The simply supported beam supports a load of P = 16 kN. Determine the smallest dimension a...

The simply supported beam supports a load of P = 16 kN. Determine the smallest dimension a of each timber if the allowable bending stress for the wood is σallow = 30 MPa and the allowable shear stress is τallow = 800 kPa. Also, if each bolt can sustain a shear of 2.5 kN, determine the spacing s of the bolts at the calculated dimension a.