Development and Performance Evaluation of Precast Drift-Hardening Concrete Wall Columns

2021 Fiscal Year Final Research Report

• Project/Area Number: 19H02289
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 23010:Building structures and materials-related
• Research Institution: Kobe University
• Principal Investigator: Sun Yuping 神戸大学, 工学研究科, 教授 (00243915)
• Co-Investigator(Kenkyū-buntansha): 藤永 隆 神戸大学, 都市安全研究センター, 准教授 (10304130) ; 竹内 崇 神戸大学, 工学研究科, 助教 (80624395)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: PCaRC壁柱 / ドリフト硬化性 / 残留変形角 / 修復性 / 能力曲線

Outline of Final Research Achievements

A novel precast concrete wall pier was proposed. The proposed wall pier consists of normal-strength concrete and ultra-high strength bars (SBPDN bars) placed in the edge zones of wall section. Through experimental and theoretical works, the following conclusions can be drawn:
1) The proposed drift-hardening PCaRC wall piers with axial load ratio of 0.075 and 0.15 exhibited drift hardening behavior till drift ratio of 3.0% and 3.5%, respectively, when each SBPDN rebar was housed in sheath duct with embedded depth of 25d. Besides, the peak drift of the proposed wall piers was proportional to the shear span ratio as well as the steel amount of transverse reinforcement in the wall panel, and was in reverse proportion to the axial load ratio.
2)Utilizing finite spring method, the hysteretic loops can be accurately predicted till large drift, and the effect of bond slip of SBPDN rebars on the overall seismic behavior of the proposed wall piers could be reliably evaluated.

Free Research Field

鉄筋コンクリート構造学

Academic Significance and Societal Importance of the Research Achievements

SBPDN筋を用いたRC壁柱のプレキャスト化により、壁板の縦筋は座屈・破断せず、せん断補強筋として働けることから、圧着PCaRC壁とほぼ同等の修復性に加え、2.5倍以上の水平耐力を持つ強靭なPCaRC壁柱を世界で初めて実現することは、学術的インパクトが高い。
本壁柱はラーメン架構に用いれば、架構高さ方向の変形モードの制御および局所的な層崩壊の回避が容易に図れる。また、本壁柱は、高い施工精度を要する定着アンカーや壁板縦筋の定着などを省くことができ、施工性に優れていることから、多様な建物への迅速な実用化が期待でき、巨大地震時の都市のレジリエンスの向上につながるので、社会的意義が極めて高い。