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Abstrak :
Tujuan dari penelitian ini adalah untuk memperoleh penjelasan mengenai faktor apa yang harus dipertimbangkan dalam pengambilan keputusan yang optimal dan untuk mengetahui pilihan mana yang lebih menguntungkan antara inap truk atau tidak inap truk. Disain penelitian ini adalah studi kasus deskriptif kuantitatif. Dari hasil penelitian dapat disimpulkan bahwa faktor-faktor yang harus dipertimbangkan dalam optimalisasi keputusan inap truk atau tidak inap truk adalah jarak tempuh dan kondisi jalan, energi (bahan bakar minyak), empty travel, kompetisi dan regulasi, serta waktu tempuh/waktu transportasi (transport time). Dan mengenai manakah yang lebih menguntungkan antara inap truk atau tidak inap truk dapat disimpulkan bahwa untuk peti kemas ukuran 20? dan lokasi truk saat ini berada di A atau B, keputusan tidak inap truk (risk order) lebih menguntungkan. Untuk lokasi truk saat ini berada di C atau D, keputusan inap truk lebih menguntungkan, namun demikian jika jumlah minimal certain order dipenenuhi maka lebih menguntungkan tidak inap truk (certain order). Untuk lokasi truk saat ini berada di E, F dan G, keputusan inap truk lebih menguntungkan. Untuk peti kemas ukuran 40?/45? dan lokasi truk saat ini berada di A, B atau C, keputusan tidak inap truk (risk order) lebih menguntungkan. Untuk lokasi truk saat ini berada di D atau E, keputusan inap truk lebih menguntungkan, namun demikian jika jumlah minimal certain order dipenuhi maka lebih menguntungkan tidak inap truk (certain order). Untuk lokasi truk saat ini berada di F dan G, keputusan inap truk lebih menguntungkan.

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The purpose of this research is to obtain explanation on what factor to be considered in optimal decision making and to find out which decision is more profitable between overnight truck and not overnight truck. This research design is quantitative descriptive case study. From the research result it can be concluded that factors to be considered in decision optimalisation of overnight truck or not overnight truck are travel distance and road condition, energy (fuel), empty travel, competition and regulation, and travel time/transport time. And regarding which one is more profitable between overnight truck and not overnight truck it can be concluded for container size 20? and current truck location is in A or B, decision of not overnight truck (risk order) is more profitable. For current truck location in C or D, decision of overnight truck is more profitable, however if minimum certain order amount is fulfilled then not overnight truck (certain order) is more profitable. For current truck location in E, F or G, decision of overnight truck is more profitable. For container size 40?/45? and current truck location is in A, B or C, decision of not overnight truck (risk order) is more profitable. For current truck location in D or E, decision of overnight truck is more profitable, however if minimum certain order amount is fulfilled then not overnight truck (certain order) is more profitable. For current truck location in F or G, decision of overnight truck is more profitable.

Abstrak :
Jembatan sebagai bagian dari jaringan jalan kondisi strukturnya perlu dalam keadaan baik sehingga bisa mendukung ekspansi ekonomi dan juga mencapai umur yang direncanakan. Untuk mempertahankan kondisi tersebut perlu dilakukan inspeksi baik saat jembatan baru selesai dibangun ataupun yang sudah operasional. Inspeksi merupakan bagian yang tidak terpisahkan dari perawatan. Untuk jembatan baru, inspeksi berbasis uji beban adalah untuk mendapatkan sertifikat laik fungsi agar jembatan tersebut bisa dioperasionalkan untuk masyarakat. Dalam laporan ini, evaluasi dari satu jembatan komposit baja-beton berbentang 60 meter menggunakan pengujian beban dinamik dan statik. Evaluasi kekuatan dan daya layan jembatan didasarkan pada respon jembatan akibat uji beban yaitu lendutan vertikal, regangan dan percepatan. Analisis numerik digunakan untuk memeriksa hasil dari uji beban tersebut. ......Bridges as part of a road system require a good structural health to support the economic expansion and to achieve its targeted life design. In order to maintain a good bridge structural health, inspection should be conducted for a new constructed or already operated bridge. Inspection is part of a maintenance program. For a new bridge, inspection using loading test is conducted to obtain worthiness functional certificate for public operational reason. In this report, an evaluation of a new 60 meter composite concrete-steel bridge has been conducted by means of a dynamic and static loading test. Strength and serviceability evaluation of the bridge was conducted using bridge responses which are vertical displacement, strain and acceleration from the loading test. Appropriate numerical analysis was used to verify the loading test results.

Abstrak :
Physical behavior of models can be measured in the laboratory, which, in turn are often used to assess the behavior of more complicated structures. Mechanical responses present physical behavior of a structure. By using three different transducer, one can measure acceleration, velocity and displacements directly. Determination of velocity and displacements from acceleration data is preferable from point of view economics; but on the other hand this procedure, at present, is still causing problem. This study shows that displacements and velocity can be calculated from its acceleration which is obtained by using one transducer. The acceleration data are obtained from a cantilever steel plate which is subjected to a transient force at a discrete location on its surface or an initial deflection on its tip. An acquisition program was first designed before starting the experimental program. By means of a piezoelectric accelerometer, a conditioning amplifier and a digital oscilloscope, acceleration data are captured and then transferred to a personal computer. The transformation of these two responses, displacements and velocity from the acceleration data are performed in two domains, time domain and frequency domain. Two integration techniques, Newton-Cotes formula and Simpson's rule were used for the calculation in the time domain. For both techniques, adjustment of basis line is performed by End Zero Time Technique Modified. Programmation has been done for both types of domain analysis. The Simpson's rule gives sufficient results and Newton-Cotes formulation gives good results only for moderate values of Cotes coefficient. High values of the coefficient give unrealistic calculated velocity and displacements. Drifting character are present on the displacements calculated by both methods. In the frequency domain, the velocity and displacements are obtained from acceleration data by means of Fast Fourier Transform and its Inverse Fourier Transform. This method give satisfactory results only for the calculation of velocity. The displacements obtained show also drifting character. Nevertheless, realistic forms of this displacements are moderately accepted. Results comparison of the two methods, both in time domain and frequency domain, show that none of the method is better than another. Analysis in frequency domain give more accurate results, but this method is not definitely a principal method for the solution of this type of problems. The two methods shall be used for the calculation of velocity and displacements. This procedure can verify one result to another to avoid wrong interpretation of transformed responses.

Abstrak :
ABSTRAK
Pendekatan penyelesaian permasalahan dinamika struktur, terutama dalam memperoleh parameter dinamik dapat dilakukan secara numerik atau secara percobaan. Salah satu cara percobaan untuk menjawab masalah tersebut adalah analisis pola percobaan (experimental modal analysis).

Pada sepuluh tahun terakhir ini penggunaan komputer personal semakin popular dalam membantu penyelesaian masalah-masalah struktur. Perkembangan analisis pola percobaan didukung pula dengan hal ini. Selain itu, perkembangannya juga dibantu dengan semakin baiknya peralatan elektronik percobaan pendukung analisis pola percobaan tersebut.

Pada studi ini dicoba dikembangkan satu perangkat lunak berbasiskan metode penentuan parameter dinamik dalam domain frekuensi untuk analisis pola percobaan. Benda uji yang digunakan adalah satu struktur sederhana yaitu pelat tipis. Parameter sistim dinamik dapat diperoleh secara percobaan dengan melakukan percobaan pola pada pelat tersebut Pelat tersebut mengalami satu eksitasi yang dapat diketahui besarannya dan respons percepatan yang dihasilkan juga dapat diukur. Sistim identifikasi yang menggunakan hasil pengukuran eksitasi dan responsnya membutuhkan satu sistim yang dapat dikontrol dan dapat diobservasi setiap waktu.

Cara penentuan parameter dinamik yang digunakan adalah berbasiskan teknik fungsi respons frekuensi. Satu model matematik dipergunakan untuk mempresentasikan sistim fisik dari pelat dimana model tersebut diasumsikan teredam viskos. Dengan mengacu pada keterbatasan kemampuan alat pengukur diasumsikan bahwa titik-titik pengukuran dapat mewakili satu model diskrit dari struktur pelat. Pemakaian akselerometer piezoelektrik, alat pengkondisian, palu dan satu osiloskop digital memungkinkan diperolehnya data percepatan maupun eksitasi; kemudian dengan memakai satu komputer mikro dan program akuisisi yang telah dikembangkan pada penelitian sebelumnya, data tersebut disimpan untuk pengolahan lebih lanjut dengan perangkat lunak yang dikembangkan pada studi ini. Dua program utama dikembangkan dalam studi ini dimana yang pertama untuk mendapatkan fungsi respons frekuensi dari kedua data yang ada dan yang kedua untuk mendapatkan parameter dinamik sistim lewat satu algoritma pencocokan kurva.

Pada akhirnya parameter pola yang didapatkan dengan cara diatas dibandingkan dengan hasil yang diperoleh dengan perangkat lunak berbasiskan metode elemen hingga.

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ABSTRACT
Processing of Signal Responses From A Vibrating Structure And Its Application On Thin Plate Problem

Structural dynamic problem can be solved with numerical approach or experimental approach. One of the latter method is experimental modal analysis.

In the last ten years, the use of personal computer as a tool for solving structural problem became more popular. The development of experimental modal analysis is also influenced by this factor. Another supporting factor is a better quality of experimental instrument.

In this study, one program based on the parameter estimation method in the frequency domain is developed. The test structure is a thin plate. Dynamic system parameter can be obtained experimentally by the performance of modal test on the plate. The plate undergoing testing is excited by applying known dynamic forces while the resulting accelerations are measured. System identification utilizing input/output measurement requires the system to be controllable and observable at any time.

Dynamic parameter estimation method utilized is based on the frequency response function technique. One mathematical model is used to represent the physical system of the plate. It is assumed that the system is viscously damped. With respect to the performance of measurements it is assumed the measurement points are appropriately distributed to yield a sufficiently accurate discrete model of the test structure.

By means of a piezoelectric accelerometer, a conditioning amplifier, an impulse hammer and a digital oscilloscope, accelerations and impulse data are captured and then transferred to a diskette by means of a personal computer and an acquisition program developed in the first year study. Program developed in this study then processes the data in the diskette to obtain dynamic system parameters. Two main routines are developed in this study, the first routine calculates the frequency response function from the two existing data and the second determines the dynamic system parameter by using a curve-fitting algorithm.

Finally the modal parameter result obtained are compared to those obtained by a software which is based on the finite element method.

Abstrak :
The shear key is an important part of a precast segmental concrete bridge. Aside from its function of contributing to the distribution of shear force from one concrete segment to another, it helps to join precast concrete segments to become a complete bridge structure and provide continuity of movement for vehicles and pedestrian traffic. This numerical study discusses the behavior of a full-scale shear key connection without epoxy joining two concrete blocks representing segmental precast concrete at which two external forces load the blocks. Ferro Casting Ductile (FCD) is used as the metal shear key material where the shear key consists of two parts, a male and a female shear key. Numerical simulation is conducted using the ANSYS academic package, with nonlinear analysis implemented accordingly. The appropriate constitutive materials in relation to the numerical program, both for concrete and FCD, are taken from the appropriate literature. Two criteria are employed in the study; failure of the concrete block and yielding of the shear key that follows the von Mises criterion. Shear key connection system capacity is evaluated by applying different magnitudes of horizontal force. The validation of two numerical simulation studies is conducted by two experimental programs that cover laboratory experimentation of full-scale shear keys connecting two concrete blocks. The numerical and experimental results produce an almost similar relation of shear stress at the male shear key and vertical displacements of the upper block relative to the lower concrete block. Finally, a contour of shear key shear stress as a function of the different magnitudes of equivalent prestressing and different quality of concrete compressive strength is proposed.