GB50010-2010 f=0.88aerae2feu 脆性折减系数 经验修正系数 小于等于C40取 棱柱体抗压强度实测值 与立方体强度实测值之比的平均值 cc2=1.0 C80取ac2=0.87 C50及以下 a=0.76 中间插值 对C80高强混凝土a。=0.82 中间插值
GB50010－2010 c c c cu f f 1 2 0.88 经验修正系数 棱柱体抗压强度实测值 与立方体强度实测值之比的平均值 0.76 c1 对C80高强混凝土 0.82 c1 中间插值 脆性折减系数 1.0 c2 小于等于C40 取 0.87 C80 取 c2 中间插值 C50及以下
Local compressive strength fo. Dimension 450*450*450mm fc1=附c A-local area Ap-calculated area + +b大b十b* *6*6*6* Ab
Local compressive strength fc,l c l c f f , Al—local area Ab—calculated area Dimension 450*450*450mm l b A A
Typical stress strain relationship ·o~a:弹性阶段 a~b:裂缝稳定发展阶段 ·b~C:不稳定裂缝发展阶段 ·c~d:破坏阶段 Compression fe Envelope curve d H 0 Tension Compression Eu 飞 Strain tTension
Typical stress strain relationship • o ～a：弹性阶段 • a ～b：裂缝稳定发展阶段 • b ～c：不稳定裂缝发展阶段 • c ～d：破坏阶段
2.1.2 Stress/strain curve in uniaxial compression Basic characteristics of stress-strain (N/mm2) curve 40 > The lower the strength of concrete, the larger the failure strain; 30 There is a distinct reduction in ductility with increased strength 20 Strain softening > Up to about 50%of the maximum stress,the stress/strain curve may be 10 approximately a straight line The peak stress is reached at a strain 10 of about 0.002 Visible cracking and disintegration of The stain-stress curve for concrete does not occur until the concrete with different strain reaches about 0.0035 strength
2.1.2 Stress/strain curve in uniaxial compression Basic characteristics of stress-strain curve Ø The lower the strength of concrete, the larger the failure strain; Ø There is a distinct reduction in ductility with increased strength Ø Up to about 50% of the maximum stress, the stress/strain curve may be approximately a straight line Ø The peak stress is reached at a strain of about 0.002 ε Ø Visible cracking and disintegration of concrete does not occur until the strain reaches about 0.0035 ε The stain-stress curve for concrete with different strength Strain softening
2.1.3 Modulus of elasticity and Poisson's ratio Initial tangent modulus(原点弹性模量) A The slope of the line OA, Initial tangent modulus Tangent modulus which is the tangent to the 'ssans B curve at the origin,is called the Initial tangent modulus Secant modulus Eo- 105 Strain,e E0 Tangent modulus(切线模量) 22,7%n) The slope of the tangent at an arbitrary point B is the Tangent modulus at that point Secant modulus(割线模量) the slope of the chord OB is the Secand modulus Ec=Eo λ一弹性特征系数
2.1.3 Modulus of elasticity and Poisson’s ratio The slope of the line OA, which is the tangent to the curve at the origin, is called the Initial tangent modulus E0 . ( ) 34.74 2.2 10 2 5 0 mm N f E cu Tangent modulus （切线模量） The slope of the tangent at an arbitrary point B is the Tangent modulus at that point Initial tangent modulus（原点弹性模量） Secant modulus（割线模量） the slope of the chord OB is the Secand modulus Ec =λE0 λ－弹性特征系数 o A B