Civil and Environmental Engineering Commons^™

Experimental Study On A New Type Of Transverse Connection For Nebraska County Bridge System, Alexander Bleyhl

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Many county-owned bridges in Nebraska need replacement due to their structural deficiency. Most of the bridges needing replacement are in the 40 to 60 ft range. This span range lacks a standard design that fits Nebraska county practices in terms of speed and simplicity of construction. The current systems being used are (a) Precast 1 by 2 ft planks which can span up to 30 ft, (b) Cast-in-place slab bridges which can span up to 50 ft but require extensive field formwork, concrete placing, and curing, and are best when constructed in three-span units, and (c) Inverted tees which can …

Investigation Of A Tractor-Tank Trailer Roadside Containment Barrier, Dean L. Whitfield

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

The objective of this research project was to develop a new, cost-effective, Manual for Assessing Safety Hardware (MASH) Test Level 6 (TL-6) barrier. A literature review on prior Test Level 5 and Test Level 6 barriers was conducted, and the cost of current TL-5 and TL-6 barriers was established. Existing and modified design procedures for roadside barrier were reviewed as well as current TL-6 design forces. A preliminary TL-6 truck model was developed in LS-DYNA. The minimum barrier height to contain a tractor-tank vehicle was determined to be 62 in. for a rigid, vertical-faced barrier through LS-DYNA computer simulation. New …

Effects Of Moving Bottlenecks On Traffic Operations On Four-Lane Level Freeway Segments, Jianan Zhou

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

The Highway Capacity Manual (HCM) was developed to provide capacity and level of service analyses for roadway facilities. Trucks may adversely affect the quality of traffic flow on a roadway. In HCM, the passenger car equivalent (PCE) of a truck, which represents the number of passenger cars that have an equivalent effect on traffic flow, is used to account for the impacts of trucks. However, in the past ten years rural freeways in the western rural U.S. have experienced conditions that lie outside the standard HCM conditions. Also, the current HCM truck PCEs may not be appropriate for the western …

Effect Of Swine Manure Pit Additives And Facility Disinfectants On The Fate Of Antibiotics And Manure Composition During Simulated Swine Manure Slurry Storage, Jon Duerschner

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

This thesis investigates the effect of time and of swine manure slurry treatment on the physical properties, nutrient content, and the concentrations of antibiotics chlortetracycline, lincomycin, and tiamulin in simulated storage of swine manure. In one experiment the slurry was treated with six additive products. In a second experiment a set of four disinfectant products were used. Control consisted of unamended slurry. Manure was stored in 60 liter stainless steel bioreactors to simulate deep pit storage and was sampled 7 times over a 40 day incubation.

From an ANOVA of the results, it was concluded that evaporation may be contributing …

Shear Strength Characteristics And Failure Mechanism Of Slopes In Overconsolidated Soils Of Nebraska, Hossein Bahmyari

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Geotechnical engineers deal with some challenging problems when encountering long-term slope stability in overconsolidated clays and clayey shales. One of these problems is determining a suitable method to estimate the reliable shear strength of overconsolidated clayey soils for long-term slope stability. According to Eversol (2013), one half of the counties in Nebraska have experienced slope failure in overconsolidated soils, especially in north and east Nebraska. In this research, shear strength characteristics of overconsolidated clayey soils of Nebraska is investigated in regard to long-term stability of slopes, and the failure mechanism in such soils is examined.

Undisturbed samples from boring logs …