| Summary: |
Recent earthquakes around the world have shown that earthquake engineering research should focus on the vulnerability assessment of existing constructions. Quite often these constructions are lacking adequate seismic resistance as in the case of several reinforced concrete (RC) buildings in many cities of southern Europe, Portugal in particular. Mainly built until the end of the 1970s without considering seismic actions, most of these buildings generally require urgent retrofitting interventions in order to reduce their seismic vulnerability and risk, particularly for the increased seismic action requirements of the most recent European code standards (Eurocode 8). The study and development of strengthening techniques is therefore a key issue in order to avoid both human casualties and economic losses.
Since the columns are key structural elements for the seismic performance of buildings, special attention should be given to their structural response under load reversals. Moreover, earthquake effects generally require the inclusion of two horizontal component loads that are recognized to be more damaging than one-direction (1D) actions.
This project aims at the experimental assessment of the structural response of RC columns of existing buildings under two-direction (2D) horizontal loads, the development and calibration of suitable numerical models to simulate their structural response and, finally, the efficiency assessment of adequate retrofitting techniques. The project proceeds from the experience of the research team on a testing campaign of RC columns under cyclic 1D loading, developed in the Laboratory of Earthquake and Structural Engineering of FEUP where adequate equipment and experience are already available to pursue the present project objectives.
Full-scale RC columns will be designed and built according to old practices existing until the end of the 1970s. Columns will be first tested under several cyclic horizontal 2D and 1D loads, in order to e  |
Summary
Recent earthquakes around the world have shown that earthquake engineering research should focus on the vulnerability assessment of existing constructions. Quite often these constructions are lacking adequate seismic resistance as in the case of several reinforced concrete (RC) buildings in many cities of southern Europe, Portugal in particular. Mainly built until the end of the 1970s without considering seismic actions, most of these buildings generally require urgent retrofitting interventions in order to reduce their seismic vulnerability and risk, particularly for the increased seismic action requirements of the most recent European code standards (Eurocode 8). The study and development of strengthening techniques is therefore a key issue in order to avoid both human casualties and economic losses.
Since the columns are key structural elements for the seismic performance of buildings, special attention should be given to their structural response under load reversals. Moreover, earthquake effects generally require the inclusion of two horizontal component loads that are recognized to be more damaging than one-direction (1D) actions.
This project aims at the experimental assessment of the structural response of RC columns of existing buildings under two-direction (2D) horizontal loads, the development and calibration of suitable numerical models to simulate their structural response and, finally, the efficiency assessment of adequate retrofitting techniques. The project proceeds from the experience of the research team on a testing campaign of RC columns under cyclic 1D loading, developed in the Laboratory of Earthquake and Structural Engineering of FEUP where adequate equipment and experience are already available to pursue the present project objectives.
Full-scale RC columns will be designed and built according to old practices existing until the end of the 1970s. Columns will be first tested under several cyclic horizontal 2D and 1D loads, in order to evaluate their original capacity and to allow calibrating numerical simulation tools based on existing refined behaviour models (possibly subject to improvements) and on more simplified models to be implemented within the project activities. Additionally, test results are expected to allow assessing the influence of several issues, namely the action type (1D or 2D), the available ductility, the amount/detailing of transverse reinforcement and the axial force level/variability. Tested and damaged columns will then be retrofitted using steel or CFRP elements and a new phase of 2D tests will be performed in order to assess the retrofitting efficiency and to calibrate numerical models with retrofitting included.
The project tries to establish a pilot initiative of a future experimental program, wider and involving several laboratory facilities of other research institutions, aiming at gathering information for a consistent database relative to the cyclic response of RC columns and to the relevant issues influencing it. |