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Civil infrastructures such as bridges and buildings are prone to damage as a result of natural disasters. To understand damages induced by these events, the structure needs to be monitored. The field of engineering focusing on the process of evaluating the location and the intensity of the damage to the structure is called Structural Health Monitoring (SHM). Early damage prognosis in structures is the fundamental part of SHM. In fact, the main purpose of SHM is obtaining information about the existence, location, and the extent of damage in the structure. Since numerous structural damage detection problems can be solved as an inverse problem based on the proposed objective functions by using optimization algorithm, in this paper, related studies are investigated which discussing objective functions based on Modal Strain Energy (MSE) and flexibility methods including Modal Flexibility (MF), and Generalized Flexibility Matrix (GFM). To illustrate the extent of effectiveness of these objective functions based on the above-mentioned modal parameters, an efficiency index called Impact Factor (IF) is defined. Finally, the best objective function is introduced for each numerical case study based on IF by means of evaluating the obtained result.

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The impact damper is a passive method for controlling vibrations of dynamic systems. It is designed by placing one or several masses in a container, which is installed on the structure. Damping performance is affected by many parameters, such as the mass ratio of the primary structure, size, number, and material of the particles, friction and restitution coefficients of the particles and gap distance. Impact damper is effective, economical, and practical and its functionality can be further enhanced by an optimal design. In this paper, first, the mathematical modeling of a rigid impact damper used in free vibration reduction of a single degree of freedom (SDOF) system is performed. The results on this step are validated with those results of previous studies, and a good agreement is achieved. Next, the robust hybrid optimization method that is called Imperialist Competitive Ant Colony Optimization (ICACO) is introduced. After that, the damper function is optimized using ICACO, and the optimum values of the effective parameters for maximizing damping effectiveness are obtained. Comparing the results of the optimized and the basic designs shows that the optimization method is robust and the optimal results are practical. The optimum design of damper parameters using ICACO method can damp more than %94 of the system’s initial energy in a short time.

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Explosions are inevitable in today’s world; therefore, building structures may be dynamically loaded by an intense loading during the explosion. This is why regulatory bodies have provided instructions for determining the response of structures under the explosion load. Previous research has shown that when the explosion happens close to a structure, the ground explosion load can be modeled as tensile and compressive loads. This research investigates the response of an elastic-plastic single-degree-of-freedom system subjected to different explosive loads with different positive durations. The maximum intensity of blast load and blast duration remains constant, and the positive phase duration is the only variable that changes. The nonlinear dynamic responses of a single-degree-of-freedom system (i.e., displacement, velocity, acceleration, and ductility) are calculated using the linear acceleration method. The results show that increasing the positive phase duration and the amount of positive impact can increase the maximum displacement and ductility of the system. Also, it can be concluded that the maximum acceleration of the studied systems remains constant when the values for the blast impact and positive phase durations change.
 

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The global population growth and the subsequent surge in housing demand have inevitably led to an increase in the demand for concrete, and consequently, cement. This has posed environmental challenges, as cement factories are significant contributors to carbon dioxide emissions. One promising solution is to incorporate pozzolanic materials into concrete production. This study investigates the effects of using travertine sludge as a partial substitute for cement. Seven different mix designs, along with a control mix, were created and compared. The primary variable was the ratio of travertine sludge to cement weight, considered in intervals of 10%, 15%, 20%, 25%, 30%, 35%, and 40% of the cement's weight. Various tests were conducted, including compressive strength and flexural strength at ages of 7, 28, and 90 days, as well as a permeability test at 28 days. The findings revealed interesting patterns. At the 7-day mark, as the percentage of travertine sludge increased, there was a decrease in compressive strength. However, by the 28-day mark, the concrete displayed a varied behavior: using up to 30% travertine sludge by weight reduced the strength, but exceeding 30% resulted in increased strength. At the 90-day mark, an overall increase in strength was observed with the rise in travertine sludge percentage. Such pozzolanic effects on compressive strength were somewhat predictable. Additionally, based on the flexural strength tests, travertine sludge can be deemed a viable substitute for a certain percentage of cement by weight. This research underscores the potential of sustainable alternatives in the construction industry, promoting both professional development and personal branding for those engaged in eco-friendly practices.