Background
The Central Missouri project demonstrated that a Mexican builder and an American Engineering company can work together to deliver a very impressive and complex project in the U.S.A. Our team overcame language barriers and different project management styles to provide a high-quality design, procurement, and installation for the project.
Project Details
SYCSA (Silos y Camiones, S.A.), located in Pachuca, Hidalgo, Mexico was contracted by a major building product manufacturer to do a “turnkey” material handling project as a subpart of a new “green field” manufacturing plant in central Missouri, U.S.A.
The project included a 28’x196’ long structure designed to support twenty-eight silos 30’ above grade, each containing 500,000 lbs. of sand material. It also included a 260 ft. long inclined conveyor bridge from the truck and rail receiving building to the silo structure, and a 425’ long bridge from the silo structure to the manufacturing plant that carried two conveyors and had two mid span breaks in the truss geometry.
The silos were 11’-8’ in diameter by 40’ tall, and there were four in each 28’ square bay. A grid work of 11’ deep trusses constituted the supporting structure, which was quite rigid, but still undergoes small deflections due to the 2,000,000 lbs. of load that can be placed in a bay. The structure can be thought of as a seat cushion that depresses in the middle when you sit on it, and the silos can be likened to 40’ tall flag poles mounted to the seat cushion.
Consequently, the tops of the silos or flag poles will move horizontally toward the center of the bay due to the tilting of the seat cushion, or support structure, toward a low point in the middle when you sit on it, or when the silos are loaded. The horizontal movements are proportional to the vertical deflections magnified by the ratio of the height of the silos to their diameter.
The project also included a 250’ long head house that is supported on top of the silos and contains a tripper conveyor. The head house and tripper conveyor bridge extend beyond the silo structure on both ends. The connections between the silos and the head house floor structure, and the silos and the tripper conveyor bridge had to allow for the maximum potential horizontal movements of the silos, while providing anchorage for the head house to meet the building code requirements for wind and seismic loads.
The project site is located about 200 miles from the center of the New Madrid Seismic Zone, which requires some of the highest earthquake design forces in the country. This resulted in a very robust silo support structure since it has to carry 14,000,000 lbs. of material with a center of gravity 50’ above ground level under these loading conditions.
All the foundations were designed by another engineering company, but AMG was responsible for providing the loads from all the structures to the foundations, and for coordinating the location of the foundations and connections details to match the structures.
When & Why AMG Got Involved
During the spring of 2014, AMG received a phone call from the project manager of SYCSA. He was looking for an engineering company in the U.S.A. that could “review and stamp” the structural drawings for the central Missouri project.
The original plan was to have staff from a structural design company in Mexico City perform the design in AMG’s offices and under AMG’s supervision, so AMG could be responsible and stamp the design drawings. However, for the Mexico City engineering firm to do the design, it was going to take more time than was available to meet the contract milestones. It was decided that AMG should perform the structural design and stamp the drawings.
The structural shop drawings were developed by SYCSA using 3D modeling software, and all the steel fabrication and galvanizing was done in Mexico and shipped to central Missouri. AMG took total responsibility for the design of the structural connections to insure all the applicable codes were met, that the strength and the required movement capabilities of the joints were provided, and to expedite shop drawing review.
Skills/Work Delivered
SYCSA, as a general contractor, had performed several “turnkey” projects in Mexico, Central America, and South America, but nothing of the magnitude of the central Missouri project in the U.S.A.
AMG has experience with projects in Mexico, Argentina, Brazil, Honduras, etc., so it was a natural reaction to want to help a Mexican contractor succeed on this project. The project is currently in production and SYCSA/AMG believe that our joint efforts resulted in a high-quality project for the end user.