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Kekuatan Geser Campuran Tanah-Kapur-Abu Sekam Padi Dengan Inklusi Kadar Serat Karung Plastik Yang Bervariasi Widianti, Anita; Hartono, Edi; Muntohar, Agus Setyo
Jurnal Semesta Teknika Vol 10, No 1 (2007): MEI 2007
Publisher : Jurnal Semesta Teknika

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Abstract

Stabilisasi tanah secara kimia yaitu dengan penambahan kapur dan abu sekam padi mampu meningkatkan kekuatan gesernya, namun campuran tersebut cenderung berperilaku getas (brittle). Keadaan ini kurang memuaskan bila digunakan sebagai bahan konstruksi yang lebih menginginkan bahan berkekuatan tinggi tetapi berperilaku ductile. Kombinasi dari teknik perbaikan tanah secara kimia dan secara mekanis (yaitu dengan perkuatan serat-serat plastik) diharapkan akan memberikan hasil yang lebih baik. Tujuan dari penelitian ini adalah untuk mengkaji kuat geser tanah yang distabilisasi dengan kapur-abu sekam padi-serat plastik dengan berbagai variasi kadar serat  dan masa perawatan. Dalam penelitian ini digunakan tanah yang dicampur 12% kapur, 24% abu sekam padi dan serat karung plastik sebanyak 0,1%, 0,2%, 0,4%, 0,8%, dan 1,2% dari berat total campuran. Uji yang dilakukan adalah uji geser langsung pada saat benda uji berumur 7 dan 14 hari. Secara umum dengan adanya penambahan serat karung plastik dan masa perawatan, nilai kohesi, sudut gesek dalam, dan kuat geser mengalami peningkatan dibandingkan nilai pada tanah asli dan tanah yang hanya dicampur dengan kapur-abu sekam padi saja. Campuran tanah - kapur-abu sekam padi dan 0,4 % serat untuk masa perawatan 14 hari memberikan peningkatan nilai kuat geser tertinggi, yaitu sebesar 178,63 % dari nilai kuat geser tanah asli (pada σ = 12,59 kN/m2).
Interpretasi Letak Bidang Longsor dan Faktor Aman Lereng dengan Bahasa Pemrograman MATLAB Anita Widianti, Joko Supriyadi ,
Jurnal Semesta Teknika Vol 14, No 2 (2011): NOVEMBER 2011
Publisher : Jurnal Semesta Teknika

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Slope stability analyses can be performed using computer program, such as Matrix Laboratory (MATLAB). In the current work, a computer program for slope stability analysis named JOZLOPE based on MATLAB and using Bishop simplified analysis method was used to determine the location of a slip surface and its safety factor. The validation is carried out by analyzing three simple slope models and comparing their results by JOZLOPE and some comparator slope stability analysis programs. It is found that the variations between JOZLOPE’s results and those of the comparators are less than 1% for bottom circle-slope geometry intersection, less than 7% for top circle-slope geometry intersection  and less than 4% for Safety Factor. These findings demonstrates  that the a MATLAB program is successfully compiled and it produced measured values that agree with those of their respective comparator.  
Pemanfaatan Batugamping Keprus Sebagai Campuran Agregat Pada Lapis Pondasi Agregat Kelas B Hardwiyono, Sentot; Widianti, Anita
Jurnal Semesta Teknika Vol 8, No 2 (2005): NOVEMBER 2005
Publisher : Jurnal Semesta Teknika

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Abstract

Batugamping keprus banyak terdapat di Kabupaten Gunung Kidul, Yogyakarta. Penelitian ini bertujuan untuk mengkaji kemungkinan pemakaian batugamping keprus sebagai bahan campuran agregat pada  lapis pondasi agregat kelas B. Penelitian dilakukan dengan membuat berbagai variasi persentasi campuran batugamping keprus, sirtu dan tanah. Batugamping keprus bervariasi dari 15% hingga 85%, sirtu bervariasi dari 75% hingga 5% dan tanah tetap sebesar 10% dari berat total campuran. Pada setiap campuran dilakukan uji batas cair, indeks plastisitas, CBR unsoaked dan CBR soaked pada kepadatan maksimal dengan mengacu pada SNI. Hasil penelitian menunjukkan bahwa nilai batas cair, nilai indeks plastisitas dan nilai CBR unsoaked dari berbagai persentasi campuran batugamping keprus, sirtu dan tanah (kecuali untuk campuran 85% batugamping keprus, 5% sirtu dan 10% tanah) memenuhi spesifikasi yang telah ditetapkan oleh Bina Marga,  namun nilai CBR soaked tidak memenuhi spesifikasi tersebut.  
Peningkatan Nilai CBR Laboratorium Rendaman Tanah dengan Campuran Kapur, Abu Sekam Padi dan Serat Karung Plastik Widianti, Anita
Jurnal Semesta Teknika Vol 12, No 1 (2009): MEI 2009
Publisher : Jurnal Semesta Teknika

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Bearing capacity of a subgrade is one of the parameters to design the thickness of road pavement. Beside the bearing capacity, swelling behavior of subgrade must be in a narrow range to avoid crack of the pavement. This paper presents an effort to improve the soaked design California Bearing Ratio (CBR) and swelling value of soil by stabilizing with lime-rice husk ash and strengthened by randomly placed plastic fiber. In this study, the portions of lime and rice husk ash were set constant to the value of 12% and 24%, respectively. Amount of waste plastic sack fibers was used in this experiment ranging from 0.1% to 1.2% of dry weight of mixtures. The samples were tested at 7 and 14 days after mixing. The results show that the soaked design CBR value increases to 867%. As a result, swelling value decreases from 62% to 100%. The optimal improvement of the soaked design CBR was found at 0.2% of plastic sack fibers.
Pengaruh Ukuran dan Kedalaman Geotekstil Teranyam Tipe HRX 200 terhadap Daya Dukung Ultimit dan Penurunan Tanah Lempung Lunak Budi Kurniawan Thirayo, Anita Widianti , Azmania ,
Jurnal Semesta Teknika Vol 16, No 1 (2013): MEI 2013
Publisher : Jurnal Semesta Teknika

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Geotextile as one of improvement material in soft clay soil has been widely used.  This study aims to examine the effect of geotextile dimention and placement depth on ultimate bearing capacity, settlement and Bearing Capacity Ratio of soft clay soil. This test was conducted on a series of square plate foundation loading of 10 cm width on clay soil sample and installing one layer of geotextile-improvement inside with several dimention variations and geotextile depth. Clay soil is on soft condition taken into a box model made of steel plate with the dimention of 120 cm x 120 cm x 100 cm. The result of this research shows that dimension and depth of geotextile affected the bearing capacity and settlement of soft clay soil. There were improvement in ultimate bearing capacity of as high as 3 times higher for geotextile 3Bx3B; 4 times higher for geotextile 4Bx4B; 5 times higher for geotextile 5Bx5B and 6 times higher for geotextile 6Bx6B comparing with bearing capacity of non supported-clay soil. Decreasing of settlement on clay soil was observed on the 3Bx3B improvement (twice lower), and 3 times lower, 4 times lower and 5 times lower for 4Bx4B, 5Bx5B, 6Bx6B, respectively. Geotextile which placed at a depth of 0.4 B and 0.8 B resulted in increased ultimate bearing capacity by 3.13 times. Dimension and depth geoxtile also affect the value of BCR. The highest BCR was on the dimention 6Bx6B on the depth of 0.6 B.
Pengaruh Jumlah Lapisan dan Spasi Perkuatan Geosintetik terhadap Kuat Dukung dan Penurunan Tanah Lempung Lunak Widianti, Anita
Jurnal Semesta Teknika Vol 15, No 1 (2012): MEI 2012
Publisher : Jurnal Semesta Teknika

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Abstract

One of the ways to improve the mechanical characteristics of soft soil is to provide soil reinforcement which is a geosynthetic sheet overlaid on the soft soil. Previous studies show that the installation of geosynthetic layers in soft soil proved to increase the bearing capacity and reduce the settlement. Theoretically, if more layers of reinforcement are given, the support will be stronger, while the soil of settlement will be reduced even greater. In this study, the influence of the number of layers and vertical distance between geosynthetic layers on the magnitude of bearing capacity, and the settlement in base soil will be assessed. The primary research is a load test on each clay included in model boxes of 120 cm x 120 cm x 100 cm size. Water was added to the soil to achieve the liquid limit conditions, then the soil was strengthened by inserting 60 x 60cm2 HRX200 woven geotextile layers whose tensile strength is 20 kN/m2 with various distances and number of layers among different boxes. The bottom of loading foundation on the top side of the samples is square whose side (B) is of 10 cm. The loading process were done until the soil collapse indicated by visual observation or by the condition of no increase of the load magnitude causing settlement. The results showed that 1 layer, 2 layers and 3 layers geosynthetic correspond to the bearing capacity increase of 60.57%, 213.00% and 402.64%, respectively, and experienced a reduction in soil settlement by 40%, 60% and 70%, respectively, compared to that without any reinforcement. Geosynthetic being placed at a distance of 0.4 B and 0.6 B gives the greatest bearing capacity increase, in the amount of 402.64%. Geosynthetic mounted on distance more than 0.6 B resulted in bearing capacity increase of diminishing percentages.
Uji Triaksial Unconsolidated-Undrained pada Campuran Tanah Lanau - Kapur - Abu Sekam Padi dan Serat Karung Plastik Widianti, Anita; Hartono, Edi; Muntohar, Agus Setyo
Semesta Teknika Vol 11, No 2 (2008): NOVEMBER 2008
Publisher : Semesta Teknika

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Geotechnical and mechanical behaviour of soil stabilized with lime-rice husk ash and strengthened by randomly placed plastic fiber depends on the portions of the added materials and curing time. This research investigates the effect of the waste plastic sack fibers portion and the curing time to the stress – strain relationship and to the shear strength parameters of the mixture. In this study the portions of lime and rice husk ash were set as constant to the value of 12% and 24% respectively. The effect of four waste plastic sack fibers portion variation from 0.1% to 0.8% was measured by unconsolidated-undrained triaxial test. The samples were tested at 7, 14 and 21 days after mixing. In general, according to the test result, the inclusion of randomly waste plastic sack fiber and curing time have enhanced the shear strength parameters, the peak stress and the strain before failure.  With 0.2% fiber content, the cohesion and the internal friction angle values of the samples have increased 335% and 409% respectively compared with those of the samples having no added materials.
Perancangan Fondasi Pada Tanah Timbunan Sampah (Studi Kasus Di Tempat Pembuangan Akhir Sampah Piyungan, Yogyakarta) Widianti, Anita; Wahyudi, Dedi; Diana, Willis
Semesta Teknika Vol 8, No 1 (2005): MEI 2005
Publisher : Semesta Teknika

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Tempat Pembuangan Akhir Sampah (TPAS) merupakan kebutuhan setiap daerah guna mengatasi masalah sampah. Apakah lahan yang sangat luas tersebut  nantinya dapat dimanfaatkan kembali ? Berdasarkan pertanyaan itulah penelitian ini dilakukan. Tujuan dari penelitian ini adalah untuk merancang fondasi berdasarkan daya dukung tanah yang mampu menahan beban dan penurunan yang tidak berlebihan dari hasil uji sondir di lapangan.Penelitian dilakukan di zona pertama dari TPAS Piyungan, Yogykarta  yang merupakan zona di mana proses penimbunan dan pemadatannya telah selesai.  Hasil uji sondir pada dua titik digunakan sebagai dasar untuk merancang fondasi dari struktur bangunan dua lantai, dengan mengacu pada Standar Tata Cara Perhitungan Struktur Beton Untuk Bangunan Gedung, SK SNI-T-15-1991-03.Dari hasil analisis menunjukkan bahwa fondasi telapak dapat digunakan dengan kedalaman 1,6 m. Fondasi tersebut  dirancang berukuran 100 cm x 100 cm dengan ketebalan 25 cm, jumlah tulangan sebanyak 8 buah dengan diameter 10 mm dan spasi tulangan 12 cm. 
Pengaruh Kadar Air Awal Dan Surcharge Pressure Pada Uji Karakteristik Pengembangan Tanah Ekspansif Diana, Wilis; Hartono, Edi; Widianti, Anita
MEDIA KOMUNIKASI TEKNIK SIPIL Volume 23, Nomor 2, DESEMBER 2017
Publisher : Department of Civil Engineering, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (404.448 KB) | DOI: 10.14710/mkts.v23i2.15985

Abstract

Expansive soils experience volumetric changes due to water content changes. These volumetric changes cause swell and shrink movement in soils, which in turn will inflict severe damage to structures built above them. A Proper understanding of how the expansive soil behaves during the wetting/drying process is essential for assessing the mitigation action of expansive soil hazard and design suitable foundation. The structures that build above expansive soil bed are susceptible to heave and to withstand swell pressure, thus the swell pressure must be considered in the design. This study focuses on swelling properties of two expansive clay from Ngawi, East Java and Wates, Yogyakarta. Laboratory test on disturbed samples is used to identified and to measured swelling properties. A series of swelling test was performed under constant soil dry density. The influence of initial water content and surcharge pressure on swelling properties (i.e swell percent and swell pressure) of compacted samples were investigated. The swelling properties test used ASTM standard 4546-03 method B. It was found that the lower initial water content the higher the swell percent, but the swell pressure seems not to be affected by initial water content. At the same initial water content, swell percent decrease with the increase of surcharge pressure, but swell pressure remains unchanged.
PERANCANGAN DAN PEMBANGUNAN ATAP HALAMAN MASJID AL ASEL, PERUMAHAN KANOMAN, BANYURADEN, GAMPING, SLEMAN, DIY Widianti, Anita; Priyo, Mandiyo; Prasetio, Eka; Alpriandi, Mulya
Jurnal Pemberdayaan: Publikasi Hasil Pengabdian Kepada Masyarakat Vol 4, No 2 (2020)
Publisher : Universitas Ahmad Dahlan, Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (544.119 KB) | DOI: 10.12928/jp.v4i2.1946

Abstract

Al Asel Mosque is one of the mosques in Banyumeneng Hamlet, Banyuraden, Gamping, Sleman, DIY, which was established in 1985. Over time the number of worshipers has increased. The current size of the mosque is no longer sufficient to accommodate people who want to worship, especially Friday prayers and Tarawih prayers in the month of Ramadhan, so that they often spill out to the courtyard of the mosque. Problems arise when it starts to enter the rainy season. The mosque yard covering an area of 12x12 m2 which has been covered by concrete block and marked for prayer can not be used anymore. As a result, prayers had to crowd within the mosque and on the porch, even forced to pray on the terrace of the kindergarten room. This of course reduces the solemnity during worship. The committee of Al Asel Mosque planned to build a roof of the mosque courtyard so that the prayers can pray on the courtyard during rain. The purpose of this activity is to help the committee of Al Asel Mosque realize the roof structure of the mosque's yard covering an area of 12x12m2. The method of activities carried out include designing the roof structure and supervision during the construction process in a few weeks. The design process produced documents consisting of design drawings and budget plans. After the completion of the mosque roof construction, the capacity of pilgrims increased and it is expected that prayers would be more solemn during worship.