西安建筑科技大学学报(自然科学版)

通过对无粘结预应力活性粉末混凝土梁进行等幅疲劳试验研究,得到了RPC应变﹑受拉钢筋应变和无粘结筋应力增量随疲劳循环次数变化的变化值.结合试验结果,提出了适用于活性粉末混凝土的疲劳残余应变演化方程及疲劳变形模量退化方程.基于损伤变量的定义形式及应变等效原理,推导了钢筋弹性模量退化模型及剩余疲劳强度模型; 受拉钢筋及无粘结筋弹性模量退化模型及剩余疲劳强度模型的不同通过两者的S-N曲线和屈服强度的不同来体现.基于上述模型采用分段线性原理来代替疲劳非线性过程,并利用材料弹性模量的退化来反应材料的疲劳损伤,提出了无粘结预应力RPC梁疲劳全过程正截面疲劳应力计算方法.将计算结果与试验值进行对比,两者吻合较好具有一定精度.

Through equal-amplitude fatigue test of unbonded prestressed reactive powder concrete beams, the variation of RPC strain, tensile strain of steel bars and stress increment of unbonded tendons with the number of fatigue cycles were obtained. Based on the experimental results, the fatigue residual strain evolution equation and the fatigue deformation modulus degradation model of the active powder concrete are proposed. Based on the definition of damage variable and strain equivalent principle, the elastic modulus degradation model and residual fatigue strength model of steel bar are derived. The elastic modulus degradation model of residual steel and unbonded tendon and the residual fatigue strength model proved to be different. The difference between the S-N curve and the yield strength is reflected. Based on the above model, the piecewise linear principle is used to replace the fatigue nonlinear process, and the degradation of the material elastic modulus is used to reflect the fatigue damage of the material. The fatigue stress calculation method of the whole section of the unbonded prestressed RPC beam is proposed. Results are compared with the experimental values, and the two coincide with a certain accuracy.

引言
1 试验概况
2 材料疲劳损伤退化模型
3 材料疲劳破坏准则
4 疲劳全过程正截面应力计算
5 结论

图1 试验梁立面图及横截面图(单位:mm)<br/>Fig.1 Test beam facade and cross-sectional view(Unit:mm)

图1 试验梁立面图及横截面图(单位:mm)
Fig.1 Test beam facade and cross-sectional view(Unit:mm)

图2 加载示意图及测点布置(单位:mm)<br/>Fig.2 Static load and fatigue test(Unit:mm)

图2 加载示意图及测点布置(单位:mm)
Fig.2 Static load and fatigue test(Unit:mm)

表1 混凝土残余应变演化方程拟合系数<br/>Tab.1 Fitting coefficient of concrete residual strain evolution equation

表1 混凝土残余应变演化方程拟合系数
Tab.1 Fitting coefficient of concrete residual strain evolution equation

图3 受压区RPC残余应变拟合曲线<br/>Fig.3 RPC residual strain fitting curve of the compression zone

图3 受压区RPC残余应变拟合曲线
Fig.3 RPC residual strain fitting curve of the compression zone

表2 RPC变形模量曲线拟合系数<br/>Tab.2 RPC deformation modulus curve fitting coefficient

表2 RPC变形模量曲线拟合系数
Tab.2 RPC deformation modulus curve fitting coefficient

图4 受压区RPC疲劳变形模量衰减曲线<br/>Fig.4 RPC fatigue deformation modulus decay curve of the compression zone

图4 受压区RPC疲劳变形模量衰减曲线
Fig.4 RPC fatigue deformation modulus decay curve of the compression zone

图5 1#、2#、3#梁疲劳最大荷载作用下截面应变分布<br/>Fig.5 Sectional strain under maximum load of 1#、2#、3#

图5 1#、2#、3#梁疲劳最大荷载作用下截面应变分布
Fig.5 Sectional strain under maximum load of 1#、2#、3#

图6 混凝土受压应力-应变关系<br/>Fig.6 Compressive stress-strain relationship of concrete

图6 混凝土受压应力-应变关系
Fig.6 Compressive stress-strain relationship of concrete

图7 无粘结预应力RPC梁正截面疲劳应力分析计算简图<br/>Fig.7 The calculation model of sectional fatigue strain of unbonded prestressed RPC beams

图7 无粘结预应力RPC梁正截面疲劳应力分析计算简图
Fig.7 The calculation model of sectional fatigue strain of unbonded prestressed RPC beams

图8 无粘结预应力RPC梁疲劳全过程分析流程图<br/>Fig.8 flow chart for nonlinear analysis of fatigue process

图8 无粘结预应力RPC梁疲劳全过程分析流程图
Fig.8 flow chart for nonlinear analysis of fatigue process

图9 受压区RPC疲劳应变图<br/>Fig.9 RPC fatigue strain of the pressure zone

图9 受压区RPC疲劳应变图
Fig.9 RPC fatigue strain of the pressure zone

图10 钢筋疲劳应变<br/>Fig.10 Steel fatigue strain

图10 钢筋疲劳应变
Fig.10 Steel fatigue strain

图11 无粘结筋应力增量<br/>Fig.11 Unbonded stress increment

图11 无粘结筋应力增量
Fig.11 Unbonded stress increment

[1] CANBAZ M. The effect of high temperature on reactive powder concrete[J].Construction &Building Materials, 2014, 70(70):508-513.
[2] RICHARD P, CHEYREZY M. Composition of reactive powder concretes[J]. Cement &Concrete Research, 1995, 25(7):1501-1511.
[3] 李莉.活性粉末混凝土梁受力性能及设计方法研究[D].哈尔滨:哈尔滨工业大学, 2010.
[4] 陶学康,王逸,杜拱辰.无粘结部分预应力混凝土受弯构件的变形计算[J].建筑结构学报, 1989, 10(1):20-27.
[5] 刘英超.无粘结部分预应力矩形截面受弯构件短期刚度的试验研究[J].土木工程学报, 1988, 21(8):37-46.
[6] 钱永久,车惠民.疲劳荷载作用下无粘结部分预应力混凝土梁的受力行为[J].铁道学报,1992, 14(4):67-74.
[7] 宋永发,王清湘,宋玉普.重复荷载作用下无粘结部分预应力高强混凝土梁正常使用阶段性能研究[J]土木工程学报, 2001, 34(1):19-23.
[8] 赵灿晖,刘日圣,江炳章.重复荷载作用下无粘结部分预应力混凝土梁的抗剪强度[J].中国公路学报, 2000, 13(4):42-46.
[9] 宋玉普.混凝土结构的疲劳性能及设计原理[M].北京:机械工业出版社, 2006.
[10]谢建斌,何天淳.循环荷载下路面用钢纤维混凝土的弯曲疲劳研究[J].兰州理工大学学报, 2004, 30(2):104-109.
[11]曾志斌,李之榕.普通混凝土梁用钢筋的疲劳S-N曲线研究[J]. 土木工程学报, 1999, 32(5):10-14.
[12]马林.国产1860级低松弛预应力钢绞线疲劳性能研究[J]. 铁道标准设计, 2000, 20(5):21-23.
[13]冯秀峰.混合配筋部分预应力混凝土梁疲劳性能研究[D].大连:大连理工大学, 2005.
[14]谢里阳,于凡.疲劳损伤临界值分析[J].应用力学学报, 1994(3):57-60.
[15] 郑文忠,王晓东,王英.预应力混凝土梁板中无粘结筋应力增量极限值计算方法研究[C]//全国混凝土及预应力混凝土学术会议. 长沙:中国土木工程学会,2007:22.
[16]杜进生.使用荷载下无粘结部分预应力混凝土梁的应力分析[J].土木工程学报, 1998(1):72-75.
[17]叶见曙.结构设计原理[M].第3版.北京:人民交通出版社股份有限公司, 2014.
[18]罗许国,刘岱鑫.钢筋活性粉末混凝土梁的疲劳性能试验研究[J].西安建筑科技大学学报(自然科学版), 2016, 48(4):484-488.

备注

引言

1 试验概况

2 材料疲劳损伤退化模型

3 材料疲劳破坏准则

4 疲劳全过程正截面应力计算

5 结论

期刊信息