Emejulu JVT

Good day, please I'm trying to design an open spandrel concrete arch of 12.8m span and 2.456m rise supporting a 588KN concentrated load at the crown. I have analyzed the structure to obtain Inclined Reaction = 820.59KN Horizontal Thrust = 766.12KN Vertical Reaction = 294KN Max. Bending Moment = 342KNm2 I am confused on how to go about with the reinforcement design. Can anyone please point me to the right direction. arch.pdf