Handbook of Civil Engineering Calculations

Alternatively, evaluate F/ by assigning an arbitrary depth to the member Thus, set A = 10 in (254 mm); yb = SJil(Sb + St) = 4.8 ...

PRESTRESSED-CONCRETE BEAM DESIGN GUIDES On the basis of the previous calculation procedures, what conclusions may be drawn that ...

vestigation. Calculate fbp and ftp by expressing these stresses as functions of the kern distances of the sec- tion. Calculation ...

Calculation Procedure: Set the initial stress in the bottom fiber at midspan equal to or less than its allowable value, and sol ...

FIGURE 37. Magnel diagram. For the case where e is restricted to 18 in (457.2 mm), minimize FJ by determining the ordinate of p ...

Thus, using the ACI Code, E 0 = (145) 15 (33)(4000)°- 5 = 3,644,000 IMn 2 (25,125.4 MPa). Construct the prestress-moment diagra ...

DESIGN OF A DOUBLE-T ROOF BEAM The beam in Fig. 39 was selected for use on a simple span of 40 ft (12.2 m) to carry the followin ...

Determine whether the section moduli are excessive Do this by setting fbf and/, equal to their allowable values and computing t ...

Compute the steel stress and resultant tensile force at ultimate load: / 0.5/?/;\ fsu=fs' 1-^M (61) V Jc I Or,fsu = 248,000(1 - ...

(275,800.0 kPa), and set s = 12 in (304.8 mm). Then Av = 12(20,200 - 0.85 x 17,000)/[0.85(11.09)(40,000)] = 0.184 in^2 /ft (3.89 ...

Calculation Procedure: Compute the properties of the cross section Since the tendons will be curved, the initial stresses at mi ...

FIGURE 44. Location of tendons at midspan. The ultimate strength is 236,000 lb/in^2 (1,627,220 kPa). Then A 8 = 0.723 in^2 (4.66 ...

(d) Values of ftf FIGURE 45 (c) Values of f* (b) Values of fbf (a) Values of fbi ...

FIGURE 46. Concrete area under stress at ultimate load. Calculate the steel index to ascertain that it is below the limit impose ...

FIGURE 47. Parabolic arc. Present the results The equations are y = 2(yl-2y 2 +y 3 )(~-}^2 -(3yl-4y 2 +y 3 )^+yl (66) \L I L d ...

FIGURE 48 lively, are ea = 1 in (25.4 mm); em, = 30 in (762.0 mm); eb = -3 in (-76.2 mm). Evaluate the prestress shear and prest ...

FIGURE 50 This result discloses that when the trajectory is parabolic, w is uniform across the span. The radial forces are alway ...

continuous member amenable to analysis by the theorem of three moments or moment distribution. Determine wL 2 /4 for each span: ...

(a) Three-hinged arch FIGURE 52. Prestress moment diagram. the trajectory has not affected the value OfW 1 and W 2 , the value o ...

= O. Under the latter prestressing system, the tendons exert three forces on the concrete- one at each end and one at the deflec ...