Shaking table tests on reinforced concrete frames without and with passive control systems (original) (raw)
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Shape memory alloys (SMAs) are unique materials well suited to be used in structural earthquake engineering applications. The uniqueness arises from two specific behaviors known as shape memory effect and superelasticity, and the suitability is mainly because of the superelastic behavior. Superelastic SMAs can be used as braces to protect structures against earthquakes, both for earthquake-resistant design and anti-seismic retrofit purposes. This paper reports on an applied research in this field, including also a case study. The case study building is a typical 4-story residential building with steel braced frames, located in Khorramshahr, Iran. Direct displacement-based design method is followed for the calculation of the dimensions of SMA elements. The superelastic behavior of SMAs is simulated through the phenomenological modeling, verified by experimental evaluations. Seismic performances are studied in details and it is shown that such an application is feasible and effective....
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Shape Memory Alloys (SMA's) are able to reach very large recoverable strains. They have found their means into many inventive applications including seismic structural control. Due to their recentering capability as well as damping capacity, SMA materials are favorable for use in earthquake applications. The main idea of this research is the simultaneous use of SMA elements in different phases and steel elements is structural systems, in order to utilize each favorable characteristics. Damping capacity of Martensite phase of the SMA will leave residual strains in structure which is in contrast with the recentering characteristic of Austenite phase of the SMA. Therefore an attentive arrangement will be required in order to get the best structural performance. In this article an initiative was taken for arranging different states of SMA materials in structures as bracing elements in order to reach the best feasible performance.
Journal of Intelligent Material Systems and Structures, 2019
Smart materials such as shape memory alloys have unique material properties that can potentially mitigate earthquake hazards on the built environment. Implementation of shape memory alloy-based devices on building structures should incorporate two key factors: (1) distinct mechanical features of the devices and (2) inherent large uncertainty stemming from material properties, building geometry, and ground motions. This study conducts seismic fragility analyses of steel building frames installed with superelastic shape memory alloy dampers, which enable both factors to be appropriately considered. First, a thermomechanical constitutive model is utilized to capture all essential characteristics of the shape memory alloy damper. Next, a probabilistic seismic analysis framework is developed to obtain the seismic demands of three critical engineering demand parameters (i.e. peak interstory drift ratio, residual drift ratio, and top floor acceleration) of the building when subjected to mo...