OBJECTIVE Within the framework of the “Field Engineering Service for the Yarigüí Development Project – Auxiliary Station / Island VI” project, owned by Ecopetrol, the construction of the TK-750 tank for the auxiliary station is planned. With a capacity of 6,227 barrels, a diameter of 10.67 m, and a total height of 10.97 m, the tank foundation must be designed to support a load of 1,100 tons. The foundation design presents an engineering challenge, given the complex geological and geotechnical environment of the project site. Additionally, because it is an existing oil infrastructure, there are multiple limitations in terms of space and constructability, which challenge conventional foundation methodologies due to the limited maneuverability of the oversized equipment required for the construction of these foundations.
SOLUCIÓN CONVENCIONAL
Due to the high load magnitudes and the geotechnical deficiencies of the soil, an array of 30 piles constructed from 12-inch diameter galvanized steel pipe, driven to a depth of 30 m, was initially planned. Because of their configuration and the low efficiency at the soil-pile interface, their load-bearing capacity was insufficient, and therefore it was necessary to significantly increase their length to improve their frictional capacity.
SOLUTION IN HELICAL PILES
Thanks to excellent engineering work, the proposal was reformulated. Considering all possible critical load scenarios based on 78 helical piles, each 15 meters long and designed for an ultimate load of 45 tons, a more efficient solution was achieved for the foundation challenge of the TK-750 tank. With a more redundant model and an external curtain of inclined piles, it is possible to meet the critical design demands while guaranteeing regulatory safety factors.
LOAD TESTS
As part of our quality assurance policy, at Axiatech we conduct load tests on all our projects, allowing us to guarantee our value engineering. At the start of the installation process, we performed a production load test on one of the system’s piles, following the guidelines of ASTM D3689. The pile was subjected to its service load (23.3 tons) under the most critical load scenario, resulting in a deformation of 9.1 mm at a rate of 0.022 inches/ton. This result allows us to guarantee a safety factor of 2.26 for the project, 11.5% higher than the estimate provided in the engineering analyses.
Helical piles are the ideal solution for foundations of fluid storage tanks…
