1. A REMOVABLE SUPPORT STRUCTURE FOR USE IN PRODUCING OVERHANGING PORTIONS OF A BRIDGE CONSTRUCTION OR THE LIKE PROJECTING OUTWARDLY OF AN I-BEAM SUPPORTING GIRDER COMPRISING, A POST ADAPTED FOR ORIENTATION BETWEEN THE UPPER AND LOWER FLANGES OF THE BRIDGE GIRDER, MEANS FOR SELECTIVELY VARYING THE LENGTH OF SAID POST, A BRACKET PIVOTALLY ATTACHED TO THE UPPER END OF SAID POST AND ADAPTED FOR ENGAGEMENT WITH THE UNDERSIDE OF THE UPPER FLANGE OF THE BRIDGE GIRDER, A SUPPORT ARM CONNECTED TO SAID BRACKET AND EXTENDING GENERALLY HORIZONTALLY OUTWARDLY FROM SAID POST, A BRACING MEMBER EXTENDING BETWEEN SAID SUPPORT ARM AND SAID POST, MEANS ON SAID BRACING MEMBER FOR SELECTIVELY VARYING THE LENGTH OF SAID BRACING MEMBER, AN ELONGATED NAILER MEMBER MOUNTED ON SAID ARM AND EXTENDING IN THE SAME GENERAL DIRECTION AS SAID ARM, MEANS LOOSELY CONNECTING SAID NAILER MEMBER TO SAID ARM FOR PROVIDING FOR LIMITED VERTICAL MOVEMENT OF SAID NAILER MEMBER WITH RESPECT TO SAID ARM, SLIDER MEANS ON SAID ARM, SAID SLIDER MEANS INCLUDING WEDGE MEANS ADAPTED FOR LIFTING COACTION WITH COMPLEMENTARY WEDGE MEANS ON SAID NAILER MEMBER UPON PREDETERMINED LENGTHWISE MOVEMENT OF SAID SLIDER MEMBER, AND MEANS ON SAID SLIDER MEMBER FOR CAUSING LENGTHWISE MOVEMENT THEREOF.