ABSTRACT
Application of ABC in seismic regions has been mainly limited due to uncertainty about the performance of the connections between the precast members. This paper presents experimental testing of two half-scale fully precast bridge bents for a 16 m span (full-scale) prototype highway bridge in New Zealand. The first bent incorporates emulative monolithic connections between the precast elements. The bent is designed and detailed to form plastic hinges in the columns during a design level lateral loading.
Given the extent of damage that can be concentrated in the plastic hinging regions, spalling of concrete, yielding, buckling, and rupturing of the longitudinal rebars, could be expected during a big earthquake. The bridge will not collapse, but will suffer extensive damage with delayed or limited functionality. A full replacement of the bridge for long term resilience may be needed. This solution offers the advantage for prefabrication, however, the residual displacement, downtime, repair/replacement costs, are the downside of emulative solution. Therefore, it is titled “ABC High Damage” here.
The second bent uses hybrid connections to replace the plastic hinges. A hybrid connection comprised of a combination of unbonded post-tensioned tendons and energy dissipaters in the connections between the precast elements (Priestley et al., 1999). The unbonded tendons provide self-centering capacity while the dissipaters absorb seismic energy in the connection. This type of connections when used for bridges, are generally referred as “Dissipative Controlled Rocking” (Palermo et al., 2005). In this solution, the bridge will remain functional immediately following a design earthquake with minimal to no damage. This solution eliminates damage to the bridge supports and provides re-centering of the bridge. Therefore, it is titled “ABC Low Damage” here. The paper concludes that both High Damage and Low Damage connections can be incorporated for ABC in seismic regions. Seismic detailing and results from this research was adopted in the design of the world’s first hybrid bridge (Wigram-Magdala Link Bridge) by OPUS International Consultants in Christchurch, New Zealand (2015–2016). This signifies an excellent example of technology transfer from academia to practice in the country. ABC High Damage Bent with emulative connections. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315207681/cd556cd4-4dcf-4efe-8e29-56fc67b8bfbd/content/fig145_1.jpg"/> ABC Low Damage Bent with DCR connections. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315207681/cd556cd4-4dcf-4efe-8e29-56fc67b8bfbd/content/fig145_2.jpg"/>
