Compression strength of aged built-up column with vanished lacing bars

Recently, Japanese aged built-up members have lost their lacing bars due to corrosion. However, remaining strength of the built-up column with vanished lacing bars has not been clarified yet. In addition, residual stress of channel shaped steel which consists built-up column has not made sufficiently clear. The authors measured residual stress distribution of channel shaped steel, which was removed from an aged steel truss bridge. Moreover, the authors numerically calculated ultimate behavior of the built-up column with vanished lacing bars using finite element method. As a result, it is found that residual stress magnitude of the channel shaped steel is small compared to that of welded member, vanishment of lacing bars does not cause significant reduction of the compression strength and column strength curve given in Japan Specifications for Highway Bridges can be used to estimate its remaining strength conservatively.