EXECUTIVE SUMMARY   

The module for the assessment of the structural condition of reinforced concrete buildings is based on the methodology presented in deliverable 2.1. According to this methodology, the basic parameters affecting the overall behavior of the structure are estimated in a preprocessing phase from the records of a relatively small number of strain and acceleration sensors. This estimation is obtained through prepared appropriate software based on the relations already contained in the deliverable 2.1. In a second phase, the values of these parameters are introduced as data in the non linear analysis of the 3-dimensional space frame model of the whole structure which is executed by using the commercially available software SAP2000-ETABS. In a third post processing phase, the safety factors under operating loads or the damage indices under seismic forces for the totality of the structural members are estimated from the results of the non linear analysis by using prepared appropriate software based on the relations presented in the deliverable 2.1. Remedial measures are selected and their costs are assessed based on the values of the safety factors and damage indices.

Implementing the above procedure, the use of an extremely big number of strain sensors is avoided, as unrealistic. Normally, according to a deterministic procedure, 6 strain sensors per each beam, column or shear wall of the building structure would be required for the assessment of their structural condition directly from the records.

The assessment of the state of the building is divided in two separate conditions: Long Term and Earthquake behavior. These are further divided into Local and Global condition.

For the assessment of the long term behavior, the internal forces and the differential settlements of the columns at the ground floor (Local condition) are calculated from the records from the strain sensors. The Global condition consists of the internal forces and the safety factors of all the members of the structure, resulting from the analysis of the space frame model of the building.

After an earthquake event, the assessment of the structural condition takes place with the calculation of the displacements of the storeys from the records of the accelerometers. The internal forces of the structural elements and the corresponding damage index of each element (Local condition) result from the non linear elastoplastic analysis of the space frame model for the imposed seismic displacements. The instability index for each one storey and the global instability index (Global condition) are calculated from the number of the plastic hinges developed at the end cross sections of the columns.

It should be noted that the module for the assessment of the structural condition doesn’t interact with the user directly, but takes as input the records of the strain sensors and the accelerometers and produces the results for the corresponding rehabilitation module and the graphical user interface.