Civil Engineer Expert

Oldcastle Materials Inc. considers rebuilding larger wheel loaders when they reach the end of their first life.

Extreme maintenance practices can help you extend equipment life spans — but be aware you are managing risk.

In today’s economy, we’re all trying to stretch things as far possible. Whether it’s stretching time between oil changes in your car or holding off on buying that new pair of work boots you know you need, we’re pushing the limits.

The construction industry is no exception. Its economic downturn has prompted many contractors to run equipment for more hours than normal. Capital for new machines is scarce so equipment is being kept longer and worked harder. Knowing that the equipment has to last, managers carefully watch oil samples for wear particle signals that mean component failure is approaching. And some equipment managers are even replacing small components, such as water pumps and alternators, before they fail.

“We’re probably adding 20 percent more to the life of our equipment than we would in normal economic times,” says Rex Davis, a vice president at RMCI Inc., Albuquerque, N.M. “Sooner or later we have to make some decisions (about trading in equipment). It doesn’t do any good to have new equipment if you don’t have work for it. Hopefully the economic tide will turn soon.”

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Gravel roads: Maintenance and Design Manual

There are over 1.6 million miles of unpaved roads (53% of all roads) in the United States.In some nations, the road network is predominantly unpaved and generally consists of gravel roads. This manual was developed with a major emphasis on the maintenance of gravel roads, including some basic design elements.

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Setting Up the Experiment

Researchers conducted approximately 700 tests at the TFHRC Hydraulics Laboratory, with the physical modeling for the culvert study occurring in two phases. The first set of experiments optimized the bevel edge of the wingwalls and top edge using two-dimensional particle image velocimetry (PIV) in a 2.75-meter (9-foot)-long and 0.46-meter (1.5-foot)-wide flume, an artificial channel for measuring water flow. This technology uses a laser and particles of silver-coated and hollow glass spheres to make the flow visible. Cameras are used to measure instantaneous velocity vectors in a flow field.

The researchers tested several bevel edge conditions, including straight top bevels (square edge), beveled edge (45 degree bevel), and radius top bevels. The criterion they used to determine the best bevel performance was the contracted distance outside the viscous boundary layer, or the effective flow depth at the vena contracta (where the flow depth is lowest inside the barrel section). The researchers used integrated streamlines, which indicate the speed and direction of flow, to visualize the contracted area (the area where water flow narrows from a wider flow) inside the culvert.
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FHWA and the South Dakota Department of Transportation recently partnered to study the effects of inlet geometry on water flow in cast-in-place and precast structures.

The South Dakota Department of Transportation (SDDOT) installed this triple-barrel box culvert, made from precast concrete, under a median crossover on Interstate 29 in Minnehaha County, just north of Sioux Falls, SD. FHWA and SDDOT recently conducted a study of various inlet section configurations for box culverts with the goal of updating industry design software and coefficients. Photo: Corey Haeder, Cretex Concrete Products West, Inc.

Understanding hydraulics and hydrology is a necessity for designing drainage structures such as culverts that control the flow of water near highway infrastructure. The size and shape of a culvert not only determine the structure’s effectiveness, especially during extreme weather events such as major floods and washouts, but they also significantly affect the overall construction costs of a project.

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A guide to asphalt materials used for paving road and airfield surfaces, this book discusses each material type, examining its constituent materials, construction processes and properties, and offering an assessment of the material types appropriate to particular sites and applications.

Asphalt Surfacings

An important note for the reader Land Transport New Zealand is a Crown entity established under the Land Transport New Zealand Amendment Act 2004. The objective of Land Transport New Zealand is toallocate resources in a way that contributes to an integrated, safe, responsive and sustainable land transport system. Each year, Land Transport New Zealand invests a portion of its funds on research that contributes to these objectives. The research detailed in this report was commissioned by Land Transport New Zealand.While this report is believed to be correct at the time of its preparation, Land Transport New Zealand, and its employees and agents involved in its preparation and publication,cannot accept any liability for its contents or for any consequences arising from its use. People using the contents of the document, whether directly or indirectly, should apply and rely on their own skill and judgement. They should not rely on its contents in isolation from other sources of advice and information. If necessary, they should seek appropriate legal or other expert advice in relation to their own circumstances, and to the use of this report. The material contained in this report is the output of research and should not be construed in any way as policy adopted by Land Transport New Zealand but may be used in the formulation of future policy

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