Structural Behavior of Reinforced Concrete Horizontally Curved Box Beam with Opening

This work is dedicated to survey the structural reinforced concrete's behavior horizontally curved box beams with and without opening. Seven horizontally circular box beams were examined in the experimental work, one without opening, three with vertical opening and three with transverse opening. The test program includes the main variables; direction of opening, location of opening through profile of curved beams (effect of combination of internal forces). The beams were tested as a continuous beam with two spans, each span represents a quarter circle and under the action of two point loads each load located at top face of midspan of beam. The findings indicate that the ultimate load capacity was decreased for all specimens (CB۲.V۳۷, CB۳.V۶۰, CB۴.V۸۲, CB۵.T۳۷, CB۶.T۶۰ and CB۷.T۸۲) by about (۵, ۱۱.۵, ۱.۵,۱.۵, ۴۶.۴ and ۱۸.۶۶%) respectively, compared to the control CB۱. When compared with the control specimen CB۱, all specimens were indicating an increase in Service deformations in terms of deflection and twisting angle at midspan of the circular beams. The ductility was deteriorated for all specimens with opening (CB۲.V۳۷, CB۳.V۶۰, CB۴.V۸۲, CB۵.T۳۷, CB۶.T۶۰ and CB۷.T۸۲), as a percent was about (۱۳.۸۸, ۱۵.۳, ۱۹.۶۲, ۰.۵, ۰.۵ and ۱۳.۸۸%) respectively, compared with that of control specimen CB۱. As a result, generally, a clear degradation with different percentages in overall structural behavior of box beams horizontally curved containing opening according to the location and direction of openings, in this study the transverse openings at ۶۰°, where the opening under the combined maximum (shear and torsion) was led to a catastrophic decrease in the structural performance of horizontally curved box beam.

کلیدواژه ها:

Circular Box Beam ، Crack pattern ، Deformation Response ، Ductility ، Failure mode ، opening ، stiffness