預鑄施工梁與版間冷縫對T形斷面梁耐震行為之影響

The Influence of the Construction Joint between Precast Beam and Cast-in-Place Slab on the Seismic Behavior of T-Beams

鄭智仁(Jhih-Ren Jheng)

指導教授 ： 洪崇展 ； 王勇智

國立中央大學/工學院/土木工程學系/碩士(2012年)

摘要

本實驗主要是針對有翼版存在的懸臂梁進行受力行為分析，就有無施工冷縫存在與剪力跨度不同進行討論。一般冷縫交接面剪應力檢核之經驗公式是由單向荷載實驗得來，本文亦探討現有規範之經驗公式是否也適用於反覆荷載之地震受力情形。
由實驗結果得知，短跨度T形梁(a/d=2.44)存在有澆置冷縫時，比一體澆置試體更容易發生交接面滑移。由於有冷縫存在之試體交接面滑移顯著，負彎矩時更會牽動版筋，使其受拉範圍較大，因此其有效版寬的貢獻為一體澆置試體的1.4倍。另外，就長跨度(a/d=5.46)與短跨度(a/d=2.44)T形梁作比較，發現當試體剪力跨度越長時，抵抗交接面滑移的面積就越大，試體就更不容易發生交接面滑移。由短跨度T形梁(a/d=2.44)交接面剪應力分析結果得知，當試體交接面滑移達0.5mm時，交接面剪應力與規範和經驗公式檢核交接面剪應力的上限值(0.2f''c)相當接近，故0.2f''c應可作為可能產生滑移介面之交接面剪應力上限值。

關鍵字

T形斷面梁 ； 耐震行為 ； 交接面剪應力 ； 預鑄施工 ； 施工冷縫

並列摘要

The purpose of this study is to observe the seismic behavior of T-shaped cantilever beams. The study investigates the effect of construction joint and shear span, and verifies the current design equations obtained from monotonic loading experience for evaluating interface shear stress is suitable for that under seismic behavior.
The test results indicate that the T-shaped short beam (a/d=2.44) with construction joint slipped more obviously at the interface than the beam without construction joint. According to test results, the effective width of T-beam flange with construction joint is 1.4 time wider than the beam without construction joint .
From the comparison between slender beams (a/d=5.46) and short beams (a/d=2.44) it was found that slender beams had less slip effect than short beams. This is because the area of shear resistance at interface for slender beams is larger than short ones.
The analytical results of horizontal shear stress obtained from T-shaped short beams (a/d=2.44) also show the horizontal shear stress is closer the upper limit of 0.2f''c specified by current design standards. This limit was concluded form the test result when the interfacial slip movement of 0.5mm was attained. Therefore, the upper shear stress limit of 0.2f''c is verified as design standards specified.

並列關鍵字

T-Beams ； Seismic Behavior ； Precast ； Construction Joint ； Interface Shear Stress

參考文獻

[13] E. N.B.S. Jùlio, F. A.B. Branco, and V. D. Silva,

[1] ACI Committee 318, Building Code Requirements for Structural Concrete , ACI 318-08 & Commentary, American Concrete Institute, 2008.

[3] J. C. Saemann, and G. W. Washa, “Horizontal Shear Connections between Precast Beams and Cast-in-Place Slabs,” ACI Journal, Vol.61, No. 69, November, 1964, pp. 1383-1410.

[4] J. A. Hofbeck, I. O. Ibrahim, and A. H. Mattock, “Shear Transfer in Reinforced Concrete,” ACI Journal, Vol.66, No.13, February, 1969, pp. 119-128.

[6] H. W. Chung, and T. Y. Chung, “Prestressed Concrete Composite Beams under Repeated Loading,” ACI Journal, Vol.73, No. 24, May, 1976, pp. 291-295.