October 2010
Alsina provided the formwork equipment and technical support for the completion of several piles in this ambitious and complex project.
The construction project of the new Miami Ballpark (future stadium for the Miami Marlins) began in 2008 and will continue until 2012. This is a huge project for which Alsina was the company of choice to build several technically complex columns with two sloped faces. The stadium has been designed with two lines of tall columns on each side that will support the rails along which the metal roof structure will move (this is a retractable roof that will cover the whole stadium when necessary).
The columns consist of two distinct parts. The lower part consists of a compact unit with a cross at the base. At a particular level, this compact unit branches into three sub-columns gently curving away from each other. These branches that rise from the base of the column have a different bend angle at each level making the formwork more complex. The most critical level is precisely where the pile is divided into three branches due to a lack of space for all the necessary formwork and the peculiar form in the shape of the trunk of a pyramid. On each arm extending from the compact block, two walls are parallel and two inclined. The Alsina engineering department worked to find the optimal solution in record time to shape the four super-columns of the north and south sides using the new single face climbing system (T1C).
The aim was to reach an average height of approximately 46 meters in 9 sections of concrete. The project is complex in that the structure is divided into sub-columns that, besides having to bear the horizontal load from concrete and absorbed by the DYWIDAG bars, the climbing system also had to withstand its own vertical loads. Likewise, there were additional considerations unique to the area: Florida is an area regularly hit by tropical storms and hurricanes and so special elements are required and must be taken into account to ensure that the structures in question can withstand the forces exerted by these weather phenomena.
To successfully build the steep walls, Alsina decided to use their universal Alisply formwork system (supporting up to 100 KN/m2 of pressure). To withstand the lateral pressure, the Alisply is completely joined from end to end on opposite sides with DYWIDAG bars made from high strength steel beams which are joined in turn to the climbing system using strong struts to counter the reaction to the weight of concrete.
The surface finish had to trace a continuous curve as detailed in the construction plan provided by the project manager. This curved shape was obtained by screwing wood slats designed with the desired curvature to the panels and then nailing phenolic coated plywood on this surface for a perfect finish. Each level requires a different curvature and so the Alsina engineering department worked intensively to generate the geometry of the curves pertaining to the various heights of the columns for each level.
Besides a different curvature, each level also had a different slope on the wall, requiring adjustment of the work platform horizontal line of the system each time it moves up a level. The geometry of the structure complicated efforts to place the climbing system elements at a height so that they did not touch each other. The Alsina engineering department designed a 3D virtual model of the structure in order to understand the situation of each level. This analysis showed that the problem became even more complex when the columns separated, and that as they separated more climbing platforms were required and thus the platforms were more likely to touch. The project began with 8 platforms and finished with 12 climbing consoles at the highest levels. Thanks to its high compensation capacity, the system was used to execute each of the levels quickly and efficiently.
These four columns were finished in three and a half months. All the formwork was done simultaneously with eight formwork teams divided into two shifts of 6 hours each. The project was carried out according to all safety standards, including the Alsina Alsipercha system, to avoid long fall risk. The efficient design of the security plan prevented accidents throughout the project and had no impact on working time.
