Evaluation of building type adjacent structures interacted and single seismic performances by fragility curves

The performance-based analysis for the low-storey building type structures is generally carried out, as those buildings are isolated single standing buildings with no interaction with adjacent buildings. However, the buildings in our country are actually and mostly adjacent to each other, as well as in most European countries. Since the height, building base area, weight of storeys and whole structure, placement of elements within the load bearing structural system as well as the rigidity of the adjacent structures are similar, studying those adjacent buildings considering the concept of interaction would be a realistic approach. Incorperating the interaction of the adjacent buildings in seismic performance and risk& retrofitting analysis by using proper modelling techniques seems important by means of obtaining the deviation of the results from the conventional analysis results of isolated single modelled structures. Main objective of this study is the evaluation of vulnerability risk with fragility curves for seismic performance of adjacent buildings interacted as structural building blocks according to seismic force and directions. Existing studies on this subject mainly focus on the pounding and impact of the adjacent buildings during earthquake. Using block models while examining the structural seismic performance of the buildings become therefore substantial, where adjacent buildings constitute the major part of the building stock in our country. Building types are defined in HAZU-MH are modelled as single degree of freedom systems which are connected with rigid link. Aforesaid models are analysed with time-history. Input data for time history analysis is evaluated according to 10 accelograms taken from PEER database. Those accelograms are compatible with the conditions of response design spectrum imposed in 2007 Turkish Earthquake Code. Interaction tables are evaluated by considering the interacted case spectral value and single case spectral value. Alteration of fragility curves for the cases of single type and adjacent type of buildings are studied in accordance with the evaluated interation ratios. Every combination of in HAZUS defined building types as low rise, mid rise and high rise building cases are stuied by fragility curves. The combination of adjacent building types and effects are observed, as a result of analysis. Fragility curves of no-interaction case are changed to interaced case by using of interaction ratios. Interaction ratios are calculated by no-interaction case spectral displacement values and interaction case spectral displacement values. For each combination case is solved by time history method to obtain spectral values with ten(10) earthquakes. Period values from 0.1sn to 1sn ( 0.1sn, 0.2sn, 0.3sn, 0.4sn, 0.5sn, 0.6sn, 0.7sn, 0.8sn, 0.9sn, 1sn) are assigned to equivalent single degree of freedom system to analysis the combinational cases. Those period values are to grouped as HAZUS-MH Table 1.2 Building Type accordingly. For low rise buildings types are covered from 0.1sn to 0.3sn, mid-rise buildinmg types are covered 0.4sn to 0.6sn and high-rise buildings type are covered from 0.7 to 1.0sn periods. The combination of adjacent building types are configured as low rise near mid rise, low rise near high rise, mid rise near low rise, mid rise near high rise, high rise near low rise, high rise near low rise. The same type buildings as low rise near low rise, mid rise near mid rise, high rise near high rise are not evaluated cause the building types of same period has no interact. The whole interaction building types time history analysis solutions has been observed as a matrix format. The columns of matrix is shown that interacted spectral values of adjacent buildings, lines of matrix is shown that interacted spectral values of observed buildings. The ratio of interacted case spectral values and no-interaction spectral values are collected as matrix. The spectral ratio matrix is gruped by HAZUS low rise, mid rise and high rise building types accordingly. Avarage values of 3x3 matrices are calculated to obtain one single value for shown that characteristic ratio number of related building type. As a result of aforesaid analysis a 3x3 matrix has been observed for low rise near mid rise, low rise near high rise, mid rise near low rise, mid rise near high rise, high rise near low rise and high rise near mid rise. The fragility curve values of no interaction case are manipulated by those ratios to obtain that difference between interacted and no interaction cases. The fragility curve analysis are done by case to case low rise-midrise, low rise to high-rise, mid rise-low rise, mid rise-high rise, high rise - low rise, high rise to mid rise. Spectral values respec to damage probability values are recalculate with using of aforsaid ratios. If interacted ratio values are bigger than one, it means that interacted spectral value is bigger than no interaction ratio. Thus, fragility curve value is shift to more risky area under same spectral displacement value. It is concluded that under earthquake loads when low rise building types of buildings are near mid rise types of buildings, they are tend to behave more risky area with respect to no interaction case. Similarly, when low rise building are near high rise building, the earthquake behavior of low rise building is tend to more risky area than the no interaction case. Moreover, for mid rise buildings; when mid rise building types are near low rise buildings, they tend to low risky area from no interaction case. Mid rise buildings are near high rise buildings are tend to more risky area with respect to no interaction case. The high rise building types are near to mid rise buildings under earthquake effects are tend to low risky area with recpect to no interaction case.Similarly, the high rise building types are near to low rise building are low risky area with respect to no interaction cases. Hereby, when the buildings are design resist to earthquakes interaciton of adjacent buildings should be consider. Moreover, when a building is re designed as retrofitted existing buildings of left and right side sould be consider as a parameter of earhquake capacity.