9416771 Anderson The research under this project will focus on experimental and analytical evaluation of two design modifications which have been suggested for welded beam to column connections. These modifications are intended for both the repair of connections which were damaged during the Northridge earthquake and for the strengthening of welded connections in new construction. Large scale beam-column components which are representative of damages during the earthquake will be considered. Cyclic testing of eight specimens having beam to column connections which are reinforced using variations of two different schemes will be carried out. The initial scheme will consider the addition of reinforcing plates to the bottom and/or top flange. The second will add a knee bracket plate (structural tee) to the bottom flange of the beam along with associated stiffener plates in the column. Parallel finite-element analytical studies of the distribution of stresses and strains in the joint region will be conducted. The nonlinear behavior of the connection model will be evaluated under equivalent static monotonic loading. These results will be calibrated against the experimental results. These studies will suggest repair procedures or design modifications for new construction to supply the moment and rotation capacity demanded by the earthquake ground motion. Recommendations for modifying the connection details so as to strengthen the connection region and avoid these types of failures will be presented. This is a Northridge Earthquake project. ***
