documents concluded in October 2010; construction is currently planned to begin in June 2011. The purpose of this project is to strengthen existing container wharves I-VII (approximately 5,940-ft of existing wharf frontage) to accommodate the planned USACE dredging. Specifically, the structures must be strengthened to provide sufficient toe depth, anchorage, and structural capacity to withstand the deeper dredge depth and the resulting soil pressures, wall stresses, and stability issues thereby imposed. Additionally, the strengthened structures were analyzed with respect to the higher berthing and mooring forces that will result from larger vessels calling at the port. Structures will be modified to withstand these forces or, depending on available construction budget, were designed for compatibility with future recommended modifications to be implemented in advance of the arrival of these larger vessels. The project design anticipated and provided for compatibility with future known upgrade projects that will be necessary for accommodating larger vessels. These include updating crane rail foundations for larger outreach cranes and replacement of fenders. Finished construction will reduce, to the extent possible, the overall impact to crane operational outreach. POM’s preference would be to retain 22-container-wide operating ability at the two (2) existing and two (2) planned future Super Post-Panamax cranes; POM would like to service the interim vessel (13-container-wide to 15-container-wide) at all nine (9) existing cranes, including the seven (7) Post-Panamax cranes. Fender replacement and other modifications (crane outreach extension, crane rail relocation,etc.) may be necessary to facilitate these goals, and are not part of the current project. The following design criteria were critical to POM: Chart 2
Due to the number of interdependent criteria, feasible alternatives were first developed to focus on the minimum structural and operational requirements (structure type and condition, required structural enhancements, and crane outreach). These were then further reduced or modified with the goal of achieving efficiency in the construction schedule and in reducing cost. Ultimately, three primary groupings were considered based on differing structure type and condition and on varying soils conditions. These were: Wharf I; Wharves I Extension and II-V (of which IV Extension and V are a subset); and Wharves VI and VII. HDR employed a cyclical development and review process to ensure that, for each structure group, viable alternatives were identified and sufficiently advanced to provide consistent solutions across differing structure types while still addressing unique requirements or opportunities for each. Included in the review process were: analysis and grouping of similar conditions; concept development; analysis of construction risk, production rates, and cost; consideration of the impact to wharf operations; and assessment of potential permitting requirements and difficulty. For each structure group, a maximum of four alternatives were retained. Included in these were at least one alternative to minimize or avoid impacts to crane outreach, and one alternative intended to minimise cost and reduce construction schedule. Relative opinions of cost and schedule were developed for each retained alternative.
Chart 3
Alternatives were further investigated to determine construction methods and details conducive to cost and schedule control. This included consideration of piling types and installation methods, supplemental anchor types and installation methods, cap replacement or re-use, etc. Once structure specific alternatives were identified, comprehensive solutions were developed by combining these and again performing a cyclical development and review procedure. These reviews were holistic in nature, based on identifying costs and schedule impacts and for refining details necessary to achieve compatibility (for example, maintaining a uniform berthing line). Five comprehensive solutions were identified
with the input of POM staff. A number of additional combinations were possible, though the presented alternatives included solutions for maintaining existing crane outreach, for minimizing overall construction schedule, and for achieving lowest cost, in addition to the more desirable structural solutions. For each comprehensive solution, opinions of cost and schedule were again developed by building from the individual structure specific alternatives. These were modified to reflect predicted construction phasing, anticipated production rates, and related mobilisation. At this conceptual phase, primary emphasis was placed on quantifying primary cost and schedule drivers in order to provide a relative comparison of options. Following the 60% completion milestone for design alternatives, HDR presented its findings to POM and its VE Team. The VE team was selected by POM and was comprised of POM staff, stakeholders, and external third-party consultants. The presentation included a summary of work to-date, key findings and assumptions, project requirements and constraints, and presented the individual and comprehensive alternatives in terms of pros/cons, cost, and schedule. Upon completion of its internal review process, the VE Team provided a recommendation for “best value alternative” as follows:
WHARF SELECTED ALTERNATIVE Chart 4
Based on the VE Team’s recommendation, the best value alternative was advanced during detailed design. The overall process involved in planning, analyzing, and designing upgrades for existing port facilities is complex and consultants need to have an understanding of what is involved when assisting a Port to prepare for larger vessels. The wharf strengthening project underway at POM’s fully developed and operating cargo terminals can be used for general guidance by consultants and Ports when determining upgrades and improvements needed to accommodate the anticipated increase in activity after the Panama Canal expansion is completed. Outlined is the partnering process followed with the Port to develop workable solutions for upgrading its facility while minimizing cost and operational interruptions. As Ports plan and prepare for future operational requirements, it is essential that they understand how to utilise their existing structures and facilities prior to paying the higher cost of constructing new ones. The strengthening project performed at the Port of Miami is emblematic of projects that will need to be performed at ports along the east and gulf coasts of the United States in preparation of the Panama Canal expansion.
This paper was presented by Frank Proctor, HDR Engineering Inc, at the Port & Terminal Technology Conference held in Long Beach, California in October 2010. Contributers: Wes Dortch, HDR Engineering Inc; Kevin E Matakis HDR Engineering Inc; Elizabeth Ogden, Port of Miami; Leonor Ortega, Port of Miami; Becky Hope, Port of Miami.