AbstrakBalok laminasi dapat menjadi alternatif pengganti kayu utuh, karena memberikan keuntungan yaitu dapat difabrikasi dengan bentang sesuai kebutuhan dan membuat penampang kayu yang lebih besar. Tujuan penelitian ini adalah menemukan persamaan empiris rasio modulus penampang elastik balok kayu laminasi-baut. Rasio modulus penampang elastik yaitu rasio antara modulus penampang elastik balok laminasi terhadap balok utuh. Ruang lingkup penelitian yaitu sistem laminasi secara horisontal, kayu Indonesia dengan berat jenis berkisar 0,4 -0,8 yaitu meranti merah (shorea spp), keruing (dipterocarpus spp), dan akasia mangium, penampang balok prismatis, penelitian dilakukan secara eksperimental di laboratorium dan numerikal metode elemen hingga nonlinier. Parameter yang dibahas adalah jenis kayu, ukuran baut, jumlah baris baut, dan jarak baut. Balok mempunyai bentang 3 meter dan disusun oleh 4 lamina. Model tegangan-regangan kayu untuk simulasi numerikal berdasarkan kriteria plastisitas Hill, model tegangan-regangan baut menggunakan model elastoplastik. Kesimpulan yang diperoleh yaitu tren kurva hubungan beban-lendutan balok kayu laminasi-baut adalah berbentuk bilinier, persamaan empiris rasio modulus penampang elastik merupakan fungsi dari jenis kayu, diameter baut, dan rasio jumlah baris terhadap jarak baut. Rasio modulus penampang elastik dapat digunakan untuk memprediksi kuat lentur balok laminasi pada beban batas proporsional.Kata-kata Kunci: Laminasi, baut, metode elemen hingga, modulus penampang elastik. AbstractLaminated beam can be an alternative for solid timber, because it provides the advantage that it can be fabricated with a needed-span and a bigger cross section. The purpose of this research is to obtain an empirical equation of the bolt-laminated timber beam elastic section modulus ratio. Elastic section modulus ratio is elastic section modulus ratio between laminated and solid beams. Scope of this research are horizontally laminated system, Indonesian timber with specific grafity ranged 0.4-0.8 which are red meranti (shorea spp), keruing (dipterocarpus spp), and acacia mangium, prismatic beam section, experimental test in laboratorium and numerical simulation using nonlinear finite element method. The parameters discussed are timber type, bolt diameter, number of row, and spacing. Beam has a 3-meter span and arranged by 4 laminae. Timber stress-strain model for numerical simulation based on Hill plasticity, bolt stress-strain model is elasto-plastic. Results obtained are beam load-displacement curve trend is bilinear, the elastic section modulus ratio equation are the fuction of timber type, bolt diameter, and number of row against bolt spacing ratio. The elastic section modulus ratio can be used to predict the bending strength at the proportional limit.

Abstract. Scarcity of wood is hindering the use of wood materials that have large dimension and high quality. Thus, wooden truss is expected to be a solution for this problem. However, the use of this system is not complemented with adequate research of its strength and behavior. In this study, wooden truss would be examined experimentally. The specimen is a wooden truss joist supporting the floor slab for typical residences with two connection type variations which are nail and glue. These specimens has dimension of 185 cm in length and 36 cm in height with 3 layers of a wooden board in width, and were produced by using Sengon wood with elasticity modulus of 2867 MPa, and specific gravity of 0.4. Destructive and nondestructive test were performed. From the result, we obtained a higher proportional strength for glue type connection truss which at 1123.34 kg compared to nail type connection truss which at 767.07 kg. However, unlike the nail type connection, the glue type connection has a brittle behavior. Moreover, the stiffness connection study resulted with partial fixity value of 0.07 for nail type and 0.98 for glue type connection. Furthermore, these results have also been validated using numerical model analysis

Reinforced concrete beams as structural elements that are often found are elements that are quite large in their role in bearing loads. Judging from the function of support as a bearer of tensile force, it is possible if the reinforced concrete beams are made with different numbers and areas of reinforcement. Reinforcement bundles are used if there is a cross-sectional dimension limitation without the distance between the reinforcement conditions being met. Beams with 2 reinforcement bundles are made to see the flexural capacity obtained. With the dimensions of the beam 150 mm x 200 mm x 1050 mm, a bundle of 2 reinforcement with a diameter of 10 mm is mounted on the tensile section of reinforced concrete beams. With a four-point bending test, a nominal bending moment is obtained. Single-section square cross-section analysis with cross-sectional area obtained using the equivalent diameter of the reinforcement bundle compared to the flexural test results. The bending moment capacity between experiment and analysis obtained the appropriate results. The bending capacity value of the two reinforcement bundles is still large so that the bending failure has not been reached.

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Wooden truss could be one of the options to be used as structural element in both building and bridge. Wooden truss overcomes the limitation of timber with great dimension with necessary strength. In this study, the wooden truss was designed with Meranti wood type with elasticity modulus of 10,520 MPa and specific gravity of 0.8. The timber used has cross-section size of 45 mm × 45 mm, with truss frame span of 2,445mm and height of 400 mm. The connection between the timbers was using 18 mm thick plywood with 6 mm lag screw fastener. The destructive testing that was conducted on 3 test samples showed a result that the strength of the truss was at an ultimate load of 31,042 N with a ductility ratio of 5.61. Numerical study of the truss' stiffness with this connection model resulted in stiffness degree value of 0.94.