标题: | 包覆型钢骨钢筋混凝土构材之强度与力学行为 STRENGTH AND BEHAVIOR OF CONCRETE ENCASED COMPOSITE STRUCTURAL MEMBERS |
作者: | 颜圣益 Sheng-I Yen 翁 正 强 C. C. Weng 土木工程学系 |
关键字: | 包覆型钢骨钢筋混凝土构材;试验研究;剪力握裹破坏;斜张剪力破坏;强度叠加法;ACI设计规范;AISC设计规范;Concrete Encased Composite Member;Experimental Study;Shear Bond Failure;Diagonal Shear Failure;Strength Superposition Approach;ACI Code;AISC Specification |
公开日期: | 2001 |
摘要: | 本研究致力于探讨包覆型钢骨钢筋混凝土结构之构材强度与力学行为。论文中主要包含两项研究课题,其一为包覆型钢骨钢筋混凝土构材之剪力强度与力学行为之研究;其二则是轴力与弯矩共同作用下钢骨钢筋混凝土构材极限强度与行为之研究。 第一个主题中,本论文进行共计九支包覆型钢骨钢筋混凝土梁剪力握裹破坏试验。试验结果发现计有五支试体发生沿着钢骨翼板的水平裂缝(本研究称之为剪力握裹破坏)。试验观察发现“钢骨翼宽比”(系指钢骨翼板宽度与构材全断面宽度之比值)对此种包覆型钢骨钢筋混凝土梁的破坏形式有关键的影响。 根据实验之观察,本研究提出一理论分析模式来预测钢骨钢筋混凝土构材之剪力握裹破坏。为验证理论模式预测结果的准确性,本研究藉由上述之试验结果与前人之实验资料来进行比较分析。分析结果发现,本研究所建议之理论分析模式可以合理的预测包覆型钢骨钢筋混凝土构材剪力握裹破坏。 在探讨包覆型钢骨钢筋混凝土构材之剪力极限强度时,本研究考虑了前述之剪力握裹破坏与传统的斜张剪力破坏两种失败模式,并且提出预测剪力强度之方法。初步结果显示,本研究之建议法可合理的预测钢骨钢筋混凝土构材之剪力强度,并适当的考量了剪力握裹破坏与斜张剪力破坏两种失败模式。此外,本研究并提出一称为“临界翼宽比”(critical steel flange ratio)的新参数,藉由该参数可使得剪力握裹破坏与斜张剪力破坏的预测更为简便。 在第二个主题中,本研究首先探讨美国ACI-318与AISC-LRFD设计规范,对于受轴力与弯矩共同作用之包覆型钢骨钢筋混凝土构材极限强度计算方法,并比较其计算结果的差异性。从力学行为的观点而言,作者发现以AISC纯钢骨设计公式或以ACI纯钢筋混凝土设计公式来预测包覆型钢骨钢筋混凝土构材极限强度似隐含着许多值得改进的问题。基于上述考量,本研究乃进一步提出一个新的预测方法,该法以强度叠加概念为基础将包覆型钢骨钢筋混凝土构材中钢筋混凝土与钢骨部分之强度分别依ACI-318与AISC-LRFD规范中相关规定计算,再予叠加,以求得钢骨钢筋混凝土构材之强度。 本法的另一特点系依据材料力学之基本原理,将作用于包覆型钢骨钢筋混凝土构材之轴力依钢骨与钢筋混凝土的相对刚度比例分配之。然后将钢骨及钢筋混凝土所受之轴力分别代入AISC-LRFD与ACI-318设计规范中之P-M交互公式中,分别求得钢骨与钢筋混凝土个别的弯矩再予叠加。为验证本法之准确性,本研究将本法之预测结果分别与数值分析法及前人之试验结果进行比较。比较结果显示,本法在预测包覆型钢骨钢筋混凝土构材之极限强度上可获致令人满意之结果。 This thesis is devoted to the investigation of the strength and behavior of concrete encased composite structural members. Two major topics are involved in this study. The first is a study on the shear strength and behavior of the composite members; and the second is a study on the strength and behavior of the composite members under combined compression and bending. In the first topic, an experimental study that focuses on the shear bond failure of concrete encased composite beams is performed. Nine full-scale specimens were constructed and tested in this study. Significant horizontal cracks along the interface of steel flange and concrete, referred to as the shear bond failure, appeared in five tested specimens. Observations from the experiments indicate that “the steel flange width ratio”, defined as the ratio of steel flange width to gross section width (bf / B), has a dominant effect on the shear bond failure of the composite beams. Then, an analytical model for predicting the shear bond failure mode of the composite members is presented in this study. To evaluate the accuracy of this model, a verification analysis is made by comparing the failure modes predicted by the proposed model to those observed from the tested specimens. The results of the analysis indicate that the proposed analytical model gives satisfactory prediction on the shear bond failure of the composite members. Through the understanding of the shear bond failure mechanism of the composite members, a new design approach is proposed to predict the shear capacities of the composite members. The newly observed shear bond failure mode and the conventional diagonal shear failure mode are taken into account in the proposed approach. This approach yields satisfactory predictions of the shear strength of a composite member and also provides rational explanations to the mechanism of shear bond failure. A new term called “the critical steel flange ratio” is introduced in the proposed approach to distinguish the shear bond failure from the conventional diagonal shear failure. In the second topic, the composite column strength provisions of ACI-318 code and AISC-LRFD specification are investigated. It is noted that using the design procedures analogous for pure reinforced concrete or for pure steel to design a composite column can be somehow misleading. Therefore, this study develops a new strength superposition approach that combines the AISC-LRFD specification and the ACI-318 code to predict the strength of the concrete encased composite columns. Based on the fundamental theory of mechanics of materials, the proposed approach also considers the relative rigidities of the steel and the RC portions in the composite column to determine the external loads shared by the steel and the RC parts. To evaluate the performance of the proposed method, comparisons between the values predicted by the proposed method and those calculated by a numerical fiber analysis are made. In addition, test results done by previous researchers are also collected to evaluate the accuracy of the proposed method. The comparative results show that the proposed approach gives satisfactory predictions of the strengths of the composite columns. |
URI: | http://140.113.39.130/cdrfb3/record/nctu/#NT900015026 http://hdl.handle.net/11536/68067 |
显示于类别: | Thesis |