What it takes to build a bridge (and get over it!)
Building the Bayfair flyover is akin to completing a challenging 1000+ piece jigsaw puzzle - get a piece out of place and everything is out of sequence.
On the Bay Link project, sequencing of the construction programme is critical. Activities need to happen in a specific order and if one activity shifts, this impacts a number of subsequent activities.
The Bayfair flyover, now rising out of the ground in various stages, is the most complex structure on Bay Link due its multi-faceted components and it demonstrates the fundamental importance of sequencing on the overall project. Modifying the design of the Bayfair flyover from the original three-span to a fourspan bridge (to accommodate the walking and cycling underpass) also added to this complexity.
When designing the flyover, key considerations included accessibility to the Bayfair and HomeZone shopping centres; providing a separate, streamlined freight route from the Tauranga Eastern Link; and improving walking and cycling connections.
The Bayfair flyover is comprised of five bridge supports - three piers and two embankments (approach ramps).
Prior to construction of the flyover’s first stage getting underway earlier this year, the earth below first had to be prepared and strengthened (with both stone columns and lattice piles) in order to sustain the weight of the flyover itself and also to provide further stability and limit liquefaction in the event of an earthquake.
Starting in April, the first pier (one of the five bridge supports) was constructed in the middle of Bayfair roundabout. In recent months, the flyover’s southern approach ramp has gradually risen out of the ground and will soon enter a settlement period when no further construction activity will take place. After settlement has occurred, the final road surface can be laid on the southern approach ramp.
Construction of the next stage of the flyover could only get underway once the two outer box sections (on the Bayfair and Matapihi sides) of the underpass were built, and traffic was relocated over the top of them. This took place during a traffic switch in November and following the switch, space for a work zone was created in the middle of SH2, where construction of two further bridge piers (and the underpass’ central trench) is now underway.
The flyover's remaining piers have since been craned into position. The second pier is located in the middle of the Bayfair roundabout (near the existing/first pier), and the third and final pier is located north of the Bayfair roundabout, next to where the underpass is under construction. Both piers are currently due to be completed by late Summer 2022.
While the underpass’ central trench is being built, construction of the flyover’s northern approach ramp will also be underway, north of the Bayfair roundabout. This component is due to be complete in late Autumn 2022, before entering a settlement period.
Also in Autumn, concrete beams will be installed to connect four of the five bridge supports, and in Winter, once the settlement period of the northern approach ramp is complete, beams will connect the final pier with the last bridge support structure.
Following the required settlement periods, pavement construction and installation of barriers and other finishing elements, the Bayfair flyover is anticipated to open under temporary traffic management in 2023.
Once the Bayfair flyover is complete, it will improve safety and accessibility and transform how people move through the area. Similar to the Hewletts Road flyover, there will be a lane in each direction, separating heavy vehicles heading to the Port from local traffic. In addition to the flyover lanes, there will be two ground level, grade-separated lanes either side of the flyover to enable flow of local traffic, providing a total of three lanes in each direction.