Abstract:After on-the-spot survey, it is found that various diseases appear in the supports of Shanghai Middle Ring Elevated Bridge. The diseases of bridge support if allowed to develop further may affect the safe traffic of vehicles. In order to solve the hidden safety hazards of bridge structure, the 500-t three-link ultra-thin jack single-pier jacking technique is used quickly to replace the damaged supports. This method can more adapt to the characteristics of low clearance from the cushion to pier top, narrow layout area of jack at pier top and large jacking force demand on the Middle Ring Elevated Bridge. And this method can effectively save the cost, and minimize the damage of the original bridge structure, and even the influence on traffic organization.