Title: A New Generation of APJ Design: the Cold Plug Joint
Author(s): Richard J. Baker and BruceE W. Adams
Publication: Symposium Paper
Appears on pages(s): 353-364
Keywords: bridge decks; bridges (structures); control joints; expansion; joints (junctions); Design
Bridge expansion joint systems perform three primary functions. The first function is to provide the designed and desired expansion/contraction movement while handling all necessary harsh climatic and traffic conditions. The second function is to provide a watertight joint to eliminate water and chlorides from gaining access to the deck and bridge substructure. The third function is to provide a smooth riding surface to eliminate undesirable stresses from traffic loading. Materials commonly used in the manufacture of expansion joint systems include steel, aluminum, and neoprene. Improvements in technology and new design methods have resulted in several innovative nonmetallic, nonrubber bridge expansion joints. The mini-plug system consists of three main components: a mild steel plate to bridge the expansion gap, 1/2 to 3/4 in. mixed double crushed granite aggregate, and a special two component polymer binder material. This system has the advantages of an asphaltic plug type joint, small movement range, smooth and flat to the existing surface, while reducing the required blockout width and eliminating most of the required equipment. This system is installed at ambient temperatures. The major advantage of this system is its capability of installation in small (6 to 12 in.) blockouts, substantially reducing material requirements. This also reduces construction time and results in less disruption of the riding surface.