Accounting for the Flexibility of Beam-Column Joints within New Zealand Steel Moment-Resisting Frame Structures

Abstract

In New Zealand there currently appears to be no simplified, effective method of analysing the rotational stiffness of beam-column joints in steel moment resisting frame structures. Many practicing engineers use simplified design tables to detail beam-column joints for strength requirements, without accounting for the flexibility of joints. This tends to underestimate the flexibility of structures and hence the drifts they undergo in wind and earthquake events. To permit improved consideration of beam-column joint stiffness in a simplified manner, this work adapts the European component method to develop a series of tables that practitioners could look up to quickly identify beam-column joint stiffness values. The potential use for such stiffness values is highlighted by examining the impact of joint flexibility on the drifts expected in a 4-storey steel MRF subject to 1 in 500 year return period earthquake loading.