Q1: According to the steel beam theory of doubly reinforced beams

ANS:E - all the above.

1. Tension is resisted by tension steel: Tension steel, also known as the bottom reinforcement, is placed in the tension zone of the beam to resist tensile forces resulting from applied loads. It provides the necessary tensile strength to counteract the bending moment and prevent the beam from failing in tension.
2. Compression is resisted by compression steel: Compression steel, also known as the top reinforcement, is placed in the compression zone of the beam to resist compressive forces resulting from applied loads. It helps enhance the compression capacity of the beam and prevent premature failure due to compression.
3. Stress in tension steel equals the stress in compression steel: In doubly reinforced beams, it's common for the tensile and compressive stresses in the tension and compression steel to be equal, assuming linear elastic behavior. This balance of stresses ensures that both types of reinforcement contribute proportionally to the overall strength and stability of the beam.
4. No stress is developed in compression concrete as well as in tension concrete: This statement is incorrect. In doubly reinforced beams, both tension and compression concrete experience stresses due to bending. The tension concrete (located below the neutral axis) experiences tensile stresses, while the compression concrete (located above the neutral axis) experiences compressive stresses. These stresses develop to resist the bending moment applied to the beam.