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Method to Calculate the Average Overal Value of Modulus Elasticity and Modulus of Rupture for Glulam I-Joist in Bending Effendi Tri Bahtiar; Naresworo Nugroho; Rentry Augusti N; Han Roliadi
Jurnal Matematika & Sains Vol 16, No 3 (2011)
Publisher : Institut Teknologi Bandung

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Abstract

Abstract Glulam consists of laminaes and each laminae influences glulams strength. Transformed cross section (TCS) method is well known as a method to calculate the average overall value of Modulus of Elasticity (E) and Modulus of Rupture (SR) of layer system (e.g. glulam) based on its laminaes.  But, TCS does not follow the principal due to assumption that the material properties depend on its shape and size. Therefore, new calculation method is required.  This paper discusses the formulation of a new method to determine the E and SR of glulam.  E and SR calculated by TCS and new method give identical value. The new method applies the independencies of E and SR which could not be fulfilled by TCS.  According to this fact, TCS could be replaced by new method. The theoretical value as a result of TCS and the new method were verified by empirical test based on ASTM D198 two points loading bending test. The theoretical E value is higher than the empirical value, but it has high correlation (R2=68.53%). On the contrary, the theoretical SR value is not significant different with its empirical value, but it has poor correlation (R2=27.93%).  This condition is happened because of finger joint effect on the compression and tension side of the sample. By including finger joint effect into regression analysis, the equation results very good estimation.  The coefficient of determination is 99.58% and 97.19%, for E and SR respectively. Keywords: Glulam I-joist, Modulus of elasticity, Modulus of rupture, Transformed cross section (TCS), New method. Abstrak Glulam tersusun dari lamina-lamina dan setiap lamina  menyumbangkan pengaruh terhadap kekuatan glulam.  Transformed Cross Section (TCS) telah dikenal luas sebagai sebuah metode untuk menghitung nilai Modulus Elastisitas (E) dan Keteguhan Lentur Statis (SR) sistem lapisan termasuk glulam berdasarkan sifat-sifat lamina penyusunnya. Namun TCS tidak memenuhi prinsip asumsi keterkaitan antara sifat material dengan ukuran dan bentuknya. Oleh karena itu diperlukan suatu metode baru yang lebih konsisten terhadap prinsip independensi tersebut. Di dalam tulisan ini dibahas formulasi metode baru untuk memperkirakan E dan SR  glulam.  Perhitungan TCS dan metode baru memberikan nilai yang identik baik untuk E maupun SR, namun metode baru menunjukkan konsisten yang lebih baik terhadap independensi sifat material. Berdasarkan fakta tersebut maka TCS dapat digantikan oleh metode baru yang dibahas. Hasil perhitungan teoritis menggunakan TCS dan metode baru tersebut, selanjutnya diverifikasi empiris melalui pengujian lentur berdasar ASTM D198 dengan konfigurasi beban ganda. Nilai E teoritis lebih tinggi daripada hasil empirisnya, namun keduanya memiliki korelasi yang relatif tinggi (R2=68,53%). Sebaliknya, SR teoritis tidak berbeda nyata dibanding nilai empirisnya, namun korelasi keduanya rendah (R2=27.93%). Kondisi ini terjadi akibat pelemahan oleh keberadaan sambungan jari pada wilayah tarik ataupun tekan pada contoh uji. Dengan memasukkan pengaruh sambungan jari pada analisis regresi berganda, dapat diperoleh persamaan regresi yang cukup baik untuk menduga nilai E dan SR glulam. Nilai koefisien determinasinya adalah 99,58% untuk E, dan 97,19% untuk SR. Kata kunci: Glulam I-joist, Modulus elastisitas, Keteguhan lentur patah, Transformed cross section (TCS), Metode baru.
Rasio Ikatan Pembuluh sebagai Substitusi Rasio Modulus Elastisitas pada Analisa Layer System pada Bilah Bambu dan Bambu Laminasi Bahtiar, Effendi Tri; Nugroho, Naresworo; Karlinasari, Lina; Darwis, Atmawi; Surjokusumo, Surjono
Jurnal Teknik Sipil Vol 21, No 2 (2014)
Publisher : Institut Teknologi Bandung

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Abstract

Abstrak. Anatomi bambu disusun oleh sel-sel yang heterogen. Komponen anatomi bambu yang memberikan sumbangan terbesar pada sifat mekanisnya adalah ikatan pembuluh, sehingga kerapatan ikatan pembuluh dapat digunakan sebagai variabel dasar untuk menganalisa sifat mekanis bambu. Kerapatan ikatan pembuluh bergradasi dari tepi hingga ke dalam bambu sehingga dapat diturunkan suatu fungsi linier ataupun non linier sebagai pendekatannya. Rasio modulus elastisitas (E) yang lazim digunakan pada metode transformed cross section, pada penelitian ini dicoba diganti dengan rasio ikatan pembuluh dengan asumsi bahwa keduanya adalah ekuivalen. Hasil penelitian memperlihatkan bahwa terdapat nilai korelasi Pearson yang tinggi antara hasil teoritis dan hasil empiris, sedangkan hasil uji t-student data berpasangan menunjukkan bahwa tidak ada perbedaan yang signifikan antara keduanya. Dengan demikian model transformasi yang diturunkan dapat digunakan untuk melakukan analisa layer system pada bilah bambu maupun bambu laminasi dengan hasil yang dapat dipertanggungjawabkan. Dari ketiga model transformasi terpilih (linier, logaritmik, dan power) model power adalah model yang terbaik karena menghasilkan nilai yang paling mendekati data empiriknya.Abstract. Bamboo anatomy is constructed from many types of cells. Vascular bundles are the cells which give the highest contribution to the bamboo strength, thus the density distribution of vascular bundles could be used as the main variable for analyzing the layer system of bamboo strip and laminated bamboo. The density of vascular bundles distribution degrade from outer to inner in a regular manner which could be fitted by linear and nonlinear function. Ratio of modulus of Elasticity (E) which widely used in transformed cross section method for analyzing the layered system was substituted by ratio of density distribution of vascular bundles within assumption that both are highly correlated. The data in this study proved that there was high Pearson’s correlation between the theoretical and empirical result, and the paired t-student test also showed both were not significantly different; thus the new method could be applied in very good result. There are three model applied in this study namely linear, logarithm, and power. Power model is the best among others since its theoretical results the nearest estimation to the empirical measurement.
Pendugaan Sisa Umur Pakai Kayu Komponen Cooling Tower di Pembangkit Listrik Tenaga Panas Bumi (PLTP) Unit II Kamojang Bahtiar, Effendi Tri; Nugroho, Naresworo; Arinana, Arinana; Darwis, Atmawi
Jurnal Teknik Sipil Vol 19, No 2 (2012)
Publisher : Institut Teknologi Bandung

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Abstrak. Struktur cooling tower di PLTP (Pembangkit Listrik Tenaga Panas Bumi) Unit II Kamojang dibangun pada tahun 1988 dengan kayu sebagai komponen utamanya. Setelah 23 tahun umur pakainya, dirasa perlu dilakukan evaluasi sisa umur pakai sebagai salah satu bahan pertimbangan untuk memutuskan perobohan atau perpanjangan pemakaiannya. Evaluasi dilakukan melalui beberapa tahap yaitu: identifikasi jenis kayu dan keberadaan sisa bahan pengawet, pengukuran kedalaman kerusakan, pengujian sifat fisis mekanis, dan pemodelan matematis yang diturunkan dari uji creep dan pengurangan luas penampang kayu. Identifikasi memperlihatkan bahwa kayu yang dipergunakan untuk komponen utama cooling tower di PLTP Unit II Kamojang adalah redwood (Sequoia sempervirens) yang diawetkan dengan CCA (Chromated Copper Arsenat). Kerusakan telah terjadi sedalam 2,95 mm, namun secara umum masih memiliki tegangan ijin yang lebih tinggi daripada persyaratan NDS2005. Penelitian ini telah menghasilkan model terbaik yang dapat dipergunakan untuk menduga sisa masa pakai kayu komponen cooling tower di PLTP Unit II Kamojang dengan koefisien determinasi sebesar 86,84%. Abstract. Cooling tower in PLTP (Geothermal Power Plant) Unit II Kamojang was built in 1988, using solid wood as its main komponen. It is 23 years old nowadays, and should be evaluated to estimate its remaining lifetime. The evaluation conducted as scientific consideration for the company to decide wheter the cooling tower should be deconstruct or maintain to lenghten their lifetime. Some steps were conducted to estimate the remaining lifetime, namely: identification of wood species and the preservative remaining,measuring the depth of damages, measuring the physical and mechanical properties, and mathematical modelling which construct from creep testing and area reduction. This research show that the cooling tower was built with redwood (Sequoia sempervirens) which were treated with CCA (Chromated Copper Arsenat) preservative. The damage was happened until 2,95 mm depth, but the mechanical properties was commonly still better than NDS 2005 requirement. The  research result mathematical equation which is suitable to predict the remaining lifetime of wood component in PLTP Unit II Kamojang with coefficient of determination 86,84%.
Pengaruh Komponen Kimia dan Ikatan Pembuluh terhadap Kekuatan Tarik Bambu Bahtiar, Effendi Tri; Nugroho, Naresworo; Suryokusumo, Surjono; Lestari, Dwi Premadha; Karlinasari, Lina; Nawawi, Deded Sarip
Jurnal Teknik Sipil Vol 23, No 1 (2016)
Publisher : Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1243.724 KB) | DOI: 10.5614/jts.2016.23.1.4

Abstract

Abstrak. Bambu merupakan salah satu contoh material komposit alami yang tersusun atas beraneka ragam sel. Sel-sel fiber yang tersusun menjadi ikatan pembuluh diyakini merupakan sel yang paling bertanggung jawab terhadap kekuatan bilah bambu. Selain jumlah ikatan pembuluh, kekuatan tarik bambu juga dipengaruhi oleh kandungan komponen kimia dan bagian ruas/buku. Penelitian ini menunjukkan bahwa semakin banyak jumlah ikatan pembuluh, maka kekuatan tarik bambu semakin besar. Kandungan lignin meningkatkan kekuatan tarik pada bagian ruas secara proporsional (linier), bahkan kuadratik pada bagian buku. Peningkatan kandungan lignin dalam selang yang ditemukan dalam penelitian ini (33%) selalu meningkatkan kekuatan tarik bilah bambu sehingga titik balik maksimum tidak dapat ditemukan. Tingginya nilai korelasi kekuatan tarik dengan proporsi alpha selulosa terhadap holoselulosa pada bagian ruas memperlihatkan pentingnya peranan proporsi alpha selulosa tersebut, meskipun prosedur best subset regression tidak membacanya akibat terjadinya autokorelasi. Abstract. Bamboo is natural composite material which is built from many types of cells. Fibers cells which are bundled become vascular bundles have highest contribution toward the strength of bamboo split among others. Besides the amount of vascular bundles, the bamboo split strength is also determined by chemical component of cell walls and its position (internodes/node). This research reported that the tensile strength has positive correlation with the amount of vascular bundles. If the amount vascular bundles increase, then the tensile strength also increases. The increasing of lignin contents in cell wall proportionally and quadratically increases the tensile stress of internodes and node of bamboo split, respectively. This research did not found the maximum stationer  point of quadratic equation for lignin content effect toward bamboo split tensile strength, thus the tensile strength always increase along with the lignin content in this research range (<33%). Correlation value between tensile strength and ratio of alpha cellulose to holocellulose is high which prove that alpha cellulose highly contribute to the tensile strength even though best subset regression procedure could not identified this phenomenon because of its autocorrelation occurrence.
Analisis keragaan panel sandwich untuk rumah pra-pabrikasi Naresworo Nugroho; Effendi Tri Bahtiar
Jurnal Ilmu Pertanian Indonesia Vol. 15 No. 3 (2010): Jurnal Ilmu Pertanian Indonesia
Publisher : Institut Pertanian Bogor

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Abstract

In the last five years, several earthquakes struck several places in Indonesia and thousands of people died caused of their masonry house. Therefore, the idea of bamboo utilization in the form of structural sandwich panel components for anti-seismic pre-fabrication house is one of appropriate way out. This research describes the performance and behavior of engineered structure wooden-bamboo sandwich panel in full sized test. The wall frame being use were meranti wood, this frame attached by plywood as face and back, then 5 em bamboo cutting as core; the fastener used in this study were isocyanate resin and nails. This study carried out by experimental data of full scale structural tests on shear wall (ISO 22452). These result showed that the seismic reliability of the wall frame system made of bamboo sandwich panel was appropriate and will be useful for prefabrication houses as anti-seismic and environment friendly residential building.
Analisis Layer System Bambu Laminasi Berdasarkan Penyebaran Kerapatan Ikatan Pembuluhnya Effendi Tri Bahtiar; Naresworo Nugroho; Surjono Surjokusumo; Lina Karlinasari; Atmawi Darwis
Jurnal Ilmu Pertanian Indonesia Vol. 18 No. 1 (2013): Jurnal Ilmu Pertanian Indonesia
Publisher : Institut Pertanian Bogor

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Abstract

Anatomically, bamboo is constructed from many types of cells. Vascular bundles are the cells which give the highest contribution to the bamboo strength, thus the density distribution of vascular bundles could be used as the main variable for analyzing the layer system of bamboo strip and laminated bamboo. The density of vascular bundles distribution decreases gradually from the outer to inner part in a regular manner which could be fitted by linear or nonlinear function. Ratio of modulus of elasticity (E) which widely used in transformed cross section (TCC) method for analyzing the layer system are substituted by ratio of density distribution of vascular bundles with asumption that both are highly correlated. The data in this study proved that there are high Pearson’s corellation between the theoretical and the empirical result, and the paired t-student test also showed both are not significantly different; thus, this new method could be applied in very good result. There are 3 models applied in this study, namely linear, logarithm, and power. Power model is the best among others since its theoretical gives the nearest estimation to the empirical measurement.
Ciri Bilah Bambu dan Buluh Utuh pada Bambu Tali dan Bambu Ampel Naresworo Nugroho; Effendi Tri Bahtiar; Azhar Anas
Jurnal Ilmu Pertanian Indonesia Vol. 18 No. 3 (2013): Jurnal Ilmu Pertanian Indonesia
Publisher : Institut Pertanian Bogor

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Abstract

Bamboo is a natural resource that can be used as a basic commodity to substitute wood. To determine the use of a basic commodity, it is needed to study the basic characteristic of bamboo, in terms of anatomy, physical, and mechanical properties. Some studies of this topic, especially for engineering purpose, have been done, but the most of them used sample experiment in the form of bamboo culm. Therefore, it is necessary to find out whether experiments using bamboo strip are equivalent with the value of bamboo culm. This study used tali and ampel bamboos. The anatomy observation followed the Manual of Anatomy Practical Work and Wood Identification by Pandit (1991) and Nuryatin (2000), tests were based on Nuryatin’s study (2000). Sample tests for mechanical properties were based on ASTM D 143-94 and modification of ISO 22157-1:2004. The results showed that physical properties of internode of tali bamboo were inferior than that of the node, in contrary to ampel bamboo, which was better than that of the node. For all mechanical properties, internodes of tali and ampel bamboos were better than that of the node. The modulus of elasticity of the bamboo culm was lower 110% than that of the bamboo strip and the modulus of rupture of the bamboo culm was lower 230% than that of the bamboo strip. On the other side, τTk// of the bamboo culm was 15% higher than that of the bamboo strip.
KARAKTERISTIK CROSS LAMINATED BAMBOO SEBAGAI BAHAN KOMPOSIT STRUKTURAL Ana Agustina, Naresworo Nugroho, Effendi Tri Bahtiar, Dede Hermawan
Jurnal Teknologi Industri Pertanian Vol. 25 No. 2 (2015): Jurnal Teknologi Industri Pertanian
Publisher : Department of Agroindustrial Technology, Bogor Agricultural University

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The research produced Cross laminated bamboo (CLB) to examine the effect of layer thickness andorientation angle of CLB layer on physical and mechanical properties of CLB products. In this study, thepreparation of the angular variation between CLB layer with an angle between the core and face/back of 0o, 45oand 90o were investigated. The type of bamboo used was betung bamboo splits were cut into size of 115 cm x 2cm with thickness of 0.80 cm, 1.00 cm and 1.33 cm respectively. The CLB products were made with a thicknessof 4 cm by using isocyanate adhesive (glue spread 280 g/m2). Testing was conducted on the test density, moisturecontent, swelling and shrinkage volume, delamination, bonding strength, compresive strength parallel to grain,MOE and MOR with reference to ASTM D 143 (2005), and JAS 1152 (2007). Based on the test results, the valueof delamination, MOE, MOR, and bonding strength were still under the standard requirements of JAS 1152(2007). When compared with CLT (Cross Laminated Timber) products of solid wood which had a value ofcompressive strength parallel to the fiber of 245 kg/cm2, compressive strength parallel to grain value of CLBcould reach 434 kg/cm2.Keywords: cross laminated bamboo, bamboo betung, isocyanate adhesive, physical mechanical properties
Pangsor (Ficus callosa WILLD) and kecapi (Sandoricum kucape MERR) are usually planted in garden and rural forest. The objective of this study was to determine its specific gravity (SG), maximum crushing strength (σc//), longitudinal modulus elasticity (EL), and Poisson’s ratio (n).  The compression test  was conducted referring to  ASTM D143-94(2000) using UTM Instron 3369 which is equipped with two biaxial clip on extensometers.  The result showed that vertical and horizontal position of wood i Lusita WARDANI; Effendi Tri BAHTIAR; Ignasia Maria SULASTININGSIH; Atmawi DARWIS; Lina KARLINASARI; Naresworo NUGROHO; Surjono SURJOKUSUMO
Jurnal Ilmu dan Teknologi Hasil Hutan Vol. 4 No. 1 (2011): Jurnal Ilmu Teknologi Hasil Hutan
Publisher : Departemen Hasil Hutan, IPB

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Abstract

Pangsor (Ficus callosa WILLD) and kecapi (Sandoricum kucape MERR) are usually planted in garden and rural forest. The objective of this study was to determine its specific gravity (SG), maximum crushing strength (σc//), longitudinal modulus elasticity (EL), and Poisson’s ratio (n).  The compression test  was conducted referring to  ASTM D143-94(2000) using UTM Instron 3369 which is equipped with two biaxial clip on extensometers.  The result showed that vertical and horizontal position of wood in the trees statistically significant influenced on SG and σc//.  Horizontal position in Pangsor wood affected its EL, but the other position in both species were not significantly different.  There were poor correlations between SG with EL and σc//.   Poisson’s ratio value of both woods were in a range 0.0045 – 0.275 for longitudinal-radial direction (nLR), and 0.0151 – 0.1289 for longitudinal-tangensial direction (nLT).   Keywords :    Longitudinal Modulus of Elasticity, Maximum Crushing Strength, Poisson’s Ratio, Pangsor wood, Kecapi wood
KEKUATAN BAMBU BETUNG (Dendrocalamus asper Backer ex K.Heyne) MENAHAN GAYA NORMAL TEKANAN DAN TARIKAN Naresworo Nugroho; Effendi Tri Bahtiar; Arya Budhijatmiko Lelono
Jurnal Penelitian Hasil Hutan Vol 40, No 1 (2022): Jurnal Penelitian Hasil Hutan
Publisher : Pusat Penelitian dan Pengembangan Hasil Hutan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20886/jphh.2022.40.1.37-48

Abstract

Bambu merupakan salah satu hasil hutan multiguna yaitu sebagai bahan baku mebel, kerajinan, alat musik, dan konstruksi. Besarnya kekuatan tekan dan tarik bambu sudah dimanfaatkan dalam desain konstruksi, namun masih terbatas, seperti untuk kolom atau penguat beton. Penelitian ini bertujuan untuk menentukan sifat mekanis bambu betung (Dendrocalamus asper Backer ex K.Heyne,) umur empat tahun, yaitu kekuatan tekan sejajar serat, tarik sejajar serat, dan tarik tegak lurus serat, serta nilai 5% batas bawah. Ukuran contoh uji dan pengujian sifat mekanis bambu betung mengacu pada ISO 22157-2019. Pengujian tekan sejajar serat dan tarik tegak lurus serat menggunakan UTM SATEC/Baldwin, sedangkan pengujian tarik sejajar serat menggunakan UTM Chun Yen. Analisis data menggunakan aplikasi Easyfit 5,5 untuk mendapatkan nilai 5% batas bawah tiap pengujian. Rata-rata kuat tekan sejajar serat yang diperoleh yaitu sebesar 52,97 N/mm², sedangkan nilai rata-rata kuat tarik sejajar serat sebesar 109,03 N/mm². Rata-rata kuat tarik tegak lurus serat dengan ukuran lubang uji 25 dan 40 mm sebesar 2,53 dan 1,19 N/mm², sedangkan nilai rata-rata MOE tekan dan MOE tarik sejajar serat sebesar 2.674 dan 9.542 N/mm². Nilai 5% batas bawah untuk kuat tekan sejajar serat sebesar 38,10 N/mm², tarik sejajar serat sebesar 61,78 N/mm², sedangkan untuk kuat tarik tegak lurus serat sebesar 0,60 N/mm². Nilai MOE tekan dan MOE tarik sejajar serat yang diperoleh sebesar 1.105 dan 6.076 N/mm².