In order to investigate shear carrying capacity of H-steel concrete beam with small shear span ratio,shear test on 5 H-steel concrete composite beams with small span ratio (from 0.7 to 1.1) are reported,including test...In order to investigate shear carrying capacity of H-steel concrete beam with small shear span ratio,shear test on 5 H-steel concrete composite beams with small span ratio (from 0.7 to 1.1) are reported,including test design,test scheme,test method,failure characteristics and test results. Influences of shear span ratio,web of H steel and concrete on shear carrying capacity of this kind of beam are investigated. The main components comprising shear bearing capacity are analyzed. The results show that with the shear span ratio increasing,the contribution of web of H steel and concrete on shear carrying capacity decrease. Based on test data,the calculation formula of shear carrying capacity for this beam is established by curve fitting.展开更多
In order to enhance the bearing capacity of structural components,save materials,and reduce cost,a glued laminated timber(glulam)I-beam that is theoretically suitable for engineering application was proposed.In this s...In order to enhance the bearing capacity of structural components,save materials,and reduce cost,a glued laminated timber(glulam)I-beam that is theoretically suitable for engineering application was proposed.In this study,18 glulam specimens were fabricated using larch dimension lumber and resorcinol-formaldehyde resin.Four-point bending tests were carried out to compare the ultimate bearing capacity,strain,and deflection of various specimens.The results showed that:(1)The typical failure mode at bending is the web shear failure parallel to grain.Before the failure,cracks and sounds appear at the beam web,which represent the sudden brittle failure.(2)The cross-sectional strain of glulam beam changed linearly with the beam height,indicating that the plane section assumption was basically established.(3)Stiffener could improve the initial flexural stiffness of glulam beam,which experiences an increase of 28.21%.Larger the shear span ratio,smaller the initial flexural stiffness.The initial flexural stiffness improves by 10-23.5%with the increase in the thickness of the lower flange.(4)The effects of stiffener and shear-span ratio on shear strength are relatively significant.After the stiffeners are set at the support and the loading point in pairs,the shear strength of the glulam beam increases by 15.05%averagely.With the increase in the shear-span ratio,the shearing strength of the glulam I-beam gradually reduces.The equation of the shearing strength with the shear span ratio is obtained,which is shown by high fitting precision.(5)The shear strength correlation,as proposed by Soltis and Rammer,is suitable not only for rectangular beams,but also for glulam I-beams.展开更多
The performance of a new fiber-reinforced cementitious matrix(FRCM)system developed using custom-designed mortar and fabrics is investigated in this study.The behavior of this system is evaluated in terms of both the ...The performance of a new fiber-reinforced cementitious matrix(FRCM)system developed using custom-designed mortar and fabrics is investigated in this study.The behavior of this system is evaluated in terms of both the flexural and shear strengthening of reinforced concrete beams.Eight beams are designed to assess the effectiveness of the FRCM system in terms of flexural strengthening,and four specimens are designed to investigate their shear behavior.The parameters investigated for flexural strengthening are the number of layers,span/depth ratio,and the strengthening method.Unlike previous studies,custom fabrics with similar axial stiffness are used in all strengthening methods in this study.In the shear-strengthened specimens,the effects of the span/depth ratio and strengthening system type(fiberreinforced polymer(FRP)or FRCM)are investigated.The proposed FRCM system exhibits desirable flexural and shear strengthening for enhancing the load capacity,provides sufficient bonding with the substrate,and prevents premature failure modes.Considering the similar axial stiffness of fabrics used in both FRCM and FRP systems and the higher load capacity of specimens strengthened by the former,cement-based mortar performs better than epoxy.展开更多
基金Sponsored by the National Key Technologies R&D Program of China during the 11th Five-Year Plan Period (Grant No.2006BAJ03A10)"New Century Excellent Talents in University"Scheme (Grant No.290)+2 种基金the National Natural Science Foundation of China(Grant No.50178026)the Natural Science Foundation of Heilongjiang Province-General Project (Grant No.E200806)the Foundation of Harbin Program (Grant No.2005AFXXJ017)
文摘In order to investigate shear carrying capacity of H-steel concrete beam with small shear span ratio,shear test on 5 H-steel concrete composite beams with small span ratio (from 0.7 to 1.1) are reported,including test design,test scheme,test method,failure characteristics and test results. Influences of shear span ratio,web of H steel and concrete on shear carrying capacity of this kind of beam are investigated. The main components comprising shear bearing capacity are analyzed. The results show that with the shear span ratio increasing,the contribution of web of H steel and concrete on shear carrying capacity decrease. Based on test data,the calculation formula of shear carrying capacity for this beam is established by curve fitting.
基金supported by the Natural Science Foundation of Jiang-su Province(Grant No.BK20181402)the National Natural Science Foundation of China(Grant No.51878354)+2 种基金a Project Funded by the National First-class Disciplines(PNFD)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)a Project Funded by the Co-Innovation Center of Efficient Processing and Utilization of Forest Resources,Nanjing Forestry University(Nanjing,210037,China).
文摘In order to enhance the bearing capacity of structural components,save materials,and reduce cost,a glued laminated timber(glulam)I-beam that is theoretically suitable for engineering application was proposed.In this study,18 glulam specimens were fabricated using larch dimension lumber and resorcinol-formaldehyde resin.Four-point bending tests were carried out to compare the ultimate bearing capacity,strain,and deflection of various specimens.The results showed that:(1)The typical failure mode at bending is the web shear failure parallel to grain.Before the failure,cracks and sounds appear at the beam web,which represent the sudden brittle failure.(2)The cross-sectional strain of glulam beam changed linearly with the beam height,indicating that the plane section assumption was basically established.(3)Stiffener could improve the initial flexural stiffness of glulam beam,which experiences an increase of 28.21%.Larger the shear span ratio,smaller the initial flexural stiffness.The initial flexural stiffness improves by 10-23.5%with the increase in the thickness of the lower flange.(4)The effects of stiffener and shear-span ratio on shear strength are relatively significant.After the stiffeners are set at the support and the loading point in pairs,the shear strength of the glulam beam increases by 15.05%averagely.With the increase in the shear-span ratio,the shearing strength of the glulam I-beam gradually reduces.The equation of the shearing strength with the shear span ratio is obtained,which is shown by high fitting precision.(5)The shear strength correlation,as proposed by Soltis and Rammer,is suitable not only for rectangular beams,but also for glulam I-beams.
基金supported by the Ferdowsi University of Mashhad.
文摘The performance of a new fiber-reinforced cementitious matrix(FRCM)system developed using custom-designed mortar and fabrics is investigated in this study.The behavior of this system is evaluated in terms of both the flexural and shear strengthening of reinforced concrete beams.Eight beams are designed to assess the effectiveness of the FRCM system in terms of flexural strengthening,and four specimens are designed to investigate their shear behavior.The parameters investigated for flexural strengthening are the number of layers,span/depth ratio,and the strengthening method.Unlike previous studies,custom fabrics with similar axial stiffness are used in all strengthening methods in this study.In the shear-strengthened specimens,the effects of the span/depth ratio and strengthening system type(fiberreinforced polymer(FRP)or FRCM)are investigated.The proposed FRCM system exhibits desirable flexural and shear strengthening for enhancing the load capacity,provides sufficient bonding with the substrate,and prevents premature failure modes.Considering the similar axial stiffness of fabrics used in both FRCM and FRP systems and the higher load capacity of specimens strengthened by the former,cement-based mortar performs better than epoxy.