Earthquake Simulation Tests of a Ten-Story Reinforced Concrete Frame with a Discontinued First-Level Beam

A small-scale, ten-story, reinforced concrete frame structure with relatively flexible lower stories was subjected successively to simulated earthquakes of increasing intensity on the University of Illinois Earthquake Simulator. The test structure comprised two frames situated opposite one another with strong axes parallel to a horizontal base motion and with story-masses spanning between. The frames had relatively "tall" first and last stories and a discontinued first floor-level, exterior-span beam. Earthquake simulation tests were complemented by free-vibration tests and steady-state sinusoidal tests at a series of frequencies bounding the apparent fundamental frequency. This report docuents the experimental work, presents data (including time-response histories), and discusses the observed dynamic response in relation to stiffness, strength, and energy-dissipative capacity.National Science Foundation Research Grant ENV74-2296

Experimental Study of Small-Scale R/C Columns Subjected to Axial and Shear Force Reversals

Small-scale reinforced concrete columns were subjected to a series of shear force or simultaneous shear and axial force reversals. The specimens were similar to the first story columns of the nine-story, three-bay frames tested dynamically on the University of Illinois Earthquake Simulator. Test variables included the reinforcement ratio~ the dead load on the column, and the rate of axial load variation during shear force reversals. Behavior of the specimens, is represented by measured hysteresis relations and crack patterns. The observed behavior is compared with the calculated response.National Science Foundation Research Grant PFR 78-1631

The 1985 Chile earthquake: observations on earthquake-resistant construction in Vina del Mar

On 3 March 1985, a major earthquake occurred near the coast of central Chile. The resort city of Vina del Mar is of particular interest from an engineering standpoint because approximately 400 moderate-rise reinforced concrete buildings and a strong-motion instrument were located in the city. The geology and seismicity of the Vina del Mar region, the development of seismic design provisions in Chile, and the ground motion records from the 1985 earthquake are described in the report. The structural characteristics of and damage in thirteen reinforced concrete buildings in Vina del Mar and Valparaiso are also described.National Science Foundation Research Grants ECE 86-03789, ECE 86-03624, and ECE 0608

Experiments to Study Earthquake Response of R/C Structures with Stiffness Interruptions

An experimental study was undertaken to investigate the response to strong earthquakes of R/C structures having abrupt interruptions in adjacent story stiffness. Four structures (total weight of 2.29 meters) comprising two nine-story, three-bay frames or two frames and a wall which acted in parallel were tested. The first story was twice the height of other stories. The experimental variable was the wall hei0ht with structures having either no wall or walls which were one-, four-, or nine-stories tall. Experimental measurements include displacements, accelerations, and forces between frames and walls at each level. Observed behavior is interpreted using simple, design-oriented numerical models. Studies using linear models include (1) comparison of modal-spectral and equivalent static procedures and (2) estimates of response maxima using SOOF oscillators. Studies using nonlinear models include (1) interpretation of behavior for a monotonic lateral loading distribution and (2) estimates of displacement maxima and waveform using SOOF models.National Science Foundation Research Grant PFR 78-1631

Pink-eyed Dilution Protein Modulates Arsenic Sensitivity and Intracellular Glutathione Metabolism

Mutations in the mouse p (pink-eyed dilution) and human P genes lead to melanosomal defects and ocular developmental abnormalities. Despite the critical role played by the p gene product in controlling tyrosinase processing and melanosome biogenesis, its precise biological function is still not defined. We have expressed p heterologously in the yeast Saccharomyces cerevisiae to study its function in greater detail. Immunofluorescence studies revealed that p reaches the yeast vacuolar membrane via the prevacuolar compartment. Yeast cells expressing p exhibited increased sensitivity to a number of toxic compounds, including arsenicals. Similarly, cultured murine melanocytes expressing a functional p gene were also found to be more sensitive to arsenical compounds compared with p-null cell lines. Intracellular glutathione, known to play a role in detoxification of arsenicals, was diminished by 50% in p-expressing yeast. By using the glutathione-conjugating dye monochlorobimane, in combination with acivicin, an inhibitor of vacuolar gamma-glutamyl cysteine transpeptidase, involved in the breakdown of glutathione, we found that p facilitates the vacuolar accumulation of glutathione. Our data demonstrate that the pink-eyed dilution protein increases cellular sensitivity to arsenicals and other metalloids and can modulate intracellular glutathione metabolism