Split Ring Connection of Coconut and Bangkirai Lumber

. This research was a further research on tensile load of three-member connection of Coconut and Bangkirai lumber (Awaludin & Triwiyono, 2003). The new thing done in this experiment is the use of split ring as the connector of the connection. In the previous research (Awaludin & Triwiyono, 2003), two bolts of 15.6 mm were used as the connectors in each connection. Besides the result from experiment, the ultimate tensile load of split ring connection was also analyzed with equations from Euro Code 5 and Awaludin & Triwiyono (2002). The dimension of split-ring connector was 40 mm in diameter, 30 mm in length, and bolt of 12.5 mm was used to tight the connection. Two split ring connectors were placed in every connection. The result shows that the ultimate tensile load of split-ring connection was thirty percent higher than the bolted connection. The displacement of split ring connection was only 67% of the displacement of bolted connection. The ultimate tensile load of experiment was scattered closely to the result of Euro Code 5 and Awaludin & Triwiyono (2002)

Studi Kuat Geser Panel Kayu Vertikal dengan Perkuatan Single Bracing Tulangan Baja Akibat Pembebanan Monotonik

Struktur panel yang digunakan sebagai dinding dalam konstruksi kayu berkontribusi dalam memberikan kekuatan lateral apabila direncanakan sesuai prosedur. Bahan panel di dalam penelitian ini terdiri dari rangka dan penutup berupa plywood yang dihubungkan ke rangka kayu dengan alat sambung paku. Kekuatan lateral pada panel ditingkatkan menggunakan penambahan bracing dari baja tulangan polos pada rangka. Benda uji divariasikan berupa panel kayu tipe I yang dihubungkan dengan rangka kayu LVL dengan alat sambung pakuCN 50 diameter 2.8 mm dan jarak antar paku 240 mm dan panel tipe II berupa panel serupa dengan tipe I tetapi diberikan perkuatan bracing tulangan polos tunggal berdiameter 8 mm posisi tarik menggunakan corner plate sebagai connector antara bracing dan rangka kayu LVL. Pengujian skala penuh dengan pembebanan monotonik dilakukan sampai penurunan 40% dari beban maksimum. Dari hasil pengujian didapatkan tahanan lateral panel yang menggunakan bracing dari tulangan polos lebih besar dibanding panel yang tidak menggunakan perkuatan. (Tahanan lateral tipe I sebesar 5625 N dan tipe II sebesar 8265 N

Prediksi Nilai Kuat Lentur Kayu Tropis Berdasarkan Nilai Modulus Elastis

Dalam SNI 7973:2013, nilai modulus elastisitas statik kayu (MoEs) digunakan sebagai dasar pengelompokan mutu kayu. Nilai MoEs juga dapat digunakan untuk memprediksi sifat mekanika kayu yang lain. Penelitian ini melakukan kajian untuk mendapatkan persamaan yang dapat digunakan untuk memprediksi nilai berdasarkan nilai rata rata modulus elastisitas dan persamaan untuk mendapatkan nilai kekuatan lentur (MoR) berdasarkan nilai MoEsnya dari kayu tropis yang ada di Indonesia. Uji lentur statik dilakukan berdasarkan EN 408, sementara itu uji lentur dinamik dilakukan menggunakan metode stress wave velocity. Selain itu, data sekunder hasil pengujian lentur dari para peneliti terdahulu juga digunakan dalam penelitian ini. Dari hasil analisis, nilai adalah sebesar 0,754 dari . Analisis regresi linear menunjukkan bahwa nilai MoR dapat didekati dengan persamaan = −1,359 + 0,0061, dimana dari persamaan ini dapat diketahui bahwa nilai desain acuan yang ada pada Tabel 4.2.1 SNI 7973:2013 cenderung memberikan faktor keamanan yang memadai. Pengujian lentur dinamik kayu menunjukkan bahwa hubungan antara modulus elastisitas dinamik (MoEd) dan MoEsdapat didekati melalui persamaan = −1330,1 + 1,254 dengan koefisien determinasi () sebesar 0,69

Mechanical Properties of Cocos Nucifera Wood Planted Around Mt. Merapi, YOGYAKARTA

This study presented test results of mechanical properties of Cocos nucifera wood that were planted around Mt. Merapi, Yogyakarta. The test specimens were obtained from trees that had been exposed to pyroclastic flow during the 2010 volcanic eruption as indicated by dark colour of the outer bark. Test set-up was designed according to ASTM D143-94 and the mechanical properties, which are determined based on the lower 5% exclusion limit, were bending strength, shear strength, dowel bearing strength and compressive strength. Results of the specific gravity measurement showed significant variation of specific gravity between the inner part (close to the pith) and the outer part (far from the pith) in a cross-section. Since mechanical properties generally depend upon specific gravity, it was decided to divide the wood specimens into two groups: specimens from the inner part and specimens from the outer part. Most of the mechanical properties of wood specimens from the inner part, except for bending strength, were found to be much lower than E10 grade of the Indonesian National Standard (SNI). Hence it is not recommended for any structural use. In the case of wood specimens from the outer part, their mechanical properties were as follows: bending strength 83.66 MPa; shear strength parallel to grain 4.41 MPa; dowel bearing strength parallel to grain 40.65 MPa; dowel bearing strength perpendicular to grain 25.88 MPa, compressive strength parallel to grain 37.89 MPa; and compressive strength perpendicular to grain 7.48 MPa. It seemed that the wood specimens from the outer part had excellent mechanical properties especially in bending, but their shear strength is extremely low

Seismic Performance Comparison of Pile Supported Slab Viaduct with PHC Pile and RC Bored Pile in South Part of Java Island

At present, infrastructures of Indonesia are developed rapidly to enhance economic growth. One of them is in terms of an elevated structure to support highway and railway infrastructures. Pile-supported slab viaduct (PSSV) with pre-stressed hollow concrete (PHC) piles has been widely used in the development of both infrastructures. The structural configuration just contains a pile as a pier, pile head, and slab. So that, quick construction time and lower cost are amongst the consideration of that type selection. Considering that the Indonesian country is mostly in the earthquake zone, the development of the high seismic performance of PSSV structures becomes a necessity. Previous researches showed that PHC piles without additional treatment have low ductility and energy dissipation. On the other hand, reinforced concrete (RC) columns could achieve medium ductility for a stand-alone seismic lateral resistance. In this study, a seismic performance comparison between PSSV with spun pile column and PSSV with RC bored pile column that designed as a medium ductility concept to be conducted with a numerical model by using OpenSees software. A non-linear beam-column element with hinge and fiber section was adopted to simulate the plastic hinge behavior of the pile element. Cyclic loading following ACI 374.1-05 loading protocol was implemented to quantify structural drift-energy dissipation. Then, to evaluate the seismic performance of the proposed structures, a set of scaled ground motion provided by the Japan Road Association (JRA) was generated. The target acceleration spectra based on SNI 2833-2016, the Indonesia seismic load provision for bridge design, for Kulonprogo, Yogyakarta Province. The result of this study concluded that utilizing RC bored pile as the piers of the PSSV structure could produce higher energy dissipation than the one with PHC pile column under cyclic loading. Also, PSSV structure with RC pile column had a better response against the seismic excitation than the one with the PHC column, even though slightly over the ultimate capacity. However, the PSSV with PHC column had significant over-limit deformation under some ground motion excitation. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd

Resistivity Models of Pantar Island Geothermal System East Nusa Tenggara, Indonesia

The subsurface geological conditions of a geothermal system are vital objects to be considered in geothermal exploration. The Magnetotellurics survey was conducted to explore for geothermal potential in Pantar Island. This is to achieve deeper penetration compared to our previous study that adopted resistivity method to determine reservoir zones based on rock resistivity models. The difference in rock resistivity in geothermal systems provides subsurface geological information in the form of low resistivity that associated the clay cap zones (high conductive), the medium resistivity zones associated with the reservoir zones, and high resistivity associated with a heat source. The results of 2D and 3D models from MT data show that the low resistivity value (<20Ωm) as a clay cover zones, this layer from the surface to -1000 meters. Medium resistivity values ​​(20-100 Ωm) starting from depths -1000 meters to -2000 meters associated with reservoirs zones, high resistivity values (> 200 Ωm) starting from depths of -2000 meters are considered as heat source from the Pantar geothermal system

Experimental characterization of multi-full-culm bamboo to steel connections

The present research examines the performance of newly developed multi-full-culm bamboo to steel connections under monotonic axial loading. The culms are of Kao Jue (Bambusa pervariabilis) bamboo species. Findings reveal that the plain (unreinforced) connections fail early by undesirable brittle longitudinal splitting of bamboo culms. The confinement provided by hose-clamps inhibits this brittle failure mode, and with sufficient end-lengths, drastically increases the strength and ductility of the connection. Compared to the hollow-section connections with hose clamps, adding mortar infill further increases the strength. However, it also restricts bolt-deformation and thus diminishes the ductility. More importantly, the European Yield Model (which refers to dowelled timber connections) can analytically estimate the obtained experimental yield loads with satisfying accuracy. This is a promising direction towards a more rational and safer structural design of bamboo structures