Zhaozhou Bridge (Photo/State Administration of Cultural Heritage)

SHIJIAZHUANG, Aug. 31 -- More than 30 relics from China's oldest stone arch bridge have been repaired, the first time such work has been undertaken on it.

The items, from Zhaozhou Bridge, are mostly sections of the bridge guardrail.

Also known as Anji Bridge, it stands over the Xiaohe River in Zhaoxian county, north China's Hebei Province. It was built in the Sui Dynasty (581 - 618) and is world's oldest open-spandrel segmental stone arch bridge.

"During past centuries, the guardrail had fallen into the river," said Li Jinshuan, former head of the Zhaoxian cultural relics preservation office. The current guardrail is a replica made in the 1950s.

Since the 1950s, archaeologists have retrieved more than 1,000 pieces of guardrail from the river, which were made during many dynasties from the Sui to Qing (1644 - 1911).

In April 2014, archaeologists started to repair 30 pieces, cleaning and reinforcing them.

Liang Shutai, an associate research fellow with the Hebei cultural relics preservation center, said that one piece had been broken into 260 fragments, and six people had spent seven days piecing it together.

The repaired relics will be exhibited to the public.