Abstract
The utilization of hidden beams in large span reinforced concrete slab construction has gained attention as a potential solution to mitigate excessive deflection. However, the absence of explicit mention in standard civil engineering literature, codes, and standards raises questions regarding its effectiveness. This paper presents a performance-based analysis of two different cases of slab arrangements involving hidden beams, employing REVIT and ROBOT Structure software. The analysis considers dead and live load combinations in accordance with the design guidelines specified in BS8110. The results of the performance-based analysis demonstrate a significant 10% reduction in the span moment for slabs incorporating hidden beams, indicating their potential to reduce deflection. However, the differences observed in terms of support moment, deflection, and stress patterns within the slabs are not significant. These findings suggest that the presence of hidden beams yields only a slight but meaningful impact on reducing deflection. Considering the observed benefits, it is recommended to cautiously consider the use of hidden beams in large slab construction projects. However, additional research and analysis are necessary to assess other factors such as specific project requirements, cost implications, structural integrity, and construction feasibility. Further investigations should encompass a broader range of parameters, including different load combinations, variations in hidden beam width, and comprehensive cost analysis. By conducting thorough evaluations, a more comprehensive understanding of the effectiveness and feasibility of hidden beams in reducing deflection in large slab construction can be obtained, facilitating informed decision-making regarding their utilization.

Key words: Deflection, Hidden beam, Performance, and Reinforced concrete slab