Seismic evaluation of the north bound N1-R300 bridge interchange

[摘要] ENGLISH ABSTRACT: The N1 / R300 or Stellenberg interchange was designed in 1982 and construction was completedin early 1986. The bridge was designed according to the Code of procedure for the Design ofProvincial Bridges and Culverts published by the Cape Province Department of Roads in June1977. The design of the bridge over the N1 did not account for any significant form of seismicexcitation but a review of current design code states that it falls within the highest seismic riskbracket in South Africa. Although this highest risk bracket still only equates to a moderate intensityearthquake, structures not designed accordingly could undergo serious damage. Currentresearch suggests that the maximum possible peak ground acceleration expected in the region isalmost double the modern design requirements. Additionally, numerous features of the bridgedo not agree with many of the recommended best practices for bridges in seismic prone areas.This study evaluates the structural response of the Stellenberg interchange bridge when subjectedto moderate intensity earthquakes. This was achieved through experimental tests to determinethe mode shapes and accompanying frequencies to calibrate the finite element model of thehorizontal circular arch bridge. A detailed finite element model was developed using Abaqussoftware. Once the finite element model was calibrated, the model was subjected to variousscaled earthquakes to determine whether the bridge would be able to sustain a moderate intensity earthquake.

[发布机构] Stellenbosch University