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Concrete corrosion and slab heaving in a sabkha environment: Long Beach-Newport Beach, California
138A
SURFACE STRUCTURES:DYNAMIC
963316 Aspects of highway rock engineering in tbe UK G. D. Ma&son. in: Enaineerina aeoloav of constrzdon, ed M. Eddleston & others, (Geoio&al-so,odety of London; Engineering Geology Special Publication, lo), 1995, pp 169187. Aspects of highway rock engineering relating to excavation and slope stability, with emphasis on the evolution of successful design and construction techniques in the UK, are considered. Techniques have now been developed for designing slopes in harmony with the geotecimical environment and for harnessing the power of high explosives without imparting damage to the design slope. Such techniques include the optimized design technique and presplit blasting, important aspects of which are described. (from Author) 963317 Study of the effect of excavation technique on rock slope stability and slope maintenance costs at two locations in Scotland D. G. Ross & G. M. Reeves, in: Engineering geology of construction, ed M. Eddleston & others, (Geological Society of London; Engineering Geology Special Publication, lo), 1995, pp 369-375. Results indicate that instability induced into the face by the technique of excavation adds considerably to the maintenance costs. Pre-splitting is advocated as a method of minimizing remedial and maintenance costs when blasting is necessary. (from Authors) 963318 Slope works associated with site formation excavation 8t Tsing Lung Tau, western New Territories, Hong Kong K. H. Nicholls, in: Engineering geology of construction, ed M. Eddleston & others, (Geological Society of London; Engineering Geology Special Publication, lo), 1995, pp 377385. The geotechnical works undertaken included excavation by drill and blast, upgrading of an existing rock slope overlooking a major highway, and stabilization works to internal slopes formed by blasting. Substantial works were required as part of the contraactor’s temporary works to safeguard the highway during construction, especially to guard against possible failures associated with blasting. (Author)
Construction methods 963319 Examples of ground response to various types of stmcturol foundation constmetion P. W. Rowe, in: Engineering geology of construction, ed M. Eddleston & others, (Geological Society of London; Engineering Geology Special Publication, lo), 1995, pp 3357. Seventeen cases of construction activities are cited that identify the ground responses to various types and methods of construction in the light of the geological age and relevant geological structure. The objective is to underline the value of case histories and the real need in site investigation reports to isolate and interpret those particular aspects of the geology relevant to the proposed engineering works. (from Author)
Groundwater problems and environmental effects 963320 Concrete corrosion and slab heaving in a sabkha environment: Long Beach-Newport Beacb, CaIifomia D. M. Robinson, Environmental & Engineering Geosciences, l(l), 1995, pp 35-40. The Long Beach to Newport area which coincides with the Downey and Santa Ana River flood plains, is an area of
LOADS
shallow brackish ground water. This area experiences a 2 to 3 m rise in water levels during heavy winter rains. This shallow ground water evaporates causing precipitation of Bypsum and halite. During the mid-1980’s, early constructed homes experienced concrete corrosion and slab heaving. The Long Beach-Newport Beach area exhibits many characteristics of a typical sabkha. The concentration of salts results in corrosion of normal concrete at the air-water interface. The growth of gypsum crustals resulted in heaving of slabs, allowing more corrosion. (from Author)
Influence of dynamic loads 963321 Application of ARMA models to estimate earthquake ground motion and stmctnral response S. Olafsson & R. Sighjomsson, Earthquake Engineering & Structural Dynamics, 24(7), 1995, pp 951-996. This paper deals with the use of ARMA models in earthquake engineering. Tools and methods applied to strong ground motion are discussed emphasizing simulation of probabilistic earthquake response spectra. The ARMA models are applied to Icelandic earthquake data and a tentative model for Icelandic earthquakes is presented. This model, which is derived using 54 accelerograms, is based on a low-or&r, timeinvariant ARMA process excited by Gaussian white noise and amplitude modulated using a simple envelope diction to account for the non-stationary characteristics. (from Authors) 963322 Non-planar pseudodynamic testing C. R. Thewalt 8~ S. A. Mahin, Earthquake Engineering &
Structural Dynamics, 24(5), 1995, pp 733-746. The pseudodynamic test method provides a mean of inex-
pensive seismic performance testing for laboratories that do not have a shaking table. In this paper a three-dimensional specimen is tested under a multicomponent fixed base excitation and the response is compared to shaking table tests. (from Authors) 963323 Calculations for constructions exposed to seismic effects: response spectrum method M. Wyjadlowski, Studia Geotechnicu et Mechonica, 16(1-2), 1994, pp 13-30. This study discusses the response spectrum method used to design structures subject to seismic loads. Basic and higher natural frequencies important also for structures with irregular plans and sections, with considerable st.ifTnesschanges in either horizontal or vertical direction and with the occurrence of torsional vibrations, are taken into consideration. Responses of each natural vibration formed at the excitation point can be computed regardless of other natural vibrations. Next, responses of each natural vibration form are superpositioned, which enables the response of the excited system to be determined. Flexible computational spectrum of response is prepared for the determined seismic zone according to the data referring to existing seismic phenomena. (from Author) 963324 A mass penalty technique to control the critical time increment in explicit dynamic finite element analyses R. W. Macek 8~ B. H. Aubert, Earthquake Engineering & Structural Dynamics, 24(10), 1995, pp 1315-1331. Presents a mass penalty technique whereby the highest natural frequencies of a dynamic system can be preferentially lowered with only a minimal effect on the structural modes. Because the critical time increment is inversely proportional to the highest natural frequency, a dramatic increase in the solution time increment may be achieved. An expression is developed for the frequency shift and a number of useful
SURFACE STRUCTURES:DYNAMIC
963316 Aspects of highway rock engineering in tbe UK G. D. Ma&son. in: Enaineerina aeoloav of constrzdon, ed M. Eddleston & others, (Geoio&al-so,odety of London; Engineering Geology Special Publication, lo), 1995, pp 169187. Aspects of highway rock engineering relating to excavation and slope stability, with emphasis on the evolution of successful design and construction techniques in the UK, are considered. Techniques have now been developed for designing slopes in harmony with the geotecimical environment and for harnessing the power of high explosives without imparting damage to the design slope. Such techniques include the optimized design technique and presplit blasting, important aspects of which are described. (from Author) 963317 Study of the effect of excavation technique on rock slope stability and slope maintenance costs at two locations in Scotland D. G. Ross & G. M. Reeves, in: Engineering geology of construction, ed M. Eddleston & others, (Geological Society of London; Engineering Geology Special Publication, lo), 1995, pp 369-375. Results indicate that instability induced into the face by the technique of excavation adds considerably to the maintenance costs. Pre-splitting is advocated as a method of minimizing remedial and maintenance costs when blasting is necessary. (from Authors) 963318 Slope works associated with site formation excavation 8t Tsing Lung Tau, western New Territories, Hong Kong K. H. Nicholls, in: Engineering geology of construction, ed M. Eddleston & others, (Geological Society of London; Engineering Geology Special Publication, lo), 1995, pp 377385. The geotechnical works undertaken included excavation by drill and blast, upgrading of an existing rock slope overlooking a major highway, and stabilization works to internal slopes formed by blasting. Substantial works were required as part of the contraactor’s temporary works to safeguard the highway during construction, especially to guard against possible failures associated with blasting. (Author)
Construction methods 963319 Examples of ground response to various types of stmcturol foundation constmetion P. W. Rowe, in: Engineering geology of construction, ed M. Eddleston & others, (Geological Society of London; Engineering Geology Special Publication, lo), 1995, pp 3357. Seventeen cases of construction activities are cited that identify the ground responses to various types and methods of construction in the light of the geological age and relevant geological structure. The objective is to underline the value of case histories and the real need in site investigation reports to isolate and interpret those particular aspects of the geology relevant to the proposed engineering works. (from Author)
Groundwater problems and environmental effects 963320 Concrete corrosion and slab heaving in a sabkha environment: Long Beach-Newport Beacb, CaIifomia D. M. Robinson, Environmental & Engineering Geosciences, l(l), 1995, pp 35-40. The Long Beach to Newport area which coincides with the Downey and Santa Ana River flood plains, is an area of
LOADS
shallow brackish ground water. This area experiences a 2 to 3 m rise in water levels during heavy winter rains. This shallow ground water evaporates causing precipitation of Bypsum and halite. During the mid-1980’s, early constructed homes experienced concrete corrosion and slab heaving. The Long Beach-Newport Beach area exhibits many characteristics of a typical sabkha. The concentration of salts results in corrosion of normal concrete at the air-water interface. The growth of gypsum crustals resulted in heaving of slabs, allowing more corrosion. (from Author)
Influence of dynamic loads 963321 Application of ARMA models to estimate earthquake ground motion and stmctnral response S. Olafsson & R. Sighjomsson, Earthquake Engineering & Structural Dynamics, 24(7), 1995, pp 951-996. This paper deals with the use of ARMA models in earthquake engineering. Tools and methods applied to strong ground motion are discussed emphasizing simulation of probabilistic earthquake response spectra. The ARMA models are applied to Icelandic earthquake data and a tentative model for Icelandic earthquakes is presented. This model, which is derived using 54 accelerograms, is based on a low-or&r, timeinvariant ARMA process excited by Gaussian white noise and amplitude modulated using a simple envelope diction to account for the non-stationary characteristics. (from Authors) 963322 Non-planar pseudodynamic testing C. R. Thewalt 8~ S. A. Mahin, Earthquake Engineering &
Structural Dynamics, 24(5), 1995, pp 733-746. The pseudodynamic test method provides a mean of inex-
pensive seismic performance testing for laboratories that do not have a shaking table. In this paper a three-dimensional specimen is tested under a multicomponent fixed base excitation and the response is compared to shaking table tests. (from Authors) 963323 Calculations for constructions exposed to seismic effects: response spectrum method M. Wyjadlowski, Studia Geotechnicu et Mechonica, 16(1-2), 1994, pp 13-30. This study discusses the response spectrum method used to design structures subject to seismic loads. Basic and higher natural frequencies important also for structures with irregular plans and sections, with considerable st.ifTnesschanges in either horizontal or vertical direction and with the occurrence of torsional vibrations, are taken into consideration. Responses of each natural vibration formed at the excitation point can be computed regardless of other natural vibrations. Next, responses of each natural vibration form are superpositioned, which enables the response of the excited system to be determined. Flexible computational spectrum of response is prepared for the determined seismic zone according to the data referring to existing seismic phenomena. (from Author) 963324 A mass penalty technique to control the critical time increment in explicit dynamic finite element analyses R. W. Macek 8~ B. H. Aubert, Earthquake Engineering & Structural Dynamics, 24(10), 1995, pp 1315-1331. Presents a mass penalty technique whereby the highest natural frequencies of a dynamic system can be preferentially lowered with only a minimal effect on the structural modes. Because the critical time increment is inversely proportional to the highest natural frequency, a dramatic increase in the solution time increment may be achieved. An expression is developed for the frequency shift and a number of useful