Warm mix asphalts (WMA), because of their low production and compact temperatures, may have different behaviors in long term. In the present work, the energy-based criteria along with the 50% reduction in initial stiffness (Nf50%) using four-point bending test under controlled-strain conditions of 1000 microstrain were applied to compare the prepared two warm mix and HMA samples. All these criteria illustrate properly the effect of mix asphalt properties (additive type) on its fatigue performance. A noteworthy point in this regard is the difference between Nf50% values of the studied samples with the real failure point. For HMA and zycotherm WMA (ZWMA), loading cyclic number at the failure moment occurs almost 80% higher than the fatigue life estimated using Nf50% while for Sasobit WMA (SWMA) this value is declined to 28%. The RDEC method, compared to other methods, indicated the maximum fatigue life and consistency with the failure point. Comparing the energy-based methods with Nf50% method revealed that ERR, ERR&B, and ERP have the maximum consistency with fatigue life in terms of 50% reduction in initial stiffness. For SWMA, the fatigue life at Nf50% was larger than that of various energy-based methods but almost equal to that of the RDEC method. However, for two WMA mixes prepared using ZWMA and HMA, all energy methods revealed a fatigue life longer than that of Nf50%.

Dynamic shear stiffness is a key parameter for determining the soil behavior for site analysis under strong ground motion. The dynamic shear modulus reduces during cyclic loading due to the loss in the soil shear strength. Besides, the soil behavior depends on the loading direction due to the anisotropic nature of the soil. Thus, the anisotropic shear stiffness should be determined for accurate modeling of the soil in the models able to incorporate the anisotropy to estimate the soil's behavior. The models based on the dissipated energy are appropriate for determining the model parameters at different loading conditions. In this study, the shear stiffness of dense Babolsar and Toyoura sands obtained from torsional shear apparatus have been compared, and the effect of major principal stress has been evaluated. The specimens were similarly prepared to the relative density of 75% and then isotopically consolidated before shearing. The shear stress was applied in a stress-controlled manner under a unique deviator stress ratio but at different major principal stress directions. The variation of shear stiffness under different loading direction were evaluated. Results indicated that the major principal stress direction has a significant influence on the dynamic shear stiffness. On the other hand, a unique relationship for the evolution of shear stiffness can be obtained using the dissipate energy approach.

Undoubtedly, bridges have substantially effect in metropolitan areas and are usually built to connect between two roads in order to decrease traffic. Pounding, is one of the important parameters to design different bridges as this structures should be controlled during seismic excitation to provide safety conditions in order to organize and support unpredictable situations. During very strong earthquake, bridges may experience large horizontal relative displacement, which may lead to pounding if sufficient gap size is not considered between adjacent slabs of bridge. Insufficient separation distance is naturally caused to collide between two slabs and, subsequently, stiffness of bridge is decreased and finally, collapse is occurred. In order to determine impact force and also absorption energy during collision, many researchers have demonstrated different theories and also suggested various equations by using impact velocity before and after impact. In this study, special element is used between two slabs to determine impact force and a new equation of motion is mathematically presented to calculate impact damping ratio focusing on coefficient of restitution.

The dissipated energy from periodic deformation is regarded as the main reason for heat generation and temperature rise inside the tire domain. However, the mechanical behavior of rubber parts is highly temperature dependent. In most performed investigations, the influence of thermal effects on stress/ deformation fields of pneumatic tires is ignored and just temperature distribution is considered. Hence in this study, using a series of 2D and 3D finite element models, a robust and efficient numerical study is presented for thermo-mechanical analysis of pneumatic tires specially 115/60R13 radial tire. Finally, the effects of loading condition s and ambient temperature on the thermo-mechanical properties of tire are investigated in detail. Comparing the obtained results with the available results in literature, shows a good agreement of the presented studies with related published works.

In this paper, the hybrid friction-yielding damper in the center of X-braced steel frame for dissipating seismic energy and its design methodology are introduced. Due to their relative simplicity and easy application with no need for any special material or technology, this high performance system have gained more attention compared to other means of energy dissipation devises. The advantage of failure localization at circular damper cause this system can be used for rehabilitation of existing building whose slender braces designed based on tension forces only. Possibility of Prompt installation of new ones after strong earthquake is another advantage of this simple system.

Baffled aprons or Chutes have been in use on irrigation projects for many years. The fact that many of these structures have been built and have performed satisfactorily indicates that they are practical and that in many cases they are an economical answer to the problem of dissipating energy. Baffled chutes are used to dissipate the energy in the flow at a drop and are most often used on channel waste ways or drops. During the past 2 decades, heuristic and metaheuristic optimization techniques have emerged as a promising solution, offering several benefits and possibilities. (Saberi et al., 2021; Sedaghat et al., 2019).

The main sources of the uncertainty in estimation of structural seismic responses is the uncertainty of the earthquake records as the input excitations. In recent years, along with the development of performance-based seismic design approaches, importance of the record selection strategies in nonlinear response history analysis of structures has been highlighted and has attracted the attention of many researchers. Record selection in performance-based seismic design approaches is often done based on the intensity measure of the records. The spectral shape has been introduced as a powerful intensity measure in record selection techniques for estimation of some structural responses such as the maximum inter-story drift ratio. In the present study, the sufficiency of the spectral shape in assessment of hysteresis energy of the structure and the maximum Park Ang damage index in plastic hinges has been investigated in special moment-resisting RC frames. In this way, four 2D structural models of special moment-resisting RC frames with inelastic characteristics have been analyzed under a set of strong ground motion records selected based on the spectral shape by the conditional spectrum method. After determination of numerical values of hysteresis energy of the structure and maximum Park-Ang damage index in the plastic hinges, the correlation of such responses have been investigated with the various secondary intensity measure. These intensity measures are selected such that they cover various properties of strong ground motion records such as frequency content and duration. The results indicate that spectral shape is not sufficient for prediction of hysteresis energy and Park-Ang damage index of special moment-resisting RC frames. To obtain an unbiased and reliable estimate of such responses, more studies on record selection strategies is needed. Among the secondary intensity measure, those associated with the energy content and duration of the records are more correlated with the aforementioned structural responses.

This research investigated the possibility of predicting the fatigue life of reinforced asphalt by recycled polyethylene terephthalate (PET) fibers based on dissipated energy parameters. Fatigue tests were performed using 4-point bending test at three temperatures of-5، 10 and 20oC and two frequencies of 10 and 2 Hz. Fibers were incorporated at two lengths of 1 and 2 cm and average diameter of 30 micrometer. Furthermore، four fiber contents including 0. 5، 1. 0، 1. 5 and 2. 0% by weight of bitumen were used. Obtained fatigue laws showed an increase by increasing the test temperature. At a constant frequency، the fatigue lives of reinforced specimens were higher than the reference one. The beneficial effects of fibers were more pronounced at higher temperature and lower initial strain levels. Traditional fatigue models used the initial dissipated energy or cumulative dissipated energy to predict fatigue life. In newly established models the plateau value (PV1) parameter has been defined using the ratio of dissipated energy changes in plateau stage of dissipated energy curve obtained from 4-point fatigue test. In this research a new definition was presented to calculate the PV parameter (PV2). Based on statistical analysis power functions were presented to predict fatigue life based on PV1 and PV2 parameters. The relationships between PV and fatigue life was unique independent of the mix type and testing conditions (i. e. temperature، frequency and strain level). Furthermore، the fatigue model based on PV2 parameter was as precise as that presented using PV1.

Since the structure and foundation are built on soil, the soil is the major platform by which seismic vibrations are transmitted to the structure, and has noticeable effects on the response and behavior of structure during earthquakes. In this research, the recently introduced Performance-Based Plastic Design (PBPD) and its Modified Performance-Based Plastic Design (MPBPD) method in which soil and structure interaction effect has been considered underwent the seismic evaluation. In order to do evaluation, a twenty-floor concrete structure with MPBPD method and conventional PBPD was designed and analyzed in accordance with the time history of the 22 far-field quake records. In this study, cone model is employed for modeling the soil and foundation. With a detailed three-dimensional finite element model of a twenty-story high-rise structure constructed and exploited in the OpenSees software, it is attempted to consider a more realistic behavior of the structure. The results of six related parameters with the maximum response of the structure demonstrate the efficiency and performance of the MPBPD method for the purpose of considering the SSI effect, compared with the conventional method of PBPD. The Results show that, in the MPBPD design method, maximum displacement, acceleration, inter-story drift and shear force dropped leading to a better distribution of energy in the structure compared to the PBPD method.

Stilling basin is one of the dissipated energy structures in water transfer systems that its dimensions depend on the characteristics of hydraulic jump. In present study, six legs elements have been used in different permeability on basin bed and the changes of shear stress, sequent depth and the length of jump have been investigated. Experiments were conducted in a rectangular flume of 7.5 m long and 0.3 m wide and six legs elements were arranged on the bed of flume with density percent 36, 63 and 100 in such a way that the incoming water jet was just above the elements surface. The incoming Froude number was in the range of 5.3 to 8.1 and during each test the water surface profile and characteristics of hydraulic jump type A were measured. The results indicate that the most reduction of sequent depth ratio and dimensionless length of jump occur when the density of elements is 36%. In this study, relations have been presented for the sequent depth of hydraulic jump and shear force coefficient of bed as a function of the Froude Number for six legs elements.