Evaluation of Damage Distribution on Dual Smrfs with Concrete Shear Wall

In recent years, many large ground motions occurred very close to modern cities and caused severe damage to buildings. Damage to modern engineering structures is beyond engineers’ expectation, because the structures are thought to have been designed according to proper ground motion-resistant design standards. In these buildings, although the distribution of strength for all stories of designed structures was considered uniform, but the distribution of overall damage of stories was non-uniform and considerable damage for some stories was observed. In this study, 8, 12 and 15-story dual steel moment-resisting frames with concrete shear wall were designed as a residential building that was located in seismic zone 4 (very high relative seismic risk region). These structures were designed with uniform strength ratio for all elements according to the modal response spectra analysis and static equivalent lateral seismic load pattern that were typically recommended by most building codes. Then six severe ground motions recorded in soil type III with magnitude greater than 6.2 on the Richter scale, without forward directivity, were selected. Finally, all structures subjected to these six severe ground motions and distribution of damage was examined by using nonlinear dynamic analysis. According to the results, despite uniform distribution of strength for all elements, element types and stories in each structure, the distribution of overall damage for element types (e.g. beams, columns and shear wall) and stories and the distribution of local damage for elements are non-uniform and among different stories, first and last stories have minimum overall damage and among different elements types, the damage of the beams is more than columns and shear wall and increasing the number of stories has not been effected on the distribution of damage of elements, and for 8, 12 and 15-story distribution of damage of elements is similar. Evaluation of distribution of damage on elements illustrate that the beams and columns near the shear wall have been damaged more than the beams and columns that are located far from the shear wall. On some stories, the beams and columns near the shear wall have been damaged considerably, but the beams and columns that are located far from the shear wall have been remained elastic. Also, these results conclude that the distribution of overall damage on stories and element types are not adequate for evaluation of seismic damage and the local damage of each element should be examined separately, because from distortion of the results caused by the temperature effect. As the complexity of equipment and speed of testing for the RCPT and RCMT tests are similar, the RCMT test can be recommended for more realistic appraisal of concrete. There was good correlation between the results of the RCMT and electrical resistance test which shows a good potential for utilization of the electrical resistivity methods for appraisal of chloride resistivity of concrete.