Deflection Estimation Model for Prestressed Concrete Slabs with Plastic Inserts Forming Voids.

Area of Science:

• Civil Engineering
• Structural Engineering
• Materials Science

Background:

• Voided slabs with plastic inserts, patented over 30 years ago, are globally adopted for cost-effective construction.
• Experimental data indicates voided slabs exhibit similar bending behavior to solid slabs, albeit with slightly reduced deflection and crack resistance.
• Pre-tensioned reinforcement enhances voided slab performance, surpassing solid slabs in deflection and crack resistance.

Purpose of the Study:

• To investigate the influence of internal voids, formed by plastic inserts, on the deflection of prestressed concrete slabs.
• To address the challenge of calculating the moment-of-inertia for slabs with variable cross-sections due to plastic inserts.
• To compare experimental, numerical, and analytical results for voided slab behavior.

Main Methods:

• Conducted bending tests on two full-scale reinforced concrete slabs.
• Developed a numerical model to simulate slab behavior under load.
• Performed analytical calculations to determine slab stiffness and moment-of-inertia.

Main Results:

• Experimental results were compared against numerical and analytical predictions.
• The study focused on quantifying the impact of voids on prestressed concrete slab deflection.
• Analysis addressed the complexities of variable cross-sections in stiffness calculations.

Conclusions:

• Voided slabs offer significant cost benefits in construction.
• Prestressed voided slabs can outperform solid slabs in terms of deflection and crack resistance.
• Accurate estimation of the moment-of-inertia is crucial for analyzing voided slabs with variable cross-sections.