Compute the safe ultimate moment of a T-beam beam with a flange width 2500mm, flange thickness of 80mm, web thickness of 300mm and an overall depth of 900mm. The beam is reinforced with an unbonded tendon having an area Aps = 1000mm2 and located 80mm from the bottom fiber of the beam, fc' =35MPa. The beam has a simple span of 6m.