Two failure modes ·Compression failure At failure The reinforcements at tensile zone do not yield in tension eo<eob 5>56 E,<8y 。Tension failure At failure The reinforcements at tensile zone yield eo-eob 5<56 Es>EyTwo failure modes • Compression failure • Tension failure At failure At failure The reinforcements at tensile zone do not yield in tension e0<e0b    b The reinforcements at tensile zone yield e0>e0b    b s y    s y   