Abstract
Purpose
This paper aims to investigate and assess a perspective of combining high-strength-steel endplate with mild-steel beam and column in endplate connections.

Design/methodology/approach
First, experimental tests on high strength steel endplate connections were conducted at fire temperature 550°C and at an ambient temperature for reference.

Findings
The moment-rotation characteristic, rotation capacity and failure mode of high-strength-steel endplate connections in fire and at an ambient temperature were obtained through tests and compared with those of mild-steel endplate connections. Further, the provisions of Eurocode 3 were validated with test results. Moreover, the numerical study was carried out via ABAQUS and verified against the experimental results.

Originality/value
It is found that a thinner high-strength-steel endplate can enhance the connection’s rotation capacity both at an ambient temperature and in fire (which guarantees the safety of an entire structure) and simultaneously achieve almost the same moment resistance with a mild steel endplate connection.