Nowadays, civil engineers are looking for novel approaches to develop structural performance and the speed of building construction simultaneously. One of these approaches is using of Rectangular spiral stirrups instead of traditional stirrups in manufacturing of RC beams. Based on recent experimental studies, these beams have shown some advantages in performance when compared with beams reinforced by traditional stirrups and in some cases, the results were much better. In this study, at the first stage, two types of RC beams with Rectangular spiral stirrup and traditional stirrups were simulated in the ABAQUS software and verified under monotonic Loading. The shear capacity was measured and based on the experimental force-displacement curves, validation was performed. Then, at the second phase of this research, another RC beam with traditional stirrups was simulated and was verified against push-over curves and force-displacement of monotonic Loading and failure mode obtained from an experimental study. A Cyclic Loading was applied to the beams with continuous Rectangular spiral and traditional stirrups. Then, the performance of those simulations was compared by envelop strength curves. But in the Cyclic Loading phase, in most cases, the performance of beams with these two transverse reinforcement methods is equivalent and in some cases, the traditional one has shown even better results.

Background and Aim: A key factor in restoring the endodontically treated teeth is ferrule preparation. When the ferrule is absent, occlusal loads may cause the post or root to fracture. The purpose of this in vitro study was to evaluate the effect of ferrule preparation on fatigue resistance of teeth restored with quartz-fiber posts.Materials and Methods: Twenty single-rooted lower premolars having similar dimentions were randomly devided into two groups of 10. In control group the teeth were prepared with 3-mm of remaining coronal tooth structure and in test group teeth were prepared with 1-mm of remaining coronal tooth structure. The teeth were endodontically treated. 9-mm long Post holes were prepared, and D.T. light quartz-fiber(RTD,France) posts were cemented with Panavia F2(Kuraray,Japan).Then the core build up was done with Bisco core build up composite(Bisco,USA) and full metal crowns were cemented with Zinc phosphate(Harvard cement, Germany). All specimens were mounted in acrylic resin blocks and intermittently loaded (180 N) at an angulation of 45- degree to the long axis of the teeth at a frequency of 4 loads per second, until failure occurred.Results: There was significant difference between the loads cycles of two groups studied. (p<0.0001).Conclusion: The results of this study showed that an increased amount of coronal dentin significantly increases the fracture resistance of teeth restored with quartz-fiber posts.

Background and Aims: Failure of bonding between artificial teeth and denture base material is a considerable problem for patients who wear dentures. According to the different impact of artificial teeth and different information about resistance force of mastication and also with deficiency in researchs, this study was designed to compare the bond strength of composite and acrylic artificial teeth to auto-polymerized denture base resins with and without Cyclic Loading.Materials and Methods: In this experimental and in vitro study, an acrylic resin auto-polymerized (Rapid Repair, Dentsply) and four artificial teeth (Acrylic Marjan new, Composite Glamour teeth and Ivoclar acrylic and composite teeth) were used. Therefore, 8 groups of 10 specimens each were evaluated. All specimens were thermocycled for 5000 cycles, in water baths between 5 and 55oC. Half the specimens in each group were treated with Cyclic Loading at 50N for 14, 400 cycles at 1.2 Hz.The shear bond strengths were measured using a Universal Testing Machine. Data were analyzed using Two-way ANOVA test.Results: Statistical analysis demonstrated no significant effect of Cyclic Loading on the shear bond strength, but the type of artificial tooth affected the shear bond strength (P=0.006). Also, the interaction between Cyclic Loading and the type of artificial tooth showed no significant difference (P=0.98). Tukey test showed that acrylic teeth (Ivoclar) had statistically higher bond strength values than that of other teeth (PGlamour=0.02), (PComposite ivoclar=0.01) and (PMarjan new=0.02).Conclusion: Within the limitation of this study, the predominant type of fracture in all groups was cohesive, therefore the bond strength was adequate in all teeth and the type of artificial tooth may influence the bond strength of denture teeth to denture base resin. Cyclic Loading had no significant effect on the bond strength of denture teeth to the auto-polymerized acrylic resin.

Background and Aim: Microgap in the implant-abutment interface is one of the main challenges in the treatment of two-piece implants. This study aimed to investigate the effect of two types of abutments (zirconia and titanium) on microgap at implant-abutment interface area under oblique Cyclic Loading in vitro. Methods and Materials In this in vitro study, 12 implant-abutment assemblies were used, each containing six sets with either zirconia or titanium abutments and vertically mounted in the modified resin blocks of auto-polymerized polyester base. The specimens were then subjected to oblique Cyclic Loading of 75 N at a 30 ± 2 degrees angle to the longitudinal axis of the implant with a frequency of 1 Hz in 500, 000 cycles, equivalent to 20 months of human mastication. For the microgap analysis, direct observation from the top was used with a scanning electron microscopy (SEM) with a magnification of 5000×. Statistical analysis was used to compare the microgap before and after the application of Loading with the paired t-test. Results: The amount of microgap before force application in the titanium abutment group was (2. 6± 0. 7) significantly higher than the zirconia abutments (1. 9± 0. 5) (P = 0. 033). The dimension of the microgap in the titanium abutment group significantly decreased following Cyclic Loading (P = 0. 047), but in the zirconia group showed a significant increase (P = 0. 035). Finally, the dimension of the microgap following oblique Cyclic Loading in the titanium abutment group (2. 0± 0. 8) was not significantly different with the zirconia abutments (2. 7± 0. 9) (P = 0. 262). Conclusion: The difference of microgap after oblique Cyclic Loading between two types of titanium abutment and zirconium abutment is not significant, and both are clinically acceptable.

Vertical drains and stone columns which have been used in infrastructure construction for highways, ports, coastal regions, etc., provide significant benefits for improving soil characteristics such as reducing the drainage length and accelerating the consolidation process. So the investigation of the radial consolidation is inevitable. Soils may be subjected to Cyclic Loading such as silos, tanks, etc. This paper presents semi-analytical solutions for radial consolidation and investigates the consolidation behavior under three types of Cyclic Loading. Consolidation under Cyclic loads was calculated using the superimposition rule. Barron (1948) and Olson (1977) have presented theories for calculating radial consolidation under static and ramp load respectively. In this study, by using a set of continuous static loads or a series of infinite ramp loads, with alternatively positive and negative signs, we have extended these theories for Rectangular, triangular and trapezoidal Cyclic loads. The obtained analytic results demonstrate that the average degree of consolidation at the steady state depends on the integral of the load-time curve for each cycle and it increases with increase of the integral and the results indicate that change in cycle period of time does not effect on the time of getting steady state. Radial and vertical consolidation under Rectangular Cyclic Loading have also compared and the effect of the distance between vertical drains on the time of getting steady state have investigated.

Background and aim: Oral microbiota could proliferate the microspace between the implant and abutment, thereby cause inflammation in the peri-implant tissues and adjacent bone. This study aimed to investigate the effect of two types of abutments (zirconia and titanium) on microleakage at implant-abutment interface area under oblique Cyclic Loading in vitro. Materials and methods: In this in vitro study, 12 implant-abutment assemblies were used, each containing six sets with either zirconia or titanium abutments and vertically mounted in the modified resin blocks of autopolymerized polyester base. The specimens were then subjected to oblique Cyclic Loading of 75 N at a 30 ± 2 degrees angle to the longitudinal axis of the implant with a frequency of 1 Hz in 500, 000 cycles, equivalent to 20 months of human mastication. To determine the penetration of fuchsine into the implant-abutment interface, the implants were cut by cutting machine from the middle. Then, the rate of penetration of fuchsine in each sample was measured by a stereomicroscope with a magnification of 75 × at three points of each semicircle, and the average of these six points was recorded as a microleakage. For comparison of the microleakage after Loading, t test was used. All tests were performed in SPSS ver. 22 software and a significant level of 0. 05 was considered. Results: The amount of microleakage after oblique Cyclic Loadingwas statistically significantly higher in the zirconia abutments (66. 08± 11. 66) compared to the titanium abutments (39. 17± 10. 65)following force application (P = 0. 002). Conclusion: The microleakage following oblique Cyclic Loading is different depending on the type of abutment, so that the titanium abutments showed significantly less microleakage than the zirconia abutments.

Pullout resistance of cement-grouted soil nails is a key factor affecting the safety conditions of retaining walls, slopes and excavations. Hence, survey of resistence of pullout nail is the one of the most important parameters in designing of nailing functions. This parameter depends on critical factors including: instalation method, overburden pressure, grouting pressure, degree of saturation of the soil, the roughness of nail surface, changes of lengh & diameter of nail and the shear strengh of the soil. Sometimes, used soil nail layers affected by Cyclic loads due of traffic passing, train and so on. Hence the research aimed to study influence of this kind Loadings on resistence of nail post-Cyclic pullout and affective factors on it. The study pointed to apply slopes and nailed retaining walls next to traffic loads and rail-roads. Several studies conducted,according to, vary factors influence on nail pullout behavior that buried into soil. Key studies carried out in form of impression of static Loading on nail pullout resistance including: overburden stress, grouting stress, impression of an addition to grouting, nail geometry, nail spaces, using spiral nails, comparison laboratory results of pullout set with direct shear test in interface grouted-nail to earn identical ratio and etc. yet, it not examineted Cyclic Loading impression on post-Cyclic pullout resistance in nails. The study just focus on geogrid. For the first time, this research provide impression of Cyclic Loading on post-Cyclic pullout resistance in nails. This research used nail pullout set,able to apply static and Cyclic loads in conditions of force or displacement controling with differnt frequencies and sinus shape of Cyclic wave. This search used the notes of specifications of pullout set,also, sampling due to test and tables of done tests. In this research examined affection of variation of static, Cyclic load rate. Resistance of post-Cyclic pullout nail generally is more to static pullout resistance,even though, more affections of Cyclic Loading lead to decrease of resistance,also, observed in the Cyclic part developing in displacement. Results shown increasing amplitude of Cyclic Loading in exchange of same satatic pullout force,is unlinear decreasing post Cyclic resistance. Even though, increasing amplitude of Cyclic Loading in exchang of decreasing of static pullout force (when affection of complex of two mentioned parameters is unchanged), it is linear decreasing post Cyclic pullout.

The energy absorption of concrete filled, hollow-steel bracing was analyzed respect to geometric and mechanical parameters including the width-to-thickness section ratio, slenderness level, and strength of the steel and concrete. Local buckling and ductility were also investigated with respect to variation in the cross-section. The infill increased the compression resistance, even after multiple, inelastic load reversals. This resulted in improved ductility capacity by limiting local buckling and in some cases preventing the local buckling. The energy absorption of such braces is appraised with respect to earthquake design presented in different international standards. The overall system effectiveness was assessed by comparing infilled bracing to an existing state-of-the-art, buckling restraint bracing system. The results showed the energy dissipation in buckling restraint bracing systems is more of in comparison with tubular bracing system designed by European and American codes in higher cycles.