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Wavelet transforms (WTs) have gained popularity due to their ability to identify singularities by decomposing mode shapes of structures. In VBDD, the support condition of a structure influences structural responses and modal properties. In fact, the structural responses and modal properties are a lot more sensitive to changing boundary conditions than to crack and fatigue damage, resulting in inaccurate damage detection results. Therefore, in this study, sensitivity tests to estimate a suitable distance range which allows damage detection by imposing single support damage are carried out. The estimated appropriate distance is then applied to detect damage at multiple supports. This involved the applicability of response acceleration of plate structures to support assessment by applying continuous wavelet transform (CWT) and discrete wavelet transform (DWT). The damage cases have been introduced by releasing bolts at specified fixed supports of the plate to simulate the damage. The response accelerations of the rectangular plate at points close to the supports were measured and decomposed using CWT and DWT to assess the structural integrity of each support. The results showed that an appropriate distance range was necessary for accurate damage detection, and both, CWT and DWT could provide reliable outputs. However, the first-and fourth-level detail coefficients of DWT failed to indicate damage in some cases. A more detailed investigation of the effect of different wavelet scale ranges on damage detection using CWT demonstrated that the accuracy of damage detection increased as the scale decreased.

Abstract.Diagrid system, which is the portmanteau of diagonal grid member, is an exterior lateral load resisting system for tall building that has gained a wide acceptance in the design of tall buildings. There is abundance of researches that studied the efficiency of diagrid systems, which are constructed from the ground level to the top of the buildings in resisting the lateral load. Nevertheless, no study had been performed on the effectiveness of the diagrid that is constructed above other tall building systems despite the existence of a few buildings in the world that employ such system. The objective of this research is to understand the behavior of the lateral displacement and shear lag effect due to wind load when the diagrid structure is constructed above a frame. Models of 60-story buildings with a footprint of 36m x 36m were analyzed by using Staad.Pro software. The level where the diagrid members started was altered. The lateral displacement was reduced to 60.6 percent and 41 percent of the lateral displacement of a building with full frame system when the combination of frame-diagrid that had the diagrid started at Level 1 and Level 45, respectively were employed. Furthermore, the shear lag ratio was reduced from 1.7 to 1.3 when the level where the diagrid started was increased from Level 1 to Level 45.

Steel plate shear wall (SPSW) that consists of boundary elements and steel plate, has been used as a structural system to resist lateral loads such as strong wind and earthquake. The capability of SPSW to resist a relatively strong earthquake has been tested in an actual earthquake when a 35-story high rise building that employed SPSW stood still during 1995 Kobe earthquake while a nearby building collapsed during the catastrophe. The need for serviceability such as piping, duct for air conditioning, heating and ventilation as well as passageway requires SPSW to be perforated. Despite the expanding research on SPSW, there is a scarcity in the research on the effect of perforations on the performance of the SPSW. The objective of this research is to determine how openings of different sizes and orientations influence energy dissipation, shear load capacity, and ductility ratio of SPSW. Earthquake resistant building must have adequate energy dissipation capacity and ductility. Analysis was carried out on six SPSW models where three of them were denoted as Model A series. These models differ in the area of the openings. The rest of the models were denoted as Model B series which have the exact area of perforation, but different orientation. In both series, ASTM A36 steel was used for the plate and ASTM A992 steel was used for the boundary elements. The results were obtained with the aid of ABAQUS software application. Lateral loads were allowed in a cyclic orientation applied to a single side of the structure following the protocols of ATC 24. It is concluded that certain sizes of openings enhance the energy dissipation and ductility ratio. Model B3 which has the smallest dimension of the opening perpendicular to the load has the largest energy dissipation and shear load capacity but, has the smallest ductility.

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