The present research is concerned with the determination of ductility, over-strength and response modification factors of coupled steel shear wall frames. Three structural models with various numbers of stories, bay width and coupling beam height were analyzed using static pushover and incremental nonlinear dynamic analyses. The ductility, over-strength and response modification factors for the three models are determined. Tentative values of 11.1, 11.6 and 10.6 are suggested for the response modification factor of coupled steel shear wall frames with deep and medium depth coupling beams, and uncoupled steel shear wall frames, respectively in the allowable stress design method.

In recent decades the use of special truss moment frames has been developed as relatively new steel frame systems in high seismic zones. These frames dissipate the seismic energy through the specific ductile parts that are located near the middle of the span of the truss beam. In this study the response modification factor of steel moment frames with specific truss beams due to the ductility and over strength was determined. The analysis was carried out using linear static analysis (pushover). In order to consider the nonlinear behavior of the material in formation of the plastic hinge, it was used the elasto-plastic behavior and it was assumed that the plastic hinge are created at the top and bottom of the column and beam. The analyses are carried out for two types of the frames, Vierendeel and across diagonals frames. These frames are evaluated for two cases, two and three spans, and also for different stories, 3 to 8-story. The results are shown that the response modification factor of the Vierendeel frame is more than the across diagonal frame’s and has a better seismic performance. The results also show that the response modification factor is dependent on the height of the structure, so that this factor is increased with increasing the height of the structure.

Road traffic crashes are one of the major causes of deaths and injuries around the world. Approximately 1. 2 million people (2. 1% of all deaths) are killed every year and over 50 million are injured or disabled worldwide due to road traffic crashes. To control speeding and deaths different approaches regarding the road function has been proposed already. Speed cameras are one of these options in use. It has been approved that they are effective in reducing speed and crashes near speed cameras locations. This Study aims at evaluating the highways speed cameras through the Naï, ve and Naï, ve adjustment method in city of Mashhad. In this study Mashhad highway network was evaluated by before and after study and speed cameras crash modification factor was calculated for the first time for these cameras. This study revealed that these cameras are most effective in reducing invulnerable crashes however they are effective in reducing vulnerable crashes.

The idea of using steel plate shear wall (SPSW) has been noted for last three decades as a lateral load resisting system in design and retrofit of buildings. Knowing the short life of researches on this system and the necessity for replying to some design problems, in this research, it has been tried to determine the effect of ductility factor on force modification factor of SPSWs by using results of two cyclic tests on ductile SPSW's with three stories and other creditable experiments which have been done around the world. In the three-storey tests, two different connections (simple and fixed) and for panel’s plate, easy-going steel (EGS) are used. Assessment in this area shows that, the force modification factor of thin SPSWs with constant overstrenght factor based on Uang's methode is more than this factor of moment resisting frames.

Response modification and deflection amplification factors are used in the current seismic design codes to account for the inelastic behaviour of structural systems without the need for complicated nonlinear analyses. A deflection amplification factor, cd, is used to compute the expected maximum inelastic displacement from the elastic displacement induced by the design seismic forces. The response modification factor, R, expressed as either a force reduction factor or a behavior factor, is used to reduce the linear elastic design response spectra. It is generally expressed as the product of three factors: overstrength factor, ductility factor, and redundancy factor. This paper tries to evaluate these factors for steel intermediate moment-resisting frames. For this purpose, two dimensional steel building models with different number of stories have been designed and analyzed. After obtaining pushover curves of the models, two different approaches have been adopted to calculate the effective parameters of the response modification and deflection amplification factors from pushover curves; the first approach that is suggested by seismic code provisions, like ATC-19, FEMA-356 and Iranian Standard No. 2800, uses the idealized pushover curve to specify the effective parameters, and the other approach that is recommended by FEMA-P695 gets the parameters directly from pushover curves. The obtained results from these two approaches for the above-mentioned factors have then been compared with each other and with the recommended values of these factors in the Iranian Standard No. 2800. In this evaluation, ductility factor of the response modification factor has been calculated based on the relations proposed by Newmark and Hall, Lai and Biggs, and Nassar and Krawinkler. According to the obtained numerical results, the average response modification factor resulted from the FEMAP695 approach is 5.26, while this factor was obtained 3.98 based on the Iranian Standard No. 2800 approach. Considering the recommended R factor of the Iranian Standard No. 2800 for the ultimate limit state design of steel intermediate moment-resisting systems equaling 5, it is obvious that the results from the FEMA-P695 approach are more compatible with the code recommendation. In addition, the average over strength factors, according to the FEMA-P695 and Iranian Standard No. 2800 approaches, are 2.37 and 1.80, respectively, when the recommended value of this factor in the Iranian Standard No. 2800 is 3. The average deflection amplification factor obtained from both approaches is 3.67 that is slightly less than the recommended value of 4 for this factor in the Iranian Standard No. 2800.

The purpose of this paper is determination of response modification factor of shaft supported concrete elevated water tanks using nonlinear static (pushover) and nonlinear dynamic analysis. At First, using incremental nonlinear time history analysis, the seismic capacity curve is obtained and structural response modification factor has been computed. Then response modification factor is computed using pushover analysis with several load patterns. Shear effect on structural behavior is evaluated using the new procedure. Finally, using the proposed analytical procedure, the response modification factor is calculated. In the analytical method the effects of P- D, type of loading, plastic hinge in shaft and effect of stiffness variability in height of shaft is considered. The result represents the validity of the proposed analytical procedure.

Frictional dampers are widely used in civil engineering structures as means of passive controler in order to dissipate the energy created by earthquake. One of the frictional dampers that have been recently introduced is called Cylindrical Frictional Damper (CFD). Several researches in the area of the energy absorption capacity of the CFD, meaning hysteretic behavior, have been performed by the authors.In this research, response modification factor of steel moment resisting frames equipped with Cylindrical Frictional Dampers is evaluated. Utilizing this factor, the standard seismic design code procedure can be applied to the frames equipped with CFDs. In order to achieve this task, Static pushover analysis, nonlinear incremental dynamic analysis and linear dynamic analysis of various structures have been performed.The results show that the response modification factor of steel frames equipped with frictional dampers is greater than that of conventional steel frames which in turns reduce the seismic forces and leads to a lighter structure. Finally, values of 11 and 16 have been suggested for ultimate limit state and allowable stress design methods respectively.

In this paper the response modification factor due to ductility and saved strength of cylindrical concrete elevated and ground tanks is obtained using finite element method and nonlinear push over analysis considering the lateral effective modes of tanks. To modeling the behavior of the tank materials, the five parameters William-Warnke and prefect elastoplastic models are used for concrete and reinforcement rebars respectively. In the calculations the reinforced bars are modeled both exactly and as percentage of concrete surface area. In addition it is assumed that the foundation of the structure is absolutely rigid and contained water has linear behavior. The response modification factor is obtained for different performance levels by changing different parameters such as height, thickness, radius, and percentage of the rein forcementbars of the shaft and shell, thickness and dimensions of stiffener and water level. The obtained results show that the factor for the elevated tanks changes between 4and 5 and the factor for the ground tanks varies between 1 and 2.5 these changes depend on the performance levels for the tanks.

Response modification factors (R-factor) are used in current seismic building codes to reduce earthquake forces associated with seismic design level to determine force levels. In recent years, many authors have shown great interest in the development of seismic structural systems and several theoretical and experimental studies have been conducted to investigate performance of dampers, but little attention is given to the response modification factors of steel-braced frames equipped with friction damper. In this study the effect of pall friction damper, as an additional element to the structure, on the parameters of seismic behavior of steel braced frame is evaluated. Along with the pushover analysis, nonlinear dynamic analysis has been adopted to investigate the components of the behavior factor. For this purpose three steel frames of 5, 8 and 10 stories were analyzed without considering the existence of dampers, then each frame equipped with a friction damper of various slip loads-3, 8, 15, 20, 50 and 100 percentages of weight of the structure- is studied. The results show that behavior factor of chevron braced frame equipped with friction damper depends on its slip load and changing the R-factor can be an appropriate method to design steel frames equipped with friction damper.

In current seismic design codes, the primary objective is to prevent structural collapse during strong earthquakes while allowing controlled damage in certain structural and non-structural components. This controlled damage mechanism provides considerable energy dissipation, which is a key factor in ensuring life safety. Most design codes formulate their requirements based on equivalent linear analyses. However, the lateral force distributions suggested by these codes such as the equivalent static method often lead to non-uniform inter-story drift demands, which may cause drift concentration in specific stories. Consequently, permanent deformations can develop in structural members due to inelastic responses. Buckling-Restrained Braces (BRBs) effectively address this issue by dissipating the majority of seismic input energy, thereby concentrating inelastic behavior within themselves and preventing the main structural members from entering the nonlinear range. Although seismic codes assign constant response modification factors (R) to different structural systems, numerous studies have shown that adopting a single fixed value can underestimate story drifts. This underestimation increases axial strain demand in BRBs and may result in residual deformations or soft-story mechanisms. In this study, the response modification factor is evaluated for diagonal and Chevron BRBF configurations in 4, 8, and 12-story buildings with both moment and pinned beam-to-column connections. The R-factors of these systems are proposed as functions of building height. Finally, the structural reliability of models designed with the calculated R-factors is compared against those designed using the constant values prescribed in Iranian Standard No. 2800. The results indicate that, due to the significant variation of R in BRBF systems (ranging from 4 to 13 depending on configuration), using constant values of 7 or 8 as recommended by Iranian and U.S. codes is not appropriate, particularly for structures with eight stories or more. Such simplification may underestimate seismic demands and consequently increase the probability of structural failure during earthquakes.