Optimal Design of Bubble Deck Concrete Slabs: Serviceability Limit State

Area of Science:

• Structural Engineering
• Optimization Methods
• Materials Science

Background:

• Traditional optimization methods struggle with structures like bubble deck slabs due to non-uniform flexural stiffness.
• Bubble deck slabs utilize air cavities to reduce dead weight, complicating structural analysis and optimization.
• Standard finite element analysis using plate or shell elements is not suitable for these complex geometries.

Purpose of the Study:

• To develop an effective procedure for minimizing the weight of bubble deck slabs.
• To address the challenges in optimizing structures with variable cross-sectional stiffness.
• To achieve material savings while ensuring structural serviceability.

Main Methods:

• Numerical homogenization was employed to determine effective stiffnesses of the bubble deck slabs.
• Sequential quadratic programming with constraints was used for the optimization process.
• Iterative correction of geometrical parameters (slab and voids) to meet deflection criteria.

Main Results:

• A significant reduction in concrete weight (approximately 23%) was achieved compared to the initial design.
• The optimization procedure successfully met the serviceability limit state requirements for deflection.
• The method provides a quick and effective way to minimize material consumption in bubble deck slabs.

Conclusions:

• The proposed optimization procedure, combining numerical homogenization and sequential quadratic programming, is effective for bubble deck slabs.
• This approach enables substantial material savings without compromising structural performance.
• The study demonstrates a viable method for optimizing complex structural elements with variable stiffness.