Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)


Mechanical and Civil Engineering

First Advisor

Nakin Suksawang

Second Advisor

Ersoy Subasi

Third Advisor

Paul Cosentino

Fourth Advisor

Albert Bleakley


All the present methods of designing the slab-on-ground (SOG) are based on the flexural slab capacity (FSC) to determine the required thickness by calculating the modulus of rupture (MOR) of the concrete beam, depending on ASTM C78 or AASHTO T 97 specifications. All previous experimental results have confirmed that the MOR is much lower than the FSC and it cannot be used to predict FSC accurately. Hence, using the MOR to predict the FSC would lead to the underestimation of FSC and require more unnecessary thickness. Therefore, this study aims to develop accurate equation for estimating the FSC based on the MOR and main parameters to provide the minimum required thickness. The equation is developed using statistical procedures from more than 100 data points of SOG from previous literature. This study found that the FSC is highly sensitive to the MOR, concrete compressive strength (f′ c), SOG width(WSOG), fibers volume content (Vf ), and subgrade reaction modulus (k). Additionally, the proposed equation was compared with the most common existing MOR equation. The study found that the proposed equation was the most accurate prediction with a coefficient of variation of 40% as compared to 84% using the ACI equation and 88% using the Eurocode equation. However, the proposed FSC equation was verified by computing the required design thickness of SOG based on the TR-34 using the MOR and the proposed FSC equation. The required thickness is decreased by an average of 45% when using the proposed FSC equation compared to MOR. Thus, this study developed new design charts based on the FSC equation to determine the required SOG thickness.


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