Observations have been made of the flow of water in an inclined trough of rectangular section, with a planed wood bottom. Defining the Reynolds criterion for such a system as Q/ν, where Q is the to...

LXXXIV. The flow of water in an inclined channel of rectangular section

Tunnel valleys are elongate depressions with overdeepened areas along their floors cut into bedrock or unconsolidated sediment. They are frequently sinuous and form anastomosing networks, although they also exist as independent, straight valleys. Their sedimentary infill is variable but is characteristically dominated by sediment gravity flow facies and thick units of glaciofluvial sands. Till tends to be rare and, where present, occurs along valley sides. Three main theories of tunnel valley formation exist at present. The first ascribes the formation of tunnel valleys cut into unconsolidated sediment to the creep of deformable subglacial sediment into a subglacial conduit from the sides and below, followed by removal of this material through the conduit by meltwater flow. Tunnel valleys are thus created by lowering of the sediment surface on either side of the conduit. The second theory argues that tunnel valleys form during deglaciation, at or close to the ice margin, by subglacial meltwater erosion an...

Tunnel valley genesis

This study presents a design criterion developed for fatigue strengthening of a 120-year-old metallic railway bridge in Switzerland and presents a pre-stressed un-bonded reinforcement (PUR) system developed to apply the strengthening. The PUR system uses carbon fiber reinforced polymer (CFRP) plates; however, unlike conventional pre-stressed CFRP reinforcement methods, preparation of the existing metallic bridge surface is not required. This decreases the time required for on-site strengthening procedures. The principle of the constant life diagram (CLD) and two fatigue failure criteria (Johnson and Goodman) are described. Analytical formulations are developed based on the CLD method to determine the minimum CFRP pre-stress level required to prevent fatigue crack initiation. The PUR system uses an applied pre-stress force to reduce the mean stress level (and stress ratio) to shift an existing fatigue-susceptible metallic detail from the 'at risk' finite life regime to the 'safe' infinite life regime. The applied CLD method is particularly valuable when the stress history of the detail is not known and it is difficult to assess the remaining fatigue life. Moreover, it is shown that the currently adopted approach in many structural codes which emphasizes stress range as the dominant parameter influencing fatigue life are non-conservative for tension-tension stress patterns (i.e., stress ratios of 0 < R < 1). Analyses show that the modified Johnson formula accurately reflects the combined effect of stress range, mean stress level, and material properties, and offers a relatively easy design procedure. Details of a retrofit field application on members of a riveted wrought iron railway bridge are given. A wireless sensor network (WSN) system is used for long-term monitoring of the on-site CFRP stress levels and temperature of the retrofitted details. WSN measurements indicate that increases in ambient temperature result in increased CFRP pre-stress levels. © 2014 Elsevier Ltd. All rights reserved.

Design criterion for fatigue strengthening of riveted beams in a 120-year-old railway metallic bridge using pre-stressed CFRP plates

Constant life diagrams : a historical review

Although it has been known for thousands of years that materials differ in hardness, quantitative methods of measuring hardness by performing careful indentation experiments only began to be developed during the nineteenth century. At the beginning of the twentieth century, hardness testing machines began to be commercially available. The methods that have persisted to this day may be divided into two broad categories: (1) those where a hardened steel ball or cone is pressed into a surface under a known load; and (2) those where sharp diamonds of various shapes are pressed into a surface also under a known load. An issue that has long been of interest is the relation of hardness to simpler measures of material strength, particularly the tensile strength. The review will cover the development of the various static and dynamic techniques and their subsequent application to a wide range of materials.

Historical origins of indentation hardness testing

THIS book bears the same title, has practically the same number of pages, and is published by the same firms, as a book by Prof. Bcvey, of McGill University, Montreal, which appeared in 1901, and was reviewed in these columns in February last year. Though, however, the present book, like its predecessor, is intended primarily for students in colleges and technical schools, and secondly for engineers, and one or more problems, intended to be solved by the reader, are appended at the end of each article, relating to the special subject treated of in the article, it deals with the various hydraulic principles and problems successively investigated in a more simple manner than the former book, which is calculated to commend It to the favourable notice of practical engineers, too engrossed in their work to be able to spare the time for fully grasping abstruse mathematical considerations.Treatise on Hydraulics.By Mansfield Merriman, Professor of Civil Engineering in Lehigh University. Eighth Edition, Rewritten and Enlarged. Pp. viii + 585. (New York: John Wiley and Sons; London: Chapman and Hall, Ltd., 1903.) Price 21s. net.

Mansfield Merriman

Papers

Treatise on hydraulics

The Materials of Construction

Frontinus and the Water Supply of the City of Rome

Past and present tendencies in engineering education

American civil engineers' pocket book,