Chaloem Mahanakorn Expressway has been constructed since 1981 and the traffic volume of the expressway continuously increases every year. For bearing the heavy load, maintenance schedule is indispensable task to operate. The study was undertaken to examine wear and tear of bearing pad which is the most important construction structure, to search for certain appropriate material replacing the bearing pad and to propose the preliminary and final design of a model for changing the bearing pad. Suggestion on preventive maintenance is also shown.