Tests on Moment Resistant Frame Connection with Replaceable Angles

A concept of moment resistant frame structure with beam-to-column connection by replaceable angles that link the flanges of steel beams has been proposed and experimentally studied. It is expected that structural damage shall be concentrated on the angles during expected earthquakes, and the damaged angles can be easily replaced in the rehabilitation process. Meanwhile, the concrete slab above the steel beam shall develop tolerable cracks only, considering the quick recovery of the building function after an earthquake. Experimental research has been carried out with three phases, including connections of bare steel beam in a sub-structural model, connections of steel-concrete beam in a sub-structural model, and dynamic tests on frame structure model.
In this paper, a brief review of the results for the first two phases is presented, a report of the third phase study is followed, i. e., the scaled frame model with the special connection tested on shaking table is reported. The following conclusions can be drawn from the experiment. The angle design about shape and size can guarantee the deformation requirement and avoid the fracture of section, thus the angle can efficiently absorb ground motion energy before the damage of other structural members. Severe cracking or crush of concrete slab can be avoided with properly designed connection details. Quick replacement work is possible when the main structural members keep elastic or experience minor plastic deformation. The structural stiffness and resistance of the repaired frame model may recover to its status as that before damaged.