基于桁架拱模型的纤维混凝土受剪性能分析毕业论文

 2021-04-16 01:04

摘 要

作为当今工程建筑材料的重点研究对象,纤维混凝土材料的各项基本力学性能都应该得到详细透彻的研究。目前对纤维混凝土受剪性能的研究较少,不能满足发展的需要,但纤维混凝土的抗剪强度对材料整体功能的影响很重大,因此,抗剪强度是实际工程设计中应该考虑的主要方面。本文概述了纤维混凝土的发展及其在现实工程中的应用背景,分别指出了纤维架桥作用、基体接触作用、不同的纤维种类、体积掺量及倾角对纤维混凝土受剪性能的影响,并分析了目前研究受剪性能主要的三种方法。其中,详细地分析了桁架系列各计算模型的受剪传力机理及优缺点,并指出桁架-拱模型的优势。

本文提出了用于分析纤维混凝土受剪性能的桁架-拱模型计算公式,并将模型计算结果与试验结果进行对比分析,得到以下结论:

模型计算结果接近试验研究结果,模型的变异系数也较小,表明用桁架-拱模型求解纤维混凝土受剪性能的计算精度较高,能够基本反映纤维混凝土的受剪传力机理及抗剪强度,通过该模型计算纤维混凝土构件的抗剪强度具有合理性、可靠性与准确性。

关键词:纤维混凝土;受剪性能;抗剪模型;桁架-拱模型

Analysis of Shear Capacity of Fiber Reinforced Concrete Based on Truss-Arch Model

ABSTRACT

As a construction material, attracting more and more attention in the research presently, the basic mechanical properties of FRC materials should be studied thoroughly and in detail. There are few studies on shear capacity worldwide, can’t meeting the demands of development, but the shear capacity of fiber reinforced concrete materials has great importance on the whole property of the composites. Therefore, the shear-bearing capacity should be the main aspect, taken into account in design calculation of practical engineering. The paper introduces the development of FRC and its application in practical engineering, respectively points out fiber bridging effect, matrix contact effect, different fiber types, fiber volume and fiber inclination on the shear capacity of fiber reinforced concrete, and analyzes the main methods to study the shear capacity. The paper analyzes the merits, shortcoming and shear transfer mechanism of truss series calculation model in detail, and points out the advantages of the truss-arch model.

In this paper, the formula of the truss-arch model is put forward to calculate the shear capacity of fiber reinforced concrete, and the results of the model are compared with the experimental results. The following conclusions are obtained:

The calculated results are close to experimental ones, and the coefficient of variation of the truss-arch model is small. It shows that the accuracy of the truss-arch model is high, that the model can reflect the shear transfer mechanism and shear-bearing capacity of the fiber reinforced concrete, and that using the model to calculate the shear-bearing capacity of the fiber reinforced concrete is reasonable, reliable and accurate.

Key words:fiber reinforced concrete;shear capacity;shear model;truss-arch model

目 录

1 绪论……………………………………………………………………………………………………1

1.1 研究背景………………………………………………………………………………………1

1.2 纤维混凝土的概述……………………………………………………………………………1

1.2.1 纤维混凝土的产生及发展………………………………………………………………1

1.2.2 增强纤维的作用及作用机制……………………………………………………………4

1.2.3 纤维混凝土在实际工程中的应用………………………………………………………6

1.3 纤维混凝土受剪性能研究现状………………………………………………………………8

1.3.1 纤维架桥作用对FRC构件受剪性能的影响…………………………………………8

1.3.2 基体接触作用对FRC构件受剪性能的影响…………………………………………9

1.3.3 纤维种类、体积掺量及倾角对FRC构件受剪性能的影响………………………10

1.3.4 纤维混凝土受剪性能的分析方法……………………………………………………12

1.4 研究方案………………………………………………………………………………………14

1.4.1 本文的主要研究目的及意义…………………………………………………………14

1.4.2 本文的主要研究内容…………………………………………………………………14

2 桁架体系各模型比选分析…………………………………………………………………………16

2.1 古典桁架模型…………………………………………………………………………………16

2.2 变角桁架模型…………………………………………………………………………………18

2.3 压力场系列理论………………………………………………………………………………18

2.3.1 压力场理论……………………………………………………………………………18

2.3.2 修正压力场理论………………………………………………………………………19

2.3.3 扰动应力场模型………………………………………………………………………20

2.4 软化桁架模型…………………………………………………………………………………20

2.4.1 变角软化桁架模型……………………………………………………………………20

2.4.2 定角软化桁架模型…………………………………………………………………………21

2.4.3 扰动应力场模型……………………………………………………………………………21

2.5 拉压杆模型……………………………………………………………………………………21

2.6 桁架拱模型……………………………………………………………………………………22

2.6.1 桁架 拱模型…………………………………………………………………………22

2.6.2 桁架-拱模型……………………………………………………………………………24

2.7 本章小结………………………………………………………………………………………24

3 桁架-拱模型的受剪分析及公式推导………………………………………………………………26

3.1 桁架模型………………………………………………………………………………………26

3.2 拱模型…………………………………………………………………………………………30

3.3 模型的参数讨论………………………………………………………………………………32

3.4 抗剪承载力计算公式…………………………………………………………………………35

3.5 本章小结………………………………………………………………………………………35

4 模型计算结果与试验结果对比分析………………………………………………………………37

4.1 SHCC构件的模型计算结果与试验值比较…………………………………………………37

4.2 PE-ECC构件的模型计算结果与试验值比较………………………………………………41

4.3 PS-ECC构件的模型计算结果与试验值比较………………………………………………43

4.4 PVA-ECC构件的模型计算结果与试验值比较……………………………………………45

4.5 计算值与试验值的比较分析…………………………………………………………………49

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