Procedure 4-5 Seismic Design - Vessel on Braced Legs

Procedure 4-5 Seismic Design - Vessel on Braced Legs 

Ca = Corrosion allowance, in Dc = Centerline diameter of eolumns, in E = Modulus of elastieity, psi f = Maximum force in brace. Lbs fa = Axial stress, eompression, psi f, = Tension stress, psi Fa = Allowable axial stress, psi Fb = Allowable stress, bending, psi Fc = Allowable stress, compression, psi Fd = Axial load on column due to dead weight, lbs Fh = Horizontal seismic force. Lbs Fl = Axial load on column due to seismic or wind, lbs Ft = Allowable stress, tension, psi Fv = Vertical seismic force. Lbs Fy = Yield strength of material at temperature, psi g = Acceleration due to gravity, 386 in/sec  

Ic = Moment of inertia, column, in k = End connection coefficient, columns Mq = Overturning moment, in-Lbs N = Number of columns 

Q = Maximum axial force in column, Lbs tb = Radius of gyration, brace, in tc = Radius of gyration, column, in Sr = Slenderness ratio T = Period of vibration, seconds V = Base shear. Lbs Vn = Horizontal force per column. Lbs Wo = Weight, operating. Lbs w = Unit weight of liquid, pcf AL = Change in length of brace, in 8 = Lateral deflection of vessel, in 

The horizontal load on any one leg is dependent on the direction of the leg bracing. The horizontal force, V, is transmitted to the legs through the bracing. Thus, the general equation  

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