Computer Analysis and Design of Concrete Beams and Grids

Abstract

Once the sizes of the cross sections of members of continuous beams or grids are assumed, it is possible to perform by computer—for any loading—the structural analysis and the design checks for serviceability and ultimate strength. A computer program that performs these tasks is described. The program is particularly suitable for bridge design. With the prestressing jacking force and cable profiles specified as data, the loss due to friction and anchorage set is automatically calculated. The effects of creep and shrinkage of concrete and relaxation of prestressed steel are accounted for from the requirements of equilibrium and compatibility of strain in concrete and steel. The instantaneous and time‐dependent displacements, the stresses, and crack width when cracking occurs are calculated. The output also includes the cross‐sectional areas of the longitudinal non‐prestressed reinforcement and the number of stirrups necessary to resist the factored bending and twisting moments and shearing forces. For segmental construction or other multi‐stage construction methods, the program gives the stresses and deformations in each construction stage and after a long period. The reinforced concrete structures considered can have any amount of prestressing, varying from zero (allowing cracking), to full prestressing (eliminating cracks).