Koch bridge joint systems (FHWA-OK-93-08) 2716

Abstract

In July and August of 1991, The Oklahoma Department of Transportation (OOOT) had 27 KOCH BRIDGE JOINT SYSTEMS (KOCH BJS) installed on an elevated portion of 1-40, in downtown Oklahoma City. When the KOCH BJS Units were inspected in January, 1992, 9 units had cracked. By April, 1992, 12 units had cracked. ODOT often places sand and/or deicers on bridges during winter, and this type of material tends to collect in open cracks. The BJS Units were next inspected in July, 1992. During this survey, it was noted that most of the cracks observed earlier had "healed". This was thought to be due to bridge deck expansion compressing the BJS Units together and the action of the traffic on the units. Sand and small rocks could be seen compressed into the modified AC where the cracks had been located. By March 1993, 19 of the units had cracked. Several has spalls located along the outside edges of the units, or adjacent to the cracks. Two of the units had open areas completely through the BJS Units. This was considered to be a substantial failure of the units, and the evaluation was terminated.