Engineering Commons^™

Stress Change Calculations In Accidentally Damaged Prestressed Bridge Girders, Habib Tabatabai, Azam Nabizadeh

Civil and Environmental Engineering Faculty Articles

Accidental damage to prestressed concrete bridge girders may occur due to impact by over-height vehicles on the bottom of the girder, or the top flange of the girder may be damaged during deck removal and replacement operations. Since stress checks at service loads are an important component of design for prestressed concrete beams, serviceability-based stress checks should be considered when assessing the structural condition of damaged girders. In this paper, step-by-step theoretical calculations are used to develop equations for estimating service load stress changes due to physical damage (partial loss of concrete section and strands) based on a differential approach. …

Reliability Of Sfrp-Strengthened Rc Bridge Columns Subjected To Blast Loads, Ahmad Alsendi, Christopher D. Eamon

Civil and Environmental Engineering Faculty Research Publications

The reliability of reinforced concrete bridge columns strengthened with externally bonded, steel-fiber reinforced polymer fabric subjected to blast loads was investigated. Columns were modeled with a nonlinear finite element approach that considers material damage, fracture, and separation. Different concrete strengths, longitudinal reinforcement ratios, and gravity and blast load levels were considered, while uncertainties in material strength and stiffness parameters, as well as load characteristics, were incorporated in the probabilistic analysis. It was found that the use of SFRP can allow significant increases in blast load while maintaining the same level of column reliability.

Low-Cost Modal Identification Sensors For Bridge Field Testing, Daniel Linzell, Saaed Eftekhar Azam, Samira Ardani, Ahmed E Rageh

Nebraska Department of Transportation: Research Reports

This report provides a framework for experimental load rating of bridges via inclusion of low-cost dynamic sensors and dynamic tests. Currently 25% of the bridges in Nebraska are posted for live load. According to the National Bridge Inventory (NBI) in 2012, 93% of all postings in the US were based analytical load ratings, 7% were posted using field evaluation and engineering judgement, and 1% were posted using experimental load rating methods.

Instrumentation costs and traffic interruptions can be problematic when load testing is necessary to accurately assess in-situ bridge live load capacity. Recent advances in (i) sensing technology and (ii) …

Quantitative Resistance Assessment Of Sfrp-Strengthened Rc Bridge Columns Subjected To Blast Loads, Ahmad Alsendi, Christopher D. Eamon

Civil and Environmental Engineering Faculty Research Publications

The blast resistance of a typical reinforced concrete bridge pier column design was modeled with a nonlinear finite element approach that considers material damage, fracture, and separation. While varying concrete strength, amount of longitudinal reinforcing steel, and gravity load, the effect of applying an externally bonded steel fiber reinforced polymer (SFRP) wrapping was assessed. The presented approach uniquely quantifies column blast resistance in terms of charge weight. It was found that blast capacity was roughly linearly related to concrete strength and steel reinforcement ratio, the former of which is most influential. It was further found that a single layer of …

Use Of Uhpc Stay-In-Place Shells In Bridge Column Construction For Accelerated Bridge Construction, Nerma Caluk

FIU Electronic Theses and Dissertations

This research utilizes Ultra-High Performance Concrete (UHPC), durable material that can be used to construct unique structural elements, to construct prefabricated shells that act as stay-in-place forms for circular bridge columns. These innovative structural elements are intended to (1) eliminate conventional formworks, (2) reduce the on-site construction time, (3) reduce life cycle costs by providing maintenance-free columns, and (4) improve the structural performance of bridge columns. The UHPC shell is placed around the column reinforcement that has been assembled using conventional methods, after which a UHPC step portion is cast at the column-to-footing interface to connect the UHPC shell with …

A Bridge-Rehabilitation Strategy Based On The Analysis Of A Bridge-Inspection Data Set, Liam Dromey, Kieran Ruane, John J. Murphy, Brian O'Rourke, Seán Lacey

Publications

Bridge-management systems (BMSs) allow bridge owners to assess the condition of their bridge stock. However, not all BMS packages have the capability to formulate network-level bridge-rehabilitation investment strategies. This research has developed a decision-support system for bridge owners in the selection of the best strategy for bridge rehabilitation at the network level. The basis of the research is an available data set of 1367 bridge-inspection records for County Cork, Ireland, that has been prepared to the Eirspan BMS inspection standard. The developed system consists of a project-prioritisation procedure that builds on previous research, a methodology for the calculation of a …

Civil Engineering Design Of Cornhusker Council's Outdoor Education Center, Kelly Weiler

Honors Theses

A team of geotechnical, structural, hydraulic, environmental, and transportation experts collaborated to provide engineering solutions to the Cornhusker Council in an effort to solve the current problems facing their Outdoor Education Center. This results of this project provided the structural design of three bridges on the property, transportation plans for two parking lots and roadway design, geotechnical recommendations for soil testing and erosion prevention, and an environmental and hydraulic analysis of the property. A major challenge in the design of this project is the consideration of the dangers and regulations that accompany the floodway and floodplain regions on site. Various …

Survival Analysis Of Bridge Superstructures In Wisconsin, Azam Nabizadeh, Habib Tabatabai, Mohammad A. Tabatabai

Civil and Environmental Engineering Faculty Articles

Although survival analyses have long been used in biomedical research, their application to engineering in general, and bridge engineering in particular, is a more recent phenomenon. In this research, survival (reliability) of bridge superstructures in Wisconsin was investigated using the Hypertabastic accelerated failure time model. The 2012 National Bridge Inventory (NBI) data for the State ofWisconsin were used for the analyses. A recorded NBI superstructure condition rating of 5 was chosen as the end of service life. The type of bridge superstructure, bridge age, maximum span length (MSL) and average daily traffic (ADT) were considered as possible risk factors in …

Optimized Health Monitoring Plans For A Steel, Double-Track Railway Bridge, Ahmed Rageh

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

Railway bridges are an essential component of any modern society and play a significant transportation role. During the 19^th and early 20^th centuries steel truss and plate girder bridges were commonly used railway designs, with most of the trusses constructed using pin and eyebar systems and most other load carrying members being riveted, built-up sections.

Many of these bridges are still in use and are subjected to increased railway traffic intensity, loads and speeds. The current practice for evaluating the integrity of bridges in the United States, irrespective of use, is primarily via visual inspection, with those inspections …

Solar Radiation Parameters For Assessing Temperature Distributions On Bridge Cross-Sections, Junqing Xue, Jianhui Lin, Bruno Briseghella, Habib Tabatabai, Baochun Chen

Civil and Environmental Engineering Faculty Articles

Solar radiation is one of the most important factors influencing the temperature distribution on bridge girder cross-sections. The bridge temperature distribution can be estimated using estimation models that incorporate solar radiation data; however, such data could be cost- or time-prohibitive to obtain. A review of literature was carried out on estimation models for solar radiation parameters, including the global solar radiation, beam solar radiation and diffuse solar radiation. Solar radiation data from eight cities in Fujian Province in southeastern China were obtained on site. Solar radiation models applicable to Fujian, China were proposed and verified using the measured data. The …

Time-Dependent Prestress Loss Behavior Of Girders In Missouri Bridge A7957 Compared With A U.S. Data Set Of High-Performance Concrete Bridge Girders, Hayder H. Alghazali, John J. Myers

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In this study, six precast, prestressed concrete girders were constructed and instrumented to measure prestress losses of bridge A7957 in Missouri. The concrete mixture for the bridge was designed with varying mechanical and rheological properties. High-strength concrete, high-strength self-consolidating concrete, and normal-strength self-consolidating concrete were used to construct the bridge girders. Vibrating wire strain gauges with integrated thermistors were embedded through the girders' cross sections to measure strains and temperatures. The measured short- and long-term prestress losses were compared with those obtained using different empirical models, specified in the AASHTO LRFD Bridge Design Specifications and in the PCI Design Handbook: …

Evaluation Of The Use Of Painted And Unpainted Weathering Steel On Bridges, Theodore Hopwood Ii, Sudhir Palle, Bobby W. Meade, Rick Younce

Kentucky Transportation Center Research Report

KTC researchers studied the use of unpainted weathering steel on bridges, using findings of inspections performed on Kentucky Transportation Cabinet (KYTC) bridges constructed with both painted and unpainted weathering steel as well as laboratory testing. Laboratory tests were conducted on test panels of conventional and weathering grades of steel to determine the performance of barrier and zinc-based coatings over abrasive-blasted substrates of those steel types in both the new and corroded conditions. The report provides the following recommendations for the use of painted and unpainted weathering steel on Kentucky bridges based upon both the field and laboratory findings:

• KYTC should …

Shear Behavior Of High-Strength Self-Consolidating Concrete In Nebraska University Bridge Girders, Alex Griffin, John J. Myers

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Current reinforced and prestressed concrete design equations were developed for conventional concrete elements. Self-consolidating concrete (SCC) typically contains a lower coarse aggregate content and size than conventional concrete, which potentially hinders the aggregate interlock contribution to a concrete's shear strength. Thus, shear design equations must be verified with SCC mixtures. Two full-scale precast, prestressed concrete Nebraska University girders were tested to assess the shear behavior of high-strength SCC. Both girders were designed to permit two tests on each girder, both with and without shear reinforcement. Ultimate shear loads and crack patterns were documented and compared with code estimates, finite element …

Identifying And Modelling Permit Trucks For Bridge Loading, Bernard Enright, Eugene J. Obrien, Cathal Leahy

Articles

Accurate estimates of characteristic traffic load effects are essential in order to optimize bridge safety assessment. Permit trucks dominate the extreme upper tail of the truck loading distribution and as a result need careful examination. This paper proposes rules for filtering these trucks from Weigh-In-Motion data for both the US and Europe. The importance of these trucks in critical bridge loading events is then examined for both regions. A Monte Carlo traffic simulation model is developed which focuses on the accurate simulation of permit trucks.

A Review Of The Hl-93 Bridge Traffic Load Model Using An Extensive Wim Database, Cathal Leahy, Eugene J. Obrien, Bernard Enright, Donya Hajializadeh

Articles

HL-93, the current bridge traffic load model used in the United States, is examined here. Weigh-in-motion from 17 sites in 16 states, and containing 74 million truck records, is used to assess the level of consistency in the characteristic load effects implied by the HL-93 model. The load effects of bending moment and shear force are considered on single-lane and two-lane same-direction slab and girder bridges with a range of spans. It is found that the ratio of WIM-implied to HL-93 load effect varies considerably from one load effect to another. An alternative model is proposed which achieves improvements in …

Probabilistic Analysis Of Indeterminate Highway Bridges Considering Material Nonlinearity, Liam Mccarthy

Masters

With ever-reducing maintenance budgets and ever-deteriorating bridge infrastructure, th assessment of existing bridges is vital. Reliability analysis techniques are becomin increasingly popular in the structural safety assessment of existing bridge structures Commonly, a component based approach is used in reliability analysis techniques Traditional reliability procedures often employ a conservative definition of failure, in that th component is deemed to have failed when the strength capacity has been exceeded at a singl cross section. As a result, the component's degree of redundancy and ductility is ignored giving an often conservative estimate of the load carrying capacity of the bridge component Therefore, …

Developing A Family Of Curves For The Hec-18 Scour Equation, Timothy Calappi, Carol J. Miller, Donald Carpenter, Travis Dahl

Civil and Environmental Engineering Faculty Research Publications

Accurate pier scour predictions are essential to the safe and efficient design of bridge crossings. Current practice uses empirical formulas largely derived from laboratory experiments to predict local scour depth around single-bridge piers. The resulting formulas are hindered by insufficient consideration of scaling effects and hydrodynamic forces. When applied to full-scale designs, these formula deficiencies lead to excessive over prediction of scour depths and increased construction costs. In an effort to improve the predictive capabilities of the HEC-18 scour model, this work uses field-scale data and nonlinear regression to develop a family of equations optimized for various non-cohesive soil conditions. …

Enhancement Factors For The Vertical Response Of Footbridges Subjected To Stochastic Crowd Loading, Colin Caprani, Joe Keogh, Paul Archbold, Paul Fanning

Articles

The vertical acceleration response of a hypothetical footbridge is predicted for a sample of single pedestrians and a crowd of pedestrians using a probabilistic approach. This approach uses statistical distributions to account for the fact that pedestrian parameters are not identical for all pedestrians. Enhancement factors are proposed for predicting the response due to a crowd based on the predicted accelerations of a single pedestrian. The significant contribution of this work is the generation of response curves identifying enhancement factors for a range of crowd densities and synchronization levels.

Wim Based Load Models For Bridge Serviceability Limit States, Przemyslaw Rakoczy

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

The safety of aging bridge inventory is one of the main concerns of the state and federal agencies. Therefore, there is a need to quantify the safety margin of existing infrastructure and new design bridges. The Serviceability Limit States, i.e. fatigue, requires additional statistical parameters and not only the maximum values but also load spectra, i.e. frequency of occurrence of loads. The maximum values are needed for shorter time periods, such as day, week, month or year. Load spectra as well as material resistance are random variables. To quantify the safety margin of existing and future bridges load and resistance …

Estimating The Characteristic Vertical Response Of A Flexible Footbridge Due To Crowd Loading, Joe Keogh, Colin C. Caprani, Paul Archbold, Paul Fanning

Conference papers

The issue of excessive vibration of footbridges due to pedestrian loading is now well documented. Bridge vibrations produced from a crowd of pedestrians have been estimated by modifying the effect caused by a single pedestrian by an enhancement factor to take crowd synchronization into account. In this paper this approach is extended to account for the fact that all pedestrians will not have the same pacing frequencies, and the effects of distributions of pacing frequency and other parameters on the enhancement factor are investigated. It is shown that this more faithful representation of pedestrian crowd walking behaviour gives reduced vibration …

Reliability-Based Optimization Of Fiber-Reinforced Polymer Composite Bridge Deck Panels, Michel D. Thompson, Christopher D. Eamon, Masoud Rais-Rohani

Civil and Environmental Engineering Faculty Research Publications

A reliability-based optimization (RBO) procedure is developed and applied to minimize the weight of eight fiber-reinforced polymer composite bridge deck panel configurations. The method utilizes interlinked finite element, optimization, and reliability analysis procedures to solve the weight minimization problem with a deterministic strength constraint and two probabilistic deflection constraints. Panels are composed of an upper face plate, lower face plate, and a grid of interior stiffeners. Different panel depths and stiffener layouts are considered. Sensitivity analyses are conducted to identify significant design and random variables. Optimization design variables are panel component ply thicknesses while random variables include load and material …

Structural Engineering, Sergio F. Brena

Science and Engineering Saturday Seminars

•Introduction to Structural Engineering • •Forces in Structures • •Structural Systems • •Civil Engineering Materials • •Some Definitions of Important Structural Properties

Effect Of Edge-Stiffening And Diaphragms On The Reliability Of Bridge Girders, Christopher D. Eamon, Andrzej S. Nowak

Civil and Environmental Engineering Faculty Research Publications

Secondary elements such as barriers, sidewalks, and diaphragms may affect the distribution of live load to bridge girders. The objective of this study is to evaluate their effect on girder reliability if these elements are designed to be sufficiently attached to the bridge so as not to detach under traffic live loads. Simple span, two lane structures are considered, with composite steel girders supporting a reinforced concrete deck. Several representative structures are selected, with various configurations of barriers, sidewalks and diaphragms. Bridge analysis is performed using a finite element procedure. Load and resistance parameters are treated as random variables. Random …

Earthquake Hazard Assessment Along Designated Emergency Vehicle Priority Access Routes, Neil Lennart Anderson, Hal Baker, Genda Chen, Tom Hertell, David J. Hoffman, Ronaldo Luna, Yulman Munaf, Shamsher Prakash, Paul Michael Santi, Richard Wesley Stephenson

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Because of the compelling need to reopen vehicular access routes to Sikeston, Cape Girardeau and St. Louis following a devastating earthquake, Missouri Department of Transportation initiated a study of those portions of US 60 and MO 100 that have been officially designated as emergency vehicle priority access routes. The primary objectives of this study were twofold. Objective 1 was to establish a current subsurface and earthquake design geographic information systems (GIS) database for areas in proximity to designated portions of US 60 and MO 100 (includes counties of Butler, Stoddard, New Madrid, Franklin and St. Louis). Objective 2 was to …