Perilaku Lentur Balok Komposit Beton Mutu Tinggi Setelah Dibebani Beban Kerja pada Lingkungan Agresif

Febrianty, Lina (2017) Perilaku Lentur Balok Komposit Beton Mutu Tinggi Setelah Dibebani Beban Kerja pada Lingkungan Agresif. Masters thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Penelitian ini adalah melanjutkan penelitian yang dilakukan oleh peneliti Eniarti (2001). Penelitian ini bertujuan untuk mengetahui pengaruh lingkungan agresif terhadap kapasitas lentur balok. Penelitian ini meliputi kegiatan eksperimental, teoritis dan analisa numerik. Balok komposit yang digunakan pada penelitian sebelumnya digunakan sebagai benda uji pada penelitian ini. Balok yang digunakan terdiri dari dua mutu beton yang disebut sebagai balok komposit. Balok mempunyai penampang berbentuk T dimana beton mutu normal pada sayap balok dan beton mutu tinggi pada badan balok. Sengkang dipasang pada balok kecuali pada sisi tengah bentang. Tulangan tarik yang digunakan berupa tulangan ulir D16 sebanyak tiga buah. Balok yang digunakan sebanyak enam buah balok yang diletakkan pada lingkungan agresif dan tidak terkondisikan. Pada tahun ke-1 balok komposit dibebani lentur sebesar beban kerja sehingga balok mengalami retak. Pada penelitian ini balok komposit disiram dengan air laut buatan selama kurun waktu 17 tahun. Selanjutnya, balok diuji four points bending dengan interval beban 0.25 ton hingga hancur. Pengujian ini menggunakan bantuan alat LVDT, dial gauge dan data logger. Satu LVDT ditempatkan pada tengah bentang di serat atas balok untuk menghitung regangan tekan. Satu LVDT ditempatkan pada tengah bentang di serat bawah untuk menghitung regangan tarik. Sementara itu, untuk menghitung lendutan ditempatkan LVDT dan dial gauge pada sisi bawah balok di tengah bentang. Hasil lendutan maupun regangan dicatat melalui data logger dan pola retak digambar secara manual setelah balok hancur. Dari pengujian four points bending didapatkan lendutan, regangan dan pola retak. Hasil pengujian tersebut akan dijadikan validasi terhadap hasil analisa numerik. Untuk mengetahui nilai sifat mekanikal balok dilakukan beberapa pengujian eksperimental meliputi pengujian destruktif, non-destruktif dan tingkat durabilitas. Pengujian non-destruktif meliputi pengujian Ultrasonic Pulse Velocity(UPV), potensial tulangan dan keseragaman hammer test. Pengujian tersebut dilakukan sebelum pengujian four points bending karena tidak merusak benda uji. Sementara itu, pengujian destruktif dan tingkat durabilitas dilakukan setelah pengujian four points bending. Pengujian destruktif meliputi kuat tekan core drill, kuat tarik splitting beton dan kuat tarik tulangan. Pengujian tingkat durabilitas meliputi porositas, corrosion rate, pH dan penetrasi klorida. Sampel yang digunakan untuk pengujian kuat tekan, kuat tarik beton dan porositas berupa silinder core pada sayap dan badan balok. Sedangkan pengujian pH dan penetrasi klorida menggunakan sampel berupa serbuk beton. Sampel untuk kuat tarik tulangan dan corrosion rate berupa tulangan tarik dari balok tesebut. Hasil pengujian four-point bending balok di lingkungan agresif dan di lingkungan yang tidak terkondisikan memiliki perbedaan yang tidak signifikan dimana beban leleh pada setiap balok memiliki nilai yang hampir sama. Retak terjadi di tengah bentang yang tidak dipasang sengkang. Retak yang terjadi merupakan tambahan dari retak sebelumnya. Keenam balok komposit mengalami kegagalan spalling bonding dimana kondisi yang terburuk terjadi pada balok di lingkungan agresif. Secara visual, tulangan belum mengalami korosi. Hal ini terjadi karena beton mutu tinggi melindungi tulangan dari korosi. Kapasitas lentur balok di lingkungan agresif dan balok di lingkungan tidak terkondisikan memiliki perbedaan yang tidak signifikan. ============================================================================================= This study is a perpetuation of research by previous researcher Eniarti(2001). This study intends to knowing influence of aggressive environment against flexural capacity of composite beam. This study are involving experimental test, theoretical and numerical analysis. The composite beams from previous study were reused as a specimen in this study. Beam was consist of two different concrete strength called composite beam. The beams have T cross section which normal strength at wing part and high strength at web part. Confinement was apllied on the beam except at the middle of span. Deformed reinforcement was used three bar D16. The beam was performed using six composite beam specimens with various environmental condition which are aggressive and non-aggressive. Composite beams used in this study were combination of two different types of concrete. It also loaded by the working load at interval 0.1 tons at that time. In this research, the beams were sprayed with artificial sea water within a period 17 years. Then, composite beams loaded by four-point bending test at intervals of 0.25 tons until it reached the ultimate strength. This test used LVDT,dial gauge and data logger. A LVDT was attached in the middle of the upper beam to measure the compressive strain. A LVDT was attached in the middle of bottom beam to measure tensile strain. Meanwhile, to calculate the vertical deformation is placed LVDT and dial gauge in the middle of the bottom beam. Deflection and strain results are recorded through the data logger and the crack pattern is manually drawn after ultimate. The data obtained from four-point bending test were deformation, strain and crack propagation. The data obtained as a result of a combination of working load and corrosion. This result were used as a validation of numerical analysis. Several experiment were also needed to determine properties of beam. Several experiment was needed to determine mechanical properties of concrete such as destructive, non destructive and durability test. Non destructive test were included Ultasonic Pulse Velocity(UPV) test, reinforcement potential and hammer test. The test was performed before four points bending test. Meanwhile, destructive and durability test were performed after four points bending test. Destructive test were included compressive strength by core drill, splitting tensile and tensile strength of reinforcement. Durability test was included corrosion rate,pH and chloride content. Compressive strength, splitting tensile and porosity used core drill cylinder as sample. While pH and chloride content used concrete powder as a sample. There was no significant difference result of four-point bending between beam on aggressive and unconditioned environment that yield load of each beams almost had the same value. Crack pattern occurred in the middle of beam that there were no shear reinforcement applied. Crack occurred as a continuation research by Eniarti (2001). Six composite beam had a failure as spalling bonding that suffered severely damage at beam on aggressive environment. Visually, bar reinforcement was not corrosion yet. Reinforcement has been protected by high strength concrete by corrosion. The different of flexural capacity between beam on aggressive environment and beam on unconditioned environment was not significant.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Composite beam, high strength concrete, corrosion, aggressive environment, crack, deformation, balok komposit, beton mutu tinggi, korosi, lingkungan agresif, retak, lendutan
Subjects: T Technology > TA Engineering (General). Civil engineering (General) > TA418.74 Corrosion and anti-corrosives
T Technology > TA Engineering (General). Civil engineering (General) > TA418.9 Composite materials. Laminated materials.
T Technology > TA Engineering (General). Civil engineering (General) > TA645 Structural analysis (Engineering)
Divisions: Faculty of Civil Engineering and Planning > Civil Engineering > 22101-(S2) Master Thesis
Depositing User: Febrinaty Lina
Date Deposited: 19 Oct 2017 09:09
Last Modified: 09 Jan 2018 06:54
URI: http://repository.its.ac.id/id/eprint/46951

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