The importance of welded connections on the behavior of steel moment resisting frames was the reason of researchers focus on welding details. In this paper result on 32 pilot tests indicate moment connection behavior are presented. In this experimental research, in order to connection strength evaluation, complete joint penetration (cjp) weld strength with different welding procedure, double side fillet weld out of plane strength, one side fillet weld out of plane strength and amperage intensity effect on welding quality, have been studied. Also in order to connection rehabilitation, rib stiffener effect on connection strength, T-stiffener effect on connection strength, electrode toughness effect on welding quality and grinding and rewelding effect on welding quality have been studied. Maximum strength of cjp weld is observed in welding with backing. Out of plane strength of double side and on side fillet weld have been determined. Connection strength increase amount with stiffener strengthening of connection have been proposed. It has also been proposed constructional recommendations about electrode toughness, rewelding and amperage intensity.