For box column to HCwide flange) beam connections of steel structures , the column section is reinforced with diaphragms at the beam flange levels. This paper presents the analytical studies to estimate the elastic stress distribution of diaphragms using Fourier series when the connection is subject to the severe earthquake loading. The connection with eccentricity between column and beam centers is also discussed. In this paper 10 various cases where the beam connects at only one side are studied, thus any cases even where the beams connect at both sides eccentrically are estimated with simple cumulative process.
