Spreading the Load a Maccaferri Project Story from Port of Guaymas, Mexico
The Port of Guaymas functions as a shipping, manufacturing, commercial and tourism centre. It lies on the shores of the Gulf of California on the Pacific Ocean, in the southwestern area of the state of Sonora, in north-western Mexico.
Its major exports include sulfuric acid, copper, wheat, and other crops grown in the region. It is currently the fastest growing seaport in Mexico and planned expansions will extend the port into the bay between Guaymas and neighbouring Empalme.
In 2013, the first of a two phase port expansion plan was approved to meet the growing demand for containerised cargo handling, in addition to the port’s traditional markets of agricultural and mineral bulk.
This first phase of expansion consisted of dredging of the seabed and the construction of ten terminals. The second phase of construction consisted of a new container terminal and multi-use terminal.
Whenever construction is carried out upon soft or unstable ground, there is the possibility of differential settlement or collapse. This risk was evident at Guaymas beneath the pavements and loading areas in the port storage area.
Soft foundation soils have always been a challenge to geotechnical engineers and typical solutions such as phased construction, excavation/replacement or grouting are often used.
More recently, the use of geosynthetic materials to form basal reinforcement to construct platforms is becoming increasingly popular to spread the loads upon the existing ground.
The performance of the platform was dramatically enhanced by the introduction of high-strength ParaLink® geogrids, inserted in layers within the construction layers. The Paralink® absorbs, spreads and dissipates the loads from above, reducing the risk of differential settlement of the soft soils beneath. The geogrid must develop high tensile resistance at low strains, and offer minimal creep over its long design life.
The use of ParaLink® provided a cost effective and simple to install alternative to the expensive options of excavation / replacement of unsuitable foundation material, or a staged construction approach. Reducing the import of quality fills, and the export of waste excavated materials also reduces the quantity of vehicle movements on local roads, reducing the environmental impact of the solution.
Bidirectional geogrids are impractical in basal platforms as the bond length required between adjacent rolls to maintain transverse tensile resistance, is often greater than the width of the roll being laid. Therefore two layers of unidirectional geogrids, laid perpendicular to each other, is more technically and cost efficient.
ParaLink® geogrids are unique planar structures consisting of a mono-axial array of high strength composite geosynthetic strips. Each longitudinal strip has a core of low creep polyester yarn, encased in a tough polyethylene sheathing. When installed it provides ultra-high unidirectional strength in soil reinforcement. At Port of Guaymas 600 and 400 kN/m strength geogrids were supplied.
Listening to, and understanding our client’s challenges, enabled us to optimise our solution and provide them with a solution which was easier and faster to install compared to similar products by our competitors. It was also more cost effective.
Construction and Materials
More than 28,000 m2 of ParaLink® was laid in four layers with a depth of 1.2m of granular material. The final layer was the pavement construction / loading area slab.
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