Static Response of Prestressed Girders with Openings

Abstract

Utility requirements can often dictate the use of openings in prestressed concrete beams and girders. Such provision of openings minimizes headroom and thus, leads to economy. In this paper the nonlinear analysis and design of statically loaded simply supported posttensioned prestressed concrete beams and girders with rectangular openings are presented. Several design parameters are varied such as: opening length and depth, vertical and horizontal locations of the opening, location of the applied load, type of cross section, and opening reinforcement. The results from the analytical study are substantiated by test results from 12 posttensioned prestressed concrete beams, eight of which are rectangular in section, the remaining four are of T‐section. Good agreement is shown between the theoretical and experimental results. A rational method of distributing the shear between the top and bottom chords of the opening is proposed, together with a design procedure against cracking of such chords. An illustrated design example is presented.