The in-situ measurement of thermal stress in beams or continuous welded rails may prevent structural anomalies such as buckling. This study proposed a non-contact monitoring/inspection approach based on the use of a smartphone and a computer vision algorithm to estimate the vibrating characteristics of beams subjected to thermal stress. It is hypothesized that the vibration of a beam can be captured using a smartphone operating at frame rates higher than conventional 30 Hz, and the first few natural frequencies of the beam can be extracted using a computer vision algorithm. In this study, the first mode of vibration was considered and compared to the information obtained with a conventional accelerometer attached to the two structures investigated, namely a thin beam and a thick beam. The results show excellent agreement between the conventional contact method and the non-contact sensing approach proposed here. In the future, these findings may be used to develop a monitoring/inspection smartphone application to assess the axial stress of slender structures, to predict the neutral temperature of continuous welded rails, or to prevent thermal buckling.

Earthquakes are one of the most important and hazardous natural disasters in the world and in our country. They also have lots of characteristics from the point of effects caused by them. For this reason it requires special engineering approach to analyze those effects and to design earthquake resistant structures. Almost all of the life losses caused by the earthquakes are related with improperly designed buildings safety of which are not ensured against severe earthquakes. Structural damages and collapses cause very important economical losses. So, understanding of the characteristics of an earthquake and correct determination of the behavior of buildings under earthquake excitation turn out to be the most important requirement to build earthquake resistant buildings. When we take into consideration the destructive effects of severe earthquakes that happened especially in recent years (Kocaeli 1999, Düzce 1999) one can easily see the importance of knowing the behavior of buildings under earthquake loads. In this study torsional effects that occur during earthquake excitations are analyzed in multi-story reinforced concrete buildings. In that manner the behavior of reinforced concrete structures under earthquake loads are examined and by the way the behaviors of structures having torsional irregularities are enlightened and clarified. Moreover the effects of rigidity, ultimate capacity and ductility on the behavior of structures under ground motion are summarized. Torsional irregularity is a key irregularity in determination of the method to be used in earthquake analysis. Definition of the torsional irregularity of a multi-story reinforced concrete building is explained in accordance with Turkish Earthquake Code and the related principles of computations that have to be followed according to the code are given. Multi-story reinforced concrete buildings are classified according to their plan geometry and the effects of plan geometry on the torsional irregularity are explained. While in certain structures torsional irregularity may happen in very high levels in some structures it may happen so small that can be safely omitted. For that reason buildings forming torsional irregularity are classified and their characteristics and torsional irregularity parameters are given. Shear walls without causing any torsional irregularity on buildings having different plan geometries are shown.

Ground vibrations induced by traffic and industrial activities can adversely affect human comfort and nearby sensitive equipment. Wave barriers, particularly open trenches (OTs), are recognized as effective vibration isolation solutions; however, their practical implementation may be limited by the difficulties associated with maintaining a fully OT. While trench infilling and sand crumb rubber mixture (SCRM) materials have been investigated separately, a continuous, non-alternating, partially SCRM-filled trench configuration has not yet been systematically evaluated through detailed numerical analysis for single and multiple trench arrangements. PLAXIS 2D was used to compare open, fully SCRM-filled, and partially SCRM-filled trenches at filling ratios of 25%, 50% and 75%, with the lower portion filled and the upper portion, within the near-surface zone of highest Rayleigh wave energy concentration, left open. Although the OT provided the highest isolation efficiency, followed by the 25% filling configuration, the 50% SCRM-filled configuration (SCRMT) emerged as a more practical alternative, achieving a barrier efficiency close to that of the OT (70% versus 75%, under identical conditions) while reducing the required unsupported open-trench depth by half and diverting waste tire material from landfills. The influence of trench depth, width, source-to-trench distance, and multiple-trench arrangement on SCRMT performance was also examined.