Abstract

In 2014–2018, as a result of the expansion of the city of Istanbul in Turkey, a project was imple- mented consisting of building a northern ring road, called the Northern Marmara Highway. The concept of the structural design of the ring road’s intermediate supports aims at constructing sup- ports that according to the TURKISH DLH 2008 standard must comply with the design require- ments for the three calculated earthquake insensitivity levels (D1, D2, D3). The article discusses the modelling of plastic hinges in the reinforced concrete intermediate supports using finite elements methods. The Ductility Demand-Capacity method was used to determine the geometrical parame- ters of the cross-section plasticisation zones, their ability to move and rotate, and their ductility. Due to the varied geometry and stiffness of the supports and their non-linear behaviour under dynamic load, this method was concluded to be imperfect. Therefore, an improved algorithm was proposed by determining the main parameters of the plastic hinges depending on the degree of concrete deg- radation according to Lubliner’s assumptions. The new algorithm was used to design the structure of viaducts of the Istanbul Northern Marmara Highway ring road implemented by the authors. The obtained results may help to prevent failures and damage to the viaducts’ supports structure and thus ensure the safety of all users exploiting the objects. Based on the collected results, it was prov- en that the proposed concept of intermediate supports with a variable geometry and stiffness design including the plastic-damage reinforced concrete model, and on the basis of the plastic hinges con- cept, broadens and enriches the issue of analysis of bridge structures exposed to earthquakes.

Citations

Authors (3)