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SUMMARYThe optimal design and placement of controllers at discrete locations is an important problem that will have impact on the control of civil engineering structures. Though algorithms exist for the placement of sensor=actuator systems on continuous structures, the placement of controllers on discrete civil structures is a very di cult problem. Because of the nature of civil structures, it is not possible to place sensors and actuators at any location in the structure. This usually creates a non-linear constrained mixed integer problem that can be very di cult to solve. Using genetic algorithms in conjunction with gradient-based optimization techniques will allow for the simultaneous placement and design of an e ective structural control system. The introduction of algorithms based on genetic search procedures should increase the rate of convergence and thus reduce the computational time for solving the di cult control problem. The newly proposed method of simultaneously placing sensors=actuators will be compared to a commonly used method of sensors=actuators placement where sensors=actuators are placed sequentially. The savings in terms of energy requirements and cost will be discussed.

SUMMARYThe dynamic response of tall civil structures due to earthquakes is very important to civil engineers. Structures exposed to earthquakes experience vibrations that are detrimental to their structural components. Structural pounding is an additional problem that occurs when buildings experience earthquake excitation. This phenomena occurs when adjacent structures collide from their out-of-phase vibrations. Many energy dissipation devices are presently being used to reduce the system response. Tuned mass dampers (TMD) are commonly used to improve the response of structures. The sti ness and damping properties of the TMD are designed to be a function of the natural frequency of the building to which it is connected. This research involves attaching adjacent structures with a shared tuned mass damper (STMD) to reduce both the structures vibration and probability of pounding. Because the STMD is connected to both buildings, the problem of tuning the STMD sti ness and damping parameters becomes an issue. A design procedure utilizing a performance function is used to obtain the STMD parameters to result in the best overall system response.