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开槽砌块灌孔砌体的抗剪性能试验研究

2014-10-27黄靓许仲远高翔

湖南大学学报·自然科学版 2014年9期
关键词:砌体

黄靓 许仲远 高翔

摘要:通过对开槽砌块灌孔砌体的抗剪试件的静力试验研究,了解了开槽砌块灌孔砌体的试件开裂荷载、极限承载力、破坏过程和破坏特征.试验结果表明,开槽砌块灌孔砌体和普通灌孔砌块砌体相比,其抗剪强度得到一定程度的提高.分析了影响灌孔砌块砌体抗剪强度的多种因素,并根据Hoffman准则以及现行的规范公式,建立了开槽砌块灌孔砌体的抗剪强度公式,公式的计算结果与实验结果吻合较好.建立了开槽与不开槽砌块灌孔砌体抗剪强度的统一表达式,结果表明,将其运用在不开槽砌块的抗剪强度的计算中是可行的.

关键词:砌体;空心砌块;破坏机理;抗剪强度

中图分类号:TU205 文献标识码:A

Abstract: 3 groups of 18 shear specimens were tested to investigate the failure processes,failure characteristics and ultimate capacity. It was shown that, due to the knocking out of the slot rib, the upper and lower core columns were connected and thus made them collaborate. As a result, the shear strength of the grouted slotted block masonry was moderately higher than that of the ordinary grouted masonry. Based on the shear mechanism of concrete block masonry, a shear strength formula of grouted slotted block masonry was built with Hoffman criteria, and a uniform shear strength formula suitable for both slotted and unslotted block masonry was proposed. The calculated values, which were generated by formula developed in this method, were in good agreement with the test results.

Key words: masonry structure; hollow block; failure mechanism; shear strength

砌体是一种历史悠久的建筑材料,具有较强的生命力\[1\],在经济欠发达地区仍然是最主要的结构形式之一,但传统砌体结构存在许多问题\[2\],而配筋砌块砌体结构则能够在很大程度上改善传统砌体的整体性能\[3\].在配筋砌块砌体结构中,为方便预留用于放置水平钢筋的水平通孔,工程中常采用肋部有开槽的混凝土砌块,砌筑墙体时,将砌块开槽肋敲掉便可形成横向通孔.

目前,国外学者建立了多种剪压复合作用下砌体抗剪强度计算式\[4\],这其中最经典的是:Turnseck以及Froeht,Borchelt等人提出的主拉应力破坏理论,Hendry和Sinha提出的库仑破坏理论,Chinwah,Pieper,Schneider和Trautsch等人根据试验研究提出的剪摩破坏机理.

国内方面,骆万康等人采用剪摩理论,引入剪压复合受力影响系数的概念,建立了砌体的抗剪强度计算式,已被我国现行砌体规范所采用\[5\].洪峰将主拉强度理论与剪摩理论相结合,提出一种新的拉摩强度理论,这种理论对剪摩和剪压两类破坏拟合均比较好,但缺乏对于斜压破坏的描述\[6\].蔡勇通过最小耗能原理建立了简捷实用的设计公式,但公式没有下降段,且缺乏对高轴压比状态的描述\[7\].

然而到目前为止,国内外学者大多只研究了未开槽砌块砌体的抗剪强度、抗压强度、本构关系等基本力学性能,却忽视了肋部开槽对砌体基本力学性能可能产生的影响,故其研究结论具有一定的局限性.开槽砌块灌孔砌体的力学性能与普通灌孔砌块砌体相比更接近工程实际,所以砌块开槽对砌体基本力学性能的影响有进一步的研究价值.

本文对3组18个开槽砌块灌孔砌体的抗剪试件进行了静力试验,以了解开槽砌块灌孔砌体的受剪开裂荷载、受剪极限承载力,并利用Hoffman准则,对开槽砌块灌孔砌体的抗剪强度的计算公式进行了建立,并以此为根据,建立了开槽与不开槽砌块灌孔砌体的抗剪强度的统一表达式.

2开槽砌块灌孔砌体的受剪破坏特征

试验结果显示,开槽砌块灌孔砌体沿竖向灰缝的受剪面有两种破坏形态:单面破坏与双面破坏,见图4.试验过程中灰缝砂浆与芯柱混凝土的破坏呈现出先后性,砌体受剪试件破坏并非瞬间发生,在竖向灰缝受力开裂时,因芯柱混凝土并没有到达抗剪承载力极限状态,试件承载力仍在增加,呈现出一定的延性.砌体试件破坏时,除了上、下两芯柱正截面受剪破坏外(图5所示AB,CD截面),还会在开裂灰缝和相应一侧的底部承压面之间出现斜裂缝.大多数试件的斜裂缝的开始位置刚好便是砌块敲掉开槽肋的地方,个别试件稍有上、下移动,且斜裂缝和底部承压面之间大致呈60°角(图5所示EF截面).由试验结果所测得的开槽砌块灌孔砌体随着灌孔混凝土强度的变化,受剪开裂荷载和极限荷载的比值的表现为A组试件是66%~88%,B组试件是55%~71%,C组试件为53%~91%,可知,当灌孔混凝土的强度增大时,砌体受剪开裂有所推迟.

5结论

本文通过对3组18个开槽砌块灌孔砌体试件进行的受剪试验研究和理论分析,主要得到了以下结论:

1)开槽砌块灌孔砌体沿通缝截面有两种受剪破坏形态:单面破坏和双面破坏.灰缝砂浆的破坏和芯柱混凝土的破坏具有先后性.

2)开槽砌块灌孔砌体试件在发生剪切破坏时,会在开裂灰缝与相应一侧的底部承压面中间产生斜向裂缝,角度大致呈60°.

3)开槽砌块灌孔砌体由于敲掉了砌块的开槽肋,被联通的上下芯柱混凝土能够协同工作,使其开槽砌块灌孔砌体的抗剪强度与普通灌孔砌块砌体相比有一定的增大.

4)利用Hoffman准则建立用于计算开槽砌块灌孔砌体抗剪强度的公式,其计算值与本文的试验结果基本吻合.

5)以开槽砌块灌孔砌体抗剪强度计算公式为基础,统一了开槽与不开槽砌块灌孔砌体的抗剪强度计算式,用此式计算不开槽砌块砌体抗剪强度是可行的,其计算值与试验结果基本吻合.

参考文献

[1]宋力. 混凝土砌块砌体基本力学性能试验研究与非线性有限元分析\[D\].长沙:湖南大学土木工程学院, 2005:1-50.

SONG Li. Research and nonlinear finite element analysis on the basic mechanical properties of concrete masonry\[D\]. Changsha: College of Civil Engineering, Hunan University, 2005:1-50. (In Chinese)

[2]SUCUOGLU H, MCNIVEN H D. Seismic shear capacity of reinforced masonry piers\[J\]. Journal of Structural Engineering, 1991, 117(7): 2166-2185.

[3]XU Zipeng, HUANG Liang, WU Zhiwei. Experimental research on seismic behavior of reinforced Nblock masonry shear wall\[C\]//Earth and Space 2010 Engineering, Science, Construction, and Operations in Challenging Environments. Honolulu, Hawaii:ASCE, 2010: 2806-2820.

[4]MINAIE E, MOTA M, MOON F L, et al. Inplane behavior of partially grouted reinforced concrete masonry shear walls\[J\]. Journal of Structural Engineering, 2010, 136(9): 1089-1097.

[5]骆万康, 李锡军. 砖砌体剪压复合受力动、静力特性与抗剪强度公式\[J\]. 重庆建筑大学学报, 2000, 22(4): 13-19.

LUO Wankang, LI Xijun. Composite masonry shear pressure force static and dynamic force characteristics and shear strength formula \[J\]. Journal of Chongqing Jianzhu University, 2000, 22(4): 13-19. (In Chinese)

[6]洪峰, 王绍博. 砌体结构抗震抗剪强度分析\[J\]. 地震工程与工程振动, 2000, 20(3): 28-33.

HONG Feng, WANG Shaobo. Analysis of earth quake shear strength of masonry structures\[J\]. Earthquake Engineering and Engineering Vibration, 2000, 20(3): 28-33.(In Chinese)

[7]蔡勇, 施楚贤, 马超林, 等. 砌体在剪―压作用下抗剪强度研究\[J\]. 建筑结构学报, 2004, 25(5): 118-123.

CAI Yong, SHI Chuxian, MA Chaolin, et al. Study of the masonry shear strength under shearcompression action\[J\]. Journal of Building Structures, 2004, 25(5): 118-123. (In Chinese)

[8]GBJ 129-90砌体基本力学性能试验方法\[S\]. 北京: 中国建筑工业出版社, 1990:2-20.

GBJ 129-90 The basic mechanics function experiments method standard of masonry \[S\]. Beijing: China Architecture & Building Press, 1990:2-20. (In Chinese)

[9]施楚贤.砌体结构理论与设计\[M\]. 2版. 北京: 中国建筑工业出版社, 2003:1-381.

SHI Chuxian. The theory and design of masonry structure \[M\]. 2nd. Beijing: China Architecture & Building Press, 2003:1-381.(In Chinese)

[10]RAMAMURTHY K, SATHISH V, AMBALAVANAN R. Compressive strength prediction of hollow concrete block masonry prisms\[J\]. ACI Structural Journal, 2000, 97(7): 61-67.

[11]GB 50003-2001 砌体结构设计规范\[S\]. 北京:中国建筑工业出版社, 2002:1-93.

GB 50003-2001 Code for design of masonry structures \[S\]. Beijing: China Architecture & Building Press, 2002:1-93. (In Chinese)

[12]杨伟军. 混凝土砌体配筋剪力墙研究及砌体结构可靠性分析\[D\]. 长沙: 湖南大学土木工程学院, 2000:1-110.

YANG Weijun. Research on concrete masonry and reinforced masonry shear wall and reliability analysis of masonry structures \[D\]. Changsha: College of Civil Engineering, Hunan University, 2000:1-110. (In Chinese)

[13]黄靓, 高翔, 陈良, 等. N式砌块砌体受剪性能试验研究\[J\]. 湖南大学学报:自然科学版, 2009, 37(2), 14-17.

1)开槽砌块灌孔砌体沿通缝截面有两种受剪破坏形态:单面破坏和双面破坏.灰缝砂浆的破坏和芯柱混凝土的破坏具有先后性.

2)开槽砌块灌孔砌体试件在发生剪切破坏时,会在开裂灰缝与相应一侧的底部承压面中间产生斜向裂缝,角度大致呈60°.

3)开槽砌块灌孔砌体由于敲掉了砌块的开槽肋,被联通的上下芯柱混凝土能够协同工作,使其开槽砌块灌孔砌体的抗剪强度与普通灌孔砌块砌体相比有一定的增大.

4)利用Hoffman准则建立用于计算开槽砌块灌孔砌体抗剪强度的公式,其计算值与本文的试验结果基本吻合.

5)以开槽砌块灌孔砌体抗剪强度计算公式为基础,统一了开槽与不开槽砌块灌孔砌体的抗剪强度计算式,用此式计算不开槽砌块砌体抗剪强度是可行的,其计算值与试验结果基本吻合.

参考文献

[1]宋力. 混凝土砌块砌体基本力学性能试验研究与非线性有限元分析\[D\].长沙:湖南大学土木工程学院, 2005:1-50.

SONG Li. Research and nonlinear finite element analysis on the basic mechanical properties of concrete masonry\[D\]. Changsha: College of Civil Engineering, Hunan University, 2005:1-50. (In Chinese)

[2]SUCUOGLU H, MCNIVEN H D. Seismic shear capacity of reinforced masonry piers\[J\]. Journal of Structural Engineering, 1991, 117(7): 2166-2185.

[3]XU Zipeng, HUANG Liang, WU Zhiwei. Experimental research on seismic behavior of reinforced Nblock masonry shear wall\[C\]//Earth and Space 2010 Engineering, Science, Construction, and Operations in Challenging Environments. Honolulu, Hawaii:ASCE, 2010: 2806-2820.

[4]MINAIE E, MOTA M, MOON F L, et al. Inplane behavior of partially grouted reinforced concrete masonry shear walls\[J\]. Journal of Structural Engineering, 2010, 136(9): 1089-1097.

[5]骆万康, 李锡军. 砖砌体剪压复合受力动、静力特性与抗剪强度公式\[J\]. 重庆建筑大学学报, 2000, 22(4): 13-19.

LUO Wankang, LI Xijun. Composite masonry shear pressure force static and dynamic force characteristics and shear strength formula \[J\]. Journal of Chongqing Jianzhu University, 2000, 22(4): 13-19. (In Chinese)

[6]洪峰, 王绍博. 砌体结构抗震抗剪强度分析\[J\]. 地震工程与工程振动, 2000, 20(3): 28-33.

HONG Feng, WANG Shaobo. Analysis of earth quake shear strength of masonry structures\[J\]. Earthquake Engineering and Engineering Vibration, 2000, 20(3): 28-33.(In Chinese)

[7]蔡勇, 施楚贤, 马超林, 等. 砌体在剪―压作用下抗剪强度研究\[J\]. 建筑结构学报, 2004, 25(5): 118-123.

CAI Yong, SHI Chuxian, MA Chaolin, et al. Study of the masonry shear strength under shearcompression action\[J\]. Journal of Building Structures, 2004, 25(5): 118-123. (In Chinese)

[8]GBJ 129-90砌体基本力学性能试验方法\[S\]. 北京: 中国建筑工业出版社, 1990:2-20.

GBJ 129-90 The basic mechanics function experiments method standard of masonry \[S\]. Beijing: China Architecture & Building Press, 1990:2-20. (In Chinese)

[9]施楚贤.砌体结构理论与设计\[M\]. 2版. 北京: 中国建筑工业出版社, 2003:1-381.

SHI Chuxian. The theory and design of masonry structure \[M\]. 2nd. Beijing: China Architecture & Building Press, 2003:1-381.(In Chinese)

[10]RAMAMURTHY K, SATHISH V, AMBALAVANAN R. Compressive strength prediction of hollow concrete block masonry prisms\[J\]. ACI Structural Journal, 2000, 97(7): 61-67.

[11]GB 50003-2001 砌体结构设计规范\[S\]. 北京:中国建筑工业出版社, 2002:1-93.

GB 50003-2001 Code for design of masonry structures \[S\]. Beijing: China Architecture & Building Press, 2002:1-93. (In Chinese)

[12]杨伟军. 混凝土砌体配筋剪力墙研究及砌体结构可靠性分析\[D\]. 长沙: 湖南大学土木工程学院, 2000:1-110.

YANG Weijun. Research on concrete masonry and reinforced masonry shear wall and reliability analysis of masonry structures \[D\]. Changsha: College of Civil Engineering, Hunan University, 2000:1-110. (In Chinese)

[13]黄靓, 高翔, 陈良, 等. N式砌块砌体受剪性能试验研究\[J\]. 湖南大学学报:自然科学版, 2009, 37(2), 14-17.

1)开槽砌块灌孔砌体沿通缝截面有两种受剪破坏形态:单面破坏和双面破坏.灰缝砂浆的破坏和芯柱混凝土的破坏具有先后性.

2)开槽砌块灌孔砌体试件在发生剪切破坏时,会在开裂灰缝与相应一侧的底部承压面中间产生斜向裂缝,角度大致呈60°.

3)开槽砌块灌孔砌体由于敲掉了砌块的开槽肋,被联通的上下芯柱混凝土能够协同工作,使其开槽砌块灌孔砌体的抗剪强度与普通灌孔砌块砌体相比有一定的增大.

4)利用Hoffman准则建立用于计算开槽砌块灌孔砌体抗剪强度的公式,其计算值与本文的试验结果基本吻合.

5)以开槽砌块灌孔砌体抗剪强度计算公式为基础,统一了开槽与不开槽砌块灌孔砌体的抗剪强度计算式,用此式计算不开槽砌块砌体抗剪强度是可行的,其计算值与试验结果基本吻合.

参考文献

[1]宋力. 混凝土砌块砌体基本力学性能试验研究与非线性有限元分析\[D\].长沙:湖南大学土木工程学院, 2005:1-50.

SONG Li. Research and nonlinear finite element analysis on the basic mechanical properties of concrete masonry\[D\]. Changsha: College of Civil Engineering, Hunan University, 2005:1-50. (In Chinese)

[2]SUCUOGLU H, MCNIVEN H D. Seismic shear capacity of reinforced masonry piers\[J\]. Journal of Structural Engineering, 1991, 117(7): 2166-2185.

[3]XU Zipeng, HUANG Liang, WU Zhiwei. Experimental research on seismic behavior of reinforced Nblock masonry shear wall\[C\]//Earth and Space 2010 Engineering, Science, Construction, and Operations in Challenging Environments. Honolulu, Hawaii:ASCE, 2010: 2806-2820.

[4]MINAIE E, MOTA M, MOON F L, et al. Inplane behavior of partially grouted reinforced concrete masonry shear walls\[J\]. Journal of Structural Engineering, 2010, 136(9): 1089-1097.

[5]骆万康, 李锡军. 砖砌体剪压复合受力动、静力特性与抗剪强度公式\[J\]. 重庆建筑大学学报, 2000, 22(4): 13-19.

LUO Wankang, LI Xijun. Composite masonry shear pressure force static and dynamic force characteristics and shear strength formula \[J\]. Journal of Chongqing Jianzhu University, 2000, 22(4): 13-19. (In Chinese)

[6]洪峰, 王绍博. 砌体结构抗震抗剪强度分析\[J\]. 地震工程与工程振动, 2000, 20(3): 28-33.

HONG Feng, WANG Shaobo. Analysis of earth quake shear strength of masonry structures\[J\]. Earthquake Engineering and Engineering Vibration, 2000, 20(3): 28-33.(In Chinese)

[7]蔡勇, 施楚贤, 马超林, 等. 砌体在剪―压作用下抗剪强度研究\[J\]. 建筑结构学报, 2004, 25(5): 118-123.

CAI Yong, SHI Chuxian, MA Chaolin, et al. Study of the masonry shear strength under shearcompression action\[J\]. Journal of Building Structures, 2004, 25(5): 118-123. (In Chinese)

[8]GBJ 129-90砌体基本力学性能试验方法\[S\]. 北京: 中国建筑工业出版社, 1990:2-20.

GBJ 129-90 The basic mechanics function experiments method standard of masonry \[S\]. Beijing: China Architecture & Building Press, 1990:2-20. (In Chinese)

[9]施楚贤.砌体结构理论与设计\[M\]. 2版. 北京: 中国建筑工业出版社, 2003:1-381.

SHI Chuxian. The theory and design of masonry structure \[M\]. 2nd. Beijing: China Architecture & Building Press, 2003:1-381.(In Chinese)

[10]RAMAMURTHY K, SATHISH V, AMBALAVANAN R. Compressive strength prediction of hollow concrete block masonry prisms\[J\]. ACI Structural Journal, 2000, 97(7): 61-67.

[11]GB 50003-2001 砌体结构设计规范\[S\]. 北京:中国建筑工业出版社, 2002:1-93.

GB 50003-2001 Code for design of masonry structures \[S\]. Beijing: China Architecture & Building Press, 2002:1-93. (In Chinese)

[12]杨伟军. 混凝土砌体配筋剪力墙研究及砌体结构可靠性分析\[D\]. 长沙: 湖南大学土木工程学院, 2000:1-110.

YANG Weijun. Research on concrete masonry and reinforced masonry shear wall and reliability analysis of masonry structures \[D\]. Changsha: College of Civil Engineering, Hunan University, 2000:1-110. (In Chinese)

[13]黄靓, 高翔, 陈良, 等. N式砌块砌体受剪性能试验研究\[J\]. 湖南大学学报:自然科学版, 2009, 37(2), 14-17.

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