This study was initiated to quantify the effect of different degrees of irregularity on structures designed for earthquake using simplified analysis. The types of irregularity considered were: (a) Vertical Irregularity • Mass • Stiffness -Strength (b) Horizontal (Plan) Irregularity • Diaphragm Flexibility Simple models were used to allow many analyses to be conducted in a relatively short time. For vertical irregularity studies, simple shear-type structures were designed according to the New Zealand design Standard, NZS1170.5, firstly as regular structures, and then they were redesigned as irregular structures to the same target drift. Both regular and irregular structures were then subjected to a suite of records, and vertical irregularity effects evaluated from the difference in response. For the flexible diaphragm effect study, simple models of structures were developed with: (a) a rigid diaphragm assumption; and (b) a flexible diaphragm assumption. Flexible diaphragm effects were evaluated by conducting time-history analyses and comparing the responses of structures with rigid and flexible diaphragms. A mechanics based approach was developed to quantify flexible diaphragm effects, which was shown to produce consistent results with those from time-history analyses. Relationships between the degree of irregularity and the change in behaviour were developed. This information facilitates designers and plan checkers to rapidly evaluate the likely effect of irregularity on structures. It provides guidance as to: (a) when the effect of structural irregularity can be ignored, and (b) the change in demands for different degrees of structural irregularity. The relations developed also provide a rigorous technical basis for future regularity provisions in the NZS1170.5 and other world-wide seismic design codes.

In Turkey, most of the existing buildings are vulnerable to earthquakes due to their poor material quality and inaccurate design. Besides, so many destructive earthquakes occurred in the past, because Turkey is located on a seismically active region. Therefore, existing buildings should be assessed and necessary precautions should be taken before a probable earthquake. To assess seismic performance of the existing buildings, the 2007 Turkish Earthquake Code offers two methods which are linear and nonlinear. For linear assessment, members are controlled by comparing the force demands and capacities where for nonlinear assessment, strains corresponding to the plastic rotations of the members are compared with the limits given in the code. In this study, the building, which stands in Bakirk&ouml / y district of istanbul, was assessed according the linear elastic and nonlinear static procedures given in the 2007 Turkish Earthquake Code. In addition, it was retrofitted by adding shear walls to the structural system and same assessment procedures were performed. In the last case study, building is re-designed according to the code and re-assessed. Comparative results and conclusions were summarized in the last chapter.

Linear elastic and nonlinear analysis procedures of 2006 Turkish Seismic Rehabilitation Code are applied to medium rise reinforced concrete buildings. In this study, four storey residential buildings are designed according to the 1998 and 1975 Turkish Seismic Design Codes, and the analysis procedures are verified on these case studies. In addition to these buildings, the analysis procedures are tested on an existing school building before and after retrofitting. The assessment procedures employed in the 2006 Turkish Seismic Rehabilitation Code are based on linear elastic analysis (equivalent lateral load method, mode superposition method) / non-linear analysis (pushover analysis with equivalent lateral load method and mode superposition method) and non-linear time history analysis. In this study, linear elastic analysis with equivalent lateral loads and non-linear static analysis (pushover analysis) with equivalent lateral loads are investigated comparatively. SAP2000 software is used for pushover analysis / however the plastic rotation values obtained from SAP2000 are not used directly but defined according to the code procedures. Post-elastic rotations at yielding sections are transferred to Excel and the corresponding strains are calculated from these rotations by Excel Macro. These strains are compared with strain limits described in the 2006 Turkish Seismic Rehabilitation Code to obtain the member performances. In the linear elastic procedure, structural analysis is performed also by SAP2000 to obtain the demand values, whereas the capacity values are calculated by another Excel Macro. With these demand and capacity values, corresponding demand to capacity ratios are calculated and compared with demand to capacity ratio limits described in 2006 Turkish Seismic Rehabilitation Code to obtain the member performances. Global performances of the buildings are estimated from the member performances and from the inter-storey drifts for both two methods. The results are compared to each other, and critically evaluated.

The thesis deals with a description and a static and dynamic analysis for an existing construction of lookout tower. The steel watchtower is located in Město Albrechtice and is made up of two lattice towers connected by a bridge. Main point was to create calculation models for the purpose of dynamic and static analysis, in the software SCIA Engineer 19.1, which is based on the principle of finite element method. Attention was paid to load created by winds according to Eurocode 1 and Eurocode 3, glaze and rime ice load and dynamic coefficient calculation. The thesis also includes an assesment of selected parts of the construction according to Eurocodes.

The Insurance Bureau of Canada released a report in 2013 that evaluated the seismic risk of two major metropolitan areas of Canada, with projected losses of $75bn in British Columbia along the Cascadia subduction zone, and $63bn in the east through the Ottawa-Montreal-Quebec corridor. Such reports should prompt researchers and designers alike to rethink the way that seismic design is approached in Canada to develop resilient and sustainable cities for the future. To mitigate the economic losses associated with earthquake damage to buildings in seismically active areas, controlled rocking steel braced frames have been developed as a seismically resilient low-damage lateral-force resisting system. Controlled rocking steel braced frames (CRSBFs) mitigate structural damage during earthquakes through a controlled rocking mechanism, where energy dissipation can be provided at the base of the frame, and pre-stressed tendons pull the frame back to its centred position after rocking. The result is a building for which the residual drifts of the system after an earthquake are essentially zero, and the energy dissipation does not result from structural damage. Design methods for the base rocking joint and the capacity-protected frame members in CRSBFs have been proposed and validated both numerically and experimentally. However, the is no consensus on how to approach the design of the frame members, questions remain regarding how best to design CRSBFs to prevent building collapse, and no experimental work has been done regarding how to connect the CRSBF to the rest of the structure to accommodate the rocking motion. Because the force limiting mechanism of a CRSBF is rocking only at the base of the frame, the frame member forces are greatly influenced by the higher-mode response, resulting in more complex methods to design the frame members. This thesis begins by outlining two new design procedures for the frame members in controlled rocking steel braced frames that target both simplicity and accuracy. The first is a dynamic procedure that requires a truncated response spectrum analysis on a model of the frame with modified boundary conditions to consider the rocking behaviour. The second is an equivalent static procedure that does not require any modifications to the elastic frame model, instead using theory-based lateral force distributions to consider the higher modes of the rocking structure. Neither method requires empirical calibration to estimate the forces at the target intensity. The base rocking joint design is generally in good agreement between the various research programs pioneering the development of the CRSBFs. However, the numerous parameters available to select during the design of the base rocking joint give designers an exceptional amount of control over the performance of the system, and little research is available on how best to select these parameters to target or minimise the probability of collapse for the building. This thesis presents a detailed numerical model to capture collapse of buildings with CRSBFs as their primary lateral force resisting system and uses this model to generate collapse fragility curves for different base rocking joint design parameters. The parameters include the response modification factor, the hysteretic energy dissipation ratio, and the post-tensioning prestress ratio. This work demonstrates that CRSBFs are resilient against collapse, as designing the base rocking joint with response modification factors as large as 30, designing the post-tensioning to prevent yielding at moderate seismic hazard levels, and using zero energy dissipation could lead to designs with acceptable margins of safety against collapse. While the design procedures are shown to be accurate for estimating the frame member force demand for the targeted intensity level, there is still a high level of uncertainty around what intensity of earthquake a building will experience during its lifespan, and there is no consensus on what intensity should be targeted for design. To address this, the ability of the capacity design procedures to provide a sufficiently low probability of collapse due to excessive frame member buckling and yielding is evaluated and compared to the probability that the building will collapse due to excessive rocking of the frame. The results of the research presented here suggest that the probability of collapse due to either frame member failure or excessive rocking should be evaluated separately, and that targeting the intensity with a 10% probability of exceedance in 50 years is sufficient for the design of the frame members. Finally, critical to the implementation of CRSBFs in practice is how they may be connected to the rest of the structure to accommodate the uplifting of the CRSBF while rocking under large lateral forces. An experimental program was undertaken to test three proposed connection details to accommodate the relative uplifts and forces. The connections that accommodate the uplifts through sliding performed better than that which accommodated the uplifts though material yielding, but the best way to transfer the forces and accommodate the uplifting without influencing the overall behaviour of the system is to position the connection such that it does not need to undergo large uplifts and carry lateral force simultaneously. A detailed numerical model of the experimental setup is presented and is shown to simulate the important response quantities for each of the tested connections. Using the results of this work, designers worldwide will be confident to design CRSBFs for structures from the base rocking joint to the selection of floor-to-frame connections for a complete system design while ensuring a safe and resilient building structure for public use and well-being. / Thesis / Doctor of Philosophy (PhD) / Traditional approaches to seismic design of buildings have generally been successful at preventing collapse and protecting the lives of the occupants. However, the buildings are often left severely damaged, often beyond repair. To address these concerns, controlled rocking steel braced frames have been proposed as part of a new construction technique to mitigate or prevent damage to steel buildings during earthquakes, but several aspects of the design and overall safety have yet to be explored or demonstrated. This thesis proposes and validates new tools to design controlled rocking steel braced frames and provides recommendations on how best to design them to achieve a safe probability against collapse. Details are proposed and presented for components to connect the controlled rocking steel braced frames into the rest of the structure. The findings of this thesis will aid practitioners looking to deliver resilient and sustainable structural designs for buildings in our cities of the future.