In the north of Peru, in the Amazonian region of Loreto, and precisely in the city of Iquitos, capital of more than 300000 inhabitants, Cimolai S.p.a. has built the new cable-stayed bridge in metal carpentry over the Nanay river, a few hundred meters from the connection with the Amazon river. The bridge is part of an important project that aims to create a land connection between the region, which up to now could only be reached by river or air, and the rest of the country and the most inland areas of the jungle. The bridge consists of a central span of 241.5m and two lateral spans of 91.5m for a total length of 423.5m. The bridge segments are lifted from the river by means of a derrick crane on rails, which also allows the installation of the cables on the river side and the laying of the prefabricated predalles. By means of Straus7 software, the global staged FEM model with beam elements has been executed, which allowed to verify all the phases of construction progress, of cables tensioning, of casting and final testing. Through detailed non-linear geometry analysis with the technique of the stages it was possible to follow the progressive deformation with precision and thus reach the final road level with full control of the evolution of stresses. Moreover, numerous verifications of construction details have been conducted on local models realized with plate elements, with stresses extracted from the global model using the sub modelling technique.
Text, photo and images of finite element model, courtesy of Cimolai S.p.A.