A Possible Explanation of Concrete Pop-Outs

This report summarizes several years of research relating to damage to concrete and aggregates undergoing freezing and thawing. Basic principles involving freezing and attendant pressures are considered. Application of these principles to the evaluation of concrete was accomplished in experiments on concrete having low and high air contents. Freeze-thaw characteristics of saturated aggregates relative to physical properties such as porosity, absorption, and bulk specific gravity were studied by submerging individual particles in pre-chilled mercury. Pressures associated with pop-outs in concrete were monitored and are presented along with accompanying theoretical considerations

A General Survey of Highway Construction Materials: Jackson Purchase Region

Much information and insight concerning the engineering behavior and characteristics of soils and geologic materials can be obtained by a review of geologic and soil reports available in the literature. This knowledge concerning the engineering behavior of these materials can be quite useful to the design and construction engineers as they proceed with their endeavors with respect to civil engineering structures such as highways. Much of this general and preliminary information is available to the public in the form of county soil survey reports that have been published by the U.S. Department of Agriculture and geologic quadrangle maps that have been published by the U.S. Geological Survey. In recent years there has been an extensive and intensive geological mapping program underway in the State of Kentucky. The USGS field parties have progressed to a very advanced stage in this mapping program in the Jackson Purchase area. Many of the quadrangle maps have already been published. In addition the USGS has made available to the Research Division certain other information concerning those areas for which published geologic maps are not yet available

Bridges: Synthesis of Load Histories and Analysis of Fatigue

Repeated stressing of metals above certain limits induces inter- and intra-crystalline dislocations and cleavages and eventually cracks which propagate to failure. Some authorities consider crack propagation to be a separate and discrete stage in the failure process. The internal damage is insidiously cumulative and irreversible. This phenomenon was recognized as early as 1829 and was termed fatigue as early as 1839(1). From the beginning of fatigue testing (Wohler, 1858-1870), results have been reported as S-N, S-log N, or log S-log N curves, where N is the number of repetitions of stress S. From a structural design point of view, the purpose of fatigue testing then was to find the endurance or fatigue limit (i.e., fEL) and so to establish the design or working stress (for many steels, fEL came to be regarded as 55 percent of fy, the yield stress, or 46 percent of fu, the ultimate strength)

A General Study of Highway Construction Materials Jefferson County (A Pilot Study)

The general geology of Jefferson County is very similar to that of other counties lying along the fringes of the Outer Bluegrass area -- that is to say, bedrocks are more-or-less horizontally stratified and consist principally of limestones and shales. The present topography is largely the result of erosion; the soil mantles are residual products of weathering of the uppermost stratum of bedrock or shale (as the case may be). The unique features of the area are associated with the Ohio River and outwashes resulting from encroachments of two glaciations. The toe or southern boundary of ice did not cross the River in this area; but the mouth of the Salt River was blocked; and the deeper channel was filled with a mantle of sediment. This sediment might be encountered in the channel of Floyd\u27s Fork and other tributaries and streams in the county; The westward flow of outwash deposited sands and gravels, etc., in the Ohio River valley; and these materia ls occur as two, fairly distinct terraces or flood plains along the interior arcs of meanders

Landslides in Kentucky

The reoccurrence of certain features of landslides in Kentucky suggests that the difficulties in the State can be readily classified. Because of this repetitive nature, one can be alerted to the possibility of slides in certain situations early in the planning and design stages of the facility to be constructed. Thus, the traveling public might be spared the inconvenience illustrated in Figure 1. Enough cannot be said concerning the necessity for having adequate soils and geological information concerning possible routes for highway locations, and a review of a number of landslides in Kentucky suggests that there are certain troublesome geologic formations

Some Effects of Fabrication Practices on the Strength Characteristics of Reinforced Concrete Culvert Pipe

Underground conduits have been used for hundreds of years for drainage and water supply purposes. With the advent of railway and auto-mobile transportation, the use of underground conduits for drainage purposes beneath the roadways increased greatly. It soon became apparent that there was a definite need for knowledge concerning the manufacture, installation, and field behavior of pipe culverts. Accordingly, in the first half of the century, much attention and research has been directed toward the development and establishment of acceptable techniques and specifications fot the manufacture and installation of pipe culverts. This work has been accomplished by many individuals and organizations

MITRACLIP IN THE SETTING OF CARDIOGENIC SHOCK: BEYOND COAPT

Title: MITRACLIP IN THE SETTING OF CARDIOGENIC SHOCK: BEYOND COAPT Authors: Deen, James, MS., Lev, Tohar, BS., Ebinger, Joseph, MD. Purpose of the study: To assess the short- and long-term outcomes of patients undergoing MitraClip for severe MR in the setting of cardiogenic shock. Methods: This was a retrospective observational cohort study of patients who underwent MitraClip at large academic institution between 2013 and 2019. Charts were reviewed to identify patients with pre-procedure cardiogenic shock if at least 1 of the following was present: 1) documentation of ongoing cardiogenic shock by a provider, 2) cardiac index \u3c2.2 or 3) use of inotropes (Dobutamine, Milrinone or Dopamine) or vasopressors (Norepinephrine, Epinephrine or Vasopressin) within 24 hours of the procedure. Results: Out of 448 MitraClip patients, 29 (6.5%) were identified as having pre-procedure cardiogenic shock. Of those in cardiogenic shock prior to MitraClip, 26 (90%) were on inotropes and 16 (55%) were on vasopressors. This decreased to 22 (76%) and 15 (52%) post-procedure, respectively, though did not reach statistical significance (p=0.80). On pre-procedure echocardiography, MR severity was graded as severe or very severe in 21 (72.4%) of those with cardiogenic shock and 301 (71.8%) of those without shock. Of these patients, MR severity was reduced to moderate or less in 26 (89.7%) of those with shock and 400 (95.5%) of those without shock following the procedure (p=0.80). Conclusion: Use of MitralClip for the treatment of MR in the setting of cardiogenic shock is feasibility, with noted reductions in the severity of MR and inotropic requirements

Fatigue Analysis from Strain Gage Data and Probability Analysis

The Central Bridge over the Ohio River between Newport, Kentucky, and Cincinnati, Ohio, was completed in 1891 and in 1972-73 was considered to be in danger of fatigue failure. A series of investigations were undertaken to determine the likelihood of failure and to estimate the time of probable failure. During the investigation, a methodology was developed to determine fatigue damage from a probability analysis of traffic data by reconstituting or synthesizing the load (traffic) history of bridges. Strain gage data obtained with Prewitt scratch gages and SR-4 resistivity gages were used to evaluate fatigue damage incurred by the Central Bridge

Freeze-and-Thaw of Concretes and Aggregates

This report summarizes several years of research relating to damage to concrete and aggregates undergoing freezing and thawing. Basic principles involving freezing and attendant pressures are considered. Application of these principles to the evaluation of concrete was accomplished in experiments on concrete having low and high air contents. The effects of air entrainment upon freeze-thaw resistance were demonstrated. Freeze-thaw characteristics of saturated aggregates relative to physical properties such as porosity, absorption, and bulk specific gravity were studied by submerging individual particles in pre-chilled mercury. Pressures associated with popouts in concrete were monitored and are presented along with accompanying theoretical considerations