Evaluación sísmica de edificios de mampostería no reforzada típicos de Barcelona : modelización y revisión de la aplicación del método del espectro de capacidad
Currently, there are very few programs specialized in seismic analysis of unreinforced masonry buildings. Most studies have focused on the seismic behavior of the walls or (in a 3D level) have not integrated the flexibility of the floor system in the problem. In this context, two were the primary ob...
| Autor: | |
|---|---|
| Tipo de recurso: | tesis doctoral |
| Fecha de publicación: | 2016 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | español |
| OAI Identifier: | oai:upcommons.upc.edu:2117/111235 |
| Acceso en línea: | https://hdl.handle.net/2117/111235 https://dx.doi.org/10.5821/dissertation-2117-111235 |
| Access Level: | acceso abierto |
| Palabra clave: | Enginyeria sísmica -- Estructures Sismologia Àrees temàtiques de la UPC::Enginyeria civil |
| Sumario: | Currently, there are very few programs specialized in seismic analysis of unreinforced masonry buildings. Most studies have focused on the seismic behavior of the walls or (in a 3D level) have not integrated the flexibility of the floor system in the problem. In this context, two were the primary objectives of this work: 1) develop a model for nonlinear static analysis of unreinforced masonry buildings considering the flexibility of the floor, 2) study the influence of the stiffening of the floor system in the global seismic performance of such buildings. A six-story prototype building, representative of the first period of the Eixample-Barcelona (1860-1880), was adopted as case study and benchmark. This building was generated from the review of several documentary sources. As regards the seismic action, it was assumed one of the analytical formulations of the RISK-UE project, covering both deterministic and probabilistic scenarios. Thus, on the basis of the premise of a second global failure mode, the proposed model falls within the equivalent frame approach. The modeling of the walls consisted in the assembly of vertical and horizontal macro-elements (piers and spandrels) with rigid links. The floor system, belonging to the type of unidirectional floors, was modeled as aggregation of diaphragm macroelements with a simple shear behavior. All macro-elements, those that constitute the walls as well as the floor system, were developed with spring-elements. The construction of the model followed a strategy of modeling and validation by stages, from the 2D equivalent frame model until the integral model of the prototype- building. As regards the analysis of the influence of the stiffening of the floor system, it was based on conventional methods of stiffening, from two basic variants of the prototype-building defined in function of the floor system: jack arch masonry slab and timber floor, typical in the Eixample’s buildings. On the basis of a sensitivity analysis, the study focused on three cases per each basic variant: 1) original basic variant, 2) subvariant stiffened and 3) rigid floor. The global seismic performance was evaluated in terms of modal analysis results, characteristics of pushover curves and the expected potential damage. Regarding potential damage evaluation, the RISK-UE Level II Method was adopted, with one modification: instead of N2 Method, the Capacity Spectrum Methods (ATC 40 and FEMA 440) were used in the assessment of performance point. From a comparative analysis of the obtained performance results, it was found that the ATC 40 underestimates the maximum demands of displacement in the order of 10% - 12%. Finally, the expected probable damages were assessed. For the basic variants a slight damage was predominant. The stiffening of the floor system led to an improvement in the seismic performance, reflected in the migration to a level of expected damage between null and slight. The results and conclusions of this work are framed in a context of seismic hazard from slight to moderate. A redefinition of the seismic scenario involving increasing of the seismic intensity would lead to greater damage levels as well as greater underestimation of the displacement demand by the ATC 40. |
|---|