ITALIAN ENGINEER AND ALGOR’S FINITE ELEMENT ANALYSIS SOFTWARE MAKE A SPLASH IN DESIGN OF DIVING PLATFORM

At 20 years old, the Olympic-sized swimming pool in Colle Val d’Elsa, Toscana, Italy, needed a makeover before it would be ready to become the new host of the annual Italian Dive Championships. Among the updates and renovations planned by Colle Val d’Elsa officials to spruce up the facility was a new four-tier diving platform. The city solicited the expertise of Italian engineer Guccio Galluzzi of Firenze to design a safe, strong, economic and aesthetically pleasant diving structure. Galluzzi associate and civil engineer Giorgio Morelli was chosen to optimize the platform design using FEA software. “I decided to use ALGOR software for linear static and dynamic stress analyses, as well as natural frequency analysis because I find the software highly reliable and it provides so many possible analysis types,” Morelli said. To design and test the diving platform structure, Morelli took advantage of ALGOR’s vibration analysis capability to perform a natural frequency analysis on the springboard structure. He built the structure with ALGOR’s composite material model. Morelli used composite plate/shell elements created with Superdraw III, ALGOR’s precision finite element model-building tool, to design a model of the diving structure’s four tiers. Each tier – at 3 meters, 5 meters, 7.5 meters and 10 meters – was a platform composed of concrete on a metal frame extending from concrete, rectangular columns. Morelli used beam elements to represent cantilevered platform supports connecting the four platforms to the towers.

Swimmers and divers enjoy the Olympic-sized swimming pool and world class platform diving tower in Colle Val d’Elsa in Toscana, Italy. The diving structure, designed by engineer Guccio Galluzzi and built for the Italian Dive Championships, was analyzed for structural stability using ALGOR, Inc.’s finite element analysis software. Engineer Giorgio Morelli used ALGOR to determine the strength and stability of the concrete and steel platforms, the concrete towers and the steel support beams.

After drawing the tower and platform geometry, Morelli defined the material properties of his elements as concrete and steel. He referred to the Italian Rules and Laws for Civil Construction to determine how the materials would behave under expected loading and stresses. Then he applied boundary conditions to fully constrain the base of the tower to the ground.

With the geometry, material models and boundary conditions in place, Morelli applied loading for analysis in three load cases to determine whether the tower and platforms would hold up to the rigors of a national championship competition.

The first case represented the weight of the diving structure and the uniformly distributed load of 100 kg/m applied along the axis of each platform. For the second load case, Morelli applied a nodal force to the end of the highest platform to represent the weight of a diver. The third load case represented the tower with a dead load to determine the allowable natural frequency of the structure under the stress of divers.

For the natural frequency analysis, Morelli analyzed each tower without platforms, each tower with platforms and each platform individually. The natural frequencies for each had much greater values than the critical value of resonance created by the divers.

After running the linear static stress and natural frequency analyses, Morelli viewed the results using ALGOR’s built-in visualization tools.

“The linear static stress results revealed that the stresses in the beam elements were greater than the determined allowable values,” Morelli said. “I improved the cross section of these tubular supports to strengthen them and reduce stresses.”

With that problem out of the way, the subsequent analyses were more favorable for Morelli. After looking at the analysis results of the optimized geometry, he found that, in the first load case, the stresses were less than the allowable stresses for both the steel and concrete components and, in the second load case, the displacement caused by the diver was less than the allowable 0.1 cm as defined by the Italian Swimming Federation.

Morelli said the Italian Swimming Federation verified his findings by testing the structure once it was built. Because of the federation’s testing and his confidence in ALGOR, Morelli was able to avoid physical prototype testing.

Morelli used ALGOR software to perform a linear static stress analysis through which he determined that the weight of a diver on the end of the dive platforms would not exceed the allowable displacement as defined by the Italian Swimming Federation.

Based on Morelli’s analyses, the city of Colle Val d’Elsa had a strong, attractive and economical diving structure that was a success during the 1998 and 1999 Italian Diving Championships, and will be tested again with the summer 2000 championships.

Morelli has extensive experience with finite element analysis, including his work designing optimal designs for such products as jet engine test facilities, fuel tanks, bridge cranes and roofs for a swimming pool and a sports facility. Morelli said he uses ALGOR software for finite element analyses of his designs because of ALGOR’s successful international track record. He is using ALGOR to verify for Galluzzi the structure of the roof of a swimming pool, which also was designed by Galluzzi, near the diving structure in Colle Val d’Elsa.