A reinforced concrete slab must be designed as _______in order to develop complete the yield line pattern

Under Reinforced Design:

• In an under reinforced design, the amount of reinforcement provided is less than the balanced reinforcement ratio.
• This ensures that the steel reinforcement yields before the concrete reaches its ultimate compressive strength. The yielding of steel reinforcement is a ductile failure, which provides ample warning before complete structural failure.
• The concept of a yield line pattern relates to the formation of plastic hinges along lines where the slab experiences maximum moments. In an under reinforced slab, the steel reinforcement reaches its yield stress first, allowing the formation of these yield lines. This enables the slab to redistribute loads and develop a collapse mechanism.
• Designing the slab to be under reinforced ensures that it can undergo significant deformation, providing a clear indication of impending failure. This ductility is crucial for safety and allows the yield line pattern to fully develop, enhancing the structural performance and load-carrying capacity of the slab.

Additional Information The different types of sections are as follows: