Retrofit effects for H-beam-to-RHS column connections - Study on Seismic Retrofit of Beam-to-column connection Using Supplemental H-section Haunches Part 3

This paper examines applicability of proposed retrofit method using H-section haunch to H-beam-to-RHS column connections. When using RHS column, it is concerned that force transfer capacity of supplemental haunch is significantly affected by detailing of the connection between the haunch and column. In particular, when the haunch directly connect to column face without diaphragm, namely, non-diaphragm connection, it is necessary that the requirement for strength of column-to-haunch connection must be revealed to achieve the satisfactory retrofit performance. For this purpose, the design strength formulae were derived through the limit analysis based on upper bound theorem approach. In order to investigate the effect of detailing of column-to-haunch connection on retrofit performance, cyclic loading tests and FEA were performed. From the test and numerical results, local yielding of column-to-haunch connection caused contribution of haunches to plateau and consequently resulted in rupture of original beam flange at the beam end. Retrofit specimen which had sufficient local strength in column-to-haunch connection could prevent the fracture of original beam end and exhibited satisfactory performance.