《钢筋－溷凝界面损伤力学模型ppt课件》由会员分享，可在线阅读，更多相关《钢筋－溷凝界面损伤力学模型ppt课件（91页珍藏版）》请在金锄头文库上搜索。
1、Experimental Study on the Damage Evolution of Re-bar Concrete InterfaceLu XinzhengSCE, THU CSE, NTU 1999/2000Abstract4 A new type of bond-slip test is developed in this study4 Constitutive relationship of bond is obtained for the test4 FEA using this constitutive relationship4 Result analysis and co
2、mparingGeneral Overview4 Introduction and Literature Review4 Experiment Procedure4 Experimental Data Analysis4 Numerical Computation Study4 Conclusion and Discussion1.1 Introduction Liu Yus Concrete Model(a). (b). (c). (d). RCED Model (RC Element Damage Model)4 Damage in the reinforced concrete 1. E
3、ffective damage in concrete 2. Slip between concrete and re-bar 3. Local damage in concrete due to slipRCED Model (RC Element Damage Model)FLocal damagexlAffected zoneLocal damage zone in RCED ModelRCED Model (RC Element Damage Model)ozyx8765432110,129,11Element in RCED Model1.2 Literature Review4 B
4、ond Test Method 1. Pull-out Test 2. Beam-type Test 3. Uniaxial-tension TestPull-out TestNo-transverse bar pull-out testWith transverse bar pull-out testPull-out Test Specimen with Hoop RebarPull-out Test Specimen with Web RebarPull-out Test Rebar in Different placesFeature of Pull-out Test4Strongpoi
5、nt 1. Can determine the anchoring strength of bond 2. Easy to procedure4 Shortage Complex stress state around the surfaceBeam-type TestHalf-beam Test to Simulate the Inclined CrackHalf-beam Test to Simulate the Vertical CrackBeam-type TestHalf-beam Test to Simulate the Inclined CrackHalf-beam Test t
6、o Simulate the Vertical CrackBeam-type TestSimply Supported Beam Test1: Lever-type Strain Gauge 2: Strain Gauge On the Bottom3: Strain Gauge on the SideFeature of Beam-type Test4 Strongpoint1. Very close to the real state 2. Can determine bond strength of both anchoring zone and between cracks4 Shor
7、tage Complex and ExpensiveUniaxial-tension TestUniaxial-tension TestFeature of Uniaxial-tension Test4 Strongpoint1. Can determine the bond stress between cracks2. Easy to Procedure4 Shortage Complex distribution of bond stress2. Procedure of Test1. Assumption in RCED Model a. Pure shear deformation
8、in the bond zone b. Linear slip field2. Test purpose a. Determine the evolution of Ds b. Determine the rational size of RCED element c. Determine the parameter of a1, a2 Test Device and MethodRC SpecimenTest Device and MethodLoading DeviceTest Device and MethodStress State of the SpecimenTest Device
9、 and Method4 Assumption in RCED Model 1. Shear deformation in bond zone2. Linear slip field4Feature of the Test 1. Constraint force is applied through PVC pipe and glue. Concrete is under pure shear stress condition 2. Specimen is as thin as possibleConclusion: This test can satisfy RCED modelTest D
10、evice and Method(a) Concrete Specimen before Test(b) PVC Pipe before TestTest Device and Method(c, d) During the Test Test Device and MethodTest Device SetupTest Procedure4 Design the Mold4 Test of Steel Bar4 Casting of Concrete4 Design of Loading Device4 Specimen Analysis before Test4 Trial Loading
11、 and Analysis of Failure4 Improving Method4 Formal Loading4Standard Specimen Test1. Design the MoldSpecimen Mold2. Test of Steel BarDisplacement Determined By LVDT 5Slip Between Steel Bar and ConcreteElongation of the Free Part of Steel BarSlip Between Steel Bar and Clamping Device2. Test of Steel B
12、ar2. Test of Steel Bar2. Test of Steel Bar5. Specimen Analysis before Test6. Trial Loading and Analysis of FailureFail Surface of 10-76. Trial Loading and Analysis of FailureTest Result of 10-76. Trial Loading and Analysis of FailureLoad Applied directly without PVC Pipe6. Trial Loading and Analysis
13、 of FailureLoad Applied directly without PVC Pipe6. Trial Loading and Analysis of Failure4 Conclusion obtained from trial loading 1. The adhesive isnt process properly 2. The confinement is still large7. Improving the Method4 Roughen the adhesive interface deeper4 Split the PVC pipe finely8. Formal
14、LoadingTest Result of 10-18. Formal LoadingTest Result of 15-58. Formal LoadingTest Result of 10-58. Formal LoadingTest Result of 10-48. Formal LoadingTest Result of 15-18. Formal LoadingTest Result of 15-68. Formal LoadingTest Result of 20-18. Formal LoadingTest Result of 20-59. Standard Specimen T
15、est4 Standard Tube SpecimenSize: 151515cmResult:9. Standard Specimen TestSix Strain Gauges on Standard Cylinder Specimen9. Standard Specimen TestLognitudinal-stress-strain Curve9. Standard Specimen TestSide-stress-strain Curve9. Standard Specimen TestStress- Poisson Ratio3. Experimental Data Analysi
16、sTopical Experiment Original Data3. Experimental Data Analysis The following information can be obtained from the experimental data: 1. -1+2 Curve 2. Influence of Height and Radius of Specimen3. Shear Stress Distribution of Steel Bar and Deformation of Concrete4. Slip Damage ZoneOriginal Data-1+2 Cu
17、rve-1+2 Curve-1+2 Curve-1+2 Curve-1+2 Curve Fitting-1+2 Curve FittingEmpirical Formula, Average bond stress, Value of 1+2 0, Value of 1+2 at peak pointInfluence of Height of SpecimenInfluence of Radius of SpecimenShear Stress Distribution along Steel Bar4 Obtain the Shear Stress Distribution from th
18、e following conditions 1. Elongation of the steel bar 2. Relationship between and 3. Linear assumption in RCED modelShear Stress Distribution along the Steel BarSlip Damage ZoneIn this test, there is no obvious slip damage zone founded with UPV. So we consider that the slip damage zone is very small
19、, which appears just around the interface of concrete and re-bar. Numerical Study4 Objectives1. Whether the empirical relationship of bond-slip obtained from the test can be used directly in finite element analysis2. To verify the assumption in RCED model Numerical Study4Finite Element Analysis Soft
20、ware1. Linear analysis: MARC k 7.3.22. Non-linear analysis: Sap 914Element Type and MeshConcrete, Steel bar, Glue and PVC pipe: 20 nodes 3D element.Bond: Spring elementMesh of Specimen Series 10Mesh of Specimen Series 15Numerical ResultComparison with Test ResultsComparison with Test ResultCompariso
21、n with Test ResultComparison with Test ResultComparison with Test ResultThe errors between the test results and numerical results are smaller than 10%.Hence, the bond-slip relationship obtained from the test can be directly used in finite element analysis.Slip Field in the SpecimenSlip Field in the
22、Specimen4 The linear degree of slip field is 0.925. The assumption of linear slip field in RCED model is rational.4 The size of the specimen influences the slip field lightly.Bond Stress along Steel BarBond Stress along Steel BarChange of Bond StressConclusions4 Obtain the full curves of the relatio
23、nship of -1+2 . The empirical formula of -1+2 is obtained for the curves. Numerical study proves that this formula can be used in FEA directly.4 The influence of specimen size to the local damage zone is not obvious.4 The linear slip field in RCED model is rationalAppendixTo apply the RCED model in
24、real structure analysis.Case 1: Using RCED model to analyze our test.Case 2: Using RCED model to analyze the Doerrs uniaxial-tension test (ASCE Vol.113, No.10, October, 1987)Mesh of Case 1Common Concrete ElementRCED ElementResult (-1+2 )Result (Deformation of Concrete)Mesh of Case 24 RCED elements25
25、0150Result (Steel bar axial-force)Element Number to Obtain the Same PrecisionTraditional elementCase 1Element used: 656Case 2Element used: 192RCED modelCase 1Element used: 5Case 2Element used: 4Conclusion: the element number RCED model needed is much less than the traditional ones.RCED model is useful in real structure analysis
