PEMANFAATAN LAHAN BEKAS TEMPAT PEMBUANGAN AKHIR DENGAN STABILISASI TANAH SECARA KIMIAWI

Landfill soil (TPA) has great potential of utilization in construction purpose. Landfill soil has similar characteristic with clay soil that has high water content also contain organic and inorganic material caused by garbage heap. One of the problem in utilizing landfill soil was the low quality of the soil that cause big settlement for the structure. Settlement was an important aspect in performing a construction. Soil stabilization for the landfill soil needed to decrease amount of settlement. Structure model using one, two, three, four floor of load and calculate the settlement occur on the heaviest load location of the foundation. Foundation base was circle and using shallow foundation reconsidering shallow foundation effective for four floor load. Chemical stabilization using 2 methods: Sodium Hydroxide 6% and Limestone 3-4,5%. Based on the calculation, found that Sodium Hydroxide is more effective in decreasing settlement occurred and able to decrease the settlement until 32,42% for the floor load. However, those methods can’t fulfil the 15 cm settlement limit. Tanah bekas tempat pembuangan akhir (TPA) memiliki potensi besar untuk dimanfaatkan dalam bidang konstruksi. Tanah bekas TPA umumnya memiliki karakteristik serupa dengan tanah lempung berkadar air serta memiliki material organik dan anorganik dari timbunan sampah. Salah satu masalah dalam memanfaatkan tanah bekas TPA adalah rendahnya kualitas tanah yang mengakibatkan penurunan besar pada struktur. Perbaikan pada tanah bekas TPA diperlukan untuk mengurangi besarnya penurunan yang terjadi. Penurunan merupakan aspek penting dalam suatu perancangan konstruksi, maka dari itu batasan pada penurunan ditetapkan untuk menghindari penurunan yang berlebihan yang dapat merusak struktur. Permodelan menggunakan beban struktur 1,2,3, dan 4 lantai dan dihitung penurunan yang terjadi pada fondasi dengan beban struktur terbesar. Penampang fondasi berbentuk lingkaran mempertimbangkan beban percobaan hingga 4 lantai cocok untuk fondasi dangkal. Stabilisasi tanah secara kimiawi menggunakan 2 metode yaitu Sodium Hidroksida 6% dan batu kapur 3-4,5%. Berdasarkan hasil perhitungan, didapati stabilisasi menggunakan Sodium Hidroksida lebih efektif dalam mengurangi penurunan tanah yang terjadi dan mampu mengurangi besarnya penurunan hingga 32,42% pada beban struktur 4 lantai. Namun, stabilisasi tanah menggunakan kedua metode belum dapat mencapai batas aman penurunan sebesar 15 cm.

Improvement of warehouse hovercraft transport devices with inclined feed channels

Introduction. The paper considers the question of the directions of mechanization and automation of rack warehouses logistics. The paper considers hovercraft transport devices operating in the storage area with inclined feeding channels. The displacement of the load center relative to the geometric center of the support surface is studied. It is noted how this affects the main characteristics of the studied devices. Problem Statement. Previous studies have proved the sufficient performance of non-powered hovercraft transport devices with inclined feed channels, their safety and efficiency in the transportation of piece goods, as well as the potential for mechanization and automation of transport and storage operations in rack warehouses. The task of this work is to present a scheme of mechanization for the storage area of a rack warehouse equipped with a transport device with inclined feeding channels. Theoretical Part. In rack warehouses designed for the storage of individual goods, the receiving, storing and sending operations are in most cases carried out using carrying and lifting machines. Stacker cranes are most common, but their use requires the creation of complex and expensive systems, i.e. significant capital and operating costs. The article considers the system of mechanization of a rack warehouse with the use of hovercraft vehicles with an off-center location of the cargo. In this case, the height of the airbag depends on the eccentricity of the load location. The points of application and the values of the resistance and traction forces, torques and friction forces that affect the total resistance are shown, which are typical for such a situation Conclusion. The results of the research allow us to state that in some cases, instead of traditional transport devices, the use of hovercraft transport devices with the inclined feed channels is effective in logistics enterprises.

The Effects of Load Location on Dropper Stress in a Catenary System for a High-Speed Railway

In this paper, the effects of load location on dropper stress are studied. We treat contact wire as a beam element and derive its response equation and then deduce the stress equation of dropper. A computer code based on MATLAB is written to calculate dropper stress using the finite difference method. The results show that there are three stages during the period of the stress changes of dropper, including instant rebound, damped sinusoidal vibration, and bending compression. The shorter the distance away from a load is, the larger the vertical displacement of the dropper is, which results in the corresponding increases of its stress amplitude and the maximum tensile stress. The load location has a significant impact on the stress changes of dropper. Compared to the condition of the load in the middle, the load acting on the edge of contact wire could induce the larger tensile stress when both ends of contact wire are considered as free boundaries. Therefore, it is necessary to add supports at both ends.

Loosening of Bolted Connections under Transverse Loading in Timber Structures

Bolted joints are widely used in timber structures, and the loosening of bolt connections will reduce the structural performance. In this paper, a mechanical model of bolt connection for timber structures is established, and the process of bolt loosening under a transverse load is investigated. By using the finite element method to construct an accurate thread model with a helix angle, the thread contact state during the bolt loosening procedure was analyzed in detail, and the factors such as load amplitude, load frequency, load location, and different timber materials on bolt loosening are also studied. In the timber structure, the load amplitude is the main factor affecting the bolt loosening, the decay rate of the preload in the bolted joint is positively correlated with the amplitude of the cyclic transverse load. The frequency of the loading has a smaller effect on the looseness, the preload decreases as the frequency increases. When the load is applied to the smooth rod part of the bolt, the preload force will decrease rapidly, and the distance between the load position and the bolt has no effect on the change in looseness. The decreasing range of the preload is different with different timber material, but the decreasing law is the same. The model can be applied to analyze the loosening rule of bolted connections in timber structures.

Investigation on the Micro Deformation Mechanism of Asphalt Mixtures under High Temperatures Based on a Self-Developed Laboratory Test

Rutting has always been considered the main disease in asphalt pavement. Dealing with rutting disease would be benefitted by understanding the formation of rutting and testing the rutting performance of mixtures more reasonably. The objective of this paper is to systematically investigate the rutting mechanism by employing a self-designed rutting tester along with the corresponding numerical simulations. The deformation of different positions of the existing tracking tester was found to be inconsistent, and the loading was not in line with reality. Accordingly, a more practical tester was proposed: the reduced scale circular tracking (RSCT) tester integrates the functions of asphalt mixture fabrication and rutting monitoring. The results demonstrated that the loading of the new tester is closer to the actual situation. In addition, determining the stress and displacement characteristics of particles in the asphalt mixture was found to be difficult due to the limitations of the testing methods. Therefore, a two-dimensional virtual rutting test based on the RSCT was built using PFC2D (Particle Flow Code 2 Dimension) to investigate the mechanism of formation in rutting and to obtain the corresponding guidance. The numerical simulation showed that all particles of the specimen tended to move away from the load location. The main cause of rutting formation was the eddy current flow of asphalt mastic driven by coarse aggregates. The aggregates with diameters ranging from 9.5 to 4.75 mm were observed to have the greatest contribution to rutting deformation. Therefore, the aggregate amount of these spans should be focused on in the design of mixture grading.

Determination of Generator Capability Curve using Modified-Single Machine to Infinite Bus (M-SMIB) System Approach

The capability curve for each generator unit is usually provided by the generator manufacturer. But in practice, the generator can reach its maximum generation limit before reaching the maximum limit on the generator capability curve provided by the generator manufacturer. This might occur because of the load location is far from the generator or the varying of the loading value so that the maximum generation limit is smaller than the value given on the generator capability curve of the manufacturer. In this paper, the generator capability curve is determined using the Modified Single Machine to Infinite Bus (M-SMIB) system approach to determine the maximum generation limit every time there is a change in loading or change in the load location. After the maximum generation limit of each unit generator is known, the generator capability curve that is always in accordance with the real time situation can be formed. Thus, the operation limit of each generator can be recognized, determine the appropriate protection system setting and can prevent the electric power system disturbance. This method will be applied to generator units in the four bus IEEE system with two generators.

Efficient Docker Container Scheduling using ABC Optimization Technique

In recent years the usage of virtualized technology is increasing rapidly. This makes enhancement in the performance efficiency leads to the need of the virtualization machine. This study is developed to enhance the performance level of the docker containers in cloud computing. The work presented in the paper considers the major parameters like availability, load, location, and energy of virtual machines to increase the system performance. The major objective of the work is to analyze and distribute the load of machines equally. The ABC (Artificial or Counterfeit Bee Colony) algorithm is used. For this purpose the ABC algorithm replaces the traditional ACO approach because of its various features such as simplicity, flexibility, and robustness. The output of the proposed work is evaluated in the terms of energy consumption and job completion. The observed values corresponding to these factors prove the proficiency of the suggested ABC algorithm based technique over traditional ACO algorithm based technique.

Load Localization and Reconstruction Using a Variable Separation Method

Load identification is very important in engineering practice. In this paper, a novel method for load reconstruction and localization is proposed. In the traditional load localization method, location information is coupled to the impulse response matrix. The inversion of the impulse response matrix leads the process of load localization to be time-consuming. So we propose a variable separation method to separate the load location information from the impulse response matrix. An error optimization function of load histories in different modes is employed to determine the true load location. After locating the external load, the load time history can be easily reconstructed by the measurement responses and determinate impulse response matrix. This method is verified by simulations of a simply supported beam acted by a sine load and an impact separately. An experiment is also carried out to validate the feasibility and accuracy of the proposed method.

Free vibration analysis of a DST-0285 truck crane considering changes in the system load configuration

A model of a truck crane, consisting of the fundamental units of the crane, is presented in this paper. The finite element method and a COSMOS/M package were applied to perform the modelling. Research into the influence of a change in the crane radius and load location on changes in the chosen free vibrations was carried out using the built models. Diagrams containing changes in the frequency of vibrations for chosen values of the crane radius and the load are presented and conclusions are drawn.