Rasio Modulus Penampang Elastik Balok Kayu Laminasi-Baut

. Laminated 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

Studi Eksperimental Karakteristik Beton Dengan Agregat Kasar Daur Ulang Dengan Fc'=25 MPa

Pada studi eksperimental ini, digunakan beton daur ulang dengan agregat kasarnya berasal dari limbah/brangkal benda uji beton di laboratorium. Benda uji silinder digunakan untuk mengetahui sifat mekanik seperti kuat tekan, kuat geser, dan kuat tarik belah. Tiga variasi persentase yang berbeda dari agregat kasar daur ulang digunakan dalam perencanaan campuran dengan fc’ = 25 MPa, yaitu 0%, 50%, dan 100% agregat kasar daur ulang. Hasil pengujian menunjukan nilai kuat tekan karakteristik fc’ = 28.7 MPa dan fc’ = 28.4 MPa untuk masing-masing campuran 50% dan 100% agregat kasar daur ulang. Nilai kuat tarik belah sebesar fct = 2.38 MPa, fct = 2.78 MPa, dan fct = 2.81 MPa untuk 0%, 50%, dan 100% agregat kasar daur ulang. Sedangkan kuat geser fv = 5,55MPa, fv = 4.28 MPa, dan fv = 3.86 MPa untuk 0%, 50%, dan 100% agregat kasar daur ulang

Optimum Lamina Configuration of I Glulam Beam

The I glulam beam may have several failure modes, such as failure in bending, wood shear, glue shear or adhesive between glue and wood. This paper presented the analitycal and experimental study of the optimum lamina configuration and dimension. The analytical results of achieving the optimum strength of I beam cross section with the same specific gravity of web and flange showed that the longer the span the smaller the web to flange width ratio needs. The I beam was not optimum when the cross section has a small ratio of span to beam height, the failure mode will be in wood shear. The contribution of sheardeflection was small at span to beam height ratio more than 20. The 12 specimens of I glulam beam made from Acacia mangium as web with flange variation using A. mangium, Meranti and Keruing. The wood specific gravity ratio of flange to web and the shear strength of glue were significant to make the wood and glue achieved the maximum strength. The oilly surface of Keruing flange made the load carrying capacity become low because of the wood-glue adhesive failure

Study on Strength and Stiffness of Meranti Wood Truss with Plywood Gusset Plate Connection and Lag Screw Fastener

Wooden truss could be one of the options to be used as structural element in both in 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