预制UHPC模板及采用预制模板的RC板受力性能及承载力分析
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摘要
采用超高性能混凝土(UHPC)制作厚度为10 mm的模板,对UHPC模板进行施工阶段加载试验,评估其作为现浇楼板的模板的可行性;以UHPC模板作为底模,分别制作了6个简支单向板和1个两跨连续单向板,对其进行静力加载试验。结果表明,厚度为10 mm的UHPC板作为建筑模板时,模板下的支撑间距可取0.5 m,模板处于弹性状态下可施加的均布荷载为6 kN/m~2,约为施工均布活荷载设计值的1.7倍。以UHPC作为模板的钢筋混凝土(RC)单向板,在板破坏时,UHPC模板与后浇混凝土界面未出现肉眼可见的粘结滑移现象;其受弯承载力约为相同截面尺寸及配筋的RC板的2倍。考虑UHPC模板及受拉区混凝土的受拉作用,建立了这种RC单向板的受弯承载力计算模型,模型的计算值与试验值符合较好。
Ultra High Performance Concrete(UHPC) was used to construct prefabricated formwork of 10 mm thick. The construction phase loading test was carried out to evaluate the feasibility of the UHPC formwork as a formwork for cast-in-place concrete slab. Six simply supported unidirectional slabs and a two-span continuous unidirectional slab were manufactured and tested, for which the prefabricated UHPC formwork was used as the bottom formwork. The results show that when the UHPC formwork of 10 mm thick is used as the building formwork, the supporting distance under the formwork can be 0.5 m, and uniformly distributed load of up to6 kN/m~2 can be applied on the UHPC formwork in the elastic state, which is approximately 1.7 times the design value of the construction uniformly distributed load. The interface between the UHPC formwork and post-cast-inplace concrete does not exhibit a visible bond-slip phenomenon when the composite slab is destroyed. The flexural strength of the slab is approximately two times that of a RC slab with the same cross-section and reinforcement. A formula for calculating the cross-sectional flexural strength of unidirectional slabs is established,which considers the tensile force in the prefabricated UHPC formwork and concrete in the tensile region. The strengths predicted by the formula show good agreement with the experimental results.
Ultra High Performance Concrete(UHPC) was used to construct prefabricated formwork of 10 mm thick. The construction phase loading test was carried out to evaluate the feasibility of the UHPC formwork as a formwork for cast-in-place concrete slab. Six simply supported unidirectional slabs and a two-span continuous unidirectional slab were manufactured and tested, for which the prefabricated UHPC formwork was used as the bottom formwork. The results show that when the UHPC formwork of 10 mm thick is used as the building formwork, the supporting distance under the formwork can be 0.5 m, and uniformly distributed load of up to6 kN/m~2 can be applied on the UHPC formwork in the elastic state, which is approximately 1.7 times the design value of the construction uniformly distributed load. The interface between the UHPC formwork and post-cast-inplace concrete does not exhibit a visible bond-slip phenomenon when the composite slab is destroyed. The flexural strength of the slab is approximately two times that of a RC slab with the same cross-section and reinforcement. A formula for calculating the cross-sectional flexural strength of unidirectional slabs is established,which considers the tensile force in the prefabricated UHPC formwork and concrete in the tensile region. The strengths predicted by the formula show good agreement with the experimental results.
引文
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[3]梁兴文,杨鹏辉,何伟,等.钢筋混凝土框架-纤维增强混凝土耗能墙结构抗震性能试验研究[J].工程力学,2018,35(1):209―218.Liang Xingwen,Yang Penghui,He Wei,et al.Ex-perimental study on seismic behavior of reinforced concrete frame-energy dissipation walls made with high performance fiber reinforced concrete[J].Engineering Mechanics,2018,35(1):209―218.(in Chinese)
[4]陆婷婷,梁兴文.预期损伤部位采用FRC增强梁柱板组合件的力-位移模型[J].工程力学,2018,35(2):133―143.Lu Tingting,Liang Xingwen.Force-displacement mechanical model of FRC beam-column-slab subassembly[J].Engineering Mechanics,2018,35(2):133―143.(in Chinese)
[5]党争,梁兴文,邓明科,等.局部采用纤维增强混凝土剪力墙压弯性能研究[J].工程力学,2015,32(2):120―130.Dang Zheng,Liang Xingwen,Deng Mingke,et al.Research of the compression bending behavior of shear wall with fiber-reinforced concrete in bottom region[J].Engineering Mechanics,2015,32(2):120―130.(in Chinese)
[6]Luaay Hussein,Lamya Amleh.Structural behavior of ultra-high performance fiber reinforced concretenormal strength concrete or high strength concrete composite members[J].Construction and Building Materials,2015,93(5):1105―1116.
[7]Ferrier E,Larbi A Si,Georgin J-F,et al.New hybrid cement-based composite material externally bonded to control RC beam cracking[J].Construction and Building Materials,2012,36(6):36―45.
[8]M A Al-Osta,M N Isa,M H Baluch,et al.Flexural behavior of reinforced concrete beams strengthened with ultra-high performance fiber reinforced concrete[J].Construction and Building Materials,2017,134(2):279―296.
[9]Ayman Mosallam,Mahmoud M Reda Taha,Jung J Kim,et al.Strength and ductility of RC slabs strengthened with hybrid high-performance composite retrofit system[J].Engineering Structures,2012,36(3):70―80.
[10]GB/T 31387―2015,活性粉末混凝土[S].北京:中国标准出版社,2015.GB/T 31387―2015,Reactive powder concrete[S].Beijing:China Standard Press,2015.(in Chinese)
[11]JGJ 162―2008,建筑施工模板安全技术规范[M].北京:中国建筑工业出版社,2008.JGJ 162―2008,Technical code for safety of forms in construction[S].Beijing:China Architecture&Building Press,2008.(in Chinese)
[12]GB/T 50152―2012,混凝土结构试验方法标准[S].北京:中国建筑工业出版社,2012.GB/T 50152―2012,Standard for test method of concrete structures[S].Beijing:China Architecture&Building Press,2012.(in Chinese)
[13]GB 50010―2010,混凝土结构设计规范[S].北京:中国建筑工业出版社,2010.GB 50010―2010,Code for design of concrete structures[S].Beijing:China Architecture&Building Press,2010.(in Chinese)
[14]梁兴文,史庆轩.混凝土结构设计[M].第三版.北京:中国建筑工业出版社,2016:64―66.Liang Xingwen,Shi Qingxuan.Design of concrete structures[M].3rd ed.Beijing:China Architecture&Building Press,2016:64―66.(in Chinese)
[15]Foster S J,Voo Y L,Chong K T.FE Analysis of steel fiber reinforced concrete beams failing in shear:variable engagement model[J].ACI Structural Journal,2006,237(SP):55―70.