1st Major Renovation Planned For Japan's 90-Yr-Old Parliament Building

TOKYO, May 3 (Bernama-Kyodo) -- Japan's iconic legislative building in the heart of the capital is set to undergo its first major renovation since being built 90 years ago, amid concerns over its safety in the earthquake-prone nation, Kyodo News reported.

Construction work at the National Diet Building will begin in fiscal 2030 and continue for some eight years, with its historically valuable interiors and exteriors expected to be preserved while minimising disruption to parliamentary proceedings when the Diet is in session.

The project is currently in the detailed planning stage and is estimated to cost 60 to 70 billion yen (US$382 to US$446 million) with the potential to increase as material costs have surged in recent years.

The renovation will see the building fitted with a seismic isolation layer below its foundations, a method that will allow it to remain in use during the construction work.

The National Diet Building was completed in 1936 after some 17 years of construction, with its pyramid-shaped roof and granite facade. It served as the seat of the Imperial Diet before the current Diet system was established under the post-World War II Constitution.

Constructed from reinforced concrete, the building, with three storeys above ground and one basement level, has a total floor area of about 53,460 square metres and contains the chambers for both the House of Representatives and the House of Councillors.

The nine-storey central tower with its pyramid-shaped dome is about 65 metres high, and the hall underneath has its windows and ceiling decorated with stained glass. A room used to receive the emperor when he visits the Diet is made entirely from Japanese cypress, finished with fine lacquer.

An inspection of the structure in 1981 found the building conformed with quake resistance standards that had been updated around that time.

But a new checkup was carried out after an expert panel established by parliament raised concerns over the ageing structure in 2019.

A report compiled in 2023 warned of risks of falling objects because of warping in steel frames of the central tower and legislative chambers. It recommended a renovation plan to enhance the structure's seismic resilience.

"Even if a major earthquake strikes directly beneath the capital, we must maintain core political functions," an official at the lower house's office said.

-- BERNAMA-KYODO