Habib Tabatabai
University of Wisconsin Milwaukee, Civil Engineering, Faculty Member
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Research Interests: Expert Systems, Materials Science, Rehabilitation, Polymers, Corrosion, and 13 moreprestressed Concrete, Corrosion Protection, Epoxy, Preventive Maintenance, Computer Programs, Silane, Literature Reviews, Beams, Deterioration, Reinforced Concrete Bridges, Fiber Reinforced Plastics, Repairing, and patching
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This study involved statistical evaluation of heavy truck loads that were recorded in 2007 using Weigh-In-Motion stations located throughout the State of Wisconsin. The heaviest 5% of all trucks in each class and axle groupings were... more
This study involved statistical evaluation of heavy truck loads that were recorded in 2007 using Weigh-In-Motion stations located throughout the State of Wisconsin. The heaviest 5% of all trucks in each class and axle groupings were selected for further analyses. Best fit unimodal and multimodal distributions for all axle loads and spacings in each truck class were determined. Multivariate Monte Carlo simulations using the marginal distributions and empirical copulas were performed to assess maximum moments and shears in simply supported bridges. Moments and shears due to the 250-kip Wisconsin Permit Vehicle were compared with simulation results. The multivariate Monte Carlo simulations of truck loadings can be used to assess the reliability of bridges and pavements as well as detailed fatigue analyses.
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ABSTRACT An accurate reliability model for bridge decks is important for effective long-term bridge deck management. The main objectives of this paper are to identify the most suitable reliability model for bridge decks in Wisconsin, and... more
ABSTRACT An accurate reliability model for bridge decks is important for effective long-term bridge deck management. The main objectives of this paper are to identify the most suitable reliability model for bridge decks in Wisconsin, and to utilize that model for detailed analyzes of bridge deck reliability and failure rates. The 2005 National Bridge Inventory (NBI) data for the State of Wisconsin were used. In this paper, the hypertabastic, Weibull, log logistic, and lognormal distributions are investigated. The end of service life is defined as the age of deck when rehabilitation or replacement is required (herein defined as a deck rating of between 4 and 5). The effects on NBI deck rating of average daily traffic (ADT), type of bridge superstructure (steel or concrete), and the deck surface area were considered. Based on the Akaike information criteria, the hypertabastic accelerated failure time model was selected as the most appropriate model for this study. Results show that deck area, type of superstructure and ADT are all important factors in reliability of bridge decks in Wisconsin.
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Permit truck models are used to consider local truck traffic in addition to national live load models in bridge design and rating practices. Weigh-in-motion (WIM) systems installed in the United States provide millions of truck records... more
Permit truck models are used to consider local truck traffic in addition to national live load models in bridge design and rating practices. Weigh-in-motion (WIM) systems installed in the United States provide millions of truck records that can be used for evaluating such truck models. In this study, the standard permit vehicle in Wisconsin was evaluated by using six million WIM truck records collected in 2007. The evaluation was on the basis of statistical analyses of the maximum moments and shear in simply supported, 2-span, and 3-span continuous girders in the selected heaviest 5% of trucks in each vehicle class/group. The comparisons showed that 5-axle, short, single-unit trucks may cause larger moment/shear in bridge girders than the standard permit vehicle, and a 5-axle truck model was proposed to supplement the standard permit vehicle for possible use in bridge design and rating in Wisconsin.
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The production of portland cement is among the major contributors to greenhouse gas emissions that adversely affect the environment. Identifying sustainable materials to partially replace portland cement in concrete, such as pozzolanic... more
The production of portland cement is among the major contributors to greenhouse gas emissions that adversely affect the environment. Identifying sustainable materials to partially replace portland cement in concrete, such as pozzolanic materials, is crucial in addressing this issue. These materials mainly consist of silica and alumina that react with the available calcium hydroxide to form strength-bearing phases such as calcium silicate hydrates. Understanding the degree of pozzolanic reactivity of materials using efficient reactivity test methods is an important consideration. The paper thoroughly reviews the available literature related to direct and indirect pozzolanic reactivity test methods that have been utilized over the years. Direct methods quantify the amount of consumed calcium hydroxide, whereas indirect methods assess changes in the physical properties of the specimen due to pozzolanic reactions. The aim of this paper is to identify affordable, time-saving, and effecti...
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Field and laboratory tests were conducted on 10 projects during base course layer construction to evaluate the quality of the constructed base layers. Base aggregates were also collected from these sites for laboratory testing. The field... more
Field and laboratory tests were conducted on 10 projects during base course layer construction to evaluate the quality of the constructed base layers. Base aggregates were also collected from these sites for laboratory testing. The field testing program consisted of the in place density by the sand cone method, the dynamic cone penetration (DCP) test, the light weight deflectometer (LWD) test, and the GeoGauge test. Laboratory tests conducted are the particle size analysis, the standard compaction test (AASHTO T 99), and the repeated load triaxial test (AASHTO T 307) for determining the resilient modulus. Analyses were conducted on field and laboratory test results. High spatial variability in field density and moisture content exists in base course layers under construction, as demonstrated by the relative compaction test results. High variability exists along the depth of base course layers, as demonstrated by the dynamic cone penetrometer test results and the estimated profile of California Bearing Ratio (CBR) along the depth of the investigated base layers. Spatial variability and non-uniformity were also demonstrated by the results of the light weight deflectometer and GeoGauge, in which the layer modulus varies within a large range of values.
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AbstractAggregates selected for Wisconsin transportation infrastructure must withstand harsh service conditions. In this paper, results of comprehensive statistical analyses on three sets of aggreg...
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There has been an increased interest in using reclaimed asphalt pavement (RAP) aggregates as a base course in Wisconsin for the offered economic and environmental benefits. Laboratory studies showed that RAP can have resilient modulus... more
There has been an increased interest in using reclaimed asphalt pavement (RAP) aggregates as a base course in Wisconsin for the offered economic and environmental benefits. Laboratory studies showed that RAP can have resilient modulus values higher than typical natural aggregates, and can also have higher durability, especially in freeze–thaw cycles. However, it is also recognized that RAP exhibits temperature sensitivity and larger permanent deformations than natural aggregates. How these characteristics manifest themselves in the northern U.S. climates can only be assessed by long-term observation of field performance. Wisconsin Department of Transportation (WisDOT) has been using RAP as a base course for over 30 years. The qualitative assessment of WisDOT roads constructed with RAP showed they are performing adequately. However, this impression has not yet been verified quantitatively. This paper presents a quantitative assessment and comparisons for field performance of pavement test sections constructed with RAP and natural crushed aggregate (CA) base course layers in Wisconsin. The performance was evaluated using pavement distress surveys of roadways containing RAP and CA, falling weight deflectometer (FWD), dynamic cone penetrometer (DCP) tests, and analysis of WisDOT’s available data. Based on the field evaluation, the performance of the hot mix asphalt (HMA) pavements with RAP was found adequate and comparable to those with CA base course layers. A recommendation was given that WisDOT shall continue the practice of using RAP in base course layers of HMA pavements, given proper quality checks for materials, and proper quality control/quality assurance measures being applied during construction.
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AbstractThe low-cycle fatigue (LCF) behavior of steel in energy-dissipating seismic connections is an important consideration, especially in light of the interest in performance-based seismic design. In this study, the LCF performance of... more
AbstractThe low-cycle fatigue (LCF) behavior of steel in energy-dissipating seismic connections is an important consideration, especially in light of the interest in performance-based seismic design. In this study, the LCF performance of seven steel bar types (AISI 8620, 1018, 1045, 1117, 1215, 4140 and ASTM A36 steel) was experimentally examined and compared. The bar specimens were subjected to sinusoidal strains of constant amplitude from zero to peak strains of 4%, 6%, or 8%. Equations that relate the applied strain amplitudes with the number of cycles to failure were developed and compared. In addition, relationships for calculating the total dissipated energy corresponding to the applied strain amplitude were proposed based on the experimental results. This study demonstrated that, in general, the LCF resistance of AISI 1045 steel type outperformed the other steel materials at a strain amplitude of ±2%. However, at ±3 and ±4% strain amplitudes, the LCF lives of ASTM A36 and AISI 1117 bars outperforme...
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Background Prestressed concrete bridge girders suffer unpredictable damage from accidental over-height-vehicle impacts and unintended construction-related damage during deck removals. These damage situations complicate strength... more
Background Prestressed concrete bridge girders suffer unpredictable damage from accidental over-height-vehicle impacts and unintended construction-related damage during deck removals. These damage situations complicate strength assessments due to section loss and the asymmetrical condition of the girder after damage. The objective of this research was to develop recommendations and guidelines for the inspection, evaluation, repair and other necessary safety and operational responses related to damaged prestressed concrete girders.
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Bridge decks are a significant factor in the deterioration of bridges, and substantially affect long-term bridge maintenance decisions. In this study, conditional survival (reliability) analysis techniques are applied to bridge decks to... more
Bridge decks are a significant factor in the deterioration of bridges, and substantially affect long-term bridge maintenance decisions. In this study, conditional survival (reliability) analysis techniques are applied to bridge decks to evaluate the age at the end of service life using the National Bridge Inventory records. As bridge decks age, the probability of survival and the expected service life would change. The additional knowledge gained from the fact that a bridge deck has already survived a specific number of years alters (increases) the original probability of survival at subsequent years based on the conditional probability theory. The conditional expected service life of a bridge deck can be estimated using the original and conditional survival functions. The effects of average daily traffic and deck surface area are considered in the survival calculations. Using Wisconsin data, relationships are provided to calculate the probability of survival of bridge decks as well...
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Research Interests: Engineering, Civil Engineering, Environmental Science, Computer Science, Analytical Chemistry, and 14 moreStructural Engineering, Concrete, Medicine, Safety, Sensors, Electrical Resistance, Resistivity, Runway, Pavements, Electrical And Electronic Engineering, Bridge Decks, Ice Detection, Black Ice, and Road Surface Condition
Fourteen reinforced concrete laboratory test specimens were used to evaluate a number of corrosion control (CoC) procedures to prolong the life of patch repairs in corrosion-damaged reinforced concrete. These specimens included layered... more
Fourteen reinforced concrete laboratory test specimens were used to evaluate a number of corrosion control (CoC) procedures to prolong the life of patch repairs in corrosion-damaged reinforced concrete. These specimens included layered mixed-in chlorides to represent chloride contamination due to deicing salts. All specimens were exposed to accelerated corrosion testing for three months, subjected to patch repairs with various treatments, and further subjected to additional three months of exposure to accelerated corrosion. The use of thermal sprayed zinc, galvanic embedded anodes, epoxy/polyurethane coating, acrylic coating, and an epoxy patch repair material was evaluated individually or in combination. The specimens were assessed with respect to corrosion currents (estimated mass loss), chloride ingress, surface rust staining, and corrosion of the reinforcing steel observed after dissection. Results indicated that when used in patch repair applications, the embedded galvanic anod...
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Approximately 10 to 11 million tons of aggregates are utilized in transportation infrastructure projects in Wisconsin annually. The quality of aggregates has a tremendous influence on the performance and durability of roadways and... more
Approximately 10 to 11 million tons of aggregates are utilized in transportation infrastructure projects in Wisconsin annually. The quality of aggregates has a tremendous influence on the performance and durability of roadways and bridges. In this Phase II research study, detailed statistical analyses were performed on over 1,000 sets of historical aggregate test results and the experimental results from the Phase I study. Test results from other states were analyzed as well. Aggregate tests were performed on 12 known marginal or poor Wisconsin aggregates to specifically address test performance of such aggregates. Selected aggregates were scanned using X-ray computed tomography to assess the effects of freeze-thaw and sodium sulfate exposure on the internal void system. The results of multi-parameter logistic regression analyses show that the pass/fail outcomes of the Micro-Deval test can be predicted when LA abrasion, absorption, and sodium sulfate soundness test results are known. The unconfined freeze-thaw test outcomes cannot be predicted from results of other tests (not correlated). Therefore, the unconfined freeze-thaw test should be part of any test protocol as it measures an aggregate characteristic that cannot be obtained from other tests. The percentiles associated with any proposed acceptance threshold limits for various aggregate tests should be determined using the statistical data provided.
Research Interests: Durability and Aggregates
The production of portland cement is among the major contributors to greenhouse gas emissions that adversely affect the environment. Identifying sustainable materials to partially replace portland cement in concrete, such as pozzolanic... more
The production of portland cement is among the major contributors to greenhouse gas emissions that adversely affect the environment. Identifying sustainable materials to partially replace portland cement in concrete, such as pozzolanic materials, is crucial in addressing this issue. These materials mainly consist of silica and alumina that react with the available calcium hydroxide to form strength-bearing phases such as calcium silicate hydrates. Understanding the degree of pozzolanic reactivity of materials using efficient reactivity test methods is an important consideration. The paper thoroughly reviews the available literature related to direct and indirect pozzolanic reactivity test methods that have been utilized over the years. Direct methods quantify the amount of consumed calcium hydroxide, whereas indirect methods assess changes in the physical properties of the specimen due to pozzolanic reactions. The aim of this paper is to identify affordable, time-saving, and effective direct and indirect methods. Based on this study, the Frattini, electrical conductivity, and pH tests are considered the most time-efficient methods to assess pozzolanic materials. Electrical conductivity and pH tests are also easy to perform. In contrast, other methods are more time-consuming.
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With current and near-term construction activities within the freeway system of Southeast Wisconsin, there is a unique opportunity to develop a detailed understanding of their in-service performance by implementing a health monitoring... more
With current and near-term construction activities within the freeway system of Southeast Wisconsin, there is a unique opportunity to develop a detailed understanding of their in-service performance by implementing a health monitoring network that can serve as a living laboratory for the State of Wisconsin. Data from this health monitoring network can be used to develop and guide maintenance and inspection operations for these and other critical infrastructure components across the State. This monitoring network can also become a model for the nation, illustrating the benefits and cost savings from an integrated, proactive maintenance program
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This paper presents development of 3D non-linear finite element model to simulate the response and predict the behavior of un-bonded mild steel bars under axial and bending loading. The models were successfully analyzed with the finite... more
This paper presents development of 3D non-linear finite element model to simulate the response and predict the behavior of un-bonded mild steel bars under axial and bending loading. The models were successfully analyzed with the finite element software ANSYS, taking into account the nonlinear material properties of the reinforced mild steel bars. A bending strain relationship is derived based on a parametric study involving multiple nonlinear finite element models. A mild steel fracture criterion based on low-cycle fatigue models is proposed to control the total (elastic and plastic) strains in the mild steel bar below a maximum permissible limit. In addition, FE predictions of bar elongation due to strain penetration reasonably agreed with a pro-posed empirical equation by Raynor and Lehman. It was concluded that the equation proposed by Raynor and Lehman is considered valid for estimating the additional unbounded length and can be used in both analysis and design.
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There has been an increased interest in using reclaimed asphalt pavement (RAP) aggregates as a base course in Wisconsin for the offered economic and environmental benefits. Laboratory studies showed that RAP can have resilient modulus... more
There has been an increased interest in using reclaimed asphalt pavement (RAP) aggregates as a base course in Wisconsin for the offered economic and environmental benefits. Laboratory studies showed that RAP can have resilient modulus values higher than typical natural aggregates, and can also have higher durability, especially in freeze–thaw cycles. However, it is also recognized that RAP exhibits temperature sensitivity and larger permanent deformations than natural aggregates. How these characteristics manifest themselves in the northern U.S. climates can only be assessed by long-term observation of field performance. Wisconsin Department of Transportation (WisDOT) has been using RAP as a base course for over 30 years. The qualitative assessment of WisDOT roads constructed with RAP showed they are performing adequately. However, this impression has not yet been verified quantitatively. This paper presents a quantitative assessment and comparisons for field performance of pavement...
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With current and near-term construction activities within the freeway system of Southeast Wisconsin, there is a unique opportunity to develop a detailed understanding of their in-service performance by implementing a health monitoring... more
With current and near-term construction activities within the freeway system of Southeast Wisconsin, there is a unique opportunity to develop a detailed understanding of their in-service performance by implementing a health monitoring network that can serve as a living laboratory for the State of Wisconsin. Data from this health monitoring network can be used to develop and guide maintenance and inspection operations for these and other critical infrastructure components across the State. This monitoring network can also become a model for the nation, illustrating the benefits and cost savings from an integrated, proactive maintenance program
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This paper presents development of 3D non-linear finite element model to simulate the response and predict the behavior of un-bonded mild steel bars under axial and bending loading. The models were successfully analyzed with the finite... more
This paper presents development of 3D non-linear finite element model to simulate the response and predict the behavior of un-bonded mild steel bars under axial and bending loading. The models were successfully analyzed with the finite element software ANSYS, taking into account the nonlinear material properties of the reinforced mild steel bars. A bending strain relationship is derived based on a parametric study involving multiple nonlinear finite element models. A mild steel fracture criterion based on low-cycle fatigue models is proposed to control the total (elastic and plastic) strains in the mild steel bar below a maximum permissible limit. In addition, FE predictions of bar elongation due to strain penetration reasonably agreed with a pro-posed empirical equation by Raynor and Lehman. It was concluded that the equation proposed by Raynor and Lehman is considered valid for estimating the additional unbounded length and can be used in both analysis and design.