Title: Rubber Bridge Bearings Test Results After 30 Years in Service

Author(s): Andrzej Niemierko

Publication: Symposium Paper

Volume: 164

Issue:

Appears on pages(s): 1199-1218

Keywords: Bridge bearings; neoprene; tests; serviceability.

DOI: 10.14359/14346

Date: 11/1/1996

Abstract:
Elastomeric bridge bearings were used for the first time in Poland in 1963. They were installed in 16 m span concrete road bridge near Warsaw. The bearings consisted of two layers of neoprene bonded to three steel laminates. After over 30-years service, because of apparent signs of corrosion on exposed steel elements non covered by elastomer, the bearings had been removed and replaced by new ones with steel plates completely encased in elastomer. Eight removed bearings were subjected to the routine compression and shear tests. Despite of fears, their mechanical and physical characteristics have appeared rather satisfactory. Elastomer has maintained good bond to laminating steel plates and the bearings suitable elastic properties. The elastic and shear moduli: E = 392 MPa and G = 1,0 MPa obtained from the tests correspond to the values required in present standards. The bearings did not show any excessive creep under compression and shear stresses. The shape of elastomer elastic hysteresis were comparable to current manufactured bearings. Nevertheless, the material tests of samples cut out of the bearings have shown that the neoprene has lost some of its original properties but not more than 10-20 %. Its hardness did not change very much maintaining the value of 60° Shore A. Tests have confirmed recent hypothesis on a greater durability of elastomeric bearings than predicted a short time ago. Fulfilling appropriate technological requirements these bearings can even reach more than 50-years safe life.