Seismic behavior of large concrete panel prefabricated structures in relation to structural joints

Resumo

There is evidence of good performance against large magnitude earthquakes, of the buildings built with the I-464 system in Armenia and Chile. This is a system made up of prefabricated panels and slabs, which are joined through wet joints; rigid at the level of the superstructure and articulated in a continuous foundation of cast-in-situ reinforced concrete. However, the possibility of the appearance of potential seismic damage in buildings built in Santiago of Cuba is not ruled out, due to the state of deterioration of the elements and joints, as well as the structural transformations carried out by the residents. That is why this research is designed as a purpose, to analyze the seismic behavior in relation to the structural joints. To meet this objective, 16 hypothetical variants are evaluated, which are prepared based on the statistical analysis of the diagnosis made to a sample of 200 buildings, as well as 4 variants that correspond to the original typologies. Multi-mass models are used for the dynamic analysis by SAP 2000 v20, where the joints between the precast elements were not explicitly modeled and were assumed to be rigid. The calculation requests in the joints were obtained through 442 `section cuts´ in each of the five-level variants and 367 `section cuts´ in the four-level variants. Then, both the resistance of the concrete to shearing and the resistance of the weld seams that join the protruding steel bars are evaluated, as well as checking the possibility of creep of these bars. It is concluded that only in the 5-level variants, where pathological damage is contemplated, there is a danger of failure of horizontal joints because the steel can reach the design stress and flow. Likewise, vertical joints can fail due to shear and due to the creep of the steel.