The Development of Precast Prestressed Concrete I-Shaped Beam with Mutiple Openings
By S. Kawamoto, M. Iijima, S. Takezaki and S. Baba
Concrete Journal, Vol.48, No.8, Aug. 2010
- Synopsis
- The utilization of high strength reinfoecement bars as prestressing steel instead of normal tendons has already been put to practical use in Precast Pre-stressed Concrete Beams (PCa PC Beam) with pre-tensioning method. Large amount of prestress transfer by SD685 reinforcement with large diameter and the adoption of high-strength concrete from 80 N/mm2 to 100 N/mm2 (Fc 80 - 100) enable the reduction of the beam section. This time, PCa PC I-shaped beam with multiple openings (T-POP: Taisei Precast Optimized beam with Prestress) has been developed. The feature of this method is that the longer span can be achieved because the weight of the beam can be lightened compared with usual PC beam. A lot of openings can be freely arranged as well as the steel beam. And vertical vibration due to walking on the floor is smaller than that of the steel beams, which means the better habitability. Moreover the amount of the CO2 exhaust in producing the beam can be reduced than the steel beam. As a result, this method can be applied to hospitals and factories, etc. besides offices. The concrete in this development achieves the quite fast gain of the strength, more than 100 N/mm2 (Specified concrete strength: Fc 130 N/mm2) within 16 hours. As a result, the term of the beam manufacturing in the precast factories can be shortened and the stable supply of these beams-to large projects has been achieved. In this paper, the outline of PCa PC I-shaped beam with multiple openings, the performance of the materials, the structures, and the fireproof are introduced.
- Keywords:
- Precast Prestressed Concrete Beams, High strength reinforcement bars, I-shaped beam, Multiple equipment opnening, Ultra rapid strength ultra high strength concrete
