Title: Design Issues and Application of High Strength Concrete for High Rise Buildings
Author(s): Hideki Kimura, Yuji Ishikawa, Hiroto Takatsu and Hassane Ousalem
Publication: Symposium Paper
Appears on pages(s): 1-20
Keywords: high-rise building; high-strength concrete; high-strength steel bar; precast concrete ; reinforced concrete column; beam-column subassembly; seismic design.
More than 500 high-rise RC buildings with height exceeding 60m (197feet) have been built since early 70's in Japan. The number of stories sometimes exceeds 50. Use of base isolation systems or vibration control devices in high-rise RC buildings has significantly increased since 1995 Kobe Earthquake. Ultra-high-strength materials have also been used in such buildings. The specified concrete strength of 150 MPa (21800psi) or higher is currently practiced and SD685 deformed bars of 685 MPa nominal yield strength are used as the main reinforcing bars.
Such buildings are subjected to intensive large axial and lateral loads in case of sever earthquakes and strong winds, particularly at their lower stories where exterior columns experience varying high-axial loads shifting from compression to tension. Furthermore, as concrete strength increases, fire resistance decreases and cracking behavior of RC members changes which affects the structural performance. A lot of experimental studies with regards to such columns and subassemblies have been carried out to investigate their structural performance and to establish appropriate design methods.
This paper presents some design issues related to the application of high-strength materials to RC columns or subassemblies. It also emphasizes recent research works and design methods for the application of ultra-high-strength concrete for high rise RC buildings.