ANALISIS GETARAN NON LINIER DAN FENOMENA CHAOS PADA SOLUSI PERSAMAAN DIFERENSIAL DUFFING

Persamaan Duffing merupakan model persamaan getaran dengan kekakuan non linier derajattiga (3). Dalam kajian ini dengan meninjau kasus getaran non linier serta kasus khusus getaranlinier. Penyelesaian persamaan diferensial Duffing menggunakan metode numerik Runge – Kuttadengan aplikasi software MAPLE ver. 14. Amplitudo yang ditinjau untuk kasus pegas yangdikeraskan (hard spring) dan pegas yang dilunakkan (soft spring) dimana semakin kecil eksitasigaya dan semakin besar nilai redaman maka lebar daerah lompatan/tidak stabil semakinberkurang. Pada kasus getaran non linier dengan fenomena chaos maka dengan tinjauansejarah waktu (time history) sangat sensitif terhadap syarat awal dengan perubahan yang kecilterhadap syarat awalnya maka akan terjadi perubahan besar dalam sistem dalam hal iniperpindahan x(t) dengan pertambahan waktu (t). Untuk Bidang Fase (phase plane) menunjukanmenunjukan lintasan yang tidak beraturan dan non stasioner, hal ini terlihat juga dengan padapemetaan Poincare (Poincare map) yang menunjukan pola tarikan yang acak (strangeattractor) dan memperlihatkan pola frakta

ANALISIS TEKNIS PEKERJAAN BALOK-PLAT LANTAI BANGUNAN PASCASARJANA UNTAD DENGAN METODE COMBIDEC-PRESTRESS

Penerapan sistem pelat lantai beton prategang tanpa lekatan masih jarang digunakan di Kota Palu. Sistem ini akan efektif jika digunakan pada bangunan tipikal dan pelat lantai bentang panjang antara  7-12 m. Gedung Pascasarjana Untad yang dibangun tahun 2009 merupakan contoh pertama penerapannya di daerah ini. Metode ini merupakan salah satu metode untuk mempercepat pekerjaan, karena prosesnya berulang, perancah bisa dilepas segera setelah dilakukan pekerjaan stressing pada umur beton 7 hari sehingga tidak perlu menunggu sampai beton berumur 28 hari. Kualitas bangunan yang dihasilkan juga memiliki kualitas yang tinggi, karena bahan-bahan yang digunakan memiliki mutu yang tinggi dari segi homogenitasnya serta tenaga pemasangan icon steel dan post-tensioned strand tidak membutuhkan tenaga ahli yang banyak. Sehingga alih teknologi dari pekerja ahli ke pekerja lokal dapat terjadi. Pekerjaan pemasangan icon steel, strand, support bar, wiremesh dan perlengkapannya tidak memerlukan keahlian khusus. Hanya pekerjaan penarikan strand saja memerlukan keahlian khusus. Perawatan elemen struktur juga lebih murah karena struktur beton yang dihasilkan tidak mengalami retak-retak sehingga prosese karat tidak tejadi pada tulangan, apalagi strand sebagai pengganti tulangan sudah dilindungi dalam selubung polyethelene Hasil yang dicapai dari penerapan system pelat lantai prategang tanpa lekatan yaitu sangat memuaskan, struktur pelat yang dihasilkan sangat kuat, ringan dan mudah dalam pemeliharaanya. Bahaya karat akibat proses retakan dan oksidasi tidak terjadi. Jikalau ditunjang oleh pengadaan material tepat waktu, pekerjaan bisa lebih cepat secara signifikan dibandingkan pekerjaan system beton konvensional

Pengaruh Penambahan Polypropylene Fiber Mesh Terhadap Sifat Mekanis Beton

Polypropylene fiber is the fiber type of plastic (polypropylene) which is a special production with high technology. It is a chemical compound with the formula C3H6 hydrocarbons in the form of a single filamentor thin fibrous tissue shaped nets with a length of 6 mm to 50 mm and has a diameter of 8-90 microns. Thesefibers can be used to improve the performance of concrete.This research aims to determine how much influence the addition of polypropylene fibers on mechanicalproperties of concrete (compressive strength. split tensile strength and flexural strength). polypropylenefibers used doses of 0; 0.40 kg/m³, 0.60 kg/m³, 0.80 kg/m³ of concrete, which is made on the type of concretef'c 20 MPa with the value of water cement factor (FAS) at 0.53. Calculation of mixed concrete plans usingguidelines DOE (Department of Environment). The research location at Concrete and Building MaterialsLaboratory of the Faculty of Engineering, University Tadulako Palu. Specimens made as many as 72 piecesof 60 cylinders (D15 x 30 cm ³) and a beam of 12 pieces (15 x 15 x 60 cm ³). Specimen testing performed at28 days.Test results obtained fiber concrete compressive strength, split tensile strength and flexural strength, higherthan normal concrete. Compressive strength testing of optimum values obtained at doses 0.60 kg/m³. with anincrease of 3.62% compared to normal concrete. From testing split tensile strength and flexural strengthoptimum values obtained of each at doses of 0.65 kg/m³ and 0.58 kg/m³. For the split tensile strengthincreased 20.44% and flexural strength increased 11.26% compared to normal concrete

KARAKTERISTIK BALOK BETON DENGAN CAMPURAN MORTAR PADA INTI CORE ZONE

Currently, structure of composite beams of concrete mortar and normal concrete are needed in construction area.This is because lightweight concrete of mortar- can enhances elasticity and decrease the loads of structure whethergravitational loads or earthquake loads. One way to gain the lightweight structures is by using timber particle waste(density 0,35-0,65 gr/cm3) into the mixture of mortar the core zone. Series of experimental tests were done with variansmodels with thickness and shear connectors. The data are form measurement of basic units interpreting concretemechanical with concrete mortar as the element of composite beams. The samples of composite concrete beams andnormal concrete beams are 15x20x120cm and shear connectors and are varied according to the shapes. The resultsshowed that modeling of normal beams and mortar beams as core zones showed significant differences. By obtaining theflexural strength of a normal concrete beam of 5.371 Mpa, the flexural stress is 7.024 MPa, the shear stress is 1.487 MPaand concrete mortar with flexural strength of 5.240 MPa, flexural stress 7.134 MPa and displaced shear 1.459 MPa ...Exterior zone thickness 5 cm has a flexural strength effective. .This indicates that the level of brittleness greatly affectsthe flexural strength of the test beam. The higher the level of elasticity of the concrete material, it will make the beamrelatively weak against bending

PENGARUH BAHAN TAMBAH PLASTIMENT-VZ TERHADAP SIFAT BETON

Concrete mixture for structure of the building is expected to according to the quality and specifications desired. With the addition of admixtures materials used for concrete mix, it is necessary to know the type, properties and benefits of admixture produced by various companies. Concrete used In this study were added admixtureof Plastiment-VZ for characters investigated.In this study used two variations of concrete, ie normal concrete and concrete with the addition PlastimentVZ with usage percentage of 0.20%, 0.40% and 0.60% of the weight of the cement used in normal concrete. Cylindrical specimens used for compressive strength testing with a total of 3 pieces for each test.The test results obtained average compressive strength of normal concrete (f'cr) of 27.554 MPa, and for concrete with the addition of-VZ Plastiment of 0.20% obtained an average compressive strength, f'cr = 29.252 MPa, the concrete with the addition of Plastiment-VZ 0.40%, obtained f'cr = 30.951 MPa, whereas the addition of 0.60% for the compressive strength at 28 days obtained at 32.083 MPa.Keywords: Compressive strength, Plastiment-V

PENGARUH PENAMBAHAN POLYPROPYLENE FIBER MESH TERHADAP SIFAT MEKANIS BETON

Polypropylene fiber is the fiber type of plastic (polypropylene) which is a special production with high technology. It is a chemical compound with the formula C3H6 hydrocarbons in the form of a single filamentor thin fibrous tissue shaped nets with a length of 6 mm to 50 mm and has a diameter of 8-90 microns. Thesefibers can be used to improve the performance of concrete.This research aims to determine how much influence the addition of polypropylene fibers on mechanicalproperties of concrete (compressive strength. split tensile strength and flexural strength). polypropylenefibers used doses of 0; 0.40 kg/m³, 0.60 kg/m³, 0.80 kg/m³ of concrete, which is made on the type of concretef'c 20 MPa with the value of water cement factor (FAS) at 0.53. Calculation of mixed concrete plans usingguidelines DOE (Department of Environment). The research location at Concrete and Building MaterialsLaboratory of the Faculty of Engineering, University Tadulako Palu. Specimens made as many as 72 piecesof 60 cylinders (D15 x 30 cm ³) and a beam of 12 pieces (15 x 15 x 60 cm ³). Specimen testing performed at28 days.Test results obtained fiber concrete compressive strength, split tensile strength and flexural strength, higherthan normal concrete. Compressive strength testing of optimum values obtained at doses 0.60 kg/m³. with anincrease of 3.62% compared to normal concrete. From testing split tensile strength and flexural strengthoptimum values obtained of each at doses of 0.65 kg/m³ and 0.58 kg/m³. For the split tensile strengthincreased 20.44% and flexural strength increased 11.26% compared to normal concrete. Keywords: polypropylene fibers. mechanical properties of concrete

ANALISIS LAJU/KETAHANAN KOROSI PADA BAJA KARBON RENDAH AKIBAT TEGANGAN DALAM MENGGUNAKAN METODE C-RING

Corrosion is one of the issues that concerns today because it can lead to destruction of metal.Low steel carbon is one of metal types that has been widely used in industry, such as motorcycle component (fuel tank), and fuel shelter. However, low carbon steel use is highly suceptible to corrosion. The corrosion of motorcycle components (fuel tank) can decrease strength, tank life, that will harm the safety of motorists. In addition, corrosion in fuel shelters (premium and pertalite) can result in leakage of the container. The leakage is very vulnerable to fire. This research aims to analize corrosion rate of low carbon steel speciments that immerse in fuels, premium and pertalite. Method of research includes preparation, cutting and weighing of specimens before immersing the specimen in the fuel. Every 384 Jam the specimens were removed from the fuel then cleaned from the impurities andre-weighed.Weight loss wass used in calculating the corrosion rate occurring in the speciments. The result showthat pertalite and premium corrode the speciments, low carbon steel. Corrosion rate of speciments immersed for 1536 Jam in premium was faster than in pertalite. The speciments immersed in premium experienced with weight reduction 0,081 gram. Meanwhile rate of corrosion of the speciments immersed in pertalite was 0,073 gram

ANALISIS MATERIAL BETON BERTULANG PASCA KEBAKARAN DAN METODE PERBAIKAN ELEMEN STRUKTURNYA

ABSTRACT Fire is often destroyed on building structures at any time. Fired caused to change physically and mechanically of properties of reinforced concrete building. Strength, stiffness and ductility of structures generally decrease and degradation after fired. Some method to estimate and assessment residual strength of reinforced structured after fired are very importat to research and to forensic engineering structure after fired. Estimated high temperature and duration of fired after fired by phenolphthalein indicator (PP-test), CaO-free test and Hammer Test. Values of concrete compression strength and tensil strength of reinforced estimate from field samples. Some samples are put by core drill apparatus to give cylendric concrete and testing by compression testing ubit. Some concrete beams to made and to give 400ºC, 600ºC, 800ºC and 1000ºC temperature to indicated middle and heavy destroyed after fired. Flexural and shear repairing to give to those beams. To found little to middle destroyed at GUDANG building and middle to heavy destroyed at PASAR INPRES MANONDA building after tst by by phenolphthalein indicator (PP-test), CaO-free test and Hammer Test. Concrete compression strength more than 50% decrease after 800ºC fired and more than 20% decrease reinforced tensil strength after fired at 1000ºC fired temperature indicated middle to heavy destroyed. Repairing by CFS to the beams give result only 63% flexural strength at 800ºC and 53% shear strength at 800ºC.If fired 400ºC to 600ºC fired temperature the repairedto the beams by CFS can increase flexural and shear strength more than intact beams.