This paper presents results of full-scale tests conducted to evaluate deformation capacity, failure mode and possible effective retrofit of welded beam-to-column connection adopted in moment frames for early high-rise buildings around 1970s. Test specimens are designed and fabricated to retrofit the moment connections in the 1970s by strengthening of the web connections and improvement of welding detail according to the latest practice. Loading tests are conducted by the cyclic loading protocol to simulate the response of frames subjected to long-period ground motions. The test results are compared with the results on original connections and the effectiveness of the strengthened web-joints on deformation capacity is revealed. The obtained capacity of specimens satisfied deformation demand predicted by numerical response analysis.
