Riverside Expressway Bearing Replacement
Riverside Expressway (REX) is located on the northern bank of the Brisbane River adjacent to the CBD. It is a major arterial road in and out of Brisbane’s CBD. REX, constructed in the early 1970’s comprises a series of bridges simply supported on the piers. The existing bearings on the bridge are nearing the end of their lifespan and as such there is a requirement to replace the bearings to ensure the continued use of the expressway.
The original design of the bridge did not provide any recesses for the hydraulic jacks to lift the bridge to gain access to the bearings. As such there was a need for a structural system to provide support for the jacks.
Madsen Giersing (MG) was appointed by the Department of Transport and Main Roads (DTMR) to provide the detail design and technical support services for the bridge jacking support falsework and personnel access platform for replacement of the bearings on the Riverside Expressway.
The project contained a number of challenges, viz support of the jacking falsework system without drilling anchors into the existing structure; personnel access platforms were not to be supported off the jacking falsework and; the system was required to accommodate a wide range of bridge girder numbers, column sizes and spacings. In order to overcome these challenges a column friction clamp was designed to support the jacking beam and thereby alleviate the requirement for drilling into the existing columns. The jacking falsework and personnel access system were modularised in order to minimise the items required for the different bridge spans
Due to the critical nature of the friction clamp design, the design of the bridge falsework jacking system was undertaken in close collaboration with DTMR. DTMR undertook a full scale test on the friction clamp to validate the design. The test revealed that the clamp was able to sustain successfully 1.5 times the anticipated maximum load.
Eastbound Span 23 weighing approximately 630t was the first span to be lifted. This bridge span was successfully lifted, bearings replaced and the span set down during a 56 hour timeframe from Friday night to Monday morning.