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Similitude Law Considering the Variation of Strain Ratio for Dynamic Test using Scaled Model with Composite Material
학위논문 (박사)-- 서울대학교 대학원 : 건설환경공학부, 2017. 2. 조재열. ; It is required to evaluate an exact dynamic response of a reinforced concrete column to prevent seismic failure of reinforced concrete structures. Considering limitations from available capacity of test equipment and expensive cost for making and experimenting specimens, a dynamic test using real scale specimen is not generally recommended. In this case, a test using small scale model specimens is an economic alternative. To design the scaled model, it is important to decide which material is used for model material. For a scaled model of reinforced concrete structures, it is necessary to use model concrete such as micro-concrete, gypsum concrete and mortar whose aggregate size is smaller than ordinary concrete of real scale specimen(=prototype). This implies the material characteristics of prototype and model concrete are different. However the material characteristics of prototype and model reinforcement are typically not different because steel is used for both prototype and model reinforcements. For this reason, strain distortion which implies that strain ratio of concrete and steel are different and become not unity is occurred. In addition, from nonlinear material characteristics of concrete, the strain ratio is not constant but variable during the model test. In this thesis a new similitude law which reasonably considers the effect of the strain distortion and the variation of strain ratio, which is caused by the difference of characteristics between prototype and model materials especially for scale model of composite material, was developed. Furthermore an iterative method for estimating strain ratio was also suggested. Numerical verifications of dynamic analysis of reinforced concrete cantilever column with rectangular section were conducted. Results indicate that prediction by the developed similitude law shows higher accuracy of prediction for the response of prototype than those by similitude laws of previous studies. After the numerical verifications, experimental verifications were conducted. Both shaking table test and pseudo dynamic test were used. Tests using prototype and scaled model applying similitude laws of previous studies and the developed similitude law were conducted. By comparing responses of prototype with predictions from the response of model by applying the similitude laws, the validation of the developed similitude law were verified experimentally. ; I. Introduction 1 1.1. Research background 1 1.2. Objectives and scope 5 1.3. Outline 7 II. Theoretical Background 9 2.1. Basic theory on similitude law 9 2.2. Similitude laws in previous studies 20 2.3. Limitations of similitude laws in previous studies 35 2.4 Concluding remarks 41 III. Development of New Similitude Law 43 3.1. Modification of scale factors 43 3.2. Evaluation of strain ratios 48 3.3. Numerical verification 53 3.4 Concluding Remarks 68 IV. Experimental Verification 69 4.1 Procedures for scaled model test 69 4.1.1 Consideration on shaking table test 69 4.1.2 Consideration on pseudo dynamic test 75 4.2 Verification by shaking table test 81 4.2.1 Test program 81 4.2.2 Test results and discussion 97 4.3 Verification by pseudo dynamic test 120 4.3.1 Test program 120 4.3.2 Test results and discussion 131 4.4 Concluding remarks 146 V. Conclusions 147 5.1 Developed similitude law and analytical verification 147 5.2 Experimental verification 149 5.3 Limitations and further researches 150 References 153 Appendix A 161 Appendix B 189 국문초록 219 ; Doctor
Similitude Law Considering the Variation of Strain Ratio for Dynamic Test using Scaled Model with Composite Material
학위논문 (박사)-- 서울대학교 대학원 : 건설환경공학부, 2017. 2. 조재열. ; It is required to evaluate an exact dynamic response of a reinforced concrete column to prevent seismic failure of reinforced concrete structures. Considering limitations from available capacity of test equipment and expensive cost for making and experimenting specimens, a dynamic test using real scale specimen is not generally recommended. In this case, a test using small scale model specimens is an economic alternative. To design the scaled model, it is important to decide which material is used for model material. For a scaled model of reinforced concrete structures, it is necessary to use model concrete such as micro-concrete, gypsum concrete and mortar whose aggregate size is smaller than ordinary concrete of real scale specimen(=prototype). This implies the material characteristics of prototype and model concrete are different. However the material characteristics of prototype and model reinforcement are typically not different because steel is used for both prototype and model reinforcements. For this reason, strain distortion which implies that strain ratio of concrete and steel are different and become not unity is occurred. In addition, from nonlinear material characteristics of concrete, the strain ratio is not constant but variable during the model test. In this thesis a new similitude law which reasonably considers the effect of the strain distortion and the variation of strain ratio, which is caused by the difference of characteristics between prototype and model materials especially for scale model of composite material, was developed. Furthermore an iterative method for estimating strain ratio was also suggested. Numerical verifications of dynamic analysis of reinforced concrete cantilever column with rectangular section were conducted. Results indicate that prediction by the developed similitude law shows higher accuracy of prediction for the response of prototype than those by similitude laws of previous studies. After the numerical verifications, experimental verifications were conducted. Both shaking table test and pseudo dynamic test were used. Tests using prototype and scaled model applying similitude laws of previous studies and the developed similitude law were conducted. By comparing responses of prototype with predictions from the response of model by applying the similitude laws, the validation of the developed similitude law were verified experimentally. ; I. Introduction 1 1.1. Research background 1 1.2. Objectives and scope 5 1.3. Outline 7 II. Theoretical Background 9 2.1. Basic theory on similitude law 9 2.2. Similitude laws in previous studies 20 2.3. Limitations of similitude laws in previous studies 35 2.4 Concluding remarks 41 III. Development of New Similitude Law 43 3.1. Modification of scale factors 43 3.2. Evaluation of strain ratios 48 3.3. Numerical verification 53 3.4 Concluding Remarks 68 IV. Experimental Verification 69 4.1 Procedures for scaled model test 69 4.1.1 Consideration on shaking table test 69 4.1.2 Consideration on pseudo dynamic test 75 4.2 Verification by shaking table test 81 4.2.1 Test program 81 4.2.2 Test results and discussion 97 4.3 Verification by pseudo dynamic test 120 4.3.1 Test program 120 4.3.2 Test results and discussion 131 4.4 Concluding remarks 146 V. Conclusions 147 5.1 Developed similitude law and analytical verification 147 5.2 Experimental verification 149 5.3 Limitations and further researches 150 References 153 Appendix A 161 Appendix B 189 국문초록 219 ; Doctor
Similitude Law Considering the Variation of Strain Ratio for Dynamic Test using Scaled Model with Composite Material
박자민 (Autor:in) / 조재열 / 공과대학 건설환경공학부
01.01.2017
Hochschulschrift
Elektronische Ressource
Englisch
DDC:
690
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