The 19 September 1985 Mexico Earthquake: Technical Problems

1986 ◽  
Vol 2 (1-4) ◽  
pp. 9-14 ◽  
Author(s):  
Walter W. Hays
Keyword(s):  
The United States ◽  
Resonance Phenomenon ◽  
Soil Amplification ◽  
Worst Case ◽  
Technical Problems ◽  
Period 2 ◽  
Earthquake Resistant Design ◽  
Earthquake Resistant ◽  
Mexico Earthquake ◽  
Potential Damage

ABSTRACTThe September 19, 1985, Mexico earthquake reminded scientists and engineers of the importance of considering soil amplification effects in earthquake-resistant design. The Mexico earthquake illustrated the “worst case”—the ground response and the building response occurring at approximately the same period, 2 seconds. This resonance phenomenon was predictable on the basis of similar experiences in past earthquakes. A number of areas in the United States also exhibit significant predictable soil amplification effects. Special steps are needed in these areas to mitigate the potential damage and losses that could occur in future earthquakes.

Proposal of orientation-independent measure of intensity for earthquake-resistant design

2021 ◽  
pp. 875529302110382
Author(s):  
Alan Poulos ◽  
Eduardo Miranda
Keyword(s):  
United States ◽  
Ground Motion ◽  
The United States ◽  
Design Codes ◽  
Intensity Measure ◽  
Independent Measure ◽  
Earthquake Resistant Design ◽  
Earthquake Resistant ◽  
Ground Motion Records ◽  
Structural Engineers

A new measure of ground motion intensity in the horizontal direction is proposed. Similarly to other recently proposed measures of intensity, the proposed intensity measure is also independent of the as-installed orientation of horizontal sensors at recording stations. This new measure of horizontal intensity, referred to as MaxRotD50, is defined using the maximum 5%-damped response spectral ordinate of two orthogonal horizontal directions and then computing the 50th percentile for all non-redundant rotation angles, that is, the median of the set of spectral ordinates in a range of 90°. This proposed measure of intensity is always between the median and maximum spectral ordinate for all non-redundant orientations, commonly referred to as RotD50 and RotD100, respectively. A set of 5065 ground motion records is used to show that MaxRotD50 is, on average, approximately 13%–16% higher than Rot50 and 6% lower than RotD100. The new measure of intensity is particularly well suited for earthquake-resistant design where a major concern for structural engineers is the probability that the design ground motion intensity is exceeded in at least one of the two principal horizontal components of the structure, which for most structures are orthogonal to each other. Currently, design codes in the United States are based on RotD100, and hence using MaxRotD50 for structures with two orthogonal principal horizontal components would result in a reduction of the ground motion intensities used for design purposes.

Damage-Limiting Aseismic Design of Buildings

1987 ◽  
Vol 3 (1) ◽  
pp. 1-26 ◽  
Author(s):  
Y. J. Park ◽  
A. H-S. Ang ◽  
Y. K. Wen
Keyword(s):  
Structural Damage ◽  
Design Method ◽  
Damage Model ◽  
Hysteretic Energy ◽  
Maximum Deformation ◽  
Earthquake Resistant Design ◽  
Earthquake Resistant ◽  
Degree Of Damage ◽  
Potential Damage ◽  
Tolerable Level

A procedure for earthquake-resistant design is developed to limit the potential damage of buildings to a tolerable level. The procedure is based on the damage model developed earlier (Park and Ang, 1984) in which structural damage is expressed as a function of the maximum deformation and dissipated hysteretic energy. The tolerable degree of damage is defined on the basis of calibration with observed damages from past major earthquakes. The design method is examined in the context of reliability.

Site-dependent spectra for earthquake-resistant design

1976 ◽  
Vol 66 (1) ◽  
pp. 221-243 ◽  
Author(s):  
H. Bolton Seed ◽  
Celso Ugas ◽  
John Lysmer
Keyword(s):  
United States ◽  
Statistical Analysis ◽  
Ground Motion ◽  
The United States ◽  
Design Criteria ◽  
Earthquake Resistant Design ◽  
Geological Conditions ◽  
Earthquake Resistant ◽  
Ground Motion Records ◽  
Spectral Shapes

abstract The paper presents the results of a statistical analysis of the spectral shapes of 104 ground-motion records obtained from 23 earthquakes, mostly in the western part of the United States. The analysis shows clear differences in spectral shapes for different soil and geological conditions, indicating the need for consideration of these effects in selecting earthquake-resistant design criteria.

scholarly journals The measurement of ground motion of destructive earthquakes

1963 ◽  
Vol 53 (2) ◽  
pp. 419-437
Author(s):  
D. E. Hudson
Keyword(s):  
United States ◽  
Transient Response ◽  
Strong Motion ◽  
The United States ◽  
Geodetic Survey ◽  
Natural Period ◽  
Earthquake Resistant Design ◽  
Earthquake Resistant ◽  
The World ◽  
Structural Engineers

abstract The need for a greatly expanded network of strong-motion accelerographs throughout the seismic regions of the world is stressed. A summary of the characteristics of currently available strong-motion accelerographs is presented, and the design details are given for an instrument suitable for acquiring the basic data needed by structural engineers for earthquake resistant design. It is shown that for such an instrument, the natural period must be less than 0.1 seconds, and that the recording speed must be at least 1 cm/sec. The critical nature of the inertia starting device is discussed, and some information is given on the transient response of the standard pendulum starter used in the United States Coast and Geodetic Survey Strong-Motion Accelerograph. The use of simpler, non-time-recording instruments such as the U.S.C.G.S. Seismoscope to supplement the accelerograph network is described.

Lessons Learned from Recent Earthquakes and Research and Implications for Earthquake-Resistant Design of Building Structures in the United States

1986 ◽  
Vol 2 (4) ◽  
pp. 825-858 ◽  
Author(s):  
Vitelmo V. Bertero
Keyword(s):  
Lateral Force ◽  
The United States ◽  
Lessons Learned ◽  
Structural Quality ◽  
Building Structures ◽  
Response Modification Factor ◽  
Earthquake Resistant Design ◽  
Earthquake Resistant ◽  
Modification Factor ◽  
Recent Earthquakes

Following an overview of the special problems inherent in the design and construction of earthquake-resistant buildings in regions of high seismic risk, the techniques that will be required to solve these problems in the U.S. are discussed. Some lessons learned from recent earthquakes, particularly those in Chile and Mexico in 1985, are discussed as are some results of integrated analytical and experimental research at the University of California, Berkeley. The implications of the ground motions recorded during the 1985 Mexican and Chilean earthquakes, the performance of buildings during the Mexican earthquake, and the research results previously discussed are then assessed with respect to seismic-resistant design regulations presently in force (UBC) as well as those formulated by ATC 3-06 and the Tentative Lateral Force Requirements recently developed by the Seismology Committee of SEAOC. The rationale for and reliability of the values suggested by the ATC for the “Response Modification Factor R” and by the SEAOC Seismology Committee for the “Structural Quality Factor Rw” are reviewed in detail. In the conclusion to the paper, two solutions for improving the earthquake-resistant design of building structures are proposed: an ideal (rational) method to be implemented in the future, and a compromise solution that can be implemented immediately.

scholarly journals Assessing Diazinon Pollution in the Three Major Rivers Flowing into the Caspian Sea (Iran)

Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 335
Author(s):  
Reza Dahmardeh Behrooz ◽  
Abbas Esmaili-sari ◽  
Magdalena Urbaniak ◽  
Paromita Chakraborty
Keyword(s):  
High Risk ◽  
Organophosphorus Pesticides ◽  
Aquatic Organisms ◽  
The United States ◽  
The Caspian Sea ◽  
Worst Case ◽  
Pollution Levels ◽  
Haraz River ◽  
Significant Difference ◽  
Medium Risk

The aim of this study was to investigate the seasonal and spatial variations in the concentrations of a widely used organophosphorous pesticide (OPP), diazinon, and the associated risk posed by this OPP in the surface water from the three largest rivers located in the northern province of Iran: the Haraz, the Talar and the Babolrood rivers. These rivers are located in the agriculture province of Mazandaran, and are exposed to high doses of organophosphorus pesticides, especially diazinon. The concentration of diazinon was determined using gas chromatography, while the potential risk posed by diazinon was elucidated using a Risk Quotient (RQ) calculated for general (RQm) and worst-case (RQex) scenarios. The obtained results demonstrated that the average diazinon concentrations ranged from 41 ± 76 ng/L in the Talar River and 57 ± 116 ng/L in the Haraz River, to 76.5 ± 145 ng/L in the Babolrood River, with a significant difference noted between summer and autumn seasons for all three rivers. For some stations, the concentration of diazinon is higher than the standard guidelines of Australian/New Zealand Guidelines for Fresh and Marine Water Quality (FMWQ) and the United States Criteria Maximum Concentration (CMC). The calculated RQs indicated a medium risk of diazinon, RQm = 0.73 and RQex = 2.27, in the Talar River; RQm = 1.02 and RQex = 2.49 in the Haraz River; and RQm = 1.35 and RQex = 4.54 in the Babolrood River. The overall exposure of diazinon was defined to have a high risk (RQm and RQex > 1); however, the summer sampling revealed a high risk (RQm and RQex > 1), while the autumn had a medium risk (RQm and RQex < 1). The obtained results revealed not only elevated concentrations of diazinon in the studied rivers but most importantly the high risk posed by this OPP for the aquatic organisms and the wellbeing of the whole river ecosystem. The current study showed that development and implementation of appropriate standards and regulations toward diazinon in countries such as Iran are required to reduce the pollution levels and risks related to elevated concentrations of the studied pesticide.

scholarly journals Trissolcus japonicus (Hymenoptera: Scelionidae) Causes Low Levels of Parasitism in Three North American Pentatomids Under Field Conditions

2019 ◽  
Vol 19 (4) ◽  
Author(s):  
Joshua M Milnes ◽  
Elizabeth H Beers
Keyword(s):  
North American ◽  
Native Species ◽  
Classical Biological Control ◽  
The United States ◽  
Host Finding ◽  
Pest Species ◽  
Case Scenario ◽  
Worst Case ◽  
Egg Masses ◽  
Trissolcus Japonicus

Abstract Trissolcus japonicus (Ashmead), an Asian parasitoid of Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), was first detected in North America in 2014. Although testing in quarantine facilities as a candidate for classical biological control is ongoing, adventive populations have appeared in multiple sites in the United States, Canada, and Europe. Extensive laboratory testing of T. japonicus against other North American pentatomids and H. halys has revealed a higher rate of parasitism of H. halys, but not complete host specificity. However, laboratory tests are necessarily artificial, in which many host finding and acceptance cues may be circumvented. We offered sentinel egg masses of three native pentatomid (Hemiptera: Pentatomidae) pest species (Chinavia hilaris (Say), Euschistus conspersus Uhler, and Chlorochroa ligata (Say)) in a field paired-host assay in an area with a well-established adventive population of T. japonicus near Vancouver, WA. Overall, 67% of the H. halys egg masses were parasitized by T. japonicus during the 2-yr study. Despite the ‘worst case’ scenario for a field test (close proximity of the paired egg masses), the rate of parasitism (% eggs producing adult wasps) on all three native species was significantly less (0.4–8%) than that on H. halys eggs (77%). The levels of successful parasitism of T. japonicus of the three species are C. hilaris > E. conspersus > C. ligata. The potential impact of T. japonicus on these pentatomids is probably minimal.

scholarly journals FUNDAMENTAL STUDY ON EARTHQUAKE RESISTANT DESIGN OF FILL-TYPE DAMS

1983 ◽  
Vol 1983 (339) ◽  
pp. 127-136 ◽  
Author(s):  
Yoshio OHNE ◽  
Hidehiro TATEBE ◽  
Kunitomo NARITA ◽  
Tetsuo OKUMURA
Keyword(s):  
Fundamental Study ◽  
Earthquake Resistant Design ◽  
Earthquake Resistant
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