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International Concrete Abstracts Portal

Showing 1-5 of 171 Abstracts search results

Document: 

SP-341-08

Date: 

June 30, 2020

Author(s):

Ruchin Khadka, Mustafa Mashal, and Jared Cantrell

Publication:

Symposium Papers

Volume:

341

Abstract:

Recently titanium alloy bars (TiABs) have been gaining popularity in civil engineering applications. They offer good deformation capacity, better fatigue performance, high-strength-to-weight ratio, lighter weight (60% that of steel), and excellent corrosion resistance. Recently, TiABs were used in the strengthening of two bridges in Oregon to increase the shear and flexural capacities of the concrete beams. The research in this paper quantifies some common mechanical properties of TiABs using experimental investigation. This is done to explore suitability of the material for wider applications in civil infrastructure. The four types of testing conducted in accordance with ASTM standards included tension, hardness, Charpy V-Notch, and galling tests. Samples of 150 ksi (1034 MPa) high strength steel were also tested for comparison. Test results showed good performance of TiABs. Analytical models are proposed for stress-strain and toughness-temperature relationships.


Document: 

SP340

Date: 

April 30, 2020

Author(s):

Andrzej S. Nowak, Hani Nassif, Victor Aguilar

Publication:

Symposium Papers

Volume:

340

Abstract:

Professor Dennis Mertz passed away after a prolonged battle with cancer. He spent a large portion of his professional career working on advancing of the state-of-the-art of bridge engineering. He was a great friend and colleague to many at ACI and ASCE. Joint ACI-ASCE Committee 343, joined with ACI Committees 342 and 348, sponsored four sessions to honor his contributions and achievements in concrete bridge design and evaluation. These sessions highlighted the important work and collaborative efforts that Dr. Mertz had with others at ACI and ASCE on various topics. These sessions also combined the efforts among ACI and ASCE researchers and practitioners in addressing various topics related to the design and evaluation of concrete bridges. The scope and outcome of the sessions are relevant to ACI’s mission. They raise awareness on established design methodologies applied for various limit states covering topics related flexure, shear, fatigue, torsion, etc. They address problems related to emerging design and evaluation approaches and recent development in design practices, code standards, and related applications. The Symposium Publication (SP) is expected to be an important reference in relation to design philosophies and evaluation methods of new and existing concrete bridges and structures.


Document: 

SP-333_05

Date: 

October 1, 2019

Author(s):

Ruo-Yang Wu and Chris P. Pantelides

Publication:

Symposium Papers

Volume:

333

Abstract:

Two severely damaged concrete column-to-cap beam specimens were successfully repaired, using a carbon fiber-reinforced polymer (CFRP) cylindrical shell, non-shrink repair concrete, and headed steel bars. The first cast-in-place specimen experienced concrete crushing and longitudinal bars fracture/buckling; for the second precast specimen, the column was completely separated from the cap beam. In this paper, two analytical models, Model Fiber and Model Rotational Spring (RS), simulating the seismic performance of the repaired specimens are proposed. In Model Fiber, plasticity considering bond-slip effects was distributed over the defined plastic hinge length of the nonlinear beam-column element. In Model RS, a non-linear rotational spring was used to consider the concentrated plasticity located at the repaired cross-section. Low-cycle fatigue of the damaged column longitudinal steel bars was included in the analytical models. Simulations show that the analytical results, in terms of hysteretic response and moment-rotation, are in very good agreement with the experimental results. Model fiber performed better for predicting the pinching effect in the hysteretic response of the repaired cast-in-place specimen; Model RS performed better for matching the hysteresis curves of the repaired precast concrete specimen. In addition, Model Fiber was able to predict the local response of the columns including the fracture of longitudinal bars due to low-cycle fatigue.


Document: 

SP327-51

Date: 

November 1, 2018

Author(s):

Mohammad Moravvej and Mamdouh El-Badry

Publication:

Symposium Papers

Volume:

327

Abstract:

Utilization of fiber-reinforced polymers (FRPs) in concrete structures, particularly bridges, has promised a safe and satisfactory performance. However, the structural performance of FRP-reinforced bridges can be affected by occurrence of various types of damage. This paper presents structural damage identification in FRP-reinforced bridge truss girders tested under static and fatigue loading. The proposed technique combines discrete wavelet transforms (DWTs) and spectral entropy in a relative procedure to detect and quantify the damage-induced disturbances in the measured vibrational signals of the girders. Various types of test-induced damage were identified using the vibrational signals obtained only from the damaged state of the girders. Results of damage identification were verified by data obtained through instrumentations and by visual inspection of the actual state of damage in the girders during and after the tests. The results show that the technique can be implemented in a protective structural health monitoring (SHM) system to identify imminent failure. It can also help with the decision-making process regarding maintenance of FRP-reinforced concrete bridges. The technique is a practical means for damage identification in in-situ cases, where the normal operation of bridges cannot be interrupted, and the data obtained from a reference state of bridges are not available.


Document: 

SP327-34

Date: 

November 1, 2018

Author(s):

Marco Rossini, Eleonora Bruschi, Fabio Matta, Carlo Poggi and Antonio Nanni

Publication:

Symposium Papers

Volume:

327

Abstract:

This paper presents a parametric analysis of the ACI 440 (2015) and AASHTO (2009) algorithms governing the flexural design of a one-way concrete member internally reinforced with glass fiber-reinforced polymer (GFRP) bars. The influence of specific design parameters on the required amount of reinforcement is investigated. The aim is to identify variables and requirements governing the design of a large-section GFRP reinforced concrete (RC) member. The member considered for this case-specific analysis is the reinforced concrete pile cap of the Halls River Bridge (Homosassa, FL), which is deemed representative of large-section GFRP-RC members operating as bent caps in short-span bridges. The influence of four critical parameters on the required amount of reinforcement is assessed. Salient analysis and design implications are discussed with respect to creep and fatigue rupture stress limits, minimum amount of flexural reinforcement, and applicable strength reduction factors. The outcomes of the parametric analysis highlight an untapped potential to reduce the required amount of reinforcement, and prioritize research areas to advance the development of rational design algorithms. Cyclic fatigue and creep rupture are identified as governing mechanisms.


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