Engineering Commons^™

Wim Based Live Load Model For Bridge Reliability, Marek Kozikowski

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

Development of a valid live load model is essential for assessment of serviceability and safety of highway bridges. The current HL-93 load model is based on the Ontario truck measurements performed in 1975. Since that time truck loads have changed significantly. Therefore, the goal of this study is to analyze 2005-2007 Weigh-In-Motion (WIM) data and develop a new statistical live load model.

The analyzed WIM data includes 47,000,000 records obtained from different states. A special program was developed to calculate the maximum live load effect. Comparison of the old and new truck data showed that on average Ontario trucks are …

Live Load Models For Long Span Bridges, Marta Lutomirska

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

In the doctoral dissertation a live load model for long span structures was derived. The live load model is valid for spans between 600 ft and 5000 ft and it is intended to reflect current traffic patterns, quantities of trucks and their weights. The live load models available were developed for short and medium span bridges. Those models were not appropriate for long span bridges due to different types of structure and critical traffic patterns. Live load on long spans depends on traffic mix. One heavily overloaded truck does not have significant influence. Moreover, the continuous increase in the number …

Precast Post-Tensioned Segmental Pole System: U.S. Patent No. Us 6,851,231 B2, Maher K. Tadros, E. Terence Foster, Sherif A. Yehia, Audra L. Hansen

Department of Civil and Environmental Engineering: Faculty Publications

A precast post-tensioned segmental pole system capable of supporting a load is provided. The pole system includes a plurality of pole segments that use connectors and strands to anchor them together. The strands extend within a cavity formed in the pole segments and are external to the wall structure of the pole segments. The strands may be coupled between both of the pole segments, or be anchored to a connector. The connector includes an upper piece that is coupled to one pole segment, and a lower piece that is coupled to the other pole segment. Upper and lower pieces interlock …

Risk Mitigation For Highway And Railway Bridges, Andrzej S. Nowak, Marek Kozikowski,, Marta Lutomirska,

Mid-America Transportation Center: Final Reports and Technical Briefs

Performance of the transportation network strongly depends on the performance of bridges. Bridges constitute a vital part of the transportation infrastructure system and they are vulnerable to extreme events such as natural disasters (i.e., hurricanes, earthquakes, floods, major storms), as well as hazards stemming from negligence and improper maintenance, collisions (vessels and vehicles), intentional acts of vandalism, and terrorist attacks. These structures must be protected but the current approach to risk is not rational. Therefore, the objective of this project is to develop efficient risk analysis procedures for assessment of the actual safety reserve in highway and railway bridges. The …

Effect Of Phase Countdown Timers On Queue Discharge Characteristics Under Heterogeneous Traffic Conditions, Anuj Sharma

Anuj Sharma Publications

Analysis of queue discharge characteristics at signalized intersections is a primary component of traffic signal analysis and design. On the basis of previous studies, mainly conducted in homogeneous traffic conditions, the discharge headway is assumed to be high at the start of green for the first few vehicles, mainly because of start-up lost times, and is also assumed to reach the minimum value by the fourth or fifth vehicle in the queue. The minimum headway is expected to continue until the end of the queue. However, this may not be the case under heterogeneous traffic conditions, such as those in …

Use Of Ground Penetrating Radar For Construction Quality Assurance Of Concrete Pavement, George Morcous Ph.D., Ece Erdogmus

Mid-America Transportation Center: Final Reports and Technical Briefs

Extracting concrete cores is the most common method for measuring the thickness of concrete pavement for construction quality control. Although this method provides a relatively accurate thickness measurement, it is destructive, labor intensive, and time consuming. Moreover, concrete cores are usually taken approximately every 750 ft, which may be inadequate for estimating the actual thickness profile of a pavement section; however extracting more cores would damage the pavement extensively and increase the labor cost and time excessively. Ground Penetrating Radar (GPR) is a well-established technique for subsurface exploration. Recently, GPR has been used for several transportation applications, such as measuring …

Application Of Ultra-High Performance Concrete To Bridge Girders, Maher K. Tadros Ph.D., P.E., George Morcous Ph.D.

Mid-America Transportation Center: Final Reports and Technical Briefs

Ultra-High Performance Concrete (UHPC) is a new class of concrete that has superior performance characteristics compared to conventional concrete. The enhanced strength and durability properties of UHPC are mainly due to optimized particle gradation that produces a very tightly packed mix, extremely low water to powder ratio, and use of steel fibers. The unique strength and durability properties of UHPC make it an attractive material for precast prestressed bridge girder construction. However, commercial UHPC mixes currently available in the US market cost about 10 times the cost of conventional concrete mixes, in addition to the need for special mixing and …

Dynamic Evaluation Of A Pinned Anchoring System For New York State’S Temporary Concrete Barriers, Christopher N. Howard, Cale J. Stolle, Karla A. Lechtenberg, Ronald K. Faller, John D. Reid, Dean L. Sicking

Mid-America Transportation Center: Final Reports and Technical Briefs

Temporary concrete barrier (TCB) systems are utilized in many circumstances, including for placement adjacent to vertical dropoffs. Free-standing TCB systems are known to have relatively large deflections when impacted, which may be undesirable when dealing with limited space behind the barrier (as seen on a bridge deck) or limited lane width in front of the barrier system. In order to allow TCB systems to be used in space-restricted locations, a variety of TCB stiffening options have been tested, including beam stiffening and pinning the barriers to the pavement. These pavement-pinning procedures have been considered time-consuming and may pose undue risk …

Computer Aided Modeling Of Soil Mix Designs To Predict Characteristics And Properties Of Stabilized Road Bases, Charles W. Berryman Ph.D., Cpc, Wayne Jensen Ph.D., Tim Hensley P.E.

Mid-America Transportation Center: Final Reports and Technical Briefs

Considerable data exists for soils that were tested and documented, both for native properties and properties with pozzolan stabilization. While the data exists there was no database for the Nebraska Department of Roads to retrieve this data for predicting soil properties. The conventional methods used to determine soil properties, such as maximum laboratory density and optimum moisture content, were tedious, labor intensive and time consuming. When soil stabilization is involved, more time and efforts are needed to determine maximum laboratory density, optimum moisture content and optimum pozzolan content. The objective of this project was to develop a computerized model to …

Inspector’S Manual For Mechanically Stabilized Earth Walls, Wayne Jensen Ph.D.

Mid-America Transportation Center: Final Reports and Technical Briefs

The scope of the project is to develop a condition rating system, creation of an inspector's manual to reference during inspection or address any training for inspectors at the district level. The research project will develop a MSE wall condition rating system and incorporate this system into the database being developed and create training and reference manuals

Steel Box System Monitoring Of N-2 Over I-80 Bridge, Atorod Azizinamini

Mid-America Transportation Center: Final Reports and Technical Briefs

The previously performed market analysis of bridge material in the range of short to medium span length indicates a declining trend for steel girders during the last two decades. The “simple for dead, continuous for live load” is a new method of bridge construction aiming at reducing the steel girder construction expenses and in essence enhancing the steel girders’ competitiveness in the short to medium span length bridges. This method of construction takes the advantage of the simple span construction as well as reduction of the forces in the bridge elements due to the continuous span behavior. The continuity of …

Investigation And Mitigation Of Driver Confusion At Modern Roundabouts, Aemal Khattak, Ram Bishu, Karen Schurr, Gregory Mcknight

Mid-America Transportation Center: Final Reports and Technical Briefs

This research deals with two related issues: investigation and mitigation of roundabout elements that lead to driver confusion, and development of a flexible criteria matrix by which the Nebraska Department of Roads (NDOR) can evaluate arterial intersections to identify good candidates for conversion to roundabouts. The use of modern roundabouts along arterial roadways is relatively new in Nebraska. The first urban arterial roundabout was opened to traffic in June of 2002 at the intersection of 33rd and Sheridan Blvd in the City of Lincoln. Citizens and some professionals were somewhat skeptical of the capability of this roundabout to improve traffic …

Effects Of Aggregate Angularity On Mix Design Characteristics And Pavement Performance, Yong-Rak Kim, Leonardo T. Souza

Mid-America Transportation Center: Final Reports and Technical Briefs

This research targeted two primary purposes: to estimate current aggregate angularity test methods and to evaluate current aggregate angularity requirements in the Nebraska asphalt mixture/pavement specification. To meet the first research objective, various aggregate angularity tests were estimated with the same sets of aggregates and were compared by investigating their characteristics on testing repeatability, cost, testing time, workability, and sensitivity of test results. For the second objective, the effect of aggregate angularity on mixture performance was investigated by conducting laboratory performance tests (the uniaxial static creep test and the indirect tensile fracture energy test) of five mixes designed with different …

Moisture Sensitivity Of Hot Mix Asphalt (Hma) Mixtures In Nebraska – Phase Ii, Yong-Rak Kim, Hoki Ban, Ingryd Pinto

Mid-America Transportation Center: Final Reports and Technical Briefs

As a consequential effort to the previous NDOR research project (P564) on moisture damage, this report presents outcomes from this project incorporated with the previous project. Performance changes and fundamental material characteristics associated with moisture damage due to various anti-stripping additives in asphalt mixtures are studied through various experimental approaches and a numerical simulation. Three additives (i.e., one reference additive, hydrated lime, and two alternative additives: fly ash and cement) are investigated by adding them into two types of mixes (SP2 for low-traffic-volume roadways and SP5 for high-traffic-volume roadways) where two different asphalt binders (PG 64-22 for the SP2 mix …

Dynamic Evaluation Of New York State’S Aluminum Pedestrian Signal Pole System, Scott K. Rosenbaugh, Ronald K. Faller, Karla A. Lechtenberg, Robert W. Bielenberg, Dean L. Sicking, John D. Reid

Mid-America Transportation Center: Final Reports and Technical Briefs

The New York State Department of Transportation (NYSDOT) mounts pedestrian “hand/man” signals to aluminum

poles and uses frangible transformer bases to allow the system to break away. However, engineers at NYSDOT believed that the material properties of the aluminum poles themselves would allow the pedestrian signal poles to break away without the use of transformer bases. Elimination of the frangible transformer base would result in significant savings.

An aluminum pedestrian signal pole system was erected at the Valmont testing facility and tested with the Valmont- MwRSF/UNL pendulum with crushable nose in accordance with NCHRP Report No. 350 test designation no. …