[ { "id": "authors:qnfp7-zw840", "collection": "authors", "collection_id": "qnfp7-zw840", "cite_using_url": "https://resolver.caltech.edu/CaltechEERL:EERL-2018-03", "type": "monograph", "title": "Can We Measure Deformation of Short and Stiff Bridges as Trucks Traverse Using a Camera?", "author": [ { "family_name": "Taghavi Larigani", "given_name": "Shervin", "orcid": "0000-0002-6599-7855", "clpid": "Taghavi-Larigani-S" }, { "family_name": "Heaton", "given_name": "Thomas H.", "orcid": "0000-0003-3363-2197", "clpid": "Heaton-T-H" } ], "abstract": "[no abstract]", "publisher": "California Institute of Technology", "publication_date": "2018-11" }, { "id": "authors:qe307-yv175", "collection": "authors", "collection_id": "qe307-yv175", "cite_using_url": "https://resolver.caltech.edu/CaltechEERL:EERL-2018-02", "type": "monograph", "title": "WeighCam: a New Electro-Optical System", "author": [ { "family_name": "Taghavi Larigani", "given_name": "Shervin", "orcid": "0000-0002-6599-7855", "clpid": "Taghavi-Larigani-S" }, { "family_name": "Heaton", "given_name": "Thomas H.", "orcid": "0000-0003-3363-2197", "clpid": "Heaton-T-H" } ], "abstract": "[no abstract]", "publisher": "California Institute of Technology", "publication_date": "2018-06" }, { "id": "authors:scwxv-rf070", "collection": "authors", "collection_id": "scwxv-rf070", "cite_using_url": "https://resolver.caltech.edu/CaltechEERL:EERL-2017-02", "type": "monograph", "title": "Can we measure deformation of short and stiff bridges when a train passes over using a camera?", "author": [ { "family_name": "Taghavi Larigani", "given_name": "Shervin", "orcid": "0000-0002-6599-7855", "clpid": "Taghavi-Larigani-S" }, { "family_name": "Heaton", "given_name": "Thomas H.", "orcid": "0000-0003-3363-2197", "clpid": "Heaton-T-H" } ], "abstract": "[no abstract]", "publisher": "California Institute of Technology", "publication_date": "2017-06" }, { "id": "authors:mqfby-3kh57", "collection": "authors", "collection_id": "mqfby-3kh57", "cite_using_url": "https://resolver.caltech.edu/CaltechEERL:EERL-2017-01", "type": "monograph", "title": "Can you measure the weight of a truck with a commercial camera?", "author": [ { "family_name": "Taghavi Larigani", "given_name": "Shervin", "orcid": "0000-0002-6599-7855", "clpid": "Taghavi-Larigani-S" }, { "family_name": "Heaton", "given_name": "Thomas H.", "orcid": "0000-0003-3363-2197", "clpid": "Heaton-T-H" } ], "abstract": "[No abstract]", "publisher": "California Institute of Technology", "publication_date": "2017-01-31" }, { "id": "authors:f3a20-t7d53", "collection": "authors", "collection_id": "f3a20-t7d53", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160726-154041262", "type": "monograph", "title": "Characterizing Deformation of Buildings from Videos", "author": [ { "family_name": "Taghavi Larigani", "given_name": "Shervin", "orcid": "0000-0002-6599-7855", "clpid": "Taghavi-Larigani-S" }, { "family_name": "Heaton", "given_name": "Thomas H.", "orcid": "0000-0003-3363-2197", "clpid": "Heaton-T-H" } ], "abstract": "We have started to explore the feasibility of extracting useful data on the deformation of buildings and structures based on optical videos, (Taghavi Larigani & Heaton). \n\nIn the beginning, we look at the characterizations and limitations of the hardware, which is composed of a high-quality digital camera, combined with its optical imaging system capturing a video-footage of the structure under test, and then introduce a straightforward targets-tracking algorithm that produces the time-series displacements of targets that we select on the video. \n\nWe performed preliminary measurements consisting of testing our targets-tracking algorithm using high definition format videos displaying the structures that we wanted to test. The measurements pertain to a 1) finite-element software-generated video of JPL/NASA principal building, 2) YouTube-video of a seismic dynamic test of a building, 3) YouTube-video of the Millennium London Bridge \"Wobbly Bridge\", 4) YouTube-video of a United Boeing 777, 4) YouTube-video of NASA space shuttle rockets during launch. \n\nSo far, our tests are encouraging. If our approach proves viable, it can be transformative for the field of earthquake engineering and structural health monitoring. Hence, we consider the prospect of using our technique for surveying buildings and other civil structures in high seismic risk urban agglomerations. \n\nIn parallel, the same technique could be applied for 1) real-time structural health monitoring of civil structures, 2) nuclear plants, 3) oil and gas infrastructures, 4) rail & road networks, 5) aircraft, 6) spacecraft, 7) etc., by simply analyzing the structure-facing camera recorded data.", "publisher": "California Institute of Technology", "publication_date": "2016-07-26" }, { "id": "authors:f86wq-79a02", "collection": "authors", "collection_id": "f86wq-79a02", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161122-122249021", "type": "monograph", "title": "Interpretation of Millikan Library's Vibrating Modes Using A Magneto Coil To Measure Phase Shifts", "author": [ { "family_name": "Cheng", "given_name": "Ming Hei", "clpid": "Cheng-Ming-Hei" }, { "family_name": "Heaton", "given_name": "Thomas H.", "orcid": "0000-0003-3363-2197", "clpid": "Heaton-T-H" }, { "family_name": "Kohler", "given_name": "Monica D.", "orcid": "0000-0002-4703-190X", "clpid": "Kohler-M-D" } ], "abstract": "A new set of natural frequencies for the 9-story reinforced concrete Millikan Library building on the Caltech campus is computed using the observed phase shift between the driving force of a shaker installed on the building's roof and structural response at resonance. The phase of the shaker's output force was recorded by a magneto coil and magnet attached to the shaker's rotating mechanism, and the phase of the structural response was obtained from acceleration time series recorded by an accelerometer on the roof. These new results refute previous studies' identification of the 3rd EW and 2nd torsional modes which used spectral analysis of forced and free vibrations, but did not consider the phase shift. In addition, the newly identified 3rd EW mode shape is independent of the other EW mode shapes, unlike previous findings. This new interpretation is compatible with results from subspace system identification based on two sets of earthquake records.", "doi": "10.7907/Z9H70CS4", "publisher": "California Institute of Technology", "publication_date": "2014-12" }, { "id": "authors:9cc84-ht018", "collection": "authors", "collection_id": "9cc84-ht018", "cite_using_url": "https://resolver.caltech.edu/CaltechEERL:EERL-2009-05", "type": "monograph", "title": "Characterizing Average Properties of Southern California Ground Motion Amplitudes and Envelopes", "author": [ { "family_name": "Cua", "given_name": "Georgia", "clpid": "Cua-Georgia-B" }, { "family_name": "Heaton", "given_name": "Thomas H.", "orcid": "0000-0003-3363-2197", "clpid": "Heaton-T-H" } ], "abstract": "We examine ground motion envelopes of horizontal and vertical acceleration, velocity, and filtered displacement recorded within 200 km from southern California earthquakes in the magnitude range 2 < M \u2264 7.3. We introduce a parameterization that decomposes the observed ground motion envelope into P-wavetrain, S-wavetrain, and ambient noise envelopes. The shape of the body wave envelopes as a function of time is further parameterized by a rise time, a duration, a constant amplitude, and 2 coda decay parameters. Each observed ground motion envelope can thus be described by 11 envelope parameters. We fit this parameterization to 30,000 observed ground motion time histories, and develop attenuation relationships describing the magnitude, distance, and site dependence of these 11 envelope parameters. We use these relationships to study 1) magnitude-dependent saturation of peak amplitudes on rock and soil sites for peak ground acceleration, peak ground velocity, and peak filtered displacement, 2) magnitude and distance scaling of P- and S-waves, and 3) the reduction of uncertainty in predicted ground motions due to the application of site-specific station corrections. We develop extended magnitude range attenuation relationships for PGA and PGV valid over the magnitude range 2 < M < 8 by supplementing our dataset of S-wave envelope amplitudes with the Next Generation Attenuation (NGA) strong motion dataset. We compare extended magnitude range attenuation relationships with the Campbell and Bozorgnia (2008) and Boore and Atkinson (2008) NGA relationships. Our extended magnitude range attenuation relationships exhibit a stronger inter-dependence between distance and magnitude scaling. This character of ground motion scaling becomes evident when examining ground motion amplitudes over an extended magnitude range, but is not apparent when considering data within a more limited magnitude range, for instance, the M>5 range typically considered for strong motion attenuation relationships.", "publisher": "Earthquake Engineering Research Laboratory", "publication_date": "2009" }, { "id": "authors:sa2rv-2pz91", "collection": "authors", "collection_id": "sa2rv-2pz91", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200518-124126273", "type": "monograph", "title": "Variations in the dynamic properties of structures: the Wigner-Ville distribution", "author": [ { "family_name": "Bradford", "given_name": "Case", "clpid": "Bradford-C" }, { "family_name": "Yang", "given_name": "Jing", "clpid": "Yang-Jing" }, { "family_name": "Heaton", "given_name": "Thomas", "orcid": "0000-0003-3363-2197", "clpid": "Heaton-T-H" } ], "abstract": "The Wigner-Ville Distribution (WVD) is a promising method for analyzing frequency variations in seismic signals, including those of interest for structural monitoring. Nonlinearities in the force displacement relationship will temporarily decrease the apparent natural frequencies of structures during strong to moderate excitation, and earthquake damage can permanently change building stiffnesses. A Fourier Transform of a building record contains information regarding frequency content, but it can not resolve the exact onset of changes in natural frequency \u2013 all temporal resolution is contained in the phase of the transform. The spectrogram is better able to resolve temporal evolution of frequency content, but has a trade-off in time resolution versus frequency resolution in accordance with the uncertainty principle. Time-frequency transformations such as the WVD allow for instantaneous frequency estimation at each data point, for a typical temporal resolution of fractions of a second. We develop a mathematical foundation for analyzing the evolution of frequency content in a signal, and apply these techniques to synthetic records from linear and nonlinear FEM analysis (including plastic rotation and weld fractures). Our analysis techniques are then applied to earthquake records from damaged buildings.", "publisher": "Caltech Library", "publication_date": "2006-04" }, { "id": "authors:0tkwf-dq711", "collection": "authors", "collection_id": "0tkwf-dq711", "cite_using_url": "https://resolver.caltech.edu/CaltechEERL:EERL-2004-03", "type": "monograph", "title": "Results of Millikan Library Forced Vibration Testing", "author": [ { "family_name": "Bradford", "given_name": "Samuel Case", "clpid": "Bradford-S-C" }, { "family_name": "Clinton", "given_name": "John F.", "orcid": "0000-0001-8626-2703", "clpid": "Clinton-J-F" }, { "family_name": "Favela", "given_name": "J.", "clpid": "Favela-J" }, { "family_name": "Heaton", "given_name": "T. H.", "orcid": "0000-0003-3363-2197", "clpid": "Heaton-T-H" } ], "abstract": "This report documents an investigation into the dynamic properties of Millikan Library under forced excitation. On July 10, 2002, we performed frequency sweeps from 1 Hz to 9.7 Hz in both the East-West (E-W) and North-South (N-S) directions using a roof level vibration generator. Natural frequencies were identified at 1.14 Hz (E-W fundamental mode), 1.67 Hz (N-S fundamental mode), 2.38 Hz (Torsional fundamental mode), 4.93 Hz (1st E-Wovertone), 6.57 Hz (1st Torsional overtone), 7.22 Hz (1st N-S overtone), and at 7.83 Hz (2nd E-Wovertone). The damping was estimated at 2.28% for the fundamental E-W mode and 2.39% for the N-S fundamental mode. On August 28, 2002, a modal analysis of each natural frequency was performed using the dense instrumentation network located in the building. For both the E-W and N-S fundamental modes, we observe a nearly linear increase in displacement with height, except at the ground floor which appears to act as a hinge. We observed little basement movement for the E-W mode, while in the N-S mode 30% of the roof displacement was due to basement rocking and translation. Both the E-W and N-S fundamental modes are best modeled by the first mode of a theoretical bending beam. The higher modes are more complex and not well represented by a simple structural system.", "publisher": "California Institute of Technology", "publication_date": "2004-01-01" }, { "id": "authors:caray-a5v71", "collection": "authors", "collection_id": "caray-a5v71", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200518-124916954", "type": "monograph", "title": "Effects of Fault Dip and Slip Rake on Near-Source Ground Motions: Why Chi-Chi Was a Relatively Mild M 7.6 Earthquake", "author": [ { "family_name": "Aagaard", "given_name": "Brad T.", "clpid": "Aagaard-B-T" }, { "family_name": "Hall", "given_name": "John F.", "orcid": "0000-0002-7863-5060", "clpid": "Hall-J-F" }, { "family_name": "Heaton", "given_name": "Thomas H.", "orcid": "0000-0003-3363-2197", "clpid": "Heaton-T-H" } ], "abstract": "This study focuses on how the fault dip and slip rake angles affect near-source ground motions as faulting transitions from strike-slip motion on a vertical fault to thrust motion on a shallow dipping fault. Ground motions are computed for five fault geometries with different combinations of fault dip and rake angles, and common values for the fault area and the average slip. With the fault reaching the surface in each scenario, the ground motions are dominated by Love and/or Rayleigh waves. The strike-slip faulting tends to generate Love waves, whereas the thrust faulting tends to generate Rayleigh waves. The degree to which the rupture reinforces these waves affects the severity of the shaking. For strike-slip faulting this directivity effect is most pronounced for unilateral rupture, while for thrust faulting it is most pronounced for up-dip rupture. These simulations suggest that the long-period ground motions in the 1999 Chi-Chi earthquake in Taiwan were not as severe as would be expected for other events of the same size with different styles of faulting or a deeper hypocenter.", "publisher": "Caltech Library", "publication_date": "2002-12" }, { "id": "authors:5637t-8we43", "collection": "authors", "collection_id": "5637t-8we43", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150227-093005080", "type": "monograph", "title": "Future Seismic Hazards in Southern California - Phase I: Implications of the 1992 Landers Earthquake Sequence", "author": [ { "family_name": "Agnew", "given_name": "Duncan C.", "clpid": "Agnew-D-C" }, { "family_name": "Aki", "given_name": "Keiiti", "clpid": "Aki-Keiiti" }, { "family_name": "Cornell", "given_name": "C. Allin", "clpid": "Cornell-C-A" }, { "family_name": "Davis", "given_name": "James F.", "clpid": "Davis-J-F" }, { "family_name": "Flores", "given_name": "Paul", "clpid": "Flores-P-J" }, { "family_name": "Heaton", "given_name": "Thomas H.", "orcid": "0000-0003-3363-2197", "clpid": "Heaton-T-H" }, { "family_name": "Idriss", "given_name": "I. M.", "clpid": "Idriss-I-M" }, { "family_name": "Jackson", "given_name": "David D.", "clpid": "Jackson-D-D" }, { "family_name": "McNally", "given_name": "Karen C.", "clpid": "McNally-K-C" }, { "family_name": "Reichle", "given_name": "Michael S.", "clpid": "Reichle-M-S" }, { "family_name": "Savage", "given_name": "James C.", "clpid": "Savage-J-C" }, { "family_name": "Sieh", "given_name": "Kerry E.", "orcid": "0000-0002-7311-2447", "clpid": "Sieh-K-E" } ], "abstract": "Southern California and its seismologists received a wake-up call on June 28, 1992. The\nlargest earthquake to strike southern California in 40 years occurred near the town of Landers,\nlocated 30 km north of the San Andreas fault. It had a magnitude of 7.5 (M7.5). Three and one-half\nhours later, a M6.5 aftershock struck the Big Bear area 40 km (kilometers) to the west of\nLanders. An ad hoc working group was rapidly convened in July, 1992, to evaluate how the\nLanders-Big Bear earthquake sequence might affect future large earthquakes along major faults\nin southern California. In particular, what are the chances of large earthquakes in the next few\nyears and how do they compare to previous estimates (such as those of the Working Group on\nCalifornia Earthquake Probabilities -- WGCEP, 1988)? Such an evaluation was made for central\nCalifornia after the Lorna Prieta earthquake of 1989 (WGCEP, 1990). The charge to the Landers\nad hoc working group included analyzing the seismicity for the last several years in southern\nCalifornia and the new paleoseismic, geologic, and geodetic data recently available for southern\nCalifornia. To inform the public about the potential hazard of plausible earthquakes, the working\ngroup was also asked to map the predicted severity of ground shaking for such earthquakes\ncompared to that from the Landers earthquake.", "publisher": "California Division of Mines and Geology", "publication_date": "1992-11" } ]