Design of Wooden Floor Joist and Girder.pptx

Basic design of wooden floor joist and girder for agricultural structures.

1. Design of Floor Joist and Girder SONY P. AQUINO Professor I ABE 112 Agricultural Structures Engineering 2 nd Semester Academic Year 2022-2023

2. Definitions Floor joists are an important part of floor framing. They hold up the weight of a building, absorb impacts on the floor, and create structural support so that the floor will be stable and secure. Girder is a structural support which is designed to carry transverse loads, and to transfer those loads to vertical supports such as columns. Girders are utilized in the construction of buildings, bridges, and some types of heavy equipment, and they come in a range of styles.

3. Step in Designing Wooden Girder and Floor Joist 6. 2.1 Data gathering: Pl = Axial load W l = Uniform live load, N/m 2 S fj = Spacing of floor joist, m W o/ hd = weight of occupants, kg/ hd SR = Space requirements (PAES) Distance between girder supporting floor joist, L fj Distance between vertical member supporting girder (Column), L g Engineering properties of wood Allowable bending stress, f b Allowable shearing stress, v Modulus of elasticity, E Allowable deflection, L/240

4. Step in Designing Girder and Floor Joist Design computation For Floor Joist Compute uniform live load, N/m b. Compute uniform dead load due weight of flooring Wdf = WF * Sfj   c. Compute uniform dead load due weight of floor joist Assume b and d , y Density of wood Wdfj = ybd   d. Compute total uniform load W= Wl+Wdf+Wdfj e. Compute axial live load acting at the center in newton, P l P l = 9.81Wm, Wm= Average weight of person in kg  

5. Step in Designing Girder and Floor Joist Design computation For Floor Joist f. Draw FBD and compute the reaction at the support g. Draw shear and moment diagram and determine the maximum shear force and moment h. Design floor joist considering bending stress i . Design floor joist considering shearing stress j. Design floor joist considering deflection

6. Steps in Designing Girder and Floor Joist Design computation 2. For Girder a. Compute axial load (This equal to the reaction- in the design of floor joist) b. Draw FBD and compute the reaction at the support (vertical support example column) c. Draw shear and moment diagram and determine the maximum shear force and bending moment d. Design girder considering bending stress f. Design girder considering shearing stress g. Design girder considering deflection

7. Sample Problem A Farmer wants to construct broiler house and he decided to hire agricultural engineer to design broiler with a capacity of 300hds. The AB Engineer started gathering data for broiler production. Based from Philippines Agricultural Engineering Standards, space requirements for broiler production is 12.5Sqm/ 100 hds . Assuming that the weight of marketable broiler is 1.50kg/ hd , distance between girder is 3.75m, length of girder is 5.0m, space between floor joist is 0.50m and length of floor joist is 3.75m (equal to space between girder that support floor joist). Determine the most economical size of floor joist and girder if it is made of 80% grade guijo . Assume weight of flooring equal to 40N/m2

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9. Sample Problem Given Axial load acting at the center of floor joist = 60kg Spacing of floor joist, Sfj = 0.50m Weight of occupants, Wo/ hd = 1.50kg/ hd SR = Space requirements (PAES)= 12.5m2/100hds-broiler Distance between girder supporting floor joist, Lfj = 3.75m Distance between vertical member supporting girder (Column), Lg = 5.0m Engineering properties of wood Allowable bending stress, fb =20.80MPa Allowable shearing stress, v = 2.36MPa Modulus of elasticity, E8470MPa Allowable deflection, L/240

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