In this paper, efforts are made to compare the safety of Steel moment resistant frames designed according to different editions of the Iranian code of Practice for seismic resistant design of buildings. Also, failure risk of a low and medium height frame which designed for high and low seismicity regions according to three editions of the code are evaluated. First, the testing cases were designed and based on a simplified method the fragility functions of frames were evaluated. The probability of failure of frames was calculated by multiplying the fragility function and hazard curves in probabilistic manner. The results indicate that, apart from some exceptions, every edition of new code pro-vides better safety for structures. However, within a single version of the code, the consistency of safety has not been maintained. The structures designed for low seismicity regions are more reliable than those which designed for high seismicity regions. Further research should address this issue and fix the possible.

During recent years, Shape Memory Alloys (SMAs) have been effectively used to control the seismic response of structural systems. Recovering the residual strains upon unloading (super-elasticity) or by heating (shape memory effect) is the main characteristic of SMA materials. This paper explores the efficiency of a proposed application of Steel & SMA bolts in improving the seismic behavior of connections in Steel Moment Resisting Frame (MRF) structures. A new semi-rigid, end-plate, beam column connection is introduced, which is based on parallel application of Steel and austenite-phase SMA bolts. A number of 3-D Steel MRF structural models with different numbers of stories and mass eccentricities are considered. These structural models that are designed by employing the conventional rigid and the proposed semi-rigid connections are subjected to bi-directional earthquake records that have been scaled according to ASCE7-05 procedure. Extensive nonlinear dynamic time history analyses are conducted to evaluate the efficiency of the Steel & SMA based connections in enhancing the seismic performance of the structural models. The obtained results indicate that the proposed Steel-SMA connection is highly promising and can efficiently reduce the seismic response parameters of the structural systems. Steel bolts of the end-plate connections contribute both to shear force transfer (from beam to column) and dissipation of the input seismic energy through hysteresis behavior. On the other hand, parallel application of Steel and SMA bolts in the connections reduces the story drifts as well as the induced forces in the structural elements while decreasing the permanent story displacements. The main goal obtained is to keep the beams away from the formation of plastic deformation. Open Sees platform is used for generating the structural models and performing the numerical analyses.

Probabilistic-based methods have been used for designing noise tolerant circuits recently. In these methods, however, there is not any reliability mechanism that is essential for nanometer digital VLSI circuits. In this paper, we propose a novel method for designing reliable probabilistic-based logic gates. The advantage of the proposed method in comparison with previous probabilistic-based methods is its ultra-high reliability. The proposed method benefits from Markov random field (MRF) as a probabilistic framework and triple modular redundancy (TMR) as a reliability mechanism. A NAND gate is used to show the design methodology. The simulation results verify the noise immunity of the proposed MRF-based gate in the presence of noise. In addition, the values from reliability estimation program show the reliability of 0. 99999999 and 0. 99941316 for transistor failure rates of 0. 0001 and 0. 001, respectively, which are much better as compared with previous reported MRF-based designs.

In this paper, the effectiveness of Tuned Mass Dampers (TMDs) in controlling building structures under earthquake excitations is studied through investigating the practical considerations and vibration control efficiency of tuned mass dampers for 5-, 8-, 10- and 15-story buildings utilizing a structural system with special Moment-Resisting Frames (MRFs) in both directions. Assuming its frequency to be near the 1st natural frequency of buildings, it is designed to control the largest response of the buildings. The effect of detuning, on some TMD parameters, on the seismic performance is studied through time-history analysis using the El Centro and Tabas earthquake records. In addition, the results of time-history analysis are compared with those of a response spectrum analysis for the structures with and without TMD, in order to judge its effectiveness. Under earthquake excitation, the performance of structures having TMDs greatly depends on the characteristics of the ground motion. When the first mode of a MDOF structure dominates the structural response, a seismic response reduction can be easily achieved. While the first mode response of a structure with TMD is proved to be substantially reduced, the higher mode response, in fact, increases as the number of stories increases. It is observed that TMD is effective in reducing maximum displacement in MRF buildings by as much as 32.2% in the Tabas earthquake and 45.3% in the El Centro earthquake. The maximum displacement results of a response spectrum analysis for the uncontrolled and controlled case in the El Centro earthquake, in an 8-story structure, are 25.70 cm and 14.59 cm, respectively, whereas themaximum displacement using time-history analysis, in the uncontrolled and controlled cases, are 27.54 cm and 15.14 cm, respectively.