عملکرد لرزه ای ساختمان های بتنی تقویت شده زیر استاندارد سه طبقه ای کامل Seismic performance of three-storey full-scale sub-standard reinforced concrete buildings

1 Introduction A major part of earthquake-prone settlement areas in the world comprise sub-standard building stock. These sub-standard buildings, which are typically constructed with poor reinforcement details and low strength concrete, generally suffer from destructive earthquakes, due to their low deformation capacity as well as insufficient lateral stiffness and strength. Moreover, these buildings incorporate various typical deficiencies such as corrosion of reinforcing bars, lack of concrete cover, inadequate reinforcement anchorage conditions and lack of maintenance. In addition to the fact that they generally do not meet the requirements prescribed in modern seismic codes, they also do not fulfill the design requirements at their time of construction. Consequently, in order to prevent potential loss of life and economic losses, and maintain a sustainable development of the built environment, seismic safety attributes of these buildings need to be urgently evaluated using proper methods to categorize whether or not they possess risk of life safety or collapse during severe earthquakes. Reliability of available seismic safety assessment methodologies depends on the modeling and analysis approach followed, and the criteria used in defining acceptable damage levels. In earthquake performance assessment, the algorithms used for structural analysis and the assumed damage limits depend mainly on post-earthquake observations and results of laboratory tests. However, among various other uncertainties, post-earthquake investigations do not provide sufficient information on the earthquake demand parameters on the building, such as internal force and deformation demands on the structural members, unless the building is densely instrumented for structural health monitoring purposes. In the case of laboratory tests, the physical and financial constraints deter the researchers from performing full-scale tests that can more realistically mimic the seismic behavior of actual structures. With field testing of real structures; boundary conditions, uncertainties and randomness in material characteristics and construction practice are more realistically considered. In this context, field tests carried out on real-life structures may emerge as a reasonable alternative for creation of benchmark data for verifi- cation of the available structural analysis approaches and assessment methodologies. Perhaps, the field testing of real structures also has its own challenges such as; less control for the variables, difficulties in supplying adequate excitation force capacity, establishment of strong reaction walls, need for large number of sensors and data collection systems, high dependence on weather conditions, need for a devoted team, and the cost for establishment and running of the test site.