Dynamics of Civil Structures, Volume 2

Preface	5
Contents	6
1 Semi-Active Base Isolation of Civil Engineering Structures Based on Optimal Viscous Damping and Zero Dynamic Stiffness	9
1.1 Introduction	9
1.2 Systems Under Consideration	10
1.2.1 Friction Pendulum	10
1.2.2 Viscous Pendulum	10
1.2.3 Semi-Active Isolator	10
1.3 Modelling	10
1.4 Control Law	11
1.4.1 General Formulation	11
1.4.2 Adaptive Controlled Stiffness	12
1.5 Results	14
1.5.1 Optimized Friction Pendulums	14
1.5.2 Pendulum with Optimized Linear Viscous Damping	14
1.5.3 Semi-Active Pendulum	14
1.6 Summary	15
References	16
2 Long-Term Performance of Specialized Fluid Dampers Under Continuous Vibration on a Pedestrian Bridge	18
2.1 Introduction	18
2.2 Specialized Damper Design [1]	19
2.3 Intermediate Inspection After 7 Years in Service	21
2.4 Principal Inspection and Testing After 11 Years in Service	23
2.5 Conclusions	23
Reference	27
3 Analysis of Variation Rate of Displacement to Temperature of Service Stage Cable-Stayed Bridge Using Temperatures and Displacement Data	28
3.1 Introduction	28
3.2 The Subject Bridge and Data Collection Method	28
3.2.1 Subject Bridge	28
3.2.2 Data Collection Method	29
3.2.3 The Analysis of Expansion per Unit Temperature	29
3.3 The Analysis	30
3.4 Conclusion	31
References	31
4 Triple Friction Pendulum: Does It Improve the Isolation Performance?	33
4.1 Introduction	33
4.2 Friction Pendulums Under Consideration	34
4.2.1 Triple Friction Pendulum	34
4.2.2 Double Friction Pendulum	34
4.3 Assessment Criterion	35
4.4 Modelling	35
4.4.1 Approach	35
4.4.2 Coupled Nonlinear Equations of Motion	35
4.5 Isolation Performance of Mock-Up Triple Friction Pendulum	36
4.6 Isolation Performance of Optimized Triple Friction Pendulum	37
4.6.1 PGAs of Optimization	37
4.6.2 Isolation Time Period	37
4.6.3 Articulated Slider Assembly of Triple FP	37
4.6.4 Restrainers 1 and 4	38
4.6.5 Optimization Parameters	38
4.6.6 Optimization Results	38
4.6.7 Isolation Performance of Optimized Triple FP	38
4.7 Summary	39
References	41
5 Experimental Investigation of the Dynamic Characteristics of a Glass-FRP Suspension Footbridge	42
5.1 Introduction	42
5.2 Bridge Description	43
5.3 Ambient Vibration Testing	43
5.4 Modal Parameter Identification	44
5.4.1 Peak-Picking Method	44
5.4.2 Stochastic Subspace Identification	45
5.5 Conclusions	48
References	51
6 Vibration-Based Occupant Detection Using a Multiple-Model Approach	53
6.1 Introduction	53
6.2 Methodology	54
6.2.1 Human Detection	54
6.2.2 Error-Domain Model Falsification	54
6.3 Test Setup	55
6.4 Results	55
6.5 Discussion	58
References	59
7 Vibration Assessment and Control in Technical FacilitiesUsing an Integrated Multidisciplinary Approach	61
7.1 Introduction	61
7.2 Structural Vibration	61
7.3 Criteria	62
7.4 Vibration Survey	64
7.5 Computational Methods	65
7.6 Mitigation	67
7.7 Summary	68
References	68
8 Iterative Pole-Zero Model Updating Using Multiple Frequency Response Functions	69
8.1 Introduction	69
8.2 IPZ Model Updating Using Multiple FRFs	70
8.3 Case Study: 2D Pinned-Sliding Beam	72
8.4 Conclusion	74
References	74
9 Vision-Based Concrete Crack Detection Using a Convolutional Neural Network	75
9.1 Introduction	75
9.2 Overall Architecture of the Proposed CNN and the Results	76
9.3 Conclusion	76
References	77
10 Analytical and Experimental Analysis of Rocking Columns Subject to Seismic Excitation	78
10.1 Introduction	78
10.2 Background	78
10.3 Analytical Model	80
10.4 Experimental Method	80
10.5 Results and Discussion	81
10.6 Conclusion	84
References	85
11 Extending the Fixed-Points Technique for Optimum Design of Rotational Inertial Tuned Mass Dampers	86
11.1 Introduction	86
11.2 Fixed-Point Technique for RITMD	87
11.3 Results and Discussion	88
References	89
12 Temperature Effects on the Modal Properties of a Suspension Bridge	90
12.1 Introduction	90
12.2 Instrumentation and Methods	91
12.2.1 The Bridge Site	91
12.2.2 Automated SSI-COV Procedure	91
12.3 Results	92
12.3.1 Influence of Temperature Variations on the Eigen-Frequencies	92
12.3.2 Influence of Temperature Variations on the Modal Damping Ratios	93
12.4 Conclusions	95
References	96
13 Mass Scaling of Mode Shapes Based on the Effect of Traffic on Bridges: A Numerical Study	97
13.1 Introduction	97
13.2 Theory	98
13.2.1 Output-Only Modal Identification	98
13.2.2 Mass Scaling	98
13.2.3 Modeling the Traffic Excitation	99
13.2.4 Estimation of the Mass loading of Traffic	101
13.3 Numerical Case Study	102
13.4 Conclusion	107
References	107
14 Covariance-Driven Stochastic Subspace Identification of an End-Supported Pontoon Bridge Under Varying Environmental Conditions	109
14.1 Introduction	109
14.2 Covariance-Driven Stochastic Subspace Identification	109
14.2.1 Selection of Weighting Matrices	111
14.2.2 Efficient Stabilization Analysis	112
14.3 The Bergsøysund Bridge	112
14.4 Operational Modal Analysis	113
14.4.1 Automatic OMA and the Effect of Varying Environment	116
14.5 Concluding Remarks	116
References	116
15 Probabilistic Analysis of Human-Structure Interaction in the Vertical Direction for Pedestrian Bridges	118
15.1 Introduction	118
References	119
16 Effects of Seismic Retrofit on the Dynamic Properties of a 4-Storey Parking Garage	121
16.1 Introduction	121
16.2 Seismic Upgrade	121
16.3 Ambient Vibration Test	122
16.4 Comparison with the Results Before Seismic Retrofit	126
16.5 Conclusions	127
References	129
17 Analytical and Experimental Study of Eddy Current Damper for Vibration Suppression in a Footbridge Structure	130
17.1 Introduction	130
17.2 Fundamental Electromagnetic Induction Theory	131
17.2.1 Modelling Eddy Currents and Electromagnetic Force of ECD	131
17.3 The Method of Image Current	132
17.4 ECD Application to Tuned Mass Damper Design for a Footbridge	134
17.5 Discussion and Conclusions	136
References	137
18 Nonlinear Damping in Floor Vibrations Serviceability: Verification on a Laboratory Structure	138
18.1 Introduction	138
18.2 Experimental Modal Testing on the Laboratory Structure	138
18.3 Resonance of the Structure	139
18.3.1 Stage 1 Configuration	139
18.3.2 Stage 2 Configuration	140
18.4 Damping Ratio Back-Calculations Using Effective Mass	140
18.5 Verification of Nonlinear Damping	143
18.6 Conclusions	143
References	143
19 Addressing Parking Garage Vibrations for the Design of Research and Healthcare Facilities	145
19.1 Introduction	145
19.2 Vehicle Vibrations in Parking Garages	146
19.3 Control Strategies	147
19.3.1 Source Control	147
19.3.2 Path Control	147
19.3.3 Receiver Control	148
19.4 Case Study: Ambulatory Surgical Clinic Located on the Ground Floor of a Multi-Story Mixed Occupancy Building	148
19.4.1 Facility Description	148
19.4.2 Design Criteria	150
19.4.3 Screening Level Assessment: Design Phase	151
19.4.4 Detailed Assessment: Construction Phase	152
19.4.5 Vibration Control Solutions	152
19.5 Concluding Remarks	153
References	154
20 Modeling and Measurement of a Pedestrian's Center-of-Mass Trajectory	156
20.1 Introduction	156
20.2 Background	158
20.2.1 Model of Pedestrian's Motion	158
20.2.2 Bayesian Model Updating	158
20.3 Experimental Setup	159
20.4 Results	161
20.5 Conclusions	162
References	164
21 Evaluation of Mass-Spring-Damper Models for Dynamic Interaction Between Walking Humans and Civil Structures	165
21.1 Introduction	165
21.2 Human-Structure Interaction Models of Walking Humans	166
21.3 Method	167
21.3.1 Test Structure	167
21.3.2 Walking Tests	168
21.3.3 Simulation of Vibration Responses	168
21.4 Results and Discussion	169
21.4.1 Results	169
21.4.2 Discussion	170
21.5 Conclusions	173
References	173
22 Numerical Model for Human Induced Vibrations	174
22.1 Introduction	174
22.2 Theoretical Model	174
22.2.1 The Case of Passive People	175
22.2.2 The Case of Active People	176
22.3 Experimental Tests	178
22.3.1 Tests with Passive People	178
22.3.2 Tests with Active People	179
22.4 Conclusion	180
References	180
23 Dynamic Testing on the New Ticino Bridge of the A4 Highway	182
23.1 Introduction	182
23.2 Description of the Bridge	183
23.3 Structural Analysis and Modelling Assumptions	183
23.4 Operational Modal Analysis	185
23.4.1 Description of the Tests	186
23.4.2 Test Results and Identification Issues	187
23.4.3 Test Results and Model Tuning Activity	188
23.4.4 Test Results and Comparison with Tuned Model	189
23.5 Conclusions	189
References	191
24 Predicting Footbridge Vibrations Using a Probability-Based Approach	192
Nomenclature	192
24.1 Introduction	192
24.2 The Load Models Considered for the Study	193
24.2.1 Load Model I	193
24.2.2 Load Model II	193
24.2.3 Parameters of the Models	194
24.2.4 A Variation of Study Assumptions	195
24.3 The Footbridges Considered for the Study	195
24.4 Extracting Response Data	195
24.5 Results	196
24.5.1 Influence of Choice of Load Model	196
24.5.2 Influence of Approach for Modelling Step Length	197
24.6 Conclusion	197
References	197
25 Flooring-Systems and Their Interaction with Usage of the Floor	199
Nomenclature	199
25.1 Introduction	199
25.2 Methodology	200
25.2.1 Computational Model of the Floor	200
25.2.2 Usage of the Floor	201
25.2.3 Extraction of Modal Properties	202
25.3 Results	202
25.3.1 Floor Frequencies	202
25.3.1.1 Masses Attached at Floor Midplane	202
25.3.1.2 Masses Attached at Elevated Positions	203
25.3.1.3 Comparisons and Supplementary Discussion	204
25.3.2 Floor Damping	204
25.4 Conclusion	205
References	205
26 Benchmark Problem for Assessing Effects of Human-Structure Interaction in Footbridges	206
26.1 Introduction	207
26.2 UV HSI Footbridge Testbed	208
26.3 Benchmark Problem	210
26.3.1 Results	211
26.4 Blind Prediction Contest	212
26.4.1 Experimental Data	213
26.4.2 Metrics	213
26.4.3 BPC Example	214
26.5 Conclusions	215
References	215
27 A Discrete-Time Feedforward-Feedback Compensator for Real-Time Hybrid Simulation	216
27.1 Introduction	216
27.2 FIR Compensator	217
27.3 Feedforward-Feedback FIR Compensator	217
27.3.1 Feedback Controller	217
27.3.2 Implementing of the Feedforward-Feedback FIR Compensator	218
27.4 Numerical Study	218
27.5 Summary and Conclusion	219
References	219
28 Sensing and Rating of Vehicle–Railroad Bridge Collision	220
28.1 Introduction	220
28.2 Impact Modeling	221
28.3 Impact Assessment	223
28.4 Impact Rating	223
28.5 Future Direction: Spatial Identification of Impact Damage	225
28.6 Conclusions and Future Work	226
References	227
29 High-Frequency Impedance Measurements for Microsecond State Detection	228
29.1 Introduction	228
29.2 Experimental Setup	230
29.3 Verification of Measurement Methodology	231
29.4 Damage Detection at High Frequencies	232
29.5 Conclusions	234
29.6 Future Work	235
References	235
30 Structural Stiffness Identification of Skewed Slab Bridges with Limited Information for Load Rating Purpose	236
30.1 Introduction	236
30.2 Stiffness Identification Method	237
30.2.1 Problem Formulation	237
30.2.2 Parametric Study	238
30.2.3 Mapping Process	239
30.3 Experimental Study	240
30.3.1 Test Description	240
30.3.2 Modal Data Identification	240
30.3.3 Stiffness Identification	241
30.4 Conclusion	241
References	242
31 Online Systems Parameters Identification for Structural Monitoring Using Algebraic Techniques	243
31.1 Introduction	243
31.2 Illustrative Vibrating Mechanical System	244
31.3 Online Structural Monitoring	245
31.4 Some Illustrative Cases	246
31.5 Conclusions	248
References	250
32 Structural Vibration Control Using High Strength and Damping Capacity Shape Memory Alloys	251
32.1 Introduction	251
32.2 High Damping and High Strength NiTiHfPd SMAs	252
32.3 Material Characterization	253
32.4 Results and Discussion	253
32.5 Shape Memory Alloy-Based Re-centering Damper	256
32.6 Conclusions	257
References	257
33 Comparative Study on Modal Identification of a 10 Story RC Structure Using Free, Ambient and Forced Vibration Data	259
33.1 Introduction	259
33.2 Test Structure	260
33.3 Dynamic Testing	260
33.3.1 Damage States	260
33.3.2 Testing Method and Sequence	261
33.3.3 Instrumentation	262
33.4 System Identification	262
33.4.1 Identification Orders and Stabilization Diagrams	263
33.4.2 Modal Frequencies and Mode Shapes	264
33.5 Conclusions and Remarks	266
References	267
34 Kronecker Product Formulation for System Identification of Discrete Convolution Filters	269
34.1 Background	269
34.2 Mathematical Methods	270
34.2.1 Solution for Time Varying Weighting Matrix	272
34.2.2 Equivalence of Time Varying Transfer Function and Time Varying Input	273
34.2.3 Spectral Processing	274
34.3 Experimental Methods	274
34.4 Results	276
34.5 Discussion	276
34.6 Conclusions	278
References	278
35 Calibration-Free Footstep Frequency Estimation Using Structural Vibration	279
35.1 Introduction	279
35.2 Online Footstep Frequency Estimation System	280
35.3 Evaluation	281
35.4 Conclusions	281
References	281
36 Optimal Bridge Displacement Controlled by Train Speed on Real-Time	282
36.1 Introduction	282
36.2 Dynamic Modelling	283
36.3 Control	286
36.4 Results	287
36.5 Conclusion	288
36.6 Future Work	289
References	290
37 System Identification and Structural Modelling of Italian School Buildings	291
Reference	293
38 Investigation of Transmission of Pedestrian-Induced Vibration into a Vibration-Sensitive Experimental Facility	294
38.1 Introduction	294
38.2 Estimation of Modal Properties of As-Built Footbridge Structure	295
38.3 Vibration Transmission from Shaker Excitation Tests	296
38.4 Results from Controlled Walking Tests	299
38.5 Vibration Criteria Curves for Response Measurements on Experimental Floor and Supported Equipment	299
38.6 Conclusions	299
References	301
39 An Ambient Vibration Test of an R/C Wall of an 18-Story Wood Building at the UBC Campus	303
39.1 Introduction	303
39.2 Description of Ambient Vibration Test	304
39.3 Data Processing	304
39.3.1 Modal Identification	304
39.3.2 Comparison of Modal Properties with Theoretical Bending- and Shear-Beam	304
39.3.3 Future Work	307
39.4 Conclusion	308
References	308
40 The Day the Earth Shook: Controlling Construction-Induced Vibrations in Sensitive Occupancies	309
40.1 Introduction	309
40.2 Vibration Criteria	310
40.3 Case Study #1: Construction Zone of Influence	310
40.4 Case Study #2: Hospital Construction Vibration Monitoring	313
40.5 Conclusions	314
References	315
41 An Exploratory Study on Removing Environmental and Operational Effects Using a Regime-Switching Cointegration Method	316
41.1 Introduction	316
41.2 Unit Roots and Cointegration	317
41.3 A Regime-Switching Cointegration Method	318
41.4 A Case Study	319
41.5 Discussions and Conclusions	323
References	324
42 Evaluation of Contemporary Guidelines for Floor Vibration Serviceability Assessment	325
42.1 Introduction	325
42.2 Experimental and Analytical Investigation of Case Study Floor	326
42.2.1 Floor Configuration	326
42.2.2 Data Acquisition	327
42.2.3 FE Analysis	328
42.3 Vibration Responses Using Current Guidelines	328
42.3.1 Source of Excitation: Walking Loads	328
42.3.2 Dynamic Properties of the Floor by the Guidelines	329
42.3.3 Vibration Response Estimation and Evaluation	329
42.4 Results and Discussion	330
42.5 Conclusion	332
References	332
43 Excitation Energy Distribution of Measured Walking Forces	333
43.1 Introduction	333
43.2 Methodology	334
43.3 Results	335
43.4 Conclusions	337
References	337
44 Identification of Human-Induced Loading Using a Joint Input-State Estimation Algorithm	338
44.1 Introduction	338
44.2 Experimental Setup	338
44.3 Results	339
44.4 Conclusions	340
References	340

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