Sessions & Events

 

Please note: All sessions and events take place in Central Daylight Time: CDT (UTC-5).

H=Hyatt Regency Dallas; U=Union Station

Concrete Olympics: Design, Construction, Evaluation, and Repair of Concrete Bridges and Structures with Members of the ACI, KCI, TCI, and FIB, Part 2 of 4

Monday, October 24, 2022  4:00 PM - 6:00 PM, H-Reunion E

Korea Concrete Institute
Taiwan Concrete Institute
International Federation for Structural Concrete
The special sessions present recent advances in the design, construction, evaluation, and repair of concrete structures and materials with an emphasis on international perspectives with members from four major concrete institutes around the globe: the American Concrete Institute (ACI), Korea Concrete Institute (KCI), Taiwan Concrete Institute (TCI), and International Federation for Structural Concrete (FIB). Presentations encompass a variety of technical aspects such as the refined analysis and assessment techniques of concrete members, damage detection and mitigation, seismic behavior, durability performance, and repair/strengthening of constructed structures. Both experimental and analytical investigations are of interest. The sessions bring to light state-of-the-art knowledge and provide an opportunity to discuss current challenges and technical demands. Critical information will be provided to those who lead tomorrow’s structural design, construction, evaluation, and repair, including practicing engineers, government officials, and academics.
Learning Objectives:
(1) Discuss the state-of-the-art of sustainable concrete structures;
(2) Identify research needs to advance the knowledge associated with constructed concrete elements;
(3) Recognize the effort to establish a new trend in concrete durability;
(4) Compare laboratory investigations with practical applications.

This session has been AIA/ICC approved for 2 CEU/PDH credits.


Towards an Alkali-Activated Prestressed Concrete Bridge in the Netherlands

Presented By: Eva Olivia Leontien Lantsoght
Affiliation: Delft University of Technology
Description: The use of ordinary Portland cement in structural concrete is an important contributor to the world’s CO2 emissions. To mitigate this problem, concrete mixes without Portland cement are being developed. In this project, Portland cement is replaced by ground granulated blast furnace slag mixed with an alkali-activator to develop an alkali-activated concrete. This mix is planned to be used for design of prestressed girders for a 7m-span bridge in the North of the Netherlands. In order to enable safe upscaling of this new type of concrete, an extensive experimental study is performed. First, short- and long-term material properties of the alkali activated concrete are investigated. Subsequently, to verify the structural performance of these girders, girders are tested in shear and flexure in the laboratory. In addition, sustained loading testing and testing of the composite system of girders and AAM-deck are carried out as well. Finally, structural monitoring is applied in the structural tests and constructed bridge to study the long-term performance of the structure. This presentation gives an overview of the experimental results and the lessons learned from this project.


Lateral Load and Displacement Backbone Curves of Existing Reinforced Concrete Columns Under High Axial Load

Presented By: Yi-An Li
Affiliation: National Chung Hsing University
Description: There was a lot of research regarding the existing reinforced concrete vertical members in recent years, such as columns, walls, etc. These test data and research generally focus on the vertical structural members sustained low axial load. However, the major cities in the world are highly developed because the usable residential area is limited, like Taiwan. The mid- and high-rise buildings are the main building type in a highly populated city. If this kind of mid- and high-rise reinforced concrete buildings were built a long time ago, and the design specifications in the construction period were the lack of the seismic design concept. Therefore, these buildings are needed reasonable seismic assessment methods. It is necessary to know the seismic behavior of vertical structural members with high axial loads if the seismic capacity of mid- and high-rise reinforced concrete buildings could be precisely evaluated. This study will execute two test programs to understand the seismic behavior of reinforced concrete columns under the high axial load. The lateral load and displacement backbone curves of reinforced concrete columns with high axial load could be established by the test observations and collected database and to understand the seismic behavior of reinforced concrete columns with high axial load more in detail.


Electrochemical Treatment to Arrest Corrosion of Steel in Concrete

Presented By: Ki Yong Ann
Affiliation: Hanyang University
Description: The present study concerns the effect of electrochemical chloride extraction in lowering the corrosiveness of steel in concrete, of which the quantitative values were evaluated by measuring the corrosion rate, potential and chloride profile at free bound and total ones. In fact, there was a dramatic decrease in the corrosion rate arising from the electrochemical treatment but did not meet the level for the passivation of the steel surface, often indicating below 1.0 mA/m2. This phenomenon was again observed by monitoring of corrosion potential: the value was always lower than the threshold voltage (-275 mV vs SCE), increasing from around -500 mV to -300 mV. It is evident that the electrochemical treatment could be effective in mitigating the corrosion process but is not promising in turning the steel surface back to passivation state. Additionally, the electrochemical treatment could lower the chloride profile at every depth of cover concrete, irrespective level of chloride contamination. Most free chlorides were extracted by the treatment, except at the surface. It was surprising that bound chloride was quite extracted under electric charge, challenging the hypothesis that bound chlorides would be physically immobile in the pore network in concrete.


Statistics of Temperature Gradient In Prestressed Concrete Bridges Based on Field Data

Presented By: Ayman Okeil
Affiliation: Louisiana State University
Description: Ignoring temperature effects during structural design may lead to adverse effects over the design life of a bridge under service conditions, which, in turn, may lead to serious issues over the structure’s design life. AASHTO LRFD Bridge Design Specifications (BDS) divided the United States for four solar radiation zones to determine the vertical temperature and provides a load factor, ?_TG, equal to 0.0, 0.5, or 1.0 based on the design limit state. The objective from applying this and other load factors in addition to the resistance factors, ?, is to produce designs with acceptable risk levels over the bridge lifespan. To the knowledge of the authors, ?_TG was not calibrated using structural reliability concepts. There is a lack of published work that addresses the statistics of thermal gradients, which is the first step in calibrating the load factors. In this work, the probability distribution type for the continuous random variable representing thermal gradient temperature is first determined. Temperature data collected from a bridge in Louisiana is analyzed, and transient heat transfer analyses are performed to complement the collected temperature data to demonstrate the proposed methodology. Since the statistical properties of the design life of maximum temperature load is the focus for calibrating temperature load factor, Extreme Value Theory is used to extrapolate the extreme value of temperature load for 75-year return period. The outcome of this study is a statistical thermal load model for inclusion in reliability.


Wind Effects on Concrete Tall Buildings and Application of PBWD

Presented By: Thomas Kang
Affiliation: Seoul National University
Description: For tall buildings, wind effects are greater than seismic effects, particularly in East Asia, the state of Florida and other coastal regions. In this presentation, structural wind effects on concrete tall buildings will be discussed. The framework of performance-based design (PBD) is well established for seismic, while wind design is primarily based on elastic analysis for both serviceability & strength, with some adjustment of damping ratio. For tall buildings with coupled core-wall system under extreme wind force, systematic application of performance-based wind design (PBWD) is needed and is being attempted by structural & wind engineers in Korea and the US. In this presentation, a framework of application of PBWD is dealt with, as well as theoretical background on the application.

Upper Level Sponsors

Ash Grove
Baker
Conseal
Controls Group
Euclid Chemical
GCP
Master Builders
PoreShield
PS=0
ACI Northeast Texas Chapter

Please enter this 5 digit unlock code on the web page.