International Concrete Abstracts Portal

ABOUT THE 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.

International Concrete Abstracts Portal

Showing 1-10 of 887 Abstracts search results

Document: 

CI4201Tarr

Date: 

January 1, 2020

Author(s):

Scott M. Tarr, Matthew J. Sheehan, and Eric J. Van Duyne

Publication:

Concrete International

Volume:

42

Issue:

1

Abstract:

Designing and constructing a slab-on-ground to act as a structural diaphragm increases the risk of out-of-joint cracking. This article discusses this risk, describes design and reinforcement requirements for such slabs, and encourages designers to consider alternative details. It also discusses construction details commonly used to limit wall-panel bowing.


Document: 

CI4106Hoskins

Date: 

June 1, 2019

Author(s):

Hoskins, J.

Publication:

Concrete International

Volume:

41

Issue:

6

Abstract:

The VST stay-in-place formwork system is used in the construction of multistory residential, mixed-use, and commercial buildings in Europe and the United Kingdom. The formwork is used to construct cast-in-place, reinforced concrete load-bearing walls, floor slabs, columns, and stairs. Formwork assemblies are custom built for each project, and they are delivered with factory-installed reinforcement. The system minimizes construction waste and field labor.


Document: 

CI4104Q&A

Date: 

April 1, 2019

Author(s):

Scott M. Tarr

Publication:

Concrete International

Volume:

41

Issue:

4

Abstract:

Q; Floor slabs in our warehouse are experiencing spalling at joints in the lift-truck traffic lanes. How can we restore the joints to provide a smooth ride?


Document: 

CI4103Q&A

Date: 

March 1, 2019

Publication:

Concrete International

Volume:

41

Issue:

3

Abstract:

Q. Our interior hard-troweled slabs have scaled (Fig. 1). Did this occur because deicing salts were used to melt snow and ice on the slabs so that construction trades could perform their work during the winter months?


Document: 

SP327-18

Date: 

November 1, 2018

Author(s):

Hikmatullah Akhundzada, Ted Donchev, Diana Petkova and Abdul Mahbob Samsoor

Publication:

Special Publication

Volume:

327

Abstract:

Structural retrofitting of flat slabs is often required mainly due to corrosion of reinforcement, change of use and design errors. Punching shear failure is a common type of failure in flat slabs in the area of connection with the column, which could lead to progressive collapse. The slab-column connection is critical as it exposes to bending moments and significant shear stresses in RC flat slabs. Utilization of FRP attachment as strengthening method for concrete structures is becoming the most popular approach for improving their characteristics. CFRP laminates are already well established structural strengthening material and the further optimisation of their application in case of punching shear strengthening will allow for developing of effective solution for this problem. The research comprises testing of seven small scale reinforced concrete slabs (550x550x75 mm) (21.7x21.7x3 inch) with a column stud (80x80x75 mm) (3.1x3.1x3 inch) at the centre to simulate the slab-column connection. One control sample and six CFRP strengthened samples were prepared and tested against punching shear failure. The primary variable of the experiment was the positioning, layout and configuration of the CFRP laminates. The total width and thickness of the CFRP laminates were kept constant and the objective was to determine the most efficient layout. It was found out that using CFRP laminates as externally bonded reinforcement significantly enhances the punching shear capacity and results in improved stiffness of the slabs. The result shows a significant increase in ultimate load and stiffness.


Document: 

CI4011Cepuritis

Date: 

November 1, 2018

Author(s):

Rolands Cepurītis, Brad J. Pease, Jānis Kamars, and Jānis Ošlejs

Publication:

Concrete International

Volume:

40

Issue:

11

Abstract:

Elevated ground slabs are an alternative for locations with poor and/or inconsistent subgrades. This article summarizes the basic slab-on-pile construction process and provides results from a load test conducted on a slab constructed using shrinkage-compensating steel fiber-reinforced concrete. Ancillary benefits of constructing such slabs are also summarized.


Document: 

CI4010Aalami

Date: 

October 1, 2018

Author(s):

Bijan O. Aalami

Publication:

Concrete International

Volume:

40

Issue:

10

Abstract:

To avoid creating a moment at the anchorage, tendons are typically anchored at the centroid of the member. This results in a uniform compression in the member, which is added to the stresses from the bending of the member to complete the design. Anchoring the tendon at the member centroid leads to a challenge in the selection of the tendon profile for the end span of multi-span slabs and beams. The article provides a preferred tendon profile and example calculations.


Document: 

SP328

Date: 

September 19, 2018

Publication:

Special Publication

Volume:

328

Abstract:

Editors: Denis Mitchell and Abdeldjelil Belarbi

This Symposium Volume reports on the latest information related to shear in structural Concrete. The volume contains 14 papers that were presented at the ACI Convention held in Salt Lake City on March 27, 2018. The symposium was sponsored by ACI/ASCE Committee 445 “Shear and Torsion”. This event honored Professor Michael P. Collins (University of Toronto) whose enormous contributions in the development of rational behavioral models for shear and torsion of structural concrete have been paramount.

The papers cover different aspects related to shear in structural concrete including: the size effect in shear for both structural concrete and reinforced masonry; developments of the Modified Compression Field Theory; aspects of shear strengthening using FRP strips; the role of experimental measurements in understanding shear behavior; accounting for shear deformations; sustained loading effects on shear in members without transverse reinforcement; crack-based assessment of shear; key aspects in the design of concrete offshore structures, behavioral models for coupling beams; finite element modeling of punching shear in slabs; and seismic design for shear.

Sincere acknowledgements are extended to all authors, speakers and reviewers as well as to ACI staff for making this symposium a success.


Document: 

SP328-12

Date: 

September 12, 2018

Author(s):

Aikaterini S. Genikomsou, Graeme J. Milligan and Maria Anna Polak

Publication:

Special Publication

Volume:

328

Abstract:

Nonlinear finite element analysis (FEA), when properly calibrated based on experimental results of reinforced concrete slabs, can be useful to perform parametric studies for the investigation of structural behavior and for the development of future design code provisions. In this paper, a study is presented on how certain modeling decisions influence the FEA results for punching shear analyses of reinforced concrete slabs. The “Concrete Damaged Plasticity” model which is offered in the commercial FEA program ABAQUS is considered to simulate the concrete slabs, where the calibration was conducted based on already tested slab-column connections. The calibrated model is further investigated to discuss the impact of numerous modeling parameters including the boundary and loading conditions, finite element mesh type and size, and the constitutive modeling of concrete. Selected parametric studies are presented and recommendations for each of the investigated parameters are provided to better understand the punching shear behavior of reinforced concrete slabs. The results from the analysis of tested slabs and the subsequent parametric studies using the calibrated model show that that the FEA can be used to predict the punching shear strength, deformation capacity and crack pattern of the slabs.


Document: 

SP328-07

Date: 

September 12, 2018

Author(s):

Adam S. Lubell

Publication:

Special Publication

Volume:

328

Abstract:

The cross-section and reinforcement in a concrete beam must be selected to provide sufficient strength at the ultimate limit state while limiting the service deflection to an acceptable magnitude. ACI 318 analytical models for flexural capacity and deflection of slender beams assume that plane sections remain plane after bending and perpendicular to the longitudinal axis, but this hypothesis ignores the presence of diagonal cracking and related deformations associated with the imposed shear. This paper reports on an analytical deflection model developed using simplifications to the Modified Compression Field Theory that superimposes contributions from the flexural deformations arising from member curvatures and the shear deformations arising from diagonal cracking. The model is shown to be in better agreement with test data than the ACI 318 deflection model that only accounts for curvatures. A parametric study was completed using the model to gain insight into the influence of beam span-to-height ratio and the longitudinal and transverse reinforcement ratios on beam deflection. Recommendations are made on using a holistic design approach to satisfy both strength and serviceability requirements for a given span-to-height ratio.


12345...>>

Results Per Page