International Concrete Abstracts Portal

International Concrete Abstracts Portal

The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.

Showing 1-5 of 502 Abstracts search results

Document: 

24-398

Date: 

September 11, 2025

Author(s):

Dorian Borosnyoi-Crawley

Publication:

Structural Journal

Abstract:

It can be demonstrated that performance-based seismic design of post-installed anchors in accordance with ACI 318 is not possible by using the anchor qualification information provided by ACI 355. The current state-of-the-art anchor qualification does not provide capacities that reflect actual earthquake responses in seismic design scenarios. This paper provides a comprehensive analysis and highlights the gaps in the current approach. A performance-based framework is proposed as the basis of future developments in seismic design and qualification of post-installed anchors. It is demonstrated that the approach is fully transparent and provides the possibility to identify key driving parameters that need further experimental investigation. The approach acknowledges that performance-based seismic design of post-installed anchors needs an understanding of the seismic damage of the concrete-anchor system. Currently, no design tools are available to predict this damage. The proposed framework adopts the theory of the accumulated damage potential (ADP) as a damage parameter. It is demonstrated that the selected damage parameter is simple but meaningful enough to represent the seismic damage of the concrete-anchor system at the design level. Possibilities for future development of the approach is explored, and directions for the next steps are suggested. It is highlighted that a definition of a framework for realistic seismic performance objectives of post-installed anchors is needed for the development of design tools in the future. The proposed framework has great practical significance and may help fill a gap in the seismic design of post-installed anchors. Promoting a transparent framework that is driven by the needs of performance-based seismic design may help develop a feasible qualification system and replace the currently used pass-or-fail assessment approach that is not suitable to provide anchor capacities for performance-based seismic design.

DOI:

10.14359/51749169


Document: 

25-040

Date: 

September 11, 2025

Author(s):

Charles Kerby and Santiago Pujol

Publication:

Structural Journal

Abstract:

The deformability of reinforced concrete walls with staggered lap splices was studied through tests of six cantilevered walls under constant axial load and cyclic reversals of lateral displacement. The height-to-length aspect ratios of the walls were approximately 3.2. Four walls had staggered laps, one wall had non-staggered laps, and one wall had mechanical couplers. Laps were detailed to yield the spliced reinforcement. Test walls with staggered laps lost lateral-load resistance at smaller drift ratios (1.0% to 2.1%) than both the test wall with non-staggered laps (2.3%) and the test wall with mechanical couplers (3.5%). Staggered lap splices resulted in larger strain concentrations than non-staggered lap splices. It was concluded that both staggered and non-staggered lap splices a) can have reduced strain capacity relative to continuous bars (leading to bond failure before or after yield) and b) alter inelastic strain distributions, causing large reductions in effective plastic hinge length.

DOI:

10.14359/51749175


Document: 

24-048

Date: 

September 10, 2025

Author(s):

Mohamed Abouyoussef, Ahmed Akl, and Mohamed Ezzeldin

Publication:

Structural Journal

Abstract:

Previous research studies have been conducted to study the seismic response of low-aspect-ratio RC shear walls when designed using normal-strength reinforcement (NSR) versus high-strength reinforcement (HSR). Such studies demonstrated that the use of HSR has the potential to address several constructability issues in nuclear construction practice by reducing the required steel areas and subsequently rebar congestion. However, the response of nuclear RC shear walls (i.e., aspect ratios of less than one) with both HSR and axial loads has not yet been evaluated under ground motion sequences. As such, most nuclear design standards restrict the use of HSR in nuclear RC shear wall systems. Such design standards do not consider the influence of axial loads when the shear strength capacity of such walls is calculated. To address this gap, the current study investigates the influence of axial load on the performance of nuclear RC shear walls with HSR when subjected to ground motion sequences using hybrid simulation testing and modelling assessment techniques. In this respect, two RC shear walls (i.e., W1-HSR and W2-HSR-AL), with an aspect ratio of 0.83, are investigated. Wall W2-HSR-AL had an axial load of 3.5% of its axial compressive strength, while wall W1-HSR had no axial load. The test walls were subjected to a wide range of ground motion records, from operational basis earthquake (OBE) to beyond design basis earthquake (BDBE) levels. The experimental results of the walls are discussed in terms of their damage sequences, cracking patterns, ductility capacities, effective periods, and rebar strains. The test results are then used to develop and validate a numerical OpenSees model that simulates the seismic response of nuclear RC shear walls with different axial load levels. Finally, the experimental and numerical results are compared to the current ASCE 41-23 backbone model for RC shear walls. The experimental results demonstrate that walls W1-HSR and W2-HSR-AL showed similar crack patterns and subsequent shear-flexure failures; however, the former had wider cracks relative to the former during the different ground motion records. In addition, the axial load reduced the displacement ductility of wall W2-HSR-AL by 18% compared to wall W1-HSR. Moreover, the ASCE 41-23 backbone model was not able to adequately capture the seismic response of the two test walls. The current study enlarges the experimental and numerical/analytical database pertaining to the seismic performance of low-aspect-ratio RC shear walls with HSR to facilitate their adoption in nuclear construction practice.

DOI:

10.14359/51749164


Document: 

24-197

Date: 

July 31, 2025

Author(s):

Altho Sagara, Iswandi Imran, Erwin Lim, and Patria Kusumaningrum

Publication:

Structural Journal

Abstract:

During past earthquakes, failures of beam–column joints have commonly been observed on the exteriors of buildings. However, only one side of these joints can be retrofitted because of the presence of beams on the other three sides. Therefore, this study aims to test four exterior beam–column joints with transverse beams, leaving the rear side as the only viable location for placing fiber-reinforced polymer (FRP) laminate. All four test specimens are designed with insufficient joint shear strength, as determined by ACI 318 equations, while satisfying the criteria for a strong-column–weak-beam mechanism and sufficient development length for bar anchorage. A total of two un-retrofitted specimens, with and without joint hoops, are constructed as controls. Subsequently, two similar specimens are retrofitted by applying an FRP laminate on the rear side. The results show that sufficient FRP laminate can enhance the seismic performance of joints in terms of deformability, energy dissipation, and failure delay.

DOI:

10.14359/51749100


Document: 

24-263

Date: 

July 1, 2025

Author(s):

Anmol S. Srivastava, Girish N. Prajapati, and Brahim Benmokrane

Publication:

Structural Journal

Volume:

122

Issue:

4

Abstract:

The present study demonstrates the feasibility of using longitudinal hybrid reinforcement in concrete columns in seismic zones. In this research, four concrete columns were constructed and subjected to quasi-static cyclic loading, featuring a combination of steel and glass fiber-reinforced polymer (GFRP) longitudinal reinforcement. Two reference columns were fabricated and reinforced in the longitudinal direction with steel bars. These columns had a 400 x 400 mm (15.8 x 15.8 in.) cross section and 1850 mm (72.8 in.) overall height. All the columns were reinforced with GFRP crossties and spirals in the horizontal direction. The variable parameters were the transverse reinforcement spacing, axial load ratio, and column configuration. The outcomes of this research clearly showed that reinforced concrete (RC) columns that are properly designed and detailed longitudinally with hybrid reinforcement (GFRP/steel) could achieve the drift limitation in building codes with no strength degradation. Further, these hybrid-RC columns displayed enhanced energy dissipation capacity, superior ductility, and improved post-earthquake recoverability compared to columns reinforced longitudinally with steel. The promising results of this study represent a step toward the use of longitudinal hybrid reinforcement in lateral-resisting systems.

DOI:

10.14359/51745488


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