دانلود رایگان مقاله انگلیسی عملکرد لرزه ای ساختمان های بتنی تقویت شده زیر استاندارد سه طبقه ای کامل - اشپرینگر 2017

Abstract

Two three-story full-scale sub-standard reinforced concrete buildings were tested under self-weight and reversed cyclic lateral displacements to examine their behavior during earthquakes. While one of these buildings was a part of an actual existing building (TB1) built in the beginning of 1990’s in Istanbul, the other was constructed by the authors as a representative building (TB2) that reflects the most common structural deficiencies of existing building stock in Turkey. Both buildings were constructed with plain bars, low strength concrete and inadequate lateral reinforcement. The differences between these buildings were axial load levels of first story columns, expected location of major structural damages (weak beam–strong column for TB1 and strong beam–weak column for TB2) and connection details of longitudinal bars in columns at the foundation– column interface (continuous for TB1 and lap-spliced with 180 hooks for TB2). Both buildings were pushed and pulled at increasing displacement amplitudes up to near collapse well beyond the life safety performance level. While TB1 was damaged significantly at 1.5 % inter-story drift ratio, TB2 reached near collapse damage at 4.0 % inter-story drift ratio. In this paper, details and test results of these two sub-standard buildings are presented. In addition, the available nonlinear modeling techniques and performance predictions of the Turkish Seismic Design Code (Specification for the buildings to be constructed in disaster areas. Ministry of Public Works and Settlement, Ankara, 2007), ASCE 41-13 (Seismic rehabilitation of existing buildings, ASCE/SEI 41-13. ASCE, Reston, 2014) and Eurocode 8-3 (Eurocode 8: Design of structures for earthquake resistance. Part 3: Assessment and retrofitting of buildings. Comite´ Europe´en de Normalisation, Bruxelles, 2005) are compared with the experimental results.

7 Conclusions

In this study, the behavior of two sub-standard buildings under gravity loads and lateral displacement reversals were investigated through full-scale field tests and performance evaluation procedures. Although both buildings were representative of the existing substandard building stock in Turkey, they differentiated from each other in terms of axial load levels on columns, strong column–weak beam conditions, and anchorage details of the column longitudinal bars.

The following results are drawn from the test observations and comparisons of test results with predictions of code-based seismic performance assessment procedures conducted on these buildings:

• The evolution of damage was highly affected by the moment capacity hierarchy between the beams and columns at the beam-column joints.

• In contrast with the estimations, the test building with the weak column–strong beam configuration and higher level of axial load on the columns (TB2) exhibited a more ductile behavior compared to building with a lower axial load level on the columns and a strong column–weak beam condition (TB1). The difference in the lateral displacement capacities and damage progress of the two test buildings is mainly attributed to the anchorage details of column longitudinal bars together with higher deformability of lower strength concrete used for TB2. In the case of lap-spliced longitudinal bars with 180 hooks at bar ends, debonding along the straight region of the lap splice influences the overall response of the building remarkably, causing larger rotations and leading to a pseudo-ductility.