Stability Analysis of High-Rise Buildings by Altering the Beam Members: A Review

For buildings larger than 15 to 20 floors, a system with a clean rigid frame is not adequate because it does not provide the required lateral rigidity and causes excessive deflection of the building. These requirements are met in two ways. By introducing the effective section such as beam, column etc in to the structure. This increases the stability and rigidity of the structure, and also limits the requirement for deformation. Now days the composite beam is also used for tall buildings. The Paper present the short summery report of use of various beam elements in building to get the effective out comes to sustained under the lateral forces response. The literature review focus on the impact on the building analysis by altering the Beam Members. Reinforced Concrete Beams, Steel Beams, and Composite Beams. The articles reviewed the concept on introducing the alternating beam in the structure are effective and achieve the higher resisting capacity against the lateral loads. Keywords: Reinforced Concrete Beams, composite beam, Steel Beams, tall buildings, deformation, stability

Plate Dampers in the Tensioning Plate Dampers in the Tensioning

The article analyses strengths and weaknesses of bandsaw machines. While analysing we have found the relationship between the weaknesses and the tension of a band saw. Its use as a cutting tool leads to a decrease in the lateral rigidity and stability of the cutting section on the pulling chain. This leads to fluctuations in the cutting width, a decrease in the geometric accuracy of sawn timber and an increase in the roughness of the side surfaces of a kirf. The main types of tensioning unit mechanisms, which strengthen the tension and maintain its stability during operation, are defined, and common design flaws are described. Oil-filled metal plate dampers promote space-saving and low-inertia dampers for bandsaw machines with any basic saw blade tensioning mechanisms. The influence of the device on the level of dynamic fluctuations of the tensile force caused by the artificial eccentricity of the tension pulley was studied. The efficiency was evaluated by computer oscillography of the tensile load sensor signal and subsequent computer processing of the obtained oscillograms. The effectiveness of using damper devices is confirmed by the quality of sawing, which is characterized by a lower level of roughness of the lateral surfaces of the cut while reducing the variation in thickness of a workpiece. Methods of eliminating flaws with different types of tensioning units are reviewed, and the effectiveness of using oil-filled plate dampers is evaluated. The article presents the research technique and parameters of the experimental unit as well as the conclusions on the effectiveness of damping devices. For citation: Alekseev A.E., Dumanskij I.O., Prokhorov A.V. Plate Dampers in the Tensioning Units of Bandsaw Machines. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 5, pp. 142–149. DOI: 10.37482/0536-1036-2021-5-142-149

Shear Wall Design within the Light of Prominent Standards

Reinforced concrete (RC) structures have their own weight, earthquake, wind, dead loads, live loads, creep, etc. throughout their service life. They are exposed to internal and external load effects. In order to meet the horizontal forces such as earthquake and wind from these loads affecting the structure, shear wall structures with high lateral rigidity are needed. Therefore, shear walls are one of the most important structural elements that can resist earthquake forces due to their high lateral rigidity and load bearing capacities. Most of the buildings today are designed according to the old regulations. Therefore, the shear wall was sized and reinforced according to these old regulations. However, to date, standards have been renewed in certain periods. Despite this, shear walls designed according to the old regulations continue to resist seismic forces. In this study, the design and behavioral differences of the reinforced concrete shear walls between the Turkish Regulation that came into force in 2019, and the old regulation were compared. In addition, RC shear walls were evaluated according to ACI-318-19 and EuroCode-2 regulations.

Influence Analysis of Parameters Variation on Dynamic Characteristic for Concrete Filled Steel Tubulur Arch Bridge

The main bridge of Zhengzhou Yellow River 2nd bridge is a concrete filled steel tubulur (CFST) arch bridge. Choosing the main bridge as the research object, the finite element procedure ANSYS was used to establish the 3D finite element dynamic model. In order to analyze the influence of structural Parameters variation on dynamic characteristic,17 different conditions were considered in the calculation and analysis process. The results show that the CFST arch bridge is a flexible structure. The vertical rigidity of the bridge is stronger than the lateral rigidity CFST arch rib. The changes of the transverse brace style have little effect on the vertical rigidity, but have great impacts on the lateral rigidity of the CFST arch rib. It is sensitive on the first step vibration if the bracing tube damage. But the bracing tube damage has little effect on the vertical rigidity. The damages of suspenders and bridge deck slabs influence weakly on the vibration modes.

Study on Critical Speed of Freight Train Derailment on Bridges

The mechanism of train derailment was demonstrated to be the loss of lateral vibration stability of train-bridge (track) system. Based on the theory of energy increment analysis for system movement stability, the energy increment criterion for derailment evaluation and the method of analyzing critical speed of train derailment Vcr were presented. The critical speed of empty freight train on Laoluanhe bridge, Huanghe bridge and Youshui bridge were calculated as 65.2 km/h，64.8 km/h and 66.5 km/h respectively, which were close to actual derailment speed. It is manifested that the method of analyzing critical speed of train derailment is reasonable. According to the calculated results of the critical speed on bridges with different lateral rigidity, it is testified that the critical speed of train derailment rises with the bridge lateral rigidity strengthened. The measure to prevent derailment on bridge is to ensure enough bridge lateral rigidity to meet the running safety of train.

Experimental Study on Dynamic Behaviors of Concrete Bridge in China Existing Railway Speed Increase to 200~250km/h

On April fifteenth, 2007, the 4 vertical and 2 horizontal railway lines were increased the sixth time by the Chinese Ministry of Railways. The electrical multiple unit (EMU) was running at speed of 200km/h in these sections. In some sections, the EMU maximum speed has reached 250km/h. Dynamic behaviors of bridges and piers under the loads of the train were analyzed with different spans and types in existing speed-raising trunk lines. The critical parameters, such as lateral and vertical natural frequency, dynamic factor, lateral amplitude, lateral natural frequency and lateral amplitude of pier and so on, which play important roles in dynamic behaviors of bridge, are analyzed by experimental data. The lateral rigidity and dynamic behaviors of bridge including beams and piers are the most obvious problems in existing speed-raising lines. Based on years of research, especially lots of dynamic behavior tests of concrete bridge in recent year, the dynamic behaviors of bridges are analyzed comprehensively considering the vibration of bridge and train characteristics. Many results are got and used in the relevant codes.