AASHTO LRFD Design of PSC I Girder Bridge by ASTRA Pro

Описание: PSC I-beam Bridges, have gained wide acceptance in freeway and bridge systems due to their structural efficiency, better stability, serviceability, economy of construction and pleasing aesthetics. PSC beam design is more complicated as structure is more complete as well as needed sophisticated from world.

The economy of pre-stressed concrete is well established for long-span structures. According to Dean6, standardized precast bridge beams between 10 and 30 m long and precast pre-stressed piles have proved to be more economical than steel and reinforced concrete in the United States. According to Abeles7, precast pre-stressed concrete is economical for floors, roofs, and bridges of spans up to 100 m and for cast in situ work, up to 100 m. In the long-span range, pre-stressed concrete is generally more
economical than reinforced concrete and steel.

Pre-stressed concrete offers great technical advantages in comparison with other forms of construction, such as reinforced concrete and steel. In the case of fully pre-stressed members, which are free from tensile stresses under working loads, the cross-section is more efficiently utilized when compared with a reinforced concrete section which is cracked under working loads. Within certain limits, a permanent dead-load may be counteracted by increasing the eccentricity of the pre-stressing force in a pre-stressed structural element, thus effecting savings in the use of materials.

Pre-stressed concrete members possess improved resistance to shearing forces, due to the effect of compressive pre-stress. This reduces the principal tensile stress. The use of curved cables, particularly in long-span members, helps to reduce the shear forces developed at the support sections. A pre-stressed concrete flexural member is stiffer under working loads than a reinforced concrete member of the same depth. However, after the onset of cracking, the flexural behavior of a pre-stressed member is similar to mat of a reinforced concrete member.