Engineering Commons^™

Sympathetic Vibration Due To Co-Ordinated Crowd Jumping, Christopher Y. Tuan

Christopher Y. Tuan

In assembly structures or places where crowds may gather such as dance halls, theaters, gymnasia and stadia, the loading is almost entirely caused by human activities. Structural resonance or near resonance and the resulting vibrations causing discomfort of spectators have often been observed during a rock concert or a sporting event. Recent research efforts have focused on developing load models to quantify the dynamic loading effects induced by individuals and groups up to 40 people. The lack of coherence of motion from a large crowd, the so-called ‘‘group effect’’, has been quantified based on simulations. The simulation results and the …

Progressive Failure Simulation Of Security Cable Barriers, Christopher Tuan, Ratul Sarmah, Alexander Tuan, Ching-Sheng Kao, Q. Li

Christopher Y. Tuan

Perimeter security cable barriers are widely used by various agencies all over the world to defeat threat vehicle penetration. New barrier designs require crash test validation prior to implementation. Full-scale vehicular crash tests are costly, whereas designs via finite element simulations are time consuming and require specialized skills. Based on full-scale crash tests, an innovative and simple algorithm has been developed to model the progressive failure of security cable barriers. A multi-body approach based on the first principles of physics was developed to substantially reduce computer runtime. The solution algorithm uses a large number of small time steps. Nonlinear vehicle …

Conductive Concrete: A Shielding Constructurion Material, A. P. Krause, L. Nguyen, Christopher Y. Tuan, J. D. Blasey

Christopher Y. Tuan

Shielding against electromagnetic phenomenon is an increasingly important consideration on a global scale. Solar storms, privacy from electronic surveillance, and EMP weapons are just a few of the concerns that must be addressed. Current methods of protection are subject to high cost and often limited in scalability. Conductive concrete is a promising solution to both of these limitations. By adding several simple materials to traditional concrete, a new type of constructible electromagnetic shield can be produced. The following will discuss the design and testing of conductive concrete for EM shielding as well as the results of those tests.

Numerical Analysis Of Concrete-Filled Circular Steel Tubes, Yaohua Deng, Terri Norton, Christopher Tuan

Christopher Y. Tuan

Concrete-filled steel tubes have been widely used in building and bridge construction. In this paper, the flexural behaviour of concrete-filled steel tubes is investigated using finite-element analysis and theoretical sectional analysis. The numerical results from both analytical methods are validated against published experimental test results. It is shown that both methods are capable of predicting the elastic and the ultimate moment capacities of concrete-filled steel tubes. Due to its computational efficiency, theoretical sectional analysis is more suitable for the design of concrete-filled steel tubes than finite-element analysis.

Sources Of End Zone Cracking Of Pretensioned Concrete Girders, Christie J. Hasenkamp, Sameh S. Badie, Christopher Y. Tuan, Maher K. Tadros

Christopher Y. Tuan

Recent developments of high performance concrete, increasing amounts of prestressing, and increasing use of deep girders have resulted in increasing popularity of precast pretensioned concrete girders in bridge construction. These developments have increasingly contributed to end zone cracking. This paper summarizes the interim results of an ongoing research sponsored by the National Cooperative Highway Research Program (NCHRP) Project 18-14. The objectives of the research are: (1) to establish procedures for the acceptance, repair, or rejection of precast/prestressed concrete girders with longitudinal web cracking, and (2) to prepare a user's manual for the application of these procedures. The results from a …

Finite Element Modelling Of Railway Turnout Systems, Sakdirat Kaewunruen

Sakdirat Kaewunruen

Finite Element Modelling of Railway Turnout System, RMS Annual Bridge Conference, Bridge and Structural Engineering, Bridge Journey through Partnerships, 04 - 05 December 2013, Sydney

Big Data, Predictive Analytics, And Data Visualization In The Construction Engineering, Joseph Shrestha

Joseph Shrestha

Experimental Evaluation Of A Joint Cognitive System For 4d Trajectory Management, Rolf Klomp, Clark Borst, Max Mulder, Gesa Praetorius, Martijn Moij

Gesa Praetorius

Effective joint human-automation coordination is essential in order to support the central role of the human operator in foreseen future trajectory-based air traffic operations. The SESAR WP-E project C-SHARE aims to achieve this by taking a Cognitive Systems Engineering approach, based upon accomplishing joint human and automation cognition through a shared representation of 4D-trajectory management. In foregoing research, a work domain model and a joint human-machine interface has been developed to support the human operator in the task of en-route 4D trajectory re-planning. This paper presents the findings of two experiments that aimed to determine the effect of both the …

Zakład Termicznego Przekształcania Odpadów Komunalnych W Krakowie – Założenia Projektowe I Stan Realizacji Budowy, Mateusz Rzeszutek, Robert Oleniacz

Robert Oleniacz

The aim of this paper is to discuss the design assumptions and to determine the current status of the construction of the Municipal Solid Waste Thermal Treatment Plant (ZTPOK) in Krakow with a capacity of 220 thousand tons per year. This plant, planned to be built by the end of 2015 years, will be an important element of municipal waste management system in the area of the Municipality of Krakow. ZTPOK in Krakow will consist of the following installations: two lines of municipal solid waste incinerators based on moving grate technology, an installation of chemical solidification and stabilization of fly …

Investigation Of Crashes And Identifying The Best Practices For Setting Up Speed Zones In Towns Along Rural Highways In Nevada, Krishna Prasad Shrestha

Joseph Shrestha

In 2010, 51,664 crashes occurred in Nevada. Only about 9% of those crashes occurred in rural areas of the state. However, if only fatal crashes are considered, 41% of those fatal crashes occurred in rural areas. Generally, speed zones are provided in towns along rural highways to reduce speed-related crashes. However, a guideline is necessary for a consistent procedure to setup speed zones throughout the state. The main objectives of this study are to determine factors associated with crashes and to identify the best practices for setting up speed zones in towns along rural highways.

Eleven towns along rural highways …

Health Hazards Of China’S Lead-Acid Battery Industry: A Review Of Its Market Drivers, Production Processes, And Health Impacts, Tsering Jan Van Der Kuijp, Lei Huang, Christopher R. Cherry

Lei Huang

Despite China’s leaded gasoline phase out in 2000, the continued high rates of lead poisoning found in children’s blood lead levels reflect the need for identifying and controlling other sources of lead pollution. From 2001 to 2007, 24% of children in China studied (N = 94,778) were lead poisoned with levels exceeding 100 μg/L. These levels stand well above the global average of 16%. These trends reveal that China still faces significant public health challenges, with millions of children currently at risk of lead poisoning. The unprecedented growth of China’s lead-acid battery industry from the electric bike, automotive, and photovoltaic …

Improving Efficiency Of Indot Traffic Data Collection Using Gps Devices, Shuo Li, Karen Zhu, Boudewijn H. W. Van Gelder, John Nagle, Carl Tuttle

John Copeland Nagle

INDOT has utilized many new technologies to reduce travel delay, mitigate traffic congestion, and enhance public and employees’ safety. Many projects are underway, including re-timing of most existing traffic signals and pavement maintenance and rehabilitation. To evaluate signal system performance, prioritize alternatives of improvement, conduct before and after studies and investigate work zone safety, it requires a large amount of traffic data such as travel time, speed and delay. Issues, such as safety, efficiency and cost, may arise associated with the current methods. For the current manual or automatic data collection, it usually requires two operators, a driver and a …

Determination Of Practical Esals Per Truck Values On Indiana Roads, Sedat Gulen, John Nagle, John Weaver, Victor Lee Gallivan

John Copeland Nagle

The Indiana Department of Transportation (INDOT) has been using ESAL (Equivalent Single Axle Load) values for pavement design. The current ESAL values were obtained in the late 1970. However, truck deregulation and higher allowable maximum loads have increased the 1970's values. Updated ESAL values are needed for better road designs. The 1998 and 1999 traffic data from the all Weight-in-Motion (WIM) stations were obtained and used to compute updated ESAL values for multiple unit trucks (Class 9/F-9) and single unit trucks (Class 5, 6 and 7). Statistical analyses indicated that average ESAL values for 1998 and 1999 are statistically the …

Communicating Intended Routes In Ecdis: Evaluating Technological Change, Thomas Porathe, Margareta Lützhöft, Gesa Praetorius

Gesa Praetorius

Misunderstanding each other's intentions is one of the most common causes of shipping accidents. By sending out a number of waypoints ahead and displaying them on the Electronic Chart Display and Information System (ECDIS) a ship's intentions would be clearly visible for other ships. Displaying ships’ intentions would be a major change compared to navigation today. It could be very beneficial but it could also have unintended consequences. This paper reports on findings from an evaluation looking for unintended consequences of change using system simulation. During the simulation an unanticipated behavior was observed. Bridge crews started to click and drag …

Municipal Solid Wastes And Water Quality Issues In Nigeria, S Isiorho, D Omole

S Isiorho

No abstract provided.

Bridge Deck Deicing, Sherif A. Yehia, Christopher Y. Tuan

Christopher Y. Tuan

Concrete bridge decks are prone to ice accumulation. The use of road salts and chemicals for deicing is cost effective but causes damage to concrete and corrosion of reinforcing steel in concrete bridge decks. This problem is a major concern to transportation officials and public works due to rapid degradation of existing concrete pavements and bridge decks. The use of insulation materials for ice control and electric or thermal heating for deicing have been attempted and met limited success. Conductive concrete may be defined as a cementitious composite, which contains a certain amount of electronically conductive components to attain stable …

Ground Shock Resistance Of Mechanically Stabilized Earth Walls, Christopher Tuan

Christopher Y. Tuan

A simple analytical method has been developed that characterizes plane shock wave propagation through reinforced soil and the dynamic interaction between soil and retaining wall panels. The shock wave due to an explosion in the backfill was modeled as a velocity boundary condition at a standoff distance from the wall. The exact solution to this problem was obtained using the Laplace transform method. Full-scale explosive test data from 4.6-m high and 24-m wide reinforced soil walls were used to validate the analytical methodology. The accuracy of the analytical method has further been verified by finite element analysis. The method is …

Airfield Pavement Deicing With Conductive Concrete Overlay, Sherif Yehia, Christopher Tuan

Christopher Y. Tuan

Conductive concrete is a cementitious admixture containing a certain volumetric ratio of electrically conductive materials to attain high and stable electrical conductivity. Due to its electrical resistance, a thin overlay of conductive concrete can generate enough heat to prevent ice formation when energized by AC power. Under a research sponsored by Nebraska Department of Roads, Yehia and Tuan developed a mix specifically for concrete bridge deck deicing while meeting the ASTM and AASHTO strength specifications for overlay construction. An average thermal power of 591 W/m2 (55 W/ft2) with a heating rate of 0.56oC/min (1oF/min) was generated by a 1.2 m …

Implementation Of Conductive Concrete Overlay For Bridge Deck Deicing At Roca, Nebraska, Christopher Y. Tuan, Sherif A. Yehia

Christopher Y. Tuan

Conductive concrete is a relatively new material technology developed to achieve high electrical conductivity and high mechanical strength. In research sponsored by Nebraska Department of Roads, a conductive concrete mix specifically for bridge deck deicing was developed. In this application, a conductive concrete overlay is cast on top of a bridge deck for deicing and anti-icing.

This technology has been successfully implemented in a demonstration project at Roca, about 15 mi south of Lincoln, Nebraska. The Roca Spur Bridge has a 36-m (117-ft) long and 8.5- m (28-ft) wide conductive concrete inlay. Temperature sensors and a microprocessor-based controller system were …

Protective Construction With Reinforced Earth, Christopher Tuan

Christopher Y. Tuan

The objective of this research is to develop a simple analytical method that characterizes plane shock wave propagation through reinforced earth and the dynamic interaction with modular retaining wall panels. The shock wave was initiated as a velocity boundary condition. The exact solution was obtained by the Laplace transform method. A step-by-step design procedure based on the "limit state" concept is proposed. Because of the impulsive nature of ground shock. the maximum response of the wall panel and reinforced soil system depends mainly on the capacity and rate of energy absorption and dissipation of the system. Therefore, the connection between …

Steel Supported Masonry Walls, Lawrence Soltis, Christopher Tuan

Christopher Y. Tuan

Structural steel beams and columns are often used to support masonry walls subjected to transverse and axial loads. Warehouse and gymnasium type buildings often have large floor-to-ceiling heights, such that allowable masonry wall heights are exceeded. Steel framing, tied to the masonry wall by shear connections, tie bars or other devices, works compositely with the wall to resist flexural and compressive loads. Standard design practice considers the steel framing as a plane grid or as simply supported framing providing lateral support to the wall. The lateral load on the contributory wall area is assumed to be transmitted directly to the …

End Zone Reinforcement For Pretensioned Concrete Girders, Christopher Y. Tuan, Sherif A. Yehia, Nipon Jongpitaksseel, Maher K. Tadros

Christopher Y. Tuan

In this study, a literature review was conducted to establish the background of current specifications and to evaluate the applicability of various theories and methods for design of end zone reinforcement. Analytical methods reviewed in this paper include finite element analysis, strut-and-tie modeling, and the Gergely-Sozen equivalent beam method. Previous experimental work combined with work conducted as part of this study was used to correlate between various theoretical and experimental results. This paper illustrates that no single theoretical method adequately represents the complex behavior at the end of a pretensioned concrete member. A general semi-empirical design procedure is proposed here. …

Curved, Precast, Pretensioned Concrete I-Girder Bridges, Wilast Amorn, Christopher Y. Tuan, Maher K. Tadros

Christopher Y. Tuan

Modern highway construction frequently requires bridges with horizontally curved alignments. Such bridges can be created by superimposing a curved deck slab onto straight girders or by splicing segmental straight girders on the chords of a curved roadway. Of these two methods, a curved superstructure usually results in simpler construction and better appearance.

Bond Strength And Transfer Length Of Pre-Tensioned Bridge Girders Cast With Self-Consolidating Concrete, Amgad Girgis, Christopher Tuan

Christopher Y. Tuan

Self-consolidating concrete (SCC) is becoming increasingly popular in the precast/prestressed concrete industry in the United States. However, there have been concerns regarding the bond strength, transfer length, and development length of prestressing strands and mild steel reinforcement with SCC. Further, there are no design guidelines for using SCC. In this study, a literature survey on the bond strength of SCC was conducted. Moustafa pullout tests were performed to determine the bond strength of 0.6 in. (15.2 mm) pretensioning strands with sec. The transfer lengths of three pretensioned concrete bridge girders were measured using Demec points. Pullout tests were also performed …

Enhanced Adaptive Management: Integrating Decision Analysis, Scenario Analysis And Environmental Modeling For The Everglades, Matteo Convertino, Christy Foran, Jeffrey Keisler, Lynn Scarlett, Andrew Loschiavo, Greg Kiker, Igor Linkov

Jeffrey Keisler

Mixing Effects On The Chloramination Process, K. Jain, I. Wei

Irvine W. Wei

According to a recent study (AwwaRF Report 2760, 2004), more than 90 percent of water treatment plants utilizing chloramination for distribution system residuals indicate a certain level of dissatisfaction towards the process performance. One factor that may lead to such dissatisfaction is the inadequacy of mixing when ammonia is added to chlorinated water. If mixing is not uniform, the actual chlorine to ammonia nitrogen molar ratio will become variable at a micro-level, even though the overall ratio at the macro-level is close to the desired 1:1 ratio. Because of the non-uniform mixing, certain portions of the mixture might have a …

Description Of Geometric Nonlinearity For Beam-Column Analysis In Opensees, Mark D. Denavit, Jerome F. Hajjar

Jerome F. Hajjar

OpenSees is a powerful, object-oriented, open source software framework for simulating the seismic response of structural and geotechnical systems. It has broad capabilities, including geometric nonlinear analysis of frame structures. This report provides a brief description of the formulation for geometric nonlinearity for beam-column elements in OpenSees. The coding structure is described along with the general procedure for state determination. A mathematical description of the various coordinate transformations currently available within the OpenSees framework is presented for two-dimensional elements. Additionally, examples that illustrate the various coordinate transformations are shown.

Drop Weight Testing On Sandwich Panels With A Novel Thermoplastic Core Material, Christopher Y. Tuan

Christopher Y. Tuan

A series of drop weight tests were conducted to evaluate the dynamic flatwise compression strength and flexural strength of sandwich panels with a novel core structure. This sandwich core material, known as Norcore, consists of interconnected cells in a unique configuration of truncated pyramid with sloping cell walls. Core materials made of thermoplastic including virgin Lexan, polycarbonate, polycarbonate regrind, high-impact polystyrene, and acrylonitrile butadiene styrene were tested. The test results showed that these sandwich panels have good strength as well as energy absorption capacities.

Hybrid Frp-Concrete Railway Sleeper, Wahid Ferdous, Amar Khennane, Obada Kayali

Wahid Ferdous

The aim of this research was to investigate the feasibility of a hybrid FRP-concrete beam as a rail sleeper. It was hoped that the new design would overcome some of the sustainability issues associated with traditional sleepers. The hybrid system consisted of a Rectangular Hollow Section (RHS) pultruded profile filled with geo- polymer concrete. The specimens were tested in a four-point bending setup to determine the flexural properties such as the bending modulus (E) and modulus of rupture (MOR). It was found that the proposed composite beam satisfied the minimum flexural requirements for composite railway sleepers as stated in the …

Efectul Confinării Asupra Conlucrării Betonului Autocompactant Cu Armătura, Marian Sabau

Marian Sabau