The shortlist for RIBA's Stirling Award for the UK's best building will be chosen from 49 national winners.
The buildings range from private homes to public institutions, such as the City of Glasgow College's City Campus.
RIBA president Jane Duncan described the list as a "roll-call of phenomenal buildings".
The RIBA National Awards are given to buildings across the UK recognised as having made a significant contribution to architecture.
RIBA said BA i360 was a modern-day vertical pier, inviting visitors to 'walk on air' and gain a new perspective of Brighton, just as the original pier welcomed Victorian society to "walk on water".
This new shopping arcade is, according to RIBA, a celebration of the opulent glitter of consumer society with its cathedral-like scale.
RIBA described the new plant as "striking" and said it was a truly sustainable project which celebrated Sheffield's industrial past and present.
RIBA said the immense scale of the building signals it is an important place of learning but said the internal spaces encouraged both formal teaching and "informal, more chance encounters".
The redesign of the cathedral's interior had to be altered to include a new memorial and tomb to Richard III after his remains were found under a nearby car park. RIBA praised the design of the new altar and the King's simple tomb behind it.
The building adds new galleries and performance spaces and RIBA said it allows the curatorial staff almost complete freedom in displaying art.
The judges said The Word was a "happy uplifting place" which caters for all and represented a significant stage in the development of the modern public library.
A full list of the winning buildings can be found here.
A biomass power plant, a cathedral and a library are among the winners of the 2017 Royal Institute of British Architects (RIBA) awards.