Abstract This paper presents a study of the performance of four techniques – visual inspection, G... more Abstract This paper presents a study of the performance of four techniques – visual inspection, Ground Penetrating Radar (GPR), Ultrasonic Surface Wave (USW), and core control – that were used to assess condition of a concrete bridge deck. The bridge deck was then rehabilitated using hydrodemolition, and the concrete removed during hydrodemolition was assumed to be deteriorated. LiDAR measurements of concrete depth removal collected after hydrodemolition were used as ground truth. Comparisons of bridge deck condition assessment data and LiDAR concrete removal measurements were performed in this study. The comparisons attempt to find and describe a possible relationship between bridge deck assessment techniques and quantities of concrete deterioration.
Page 1. EVALUATION OF THE ORIENTATION OF 90° AND 180° REINFORCING BAR HOOKS by Nichole Podhorsky ... more Page 1. EVALUATION OF THE ORIENTATION OF 90° AND 180° REINFORCING BAR HOOKS by Nichole Podhorsky Lesley Sneed NUTC R257 Page 2. Disclaimer The contents of this report reflect the views of the author(s), who are responsible for the facts and the ...
ABSTRACT widely used to determine the relative condition of reinforced concrete. This paper prese... more ABSTRACT widely used to determine the relative condition of reinforced concrete. This paper presents case studies from Missouri, USA, where a ground-coupled GPR system was used to assess the condition of eleven concrete bridge decks. The main goal of this paper is to develop appropriate acquisition and processing parameters in order to conduct rapid, efficient, and cost-effective assessment of bridge decks. To accomplish this goal, the GPR data sets were collected with slightly different acquisition parameters and processed using different parameters. The quality of the results and the time required for each bridge deck survey are analyzed. Additionally, several experimental data sets were collected across a 12th concrete bridge deck to examine the influence of weather conditions on reflection amplitude values, since amplitude analysis is used in this study. Based on the authors’ experience and findings, appropriate GPR acquisition and processing parameters are suggested and described for use of the ground-coupled GPR method for bridge deck assessment.
ABSTRACT This study examined the direct shear transfer across an interface of lightweight aggrega... more ABSTRACT This study examined the direct shear transfer across an interface of lightweight aggregate concretes cast at different times. Increasing use of lightweight aggregate concretes prompted this investigation to determine the appropriateness of current shear friction design provisions with respect to all-lightweight and sand-lightweight concrete. The experimental investigation included 36 push-off specimens constructed with a cold joint along the shear plane. Test variables included concrete type (unit weight), compressive strength of concrete, and surface preparation of the shear interface. A constant amount of reinforcing steel (1.33%) was provided across the shear plane. Applied shear force–slip relations were presented and discussed. Peak and residual shear strengths were also compared. Results suggest that concrete type did not play a significant role in the shear strength of the specimens in this study. Shear strengths computed using the shear friction design provisions in the Building Code Requirements for Structural Concrete (ACI 318-11) and Commentary (ACI 318R- 11) and PCI Design Handbook: Precast and Prestressed Concrete were conservative for the sand-lightweight and all-lightweight specimens.
Abstract This paper presents a study of the performance of four techniques – visual inspection, G... more Abstract This paper presents a study of the performance of four techniques – visual inspection, Ground Penetrating Radar (GPR), Ultrasonic Surface Wave (USW), and core control – that were used to assess condition of a concrete bridge deck. The bridge deck was then rehabilitated using hydrodemolition, and the concrete removed during hydrodemolition was assumed to be deteriorated. LiDAR measurements of concrete depth removal collected after hydrodemolition were used as ground truth. Comparisons of bridge deck condition assessment data and LiDAR concrete removal measurements were performed in this study. The comparisons attempt to find and describe a possible relationship between bridge deck assessment techniques and quantities of concrete deterioration.
Page 1. EVALUATION OF THE ORIENTATION OF 90° AND 180° REINFORCING BAR HOOKS by Nichole Podhorsky ... more Page 1. EVALUATION OF THE ORIENTATION OF 90° AND 180° REINFORCING BAR HOOKS by Nichole Podhorsky Lesley Sneed NUTC R257 Page 2. Disclaimer The contents of this report reflect the views of the author(s), who are responsible for the facts and the ...
ABSTRACT widely used to determine the relative condition of reinforced concrete. This paper prese... more ABSTRACT widely used to determine the relative condition of reinforced concrete. This paper presents case studies from Missouri, USA, where a ground-coupled GPR system was used to assess the condition of eleven concrete bridge decks. The main goal of this paper is to develop appropriate acquisition and processing parameters in order to conduct rapid, efficient, and cost-effective assessment of bridge decks. To accomplish this goal, the GPR data sets were collected with slightly different acquisition parameters and processed using different parameters. The quality of the results and the time required for each bridge deck survey are analyzed. Additionally, several experimental data sets were collected across a 12th concrete bridge deck to examine the influence of weather conditions on reflection amplitude values, since amplitude analysis is used in this study. Based on the authors’ experience and findings, appropriate GPR acquisition and processing parameters are suggested and described for use of the ground-coupled GPR method for bridge deck assessment.
ABSTRACT This study examined the direct shear transfer across an interface of lightweight aggrega... more ABSTRACT This study examined the direct shear transfer across an interface of lightweight aggregate concretes cast at different times. Increasing use of lightweight aggregate concretes prompted this investigation to determine the appropriateness of current shear friction design provisions with respect to all-lightweight and sand-lightweight concrete. The experimental investigation included 36 push-off specimens constructed with a cold joint along the shear plane. Test variables included concrete type (unit weight), compressive strength of concrete, and surface preparation of the shear interface. A constant amount of reinforcing steel (1.33%) was provided across the shear plane. Applied shear force–slip relations were presented and discussed. Peak and residual shear strengths were also compared. Results suggest that concrete type did not play a significant role in the shear strength of the specimens in this study. Shear strengths computed using the shear friction design provisions in the Building Code Requirements for Structural Concrete (ACI 318-11) and Commentary (ACI 318R- 11) and PCI Design Handbook: Precast and Prestressed Concrete were conservative for the sand-lightweight and all-lightweight specimens.
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