Centrifuge modeling of seismically - induced lateral deformation during liquefaction and its effect on a pile foundation

A cooperative project is reported between teams at Renssealaer Polytechnic Institute (RPI) and Cornell University to investigate the effects of lateral spreading on pile foundations. Centrifuge tests of lateral spreading and the corresponding permanent bending moments measured in instrumented model piles conducted at RPI, are used to study the problem and verify and calibrate Cornell University's computer program B-STRUCT. Individual piles and pile groups are investigated in a variety of pile and soil configurations. The paper reports in detail the results of Model 1, corresponding to the simulation of reinforced concrete piles that were deformed by lateral spread under the NFCH building in Niigata during the 1964 earthquake.(AU)

Engineering evaluation of permanent ground deformations due to seismically-induced liquefaction

A study is presented on the engineering evaluation of permanent lateral ground deformation associated with liquefaction and lateral spreading during earthquakes. Newmark's rigid sliding block model is used as main analytical technique, based on the reasonable assumption that generally the deformation occurs during shaking in the downhill direction of the ground surface slope. The study involves laboratory tests, analitical work, and comparisons with case histories and field observations. It culminates with a simplified method to predict lateral deformation using regional attenuation relations for peak ground acceleration and velocity. The laboratory work includes two series of tests. In the first series, drained and undrained cyclic triaxial experiments at different frecuencies on clean, medium dense Ottawa sand were used test a basic assumption of Newmak's method. It is concluded that the method can be applied to dry sand but not to saturated medium dense sand, due to their dilative character and to the shape of their dense stress-strain curves, which do not exhibit the strenght plateau required by the method(AU)

Heparin lock for nighttime intravenous fluid management in a dysphagic patient.

Dysphagia, with its inherent risk of aspiration, is a clinical problem frequently encountered in patients with brain injury from trauma or cerebrovascular accident. The use of nasogastric tubes and intravenous lines for nutrition and hydration can be cumbersome and uncomfortable for the patient, and can interfere with rehabilitation therapy. With the advent and increased use of video- and cinefluoroscopy to evaluate swallowing, the type of dysphagia can be defined more readily. This article describes the use of a heparin lock at night to provide fluids intravenously to a patient who could swallow solid or semisolid food, but aspirated thin liquids. This approach insured adequate hydration while keeping the patient free of parenteral lines and nasogastric tubes during therapy. This technique was continued for 3 1/2 weeks until the patient's dysphagia improved and a full oral diet could be resumed. The authors recommend the use of nighttime intravenous feeding via a heparin lock as an option for managing this subset of dysphagic patients in a rehabilitation setting.