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A Caltech Library Repository Feedhttp://www.rssboard.org/rss-specificationpython-feedgenenTue, 16 Apr 2024 15:22:32 +0000Structural Damage in Mexico City
https://resolver.caltech.edu/CaltechAUTHORS:20120830-155816195
Authors: {'items': [{'id': 'Hall-J-F', 'name': {'family': 'Hall', 'given': 'John F.'}, 'orcid': '0000-0002-7863-5060'}, {'id': 'Beck-J-L', 'name': {'family': 'Beck', 'given': 'James L.'}}]}
Year: 1986
DOI: 10.1029/GL013i006p00589.
This paper describes the structural damage in Mexico City caused by the September 19, 1985 earthquake. Photographs which illustrate various features of structural behavior are included. One explanation is presented as to why buildings with fundamental periods of elastic vibration considerably below the predominant two‐second period of the ground motion were most vulnerable to damage.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/w3tde-jb050Factors Contributing to the Catastrophe in Mexico City During the Earthquake of September 19, 1985
https://resolver.caltech.edu/CaltechAUTHORS:20120830-155433286
Authors: {'items': [{'id': 'Beck-J-L', 'name': {'family': 'Beck', 'given': 'James L.'}}, {'id': 'Hall-J-F', 'name': {'family': 'Hall', 'given': 'John F.'}, 'orcid': '0000-0002-7863-5060'}]}
Year: 1986
DOI: 10.1029/GL013i006p00593
The extensive damage to high‐rise buildings in Mexico City during the September 19, 1985 earthquake is primarily due to the intensity of the ground shaking exceeding what was previously considered credible for the city by Mexican engineers. There were two major factors contributing to the catastrophe, resonance in the sediments of an ancient lake that once existed in the Valley of Mexico, and the long duration of shaking compared with other coastal earthquakes in the last 50 years. Both of these factors would be operative again if the Guerrero seismic gap ruptured in a single earthquake.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/bg21b-1fs19The dynamic and earthquake behaviour of concrete dams: review of experimental behaviour and observational evidence
https://resolver.caltech.edu/CaltechAUTHORS:20180522-142427900
Authors: {'items': [{'id': 'Hall-J-F', 'name': {'family': 'Hall', 'given': 'John F.'}, 'orcid': '0000-0002-7863-5060'}]}
Year: 1988
DOI: 10.1016/S0267-7261(88)80001-0
Knowledge of the dynamic and earthquake behaviour of concrete dams comes from four sources: observations made from actual earthquakes including recorded histories of the dam response, experiments conducted on prototype dams for the purpose of determining their dynamic properties, experiments conducted on model dams including shaking table tests, and analytical investigations. The first three sources are extensively reviewed in this paper, while analytical investigations are included only if they were conducted to establish correlation to earthquake observations or experimental results. The subject of nonlinear constitutive modelling of concrete and foundation materials, together with its large body of experimental data, is omitted. While the review of the indicated subjects is by no means complete, it represents a much greater effort than has previously been attempted. Significant gaps occur with the non-English literature, including Japanese, Chinese and Russian, and with the work performed at ISMES in Italy and LNEC in Portugal which has not appeared to much extent in the earthquake engineering literature. A summary with recommendations for future work follows the review.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/ejzd9-mjs90Centrifuge Study of Faulting Effects on Tunnel
https://resolver.caltech.edu/CaltechAUTHORS:20141104-105321976
Authors: {'items': [{'id': 'Burridge-P-B', 'name': {'family': 'Burridge', 'given': 'Paul Brian'}}, {'id': 'Scott-R-F', 'name': {'family': 'Scott', 'given': 'Ronald F.'}}, {'id': 'Hall-J-F', 'name': {'family': 'Hall', 'given': 'John F.'}, 'orcid': '0000-0002-7863-5060'}]}
Year: 1989
DOI: 10.1061/(ASCE)0733-9410(1989)115:7(949)
If a tunnel crosses a geological fault which is considered to be active, the possibility of a displacement in the fault must be accounted for in the tunnel design. When the tunnel is embedded in soil, the assessment of the effect of the fault movement is not easy to assess. As a guide to analysis, a series of correctly scaled model experiments in a centrifuge is undertaken. The deflections and stresses induced in a tunnel crossing a fault caused by: (a) Fault displacement; and (b) differential earthquake motions across the fault are quantified by a series of centrifuge tests on a finite length model tunnel. The centrifuge results are used to calibrate a one‐dimensional finite element model of the tunnel for soil‐tunnel interaction effects. The numerical model is then used to predict the response of an essentially infinite length tunnel for design purposes. Bending movements, displacements and shears are displayed. Surprisingly small changes in the bending movements from the finite‐length to the infinite tunnel case are obtained.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/kw2y0-q3e62Shaking table study of concrete gravity dam monoliths
https://resolver.caltech.edu/CaltechAUTHORS:20180330-135229464
Authors: {'items': [{'id': 'Donlon-W-P', 'name': {'family': 'Donlon', 'given': 'William P.'}}, {'id': 'Hall-J-F', 'name': {'family': 'Hall', 'given': 'John F.'}, 'orcid': '0000-0002-7863-5060'}]}
Year: 1991
DOI: 10.1002/eqe.4290200805
A series of shaking table tests was performed on three small‐scale models of a monolith of a concrete gravity dam in order to simulate earthquake shaking. The purpose of the tests was to examine the nature of crack formation in a gravity dam and the stability of the dam in the presence of cracks. No failures occurred even though the levels of shaking employed were unrealistically high. The good performance owed to the development of crack profiles which had favourable orientations to resist sliding failures in each case. However, the development of an unfavourable crack profile, which cannot be ruled out, and the possibility of water intrusion into open cracks, something not included in the experiments, could lead to failure under significantly lower levels of excitation than those employed.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/gsdwa-mwg49Defensive design of concrete gravity dams
https://resolver.caltech.edu/CaltechEERL:1991.EERL-91-02
Authors: {'items': [{'id': 'Hall-J-F', 'name': {'family': 'Hall', 'given': 'John F.'}, 'orcid': '0000-0002-7863-5060'}, {'id': 'Dowling-M-J', 'name': {'family': 'Dowling', 'given': 'Michael J.'}}, {'id': 'El-Aidi-Bahaa', 'name': {'family': 'El-Aidi', 'given': 'Bahaa'}}]}
Year: 1991
Failure of a concrete gravity dam during an earthquake could occur as a sliding instability along an earthquake-induced crack, possibly assisted by uplift pressures from water flowing into the crack. Reliable assessment of the likelihood of such an event is thought to be difficult, and this suggests a need for designs which are less prone to cracking and uncertain behavior than are typical existing designs. Several schemes for reducing the potential for cracking during earthquake loading are investigated by finite element simulations: use of a sliding plane at the base of the dam, modification of the cross-sectional shape, use of a joint in the upper part of the clam, prestressing, and hydrodynamic isolation. The sliding plane, modified cross-section, and upper joint may only be applicable to new construction, while prestressing and hydrodynamic isolation could also be used to upgrade existing dams. While all of the schemes show potential, modification of the cross-sectional shape is probably the most practical considering acceptability, cost and effectiveness.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/cvt8x-67s08Linear System Response by DFT: Analysis of a Recent Modified Method
https://resolver.caltech.edu/CaltechAUTHORS:20120830-153213661
Authors: {'items': [{'id': 'Hall-J-F', 'name': {'family': 'Hall', 'given': 'John F.'}, 'orcid': '0000-0002-7863-5060'}, {'id': 'Beck-J-L', 'name': {'family': 'Beck', 'given': 'James L.'}}]}
Year: 1993
DOI: 10.1002/eqe.4290220705
An analysis of a recent modified frequency-domain procedure for computing the response of linear systems using the fast Fourier transform (FFT) algorithm is described. This modified procedure eliminates the appended free-vibration interval that is used in the standard approach. The duration of the period of computation still needs to be longer than that of the response interval of interest, but only slightly. Reducing the period of computation lowers the number of frequencies at which the transfer function needs to be defined. The major drawback of the method is a high sensitivity to errors in the computed values of the transfer function, which reduces the role of interpolation in the transfer function definition. The modified method is related to the discrete Laplace transform.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/t29zg-0yg33Direct Boundary Element Method for Dynamics in a Half-Space
https://resolver.caltech.edu/CaltechAUTHORS:20140806-091621728
Authors: {'items': [{'id': 'Nowak-Paul-Scott', 'name': {'family': 'Nowak', 'given': 'Paul S.'}}, {'id': 'Hall-J-F', 'name': {'family': 'Hall', 'given': 'John F.'}, 'orcid': '0000-0002-7863-5060'}]}
Year: 1993
An application of the direct boundary element method for solving the response of a linearly elastic half-space with a canyon cut into the surface is presented. This approach uses source solutions for an undamped half-space where the resulting singular integral equations are solved directly without adding any artificial damping. Solutions for the displacements on the canyon surface reveal an artificial resonance phenomenon when solving the exterior problem in the frequency domain. The use of an additional source loading in the boundary element method is shown to eliminate these resonances and yield accurate results. A method for solving the Rayleigh waves generated on the surface of the half-space caused by the canyon is shown.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/hayam-2yb34The Magnitude 6.7 Northridge, California, Earthquake of 17 January 1994
https://resolver.caltech.edu/CaltechAUTHORS:20121120-075947813
Authors: {'items': [{'id': 'Jones-L-M', 'name': {'family': 'Jones', 'given': 'L.'}, 'orcid': '0000-0002-2690-3051'}, {'id': 'Aki-Keiiti', 'name': {'family': 'Aki', 'given': 'K.'}}, {'id': 'Boore-D', 'name': {'family': 'Boore', 'given': 'D.'}}, {'id': 'Celebi-M', 'name': {'family': 'Celebi', 'given': 'M.'}}, {'id': 'Donnellan-A', 'name': {'family': 'Donnellan', 'given': 'A.'}}, {'id': 'Hall-J-F', 'name': {'family': 'Hall', 'given': 'J.'}, 'orcid': '0000-0002-7863-5060'}, {'id': 'Harris-R', 'name': {'family': 'Harris', 'given': 'R.'}}, {'id': 'Hauksson-E', 'name': {'family': 'Hauksson', 'given': 'E.'}, 'orcid': '0000-0002-6834-5051'}, {'id': 'Heaton-T-H', 'name': {'family': 'Heaton', 'given': 'T.'}, 'orcid': '0000-0003-3363-2197'}, {'id': 'Hough-S-E', 'name': {'family': 'Hough', 'given': 'S.'}, 'orcid': '0000-0002-5980-2986'}, {'id': 'Hudnut-K-W', 'name': {'family': 'Hudnut', 'given': 'K.'}, 'orcid': '0000-0002-3168-4797'}, {'id': 'Hutton-K', 'name': {'family': 'Hutton', 'given': 'K.'}}, {'id': 'Johnston-M-L', 'name': {'family': 'Johnston', 'given': 'M.'}}, {'id': 'Joyner-W', 'name': {'family': 'Joyner', 'given': 'W.'}}, {'id': 'Kanamori-H', 'name': {'family': 'Kanamori', 'given': 'H.'}, 'orcid': '0000-0001-8219-9428'}, {'id': 'Marshall-G', 'name': {'family': 'Marshall', 'given': 'G.'}}, {'id': 'Michael-A', 'name': {'family': 'Michael', 'given': 'A.'}}, {'id': 'Mori-Jim', 'name': {'family': 'Mori', 'given': 'J.'}}, {'id': 'Murray-M', 'name': {'family': 'Murray', 'given': 'M.'}}, {'id': 'Ponti-D', 'name': {'family': 'Ponti', 'given': 'D.'}, 'orcid': '0000-0002-2437-5144'}, {'id': 'Reasenberg-P', 'name': {'family': 'Reasenberg', 'given': 'P.'}}, {'id': 'Schwartz-D', 'name': {'family': 'Schwartz', 'given': 'D.'}}, {'id': 'Seeber-L', 'name': {'family': 'Seeber', 'given': 'L.'}}, {'id': 'Shakal-A-K', 'name': {'family': 'Shakal', 'given': 'A.'}}, {'id': 'Simpson-R', 'name': {'family': 'Simpson', 'given': 'R.'}}, {'id': 'Thio-H', 'name': {'family': 'Thio', 'given': 'H.'}}, {'id': 'Tinsley-J', 'name': {'family': 'Tinsley', 'given': 'J.'}}, {'id': 'Todorovska-M', 'name': {'family': 'Todorovska', 'given': 'M.'}}, {'id': 'Trifunac-M-D', 'name': {'family': 'Trifunac', 'given': 'M.'}}, {'id': 'Wald-D', 'name': {'family': 'Wald', 'given': 'D.'}}, {'id': 'Zoback-M-L', 'name': {'family': 'Zoback', 'given': 'M. L.'}}]}
Year: 1994
DOI: 10.1126/science.266.5184.389
The most costly American earthquake since 1906 struck Los Angeles on 17 January 1994. The magnitude 6.7 Northridge earthquake
resulted from more than 3 meters of reverse slip on a 1 5-kilometer-long south-dipping thrust fault that raised the Santa Susana mountains
by as much as 70 centimeters. The fault appears to be truncated by the fault that broke in the 1971 San Fernando earthquake at a depth
of 8 kilometers. Of these two events, the Northridge earthquake caused many times more damage, primarily because its causative fault
is directly under the city. Many types of structures were damaged, but the fracture of welds in steel-frame buildings was the greatest
surprise. The Northridge earthquake emphasizes the hazard posed to Los Angeles by concealed thrust faults and the potential for strong
ground shaking in moderate earthquakes.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/579x8-mcc53Parameter study of the response of moment-resisting steel frame buildings to near-source ground motions
https://resolver.caltech.edu/CaltechEERL:1995.EERL-95-08
Authors: {'items': [{'id': 'Hall-J-F', 'name': {'family': 'Hall', 'given': 'John F.'}, 'orcid': '0000-0002-7863-5060'}]}
Year: 1995
A parameter study is performed to investigate the effects of strong near-source ground motions from moderate-size earthquakes (Mw=7) on moment-resisting steel frame buildings. Two buildings, one 6 stories and the other 20 stories, are subjected to the Olive View Hospital free-field record from the Northridge earthquake and other ground motions from three earthquake simulations (Northridge earthquake, a hypothetical Mw7.1 Elysian Park blind-thrust earthquake, and another blind-thrust earthquake of Mw7.0). Parameters examined for the buildings include material yielding, weld fracture, presence of slab, accumulation of damage from a second earthquake, and vertical ground motion.
A significant fraction of the ground motions cause excessive amounts of deformations in the buildings, especially the 6-story one, even for the case where all welds are assumed to be perfect. These ground motions exceed the earthquake representation in the code, and, since they appear to be reasonable motions that should be considered in design, the implication is that the code design force levels need to be raised for locations in near-fault regions. Including weld fracture increases the displacements of the building and the potential for severe damage or collapse from column failure or excessive lateral sway. The buildings collapsed in several of the analyses. Including the floor slab increased the amount of column yielding and did not improve the behavior. A second earthquake such as a strong aftershock or subsequent main shock is a concern, especially if many welds are cracked from the initial event. However, a limited study of vertical ground motion showed it to be of minor importance. Strongly nonlinear building behavior is sensitive to many assumptions about features which are poorly understood, both structure and ground motion, and so the results need to be carefully interpreted.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/jqazq-bk791Response of High-Rise and Base-isolated Buildings to a Hypothetical M_w 7.0 Blind Thrust Earthquake
https://resolver.caltech.edu/CaltechAUTHORS:20130220-113228201
Authors: {'items': [{'id': 'Heaton-T-H', 'name': {'family': 'Heaton', 'given': 'Thomas H.'}, 'orcid': '0000-0003-3363-2197'}, {'id': 'Hall-J-F', 'name': {'family': 'Hall', 'given': 'John F.'}, 'orcid': '0000-0002-7863-5060'}, {'id': 'Wald-D-J', 'name': {'family': 'Wald', 'given': 'David J.'}}, {'id': 'Halling-M-W', 'name': {'family': 'Halling', 'given': 'Marvin W.'}}]}
Year: 1995
DOI: 10.1126/science.267.5195.206
High-rise flexible-frame buildings are commonly considered to be resistant to shaking from the largest earthquakes. In addition, base isolation has become increasingly popular
for critical buildings that should still function after an earthquake. How will these two types of buildings perform if a large earthquake occurs beneath a metropolitan area? To answer this question, we simulated the near-source ground motions of a M_w 7.0 thrust earthquake and then mathematically modeled the response of a 20-story steel-frame building and a 3-story base-isolated building. The synthesized ground motions were characterized by
large displacement pulses (up to 2 meters) and large ground velocities. These ground motions caused large deformation and possible collapse of the frame building, and they
required exceptional measures in the design of the base-isolated building if it was to remain functional.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/w5d1k-1ke70Near-Source Ground Motion and its Effects on Flexible Buildings
https://resolver.caltech.edu/CaltechAUTHORS:HALes95
Authors: {'items': [{'id': 'Hall-J-F', 'name': {'family': 'Hall', 'given': 'John F.'}, 'orcid': '0000-0002-7863-5060'}, {'id': 'Heaton-T-H', 'name': {'family': 'Heaton', 'given': 'Thomas H.'}, 'orcid': '0000-0003-3363-2197'}, {'id': 'Halling-M-W', 'name': {'family': 'Halling', 'given': 'Marvin W.'}}, {'id': 'Wald-D-J', 'name': {'family': 'Wald', 'given': 'David J.'}}]}
Year: 1995
DOI: 10.1193/1.1585828
Occurrence of large earthquakes close to cities in California is inevitable. The resulting ground shaking will subject buildings in the near-source region to large, rapid displacement pulses which are not represented in design codes. The simulated Mw7.0 earthquake on a blind-thrust fault used in this study produces peak ground displacement and velocity of 200 cm and 180 cm/sec, respectively. Over an area of several hundred square kilometers in the near-source region, flexible frame and base-isolated buildings would experience severe nonlinear behavior including the possibility of collapse at some locations. The susceptibility of welded connections to fracture significantly increases the collapse potential of steel-frame buildings under strong ground motions of the type resulting from the Mw7.0 simulation. Because collapse of a building depends on many factors which are poorly understood, the results presented here regarding collapse should be interpreted carefully.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/4bbmv-31014System Identification of Base-isolated Buildings Utilizing Records from Recent Southern California Earthquakes
https://resolver.caltech.edu/CaltechAUTHORS:20121022-105845475
Authors: {'items': [{'id': 'Halling-M-W', 'name': {'family': 'Halling', 'given': 'Marvin W.'}}, {'id': 'Hall-J-F', 'name': {'family': 'Hall', 'given': 'John F.'}, 'orcid': '0000-0002-7863-5060'}, {'id': 'Okahashi-Y', 'name': {'family': 'Okahashi', 'given': 'Yasuteru'}}]}
Year: 1996
System identification is used in this study as a systematic approach to determine modal periods, mode shapes,
and estimated damping for three Southern California base-isolated buildings. In addition, estimates of the
level of response each building experienced during recent earthquakes can be evaluated. Of particular
interest are the variations in modal parameters as a function of the level of excitation due to the non-linear
nature of these structures.
By using identification of each building for several earthquakes and dividing the time histories into short
segments, structural response trends can be investigated.
It is shown that structural period and damping vary with amplitude of excitation. Since the bearings are
hysteretic and softening elements, under increased structural response, the periods of vibration as well as the
equivalent modal viscous damping increase. It is also shown that although the 1994 Northridge California
earthquake generated moderate levels of horizontal ground acceleration at building sites, the bearings were
exercised well below their maximum design levels.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/48qsd-7jp04Efficient nonlinear seismic analysis of arch dams: User's manual for SCADA, Smeared Crack Arch Dam Analysis
https://resolver.caltech.edu/CaltechEERL:1997.EERL-96-01
Authors: {'items': [{'id': 'Hall-J-F', 'name': {'family': 'Hall', 'given': 'John F.'}, 'orcid': '0000-0002-7863-5060'}]}
Year: 1997
Linear earthquake analysis of a concrete arch dam, conducted either in the evaluation of an existing dam or in the design of a new one, typically shows large tensile stresses when the ground motion employed represents strong shaking. This result has spurred development of nonlinear analysis capabilities that attempt to model the opening and closing of contraction joints as well as cracks that are produced. Two recent computer programs (1a and lb, 2) both treat joints and cracks as zero-width zones of nonlinear springs connecting adjacent finite elements, but differ in detail.
ADAP-88 (la and lb) uses a multi-element discretization of solid elements through the thickness of the dam so as to be able to represent states of partial contact in the joints and cracks. Standard joint elements are used in the joint and crack planes. The program of reference 2 uses a single shell element discretization in the thickness direction with specially calibrated nonlinear rotational and axial springs to represent states of partial contact. The disadvantage of ADAP-88 is the relatively high computational effort required, while disadvantages of the formulation of reference 2 are some loss of accuracy and an inability to be generalized to include sliding in the joints and cracks. However, while sliding is straightforward conceptionally when using the standard joint elements such as employed in ADAP-88, including friction may lead to severe convergence difficulties.
At present, nonlinear analysis methods have not gained acceptance in the dam engineering community. Reliance is still based on the inadequate linear methods and ad hoc procedures to assess the high tensile stresses that are computed. Part of the problem is the difficulty of validating the nonlinear analysis capabilities. Some progress is being made, however, by different researchers taking different approaches of nonlinear analysis and then comparing results. In this spirit and also with the goal of developing a practical nonlinear analysis technique that attempts to reach a compromise between computational effort and model complexity, while still giving useful results, this simplified nonlinear earthquake analysis procedure for concrete arch dams is offered together with fully documented computer program.
The procedure is based on the "smeared" approach to model joints and cracks whereby the contact nonlinearities are incorporated through conditions placed on the stresses at the
integration points of the (shell) finite elements of the dam. This approach sacrifices some accuracy for computational efficiency. The faster computation comes about by a reduction in the number of degrees of freedom and an improvement in convergence even to the point of being able to handle frictional sliding. A typical computer run for an earthquake analysis of an arch dam to strong ground motion takes about one hour on a DEC 3000 Model 400 computer with a 100 MEPS processor. This efficiency allows parameter studies to be undertaken which are an essential part of any evaluation process.
As with the linear analysis methods, engineering judgment is still a necessary and important element. However, it is hoped that the gap between mathematical model and real-world situation is reduced enough with the offered program so that the engineer can now be confident in spanning between them.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/csa73-tvv57Seismic response of steel frame buildings to near-source ground motions
https://resolver.caltech.edu/CaltechAUTHORS:20180418-153910412
Authors: {'items': [{'id': 'Hall-J-F', 'name': {'family': 'Hall', 'given': 'John F.'}, 'orcid': '0000-0002-7863-5060'}]}
Year: 1998
DOI: 10.1002/(SICI)1096-9845(199812)27:12%3C1445::AID-EQE794%3E3.0.CO;2-C
Simulated ground motions from the M_W 6·7 Northridge earthquake and a simulated M_W 7·0 Elysian Park event are generated over a large grid of sites and used as input to mathematical models of six‐storey and 20‐storey steel‐frame buildings. Purpose of the study is to quantify effects of strong near‐source ground motion on frame buildings of different height and strength (UBC vs. Japanese design) and with welded connections prone to fracture. Best performance is achieved by the six‐storey building which meets the stronger Japanese design provisions. The detrimental effect of connection fracture is significant, especially for the larger earthquake.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/91d4p-dw770Sensitivity study of near-source ground motion
https://resolver.caltech.edu/CaltechAUTHORS:20121218-110709492
Authors: {'items': [{'id': 'Aagaard-B-T', 'name': {'family': 'Aagaard', 'given': 'Brad T.'}}, {'id': 'Hall-J-F', 'name': {'family': 'Hall', 'given': 'John F.'}, 'orcid': '0000-0002-7863-5060'}, {'id': 'Heaton-T-H', 'name': {'family': 'Heaton', 'given': 'Thomas H.'}, 'orcid': '0000-0003-3363-2197'}]}
Year: 2000
We studied the sensitivity of near-source ground motions for hypothetical events on a thrust fault
(M_w 6.6 to 7.0) and a strike-slip fault (M_w 7.0 to 7.1) to five earthquake source parameters. We
systematically varied the rupture speed, maximum slip rate, hypocentre location, distribution of
final slip, and fault depth. We used the finite element method to discretize a homogeneous or
layered half-space into an unstructured mesh to model the wave propagation in the domain
surrounding the fault.
Our sensitivity study of near-source ground motion indicates it is very important to include
directivity effects when modelling near-source ground motion. In the thrust fault scenarios a
double velocity pulse sweeps along the surface in the direction of the propagating rupture. For
most of the scenarios the peak velocity, filtered to periods longer than 2.0 sec, exceeds 1.0 m/sec
over an area of 100 square kilometres. In the strike-slip scenarios a complex series of pulses
involving the shear wave and Rayleigh waves propagates in the direction of the rupture with the
most severe motion confined to a narrow region along the fault. The peak, filtered velocity
exceeds 1.0 m/sec over an area of 700 square kilometres. We found the ground motions strongly
sensitive to the material properties and fault depth, moderately sensitive to the hypocentre
location, rupture speed, and maximum slip rate, and relatively insensitive to the distribution of
final slip. The shape of the near-source factor, N_v, from the 1997 Uniform Building Code does not
correlate with the zone of severe shaking in the case of blind thrust faults, because the maximum
displacements and maximum velocities tend to occur up-dip from the top of the fault.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/ajhsw-5y970Simulation of near-source ground motions with dynamic failure
https://resolver.caltech.edu/CaltechAUTHORS:20121220-152414173
Authors: {'items': [{'id': 'Aagaard-B-T', 'name': {'family': 'Aagaard', 'given': 'Brad T.'}}, {'id': 'Hall-J-F', 'name': {'family': 'Hall', 'given': 'John F.'}, 'orcid': '0000-0002-7863-5060'}, {'id': 'Heaton-T-H', 'name': {'family': 'Heaton', 'given': 'Thomas H.'}, 'orcid': '0000-0003-3363-2197'}]}
Year: 2000
DOI: 10.1061/40492(2000)113
We simulate long-period near-source ground motions due to hypothetical events
on a strike-slip fault (M_w 6.9) and a buried thrust fault (M_w 7.0). We include the dynamics
of the rupture process using a model of sliding friction. The directivity of the rupture
creates large displacement and velocity pulses in the ground motions in the forward
direction. For the strike-slip fault the peak values occur near the tip of the fault, while for
the buried thrust fault the peak values occur up-dip from the top of the fault. The
acceleration response spectra in the 2.0 sec to 3.0 sec range exceed 1.0 g near the
strike-slip fault in the forward direction, and 0.5 g up-dip from the top of the thrust fault.
These results quantify the threat posed to long-period structures near faults.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/z745f-50k14Isolated Buildings and the 1997 UBC Near-Source Factors
https://resolver.caltech.edu/CaltechAUTHORS:HALes00
Authors: {'items': [{'id': 'Hall-J-F', 'name': {'family': 'Hall', 'given': 'John F.'}, 'orcid': '0000-0002-7863-5060'}, {'id': 'Ryan-K-L', 'name': {'family': 'Ryan', 'given': 'Keri L.'}}]}
Year: 2000
DOI: 10.1193/1.1586118
Computer simulations are employed to assess the effects of near-source ground motions on base-isolated buildings that meet the provisions of the 1997 Uniform Building Code. A six-story base-isolated building designed for Nv = 1.6 exhibits essentially elastic structural behavior when subjected to six actual ground motions containing strong near-source effects. However, two simulated records, one intended to represent the most severe motions from the 1994 Northridge earthquake and the other a strong motion from a hypothetical Mw7.0 thrust earthquake produce larger responses well into the nonlinear range. In addition, a 113 cm ground displacement pulse of three-second duration, which is close to the period of the isolated buildings, causes story drifts of nearly 5% for the Nv = 1.6 design and over 2% for a stronger Nv = 2 design. Such drifts are effectively reduced when supplemental dampers are added alongside the isolators. The original Nv = 1.6 design with supplemental damping in the amount of 20% of critical experiences only 1.3% drift for the same three-second ground displacement pulse.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/apzer-jbg19Characterization of near-source ground motions with earthquake simulations
https://resolver.caltech.edu/CaltechAUTHORS:AAGes01
Authors: {'items': [{'id': 'Aagaard-B-T', 'name': {'family': 'Aagaard', 'given': 'Brad T.'}}, {'id': 'Hall-J-F', 'name': {'family': 'Hall', 'given': 'John F.'}, 'orcid': '0000-0002-7863-5060'}, {'id': 'Heaton-T-H', 'name': {'family': 'Heaton', 'given': 'Thomas H.'}, 'orcid': '0000-0003-3363-2197'}]}
Year: 2001
DOI: 10.1193/1.1586171
We examine the characteristics of long-period near-source ground motions by conducting a sensitivity study with variations in six earthquake source parameters for both a strike-slip fault (M 7.0-7.1) and a thrust fault (M 6.6-7.0). The directivity of the ruptures creates large displacement and velocity pulses in the forward direction. The dynamic displacements close to the fault are comparable to the average slip. The ground motions exhibit the greatest sensitivity to the fault depth with moderate sensitivity to the rupture speed, peak slip rate, and average slip. For strike-slip faults and thrust faults with surface rupture, the maximum ground displacements and velocities occur in the region where the near-source factor from the 1997 Uniform Building Code is the largest. However, for a buried thrust fault the peak ground motions can occur up-dip from this region.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/x0ms8-hwx90Seismic response of steel frame buildings to near-source ground motions
https://resolver.caltech.edu/CaltechEERL:1997.EERL-97-05
Authors: {'items': [{'id': 'Hall-J-F', 'name': {'family': 'Hall', 'given': 'John F.'}, 'orcid': '0000-0002-7863-5060'}]}
Year: 2001
Strong near-source ground motions contain large, rapid displacement pulses that can have severe effects on structures. In the U.S. it is generally agreed that our design codes do not adequately address this kind of ground motion, and changes are being made to increase the design force levels, which will result in stronger buildings. In Japan, the design force levels for buildings have for some time been considerably greater than in the U.S. Even so, Japanese engineers are also concerned about the adequacy of their design provisions for strong near-source ground motions.
The issue of building strength appropriate for near-source ground motions is investigated in this report. Two different heights of buildings are selected, 6 stories and 20 stories, and for each height, designs of two different strengths are produced. The first design is according to the 1994 Uniform Building Code (1), and the second design follows current Japanese provisions (2). All four buildings are steel moment frames.
One important part of assessing near-source ground motions is to quantify the size of the region that is affected. An aspect of this is that near-source effects are directional and so are confined to only a portion of the near-fault zone. In this study, ground motions at a grid of sites sufficient to cover the region of near-source effects are employed. This is accomplished by using simulated ground motions. Three earthquake simulations are run: one based on the 1994 Northridge earthquake (Mw 6.7), another for the 1995 Kobe earthquake (Mw 6.9), and the third of a hypothetical Mw 7.0 earthquake on the Elysian Park fault in Los Angeles. In addition, various recorded motions from actual earthquakes, including Northridge and Kobe, are employed.
Previous studies of strong near-source ground motions have shown the potential for large story drifts in buildings and even collapse (3-7). Future design measures for near-source ground motions will likely have to consider all contributions to the strength of a building in order to be feasible. It follows from this that since future design methods will be based on assessment studies like the present one, the assessments should also be done as realistically as possible and include all important contributions to the strength of a structure. Such an approach is followed here. In addition, since strong near-source ground motions will likely produce severely nonlinear responses, it becomes necessary to include structural degradation effects. In this study, due to the common occurrence of welded connection failure in the Northridge and Kobe earthquakes and because this behavior would seem to be an important degradation mode, treatment of connection fracture is included. As there is now wide-spread interest in fracture of welded connections, this is an important part of the present investigation.
The Appendix contains a description of the computer program used for the analyses. Some of the notation used in this report is defined in this Appendix.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/zew36-35m20Dynamic Earthquake Ruptures in the Presence of Lithostatic Normal Stresses: Implications for Friction Models and Heat Production
https://resolver.caltech.edu/CaltechAUTHORS:20121120-094358596
Authors: {'items': [{'id': 'Aagaard-B-T', 'name': {'family': 'Aagaard', 'given': 'Brad T.'}}, {'id': 'Heaton-T-H', 'name': {'family': 'Heaton', 'given': 'Thomas H.'}, 'orcid': '0000-0003-3363-2197'}, {'id': 'Hall-J-F', 'name': {'family': 'Hall', 'given': 'John F.'}, 'orcid': '0000-0002-7863-5060'}]}
Year: 2001
DOI: 10.1785/0120000257
We simulate dynamic ruptures on a strike-slip fault in homogeneous and layered half-spaces and on a thrust fault in a layered half-space. With traditional friction models, sliding friction exceeds 50% of the fault normal compressive stress, and unless the pore pressures approach the lithostatic stress, the rupture characteristics depend strongly on the depth, and sliding generates large amounts of heat. Under application of reasonable stress distributions with depth, variation of the effective coefficient of friction with the square root of the shear modulus and the inverse of the depth creates distributions of stress drop and fracture energy that produce realistic rupture behavior. This ad hoc friction model results in (1) low-sliding friction at all depths and (2) fracture energy that is relatively independent of depth. Additionally, friction models with rate-weakening behavior (which form pulselike ruptures) appear to generate heterogeneity in the distributions of final slip and shear stress more effectively than those without such behavior (which form cracklike ruptures). For surface rupture on a thrust fault, the simple slip-weakening friction model, which lacks rate-weakening behavior, accentuates the dynamic interactions between the seismic waves and the rupture and leads to excessively large ground motions on the hanging wall. Waveforms below the center of the fault (which are associated with waves radiated to teleseismic distances) indicate that source inversions of thrust events may slightly underestimate the slip at shallow depths.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/d3amz-qvs61Dynamic Characteristics of Woodframe Buildings
https://resolver.caltech.edu/CaltechAUTHORS:20120919-152338184
Authors: {'items': [{'id': 'Carmelo-V-S', 'name': {'family': 'Camelo', 'given': 'Vanessa'}}, {'id': 'Beck-J-L', 'name': {'family': 'Beck', 'given': 'James'}}, {'id': 'Hall-J-F', 'name': {'family': 'Hall', 'given': 'John'}, 'orcid': '0000-0002-7863-5060'}]}
Year: 2002
Through analysis of recorded earthquake response and by forced vibration and shake-table
testing, a database of dynamic characteristics of woodframe buildings was developed. Modal
identification was performed on eight sets of strong-motion records obtained from five
buildings, and forced vibration tests were performed on five other buildings. The periods
identified were sensitive to the amplitude of shaking, due to the reduction in lateral stiffness at
stronger shaking levels. Data obtained from the UC San Diego and UC Berkeley full-scale
shake-table tests illustrate the shift in periods due to increasing shaking amplitude. A
regression analysis was performed on the data to obtain a simple but reasonably accurate
period formula for woodframe buildings at low drift levels (less than 0.1%). The equivalent
viscous dampings were usually more than 10% of critical during earthquake shaking.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/53kj5-vbt47Effects of Fault Dip and Slip Rake Angles on Near-Source Ground Motions: Why Rupture Directivity Was Minimal in the 1999 Chi-Chi, Taiwan, Earthquake
https://resolver.caltech.edu/CaltechAUTHORS:20121212-153925352
Authors: {'items': [{'id': 'Aagaard-B-T', 'name': {'family': 'Aagaard', 'given': 'Brad T.'}}, {'id': 'Hall-J-F', 'name': {'family': 'Hall', 'given': 'John F.'}, 'orcid': '0000-0002-7863-5060'}, {'id': 'Heaton-T-H', 'name': {'family': 'Heaton', 'given': 'Thomas H.'}, 'orcid': '0000-0003-3363-2197'}]}
Year: 2004
DOI: 10.1785/0120030053
We study how the fault dip and slip rake angles affect near-source ground velocities and displacements 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. The nature of the shear-wave directivity is the key factor in determining the size and distribution of the peak velocities and displacements. Strong shear-wave directivity requires that (1) the observer is located in the direction of rupture propagation and (2) the rupture propagates parallel to the direction of the fault slip vector. We show that predominantly along-strike rupture of a thrust fault (geometry similar in the Chi-Chi earthquake) minimizes the area subjected to large-amplitude velocity pulses associated with rupture directivity, because the rupture propagates perpendicular to the slip vector; that is, the rupture propagates in the direction of a node in the shear-wave radiation pattern. In our simulations with a shallow hypocenter, the maximum peak-to-peak horizontal velocities exceed 1.5 m/sec over an area of only 200 km^2 for the 30°-dipping fault (geometry similar to the Chi-Chi earthquake), whereas for the 60°- and 75°-dipping faults this velocity is exceeded over an area of 2700 km^2. These simulations indicate that the area subjected to large-amplitude long-period ground motions would be larger for events of the same size as Chi-Chi that have different styles of faulting or a deeper hypocenter.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/1z5zy-jam38Effect of Ground Motion Uncertainty on Predicting the Response of an Existing RC Frame Structure
https://resolver.caltech.edu/CaltechAUTHORS:20120912-152205285
Authors: {'items': [{'id': 'Jalayer-F', 'name': {'family': 'Jalayer', 'given': 'Fatemeh'}}, {'id': 'Beck-J-L', 'name': {'family': 'Beck', 'given': 'James L.'}}, {'id': 'Porter-K-A', 'name': {'family': 'Porter', 'given': 'Keith A.'}}, {'id': 'Hall-J-F', 'name': {'family': 'Hall', 'given': 'John F.'}, 'orcid': '0000-0002-7863-5060'}]}
Year: 2004
Estimation of structural response may be significantly affected by the representation of seismic ground
motion uncertainty. A complete probabilistic presentation of ground motion can be constructed by
specifying a stochastic model that depends on seismic source parameters. Alternatively, the ground
motion uncertainty can be represented by adopting parameters known as the intensity measures (IM), and
using attenuation relationships to relate the IM to seismic source parameters. The uncertainty in the
prediction of structural response can be expressed in terms of the probability of exceeding a given value
of the structural response. In this study, the uncertainty in the ground motion is represented in these two
alternative ways: (a) a full probabilistic representation using an advanced simulation technique known as
subset simulation (Au [4]) based on a stochastic ground motion model conditional on magnitude and
distance proposed by Atkinson and Silva (Atkinson [3]), and, (b) by adopting spectral acceleration at the
small amplitude fundamental period as the intensity measure. In alternative (b), a suite of ground motion
recordings are used to represent ground motion characteristics not already captured by the IM. The
attenuation relation relating the IM to the seismic source parameters is obtained by two alternative
approaches: (i) by simulating stochastic ground motions and applying them to an elastic SDOF system
and (ii) by using the empirical regression equation of Abrahamson and Silva (1997). The alternative
approaches are compared based on their prediction of the uncertainty in structural response. Another
comparison is done between the following two cases: (1) by predicting the structural response following
alternative (b) and using a suite of real ground motion recordings and (2) by predicting the structural
response following alternative (b) and using a suite of synthetic records. The suite of synthetic records are
generated according to the same stochastic model used in alternative (a) for a given magnitude and
distance; this provides a common basis for comparisons. In order to emulate selection of a suite of real
records from a bin, alternative (a) and case (2) of alternative (b) described above are repeated using a
suite of synthetic records generated for magnitude and distance as uncertain variables belonging to a
designated bin. An existing 7-story reinforced concrete structure is used as a case-study. The structural
model (Jalayer [9]) includes stiffness and strength degradation.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/r9ht3-va475Simulated performance of steel moment-resisting frame buildings in the 2003 Tokachi-oki earthquake
https://resolver.caltech.edu/CaltechAUTHORS:20121126-150844917
Authors: {'items': [{'id': 'Heaton-T-H', 'name': {'family': 'Heaton', 'given': 'Thomas'}, 'orcid': '0000-0003-3363-2197'}, {'id': 'Yang-Jing', 'name': {'family': 'Yang', 'given': 'Jing'}}, {'id': 'Hall-J-F', 'name': {'family': 'Hall', 'given': 'John'}, 'orcid': '0000-0002-7863-5060'}]}
Year: 2006
We simulate the response of 6 and 20 story steel moment-resisting frame buildings (US 1994 UBC) for ground motions recorded in the 2003 Tokachi-oki earthquake. We consider buildings with both perfect welds and also with brittle welds similar to those observed in the 1994 Northridge earthquake. Although existing short, strong buildings in Japanese towns performed well in this earthquake, our simulations indicate that flexible buildings would have been strongly excited by this earthquake. Simulated deformations are large enough in some basin regions that one could expect irreparable damage at many locations for both the 6- and 20-story buildings. In a few instances, the 20-story building with brittle welds experienced dangerously large deformations.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/q9xtw-1ne31Modeling Steel Frame Buildings in Three Dimensions. I: Panel Zone and Plastic Hinge Beam Elements
https://resolver.caltech.edu/CaltechAUTHORS:20130311-091205741
Authors: {'items': [{'id': 'Krishnan-Swaminathan', 'name': {'family': 'Krishnan', 'given': 'Swaminathan'}, 'orcid': '0000-0002-2594-1523'}, {'id': 'Hall-J-F', 'name': {'family': 'Hall', 'given': 'John F.'}, 'orcid': '0000-0002-7863-5060'}]}
Year: 2006
DOI: 10.1061/(ASCE)0733-9399(2006)132:4(345)
A procedure for efficient three-dimensional nonlinear time-history analysis of steel framed buildings is derived. It incorporates two types of nonlinear beam elements—the plastic hinge type and the elastofiber type—and nonlinear panel zone elements to model yielding and strain-hardening in moment-frames. Floors and roofs of buildings are modeled using 4-node elastic diaphragm elements. The procedure utilizes an iteration strategy applied to an implicit time-integration scheme to solve the nonlinear equations of motion at each time step. Geometric nonlinearity is included. An overview of the procedure and the theories for the panel zone and the plastic hinge elements are presented in this paper. The theory for the elastofiber element along with illustrative examples are presented in a companion paper. The plastic hinge beam element consists of two nodes at which biaxial flexural yielding is permitted, leading to the formation of plastic hinges. Elastic rotational springs are connected across the plastic hinge locations to model strain-hardening. Axial yielding is also permitted. The panel zone element consists of two orthogonal panels forming a cruciform section. Each panel may yield and strain-harden in shear.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/0z74g-f6c59Parallelized Implicit Nonlinear FEA Program for Real Scale RC Structures under Cyclic Loading
https://resolver.caltech.edu/CaltechAUTHORS:20120608-145954084
Authors: {'items': [{'id': 'Cho-In-Ho', 'name': {'family': 'Cho', 'given': 'In Ho'}}, {'id': 'Hall-J-F', 'name': {'family': 'Hall', 'given': 'John F.'}, 'orcid': '0000-0002-7863-5060'}]}
Year: 2012
DOI: 10.1061/(ASCE)CP.1943-5487.0000138
Parallel computing in civil engineering has been restricted to monotonic shock or blast loading with explicit algorithm which is characteristically feasible to be parallelized. In the present paper, efficient parallelization strategies for the highly demanded implicit nonlinear finite-element analysis (FEA) program for real scale reinforced concrete (RC) structures under cyclic loading are proposed. Quantitative comparison of state-of-the-art parallel strategies in terms of factorization were carried out, leading to the problem-optimized solver, which successfully embraces the penalty method and banded nature. Particularly, the penalty method employed imparts considerable smoothness to the global response, which yields practical superiority of the parallel triangular system solution over those of advanced solvers such as the parallel preconditioned conjugate gradient method. Other salient issues on parallelization are also addressed. By virtue of the parallelization, the analysis platform offers unprecedented access to physics-based mechanisms and probabilistic randomness at the entire system level and realistically reproduces global degradation and localized damage, as reflected from the application to a RC structure. Equipped with accuracy, stability and scalability, the parallel platform is believed to serve as a fertile ground for the introducing of further physical mechanisms into various research fields, as well as the earthquake engineering community.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/xrr1f-fby16Dynamic Characteristics of Woodframe Buildings
https://resolver.caltech.edu/CaltechAUTHORS:20120919-160907030
Authors: {'items': [{'id': 'Camelo-Vanessa-Sabrina', 'name': {'family': 'Camelo', 'given': 'V. S.'}}, {'id': 'Beck-J-L', 'name': {'family': 'Beck', 'given': 'J. L.'}}, {'id': 'Hall-J-F', 'name': {'family': 'Hall', 'given': 'J. F.'}, 'orcid': '0000-0002-7863-5060'}]}
Year: 2012
The dynamic properties of wood shearwall buildings were evaluated, such as modal frequencies, damping and mode shapes of the structures. Through analysis of recorded earthquake response and by forced vibration testing, a database of periods and damping ratios of woodframe buildings was developed. Modal identification was performed on strong-motion records obtained from five buildings, and forced vibration tests were performed on a two-story house and a three-story apartment building, among others. A regression analysis is performed on the database to obtain a period formula specific for woodframe buildings. It should be noted that all test results, including the seismic data, are at small drift ratios (less than 0.1%), and the periods would be significantly longer for stronger shaking of these structures. Despite these low amplitudes, the equivalent viscous dampings for the fundamental modes were usually more than 10% of critical during earthquake shaking.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/ypdfe-2k042General Confinement Model Based on Nonlocal Information
https://resolver.caltech.edu/CaltechAUTHORS:20140612-082336397
Authors: {'items': [{'id': 'Cho-In-Ho', 'name': {'family': 'Cho', 'given': 'In Ho'}}, {'id': 'Hall-J-F', 'name': {'family': 'Hall', 'given': 'John F.'}, 'orcid': '0000-0002-7863-5060'}]}
Year: 2014
DOI: 10.1061/(ASCE)EM.1943-7889.0000724
The confinement effect has been of significant importance for improving the resilience against extreme compression loadings such as seismic excitations. Notwithstanding the accuracy of previous confinement models, some challenges remain regarding their applicability. The previous approaches often build on structure-dependent parameters necessitating intractable calibrations, and their formulations are defined on an integration point or a small portion of the structure, thereby precluding general applicability to complicated real-scale RC structures. Here a general confinement model is proposed in a novel way that it can harness physical information inside the real-scale system. The information is denoted nonlocal information, since it is processed by the nonlocal formulation for assuring the mesh-objectivity. Physically, the nonlocal information provides the proximity to adjacent stiff materials and boundaries through the information index suggested herein. Numerical issues regarding the parallel computing and the optimal selection of the length parameter for the nonlocal formulation are also addressed. The unprecedentedly broad applications include a solid column, a hollow column, a rectangular wall, a T-shaped wall, and even a wall with opening, which strongly bear out the promising potential and universality of the novel confinement model.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/s2mxr-32359Characterizing Ground Motions That Collapse Steel Special Moment-Resisting Frames or Make Them Unrepairable
https://resolver.caltech.edu/CaltechAUTHORS:20150625-084904354
Authors: {'items': [{'id': 'Olsen-A-H', 'name': {'family': 'Olsen', 'given': 'Anna H.'}}, {'id': 'Heaton-T-H', 'name': {'family': 'Heaton', 'given': 'Thomas H.'}, 'orcid': '0000-0003-3363-2197'}, {'id': 'Hall-J-F', 'name': {'family': 'Hall', 'given': 'John F.'}, 'orcid': '0000-0002-7863-5060'}]}
Year: 2015
DOI: 10.1193/102612EQS318M
This work applies 64,765 simulated seismic ground motions to four models each of 6- or 20-story, steel special moment-resisting frame buildings. We consider two vector intensity measures and categorize the building response as "collapsed," "unrepairable," or "repairable." We then propose regression models to predict the building responses from the intensity measures. The best models for "collapse" or "unrepairable" use peak ground displacement and velocity as intensity measures, and the best models predicting peak interstory drift ratio, given that the frame model is "repairable," use spectral acceleration and epsilon (ϵ) as intensity measures. The more flexible frame is always more likely than the stiffer frame to "collapse" or be "unrepairable." A frame with fracture-prone welds is substantially more susceptible to "collapse" or "unrepairable" damage than the equivalent frame with sound welds. The 20-story frames with fracture-prone welds are more vulnerable to P-delta instability and have a much higher probability of collapse than do any of the 6-story frames.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/f9zc3-qq302Discussion of 'Modelling viscous damping in nonlinear response history analysis of buildings for earthquake excitation' by Anil K. Chopra and Frank McKenna
https://resolver.caltech.edu/CaltechAUTHORS:20161111-101200256
Authors: {'items': [{'id': 'Hall-J-F', 'name': {'family': 'Hall', 'given': 'John F.'}, 'orcid': '0000-0002-7863-5060'}]}
Year: 2016
DOI: 10.1002/eqe.2761
This discussion deals with recommendations in the paper on appropriate damping formulations for use in nonlinear response history analysis of buildings. Concern over potentially excessive damping forces and moments should extend beyond the damping moments produced by the stiffness proportional part of Rayleigh damping that corresponds to rotational springs used to explicitly model plastic hinges. The key to an appropriate damping formulation for nonlinear analysis is a realistic mechanism that allows all damping forces and moments to be meaningfully assessed. Then features can be added to keep these forces and moments within reasonable bounds.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/0j0mj-r0181Discussion on 'an investigation into the effects of damping and nonlinear geometry models in earthquake analysis' by Andrew Hardyniec and Finley Charney
https://resolver.caltech.edu/CaltechAUTHORS:20170323-081803283
Authors: {'items': [{'id': 'Hall-J-F', 'name': {'family': 'Hall', 'given': 'John F.'}, 'orcid': '0000-0002-7863-5060'}]}
Year: 2017
DOI: 10.1002/eqe.2786
The discussed paper explores how various assumptions for damping and geometric nonlinearity affect the seismic collapse behavior of steel-frame buildings. The recommended damping scheme is questioned, and an alternative is suggested. Additional explanation is sought to justify the differences observed between the P-delta and co-rotational models for geometric nonlinearity.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/anxhk-y5g63On the descending branch of the pushover curve for multistory buildings
https://resolver.caltech.edu/CaltechAUTHORS:20180215-093244268
Authors: {'items': [{'id': 'Hall-J-F', 'name': {'family': 'Hall', 'given': 'John F.'}, 'orcid': '0000-0002-7863-5060'}]}
Year: 2018
DOI: 10.1002/eqe.2990
The paper discusses nonlinear pushover curves for multistory moment-frame buildings. Attention is brought to the steepening effect that elastic unloading has on the slope of the descending branch of the pushover curve, with the possibility of snapback. Displacement control is shown to be effective for the entire range of pushover analysis, including the descending branch. The method is enhanced by controlling the difference in displacement of 2 floors in the vicinity of the collapse mechanism rather than, say, controlling the roof displacement. An automated drift control version is described and tested. Analysis of a 20-story building demonstrates that variable strength of plastic hinges and inclusion of the strength and stiffness of the gravity frames in the model affect the pushover curve significantly, especially the descending branch. The concept of dynamic pushover is described, and results are compared with the static version.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/7ranq-cqw73Performance of Viscous Damping in Inelastic Seismic Analysis of Moment-Frame Buildings
https://resolver.caltech.edu/CaltechAUTHORS:20180416-115953567
Authors: {'items': [{'id': 'Hall-J-F', 'name': {'family': 'Hall', 'given': 'John F.'}, 'orcid': '0000-0002-7863-5060'}]}
Year: 2018
This report investigates the performance of several viscous damping formulations in the inelastic seismic response of moment-frame buildings. The evaluation employs a detailed model of a 20-story steel building. Damping schemes included in the study are Rayleigh, condensed Rayleigh, Wilson-Penzien, two versions of tangent Rayleigh and one implementation of capped damping. Caughey damping is found not to be computationally viable. Differences among the damping schemes, as quantified by amounts of plastic hinge rotations and story drifts, become noticeable once these quantities reach the 3% level. In order of least to greatest hinge rotations and drifts that occur under lateral response to horizontal ground motion, the damping schemes rank as Rayleigh (most damping action), condensed Rayleigh, Wilson-Penzien, the standard form of tangent Rayleigh and capped damping, which are about the same, and the elastic velocity version of tangent Rayleigh (least damping action). Performance of Rayleigh damping under vertical ground motion is discussed, including the effect of soil-structure interaction. The propensity of Rayleigh damping to generate excessive damping forces and moments during inelastic seismic analysis is explained, and a parameter is introduced that can predict the potential magnitude of the effect. A review of some literature on the role of viscous damping on the inelastic seismic response of moment frames is also presented.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/jq43r-40k43Discussion of "A new inherent damping model for inelastic time‐history analyses" by Enrique Luco and Armando Lanzi
https://resolver.caltech.edu/CaltechAUTHORS:20180726-100724376
Authors: {'items': [{'id': 'Hall-J-F', 'name': {'family': 'Hall', 'given': 'John F.'}, 'orcid': '0000-0002-7863-5060'}]}
Year: 2018
DOI: 10.1002/eqe.3061
This discussion examines several aspects of the proposed elastic velocity damping formulation that pertain to the suitability of the method for use in inelastic time history analysis. These aspects include the absence of damping actions as a structure moves through a collapse mechanism, lack of physical justification, and potential computational issues.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/sxztc-jzn29Performance of viscous damping in inelastic seismic analysis of moment-frame buildings
https://resolver.caltech.edu/CaltechAUTHORS:20181024-134613535
Authors: {'items': [{'id': 'Hall-J-F', 'name': {'family': 'Hall', 'given': 'John F.'}, 'orcid': '0000-0002-7863-5060'}]}
Year: 2018
DOI: 10.1002/eqe.3104
This paper investigates the performance of viscous damping in the inelastic seismic analysis of moment‐frame buildings using a detailed model of a 20‐story steel structure. Damping schemes included are Rayleigh, condensed Rayleigh, Wilson‐Penzien, tangent Rayleigh, elastic velocity Rayleigh, and capped damping. Caughey damping is found not to be computationally viable. Differences among the damping schemes, as quantified by plastic hinge rotations and story drifts, become noticeable once these quantities reach the 3% level. In order of least to greatest hinge rotations and story drifts that occur under lateral response to horizontal ground motion, the damping schemes rank as Rayleigh (most damping action), condensed Rayleigh, Wilson‐Penzien, tangent Rayleigh and capped damping, which are about the same, and elastic velocity Rayleigh (least damping action). Performance of Rayleigh damping under vertical ground motion is discussed, including the effect of soil‐structure interaction. The propensity of Rayleigh damping to generate excessive damping forces and moments during inelastic seismic analysis is explained, and a parameter is introduced that can predict the potential magnitude of the effect. A review of some literature on amplified Rayleigh damping moments is also presented.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/3vzp2-2f314Comments on Philippe de la Hire's Memoir on Arch Abutment Design (1712)
https://resolver.caltech.edu/CaltechAUTHORS:20200213-143540977
Authors: {'items': [{'id': 'Hall-J-F', 'name': {'family': 'Hall', 'given': 'John F.'}, 'orcid': '0000-0002-7863-5060'}]}
Year: 2020
DOI: 10.7907/1GPB-EC73
Philippe de la Hire (1640-1718), a multi-disciplinary French scientist, is generally credited as being the first person to apply the principles of statics to the analysis and design of arches. Prior efforts employed geometric design rules that were based on experience. Thus, de la Hire plays an important role in the transition to scientifically based methods for civil engineering structures. Therefore, it is of historical interest to understand de la Hire's approach and perspective.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/x950r-xr114Effects of Fault Dip and Slip Rake on Near-Source Ground Motions: Why Chi-Chi Was a Relatively Mild M 7.6 Earthquake
https://resolver.caltech.edu/CaltechAUTHORS:20200518-124916954
Authors: {'items': [{'id': 'Aagaard-B-T', 'name': {'family': 'Aagaard', 'given': 'Brad T.'}}, {'id': 'Hall-J-F', 'name': {'family': 'Hall', 'given': 'John F.'}, 'orcid': '0000-0002-7863-5060'}, {'id': 'Heaton-T-H', 'name': {'family': 'Heaton', 'given': 'Thomas H.'}, 'orcid': '0000-0003-3363-2197'}]}
Year: 2020
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.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/caray-a5v71Modeling the Rocking and Sliding of Free-Standing Objects Using Rigid Body Dynamics
https://resolver.caltech.edu/CaltechAUTHORS:20200514-144614293
Authors: {'items': [{'id': 'Veeraraghavan-Swetha', 'name': {'family': 'Veeraraghavan', 'given': 'Swetha'}, 'orcid': '0000-0002-8667-6022'}, {'id': 'Hall-J-F', 'name': {'family': 'Hall', 'given': 'John F.'}, 'orcid': '0000-0002-7863-5060'}, {'id': 'Krishnan-Swaminathan', 'name': {'family': 'Krishnan', 'given': 'Swaminathan'}, 'orcid': '0000-0002-2594-1523'}]}
Year: 2020
DOI: 10.1061/(asce)em.1943-7889.0001739
A rigid body dynamics algorithm is presented in this paper to simulate the interaction between two rigid bodies, a free-standing rigid object, and a pedestal that has infinite mass, in the presence of static and kinetic friction forces. Earlier algorithms led to different solutions for the contact forces when parameters external to problem description, such as the ordering of contact points, are changed. This paper addresses the issue of selecting an appropriate solution for the contact forces and impulses from the infinite set of solutions by picking the solution that is closest to the previous state of the rigid body. The capability of this algorithm in simulating pure rocking, pure sliding, and coupled rocking-sliding response modes of a rectangular block is validated using analytical/semianalytical results. This validated algorithm is later used to identify the various response modes of a rectangular block, which is given an initial tilt and then released.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/0sb59-t4y92