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Home > Publications > International Concrete Abstracts Portal
Showing 1-5 of 22 Abstracts search results
Document:
20-386
Date:
January 1, 2022
Author(s):
Carlos N. Morales, Guillermo Claure, and Antonio Nanni
Publication:
Structural Journal
Volume:
119
Issue:
1
Abstract:
Forty-eight simply supported glass fiber-reinforced polymer (GFRP) reinforced concrete (RC) slabs made with seawater-mixed concrete were tested to study potential performance degradation over different environmental conditions for 1, 6, 12, and 24 months. The environments consisted of typical field conditions of a subtropical region and immersion in seawater at 60°C (140°F) as an accelerated aging regimen. The GFRP-RC slab strips were 1828 mm (72 in.) long, 304 mm (12 in.) wide, and 152 mm (6 in.) deep and were reinforced with a 9.5 mm (0.375 in.) diameter GFRP bar. All the slabs were tested under three-point flexural loading and all exhibited bar rupture as the failure mode. The test results are reported in terms of the cracking load, ultimate moment capacity, and service-load deflections. Experimental results were compared to the analytical and ACI 440.1R-15 expected values. The type of concrete mixture design as well as the accelerated aging exposure seems to affect the ultimate capacity of GFRP-RC slabs. Analytical and ACI approaches reasonably predicted the experimental failure-moment capacity of most of the seawater-mixed GFRP-RC slabs, specifically for those exposed to field conditioning. The ACI 440.1R-15 equations were in good agreement with the experimentally measured deflections, where the largest deviations were observed for accelerated-aged specimens.
DOI:
10.14359/51733006
20-304
Andor Windisch
Torsion in structural concrete members is a discipline where in-depth research is still possible and desirable. Sophisticated computer programs have been developed that deliver the ultimate load-bearing capacities after following the whole loading/deformation process. This paper presents the model of the characteristic failure cross sections (MCFC) and the efficiency factor, ψ, of the skew reinforcement and applies them to fundamental test series from the literature on beams with rectangular cross sections loaded in pure torsion. A simple design formula is proposed and validated on test results from the literature. Failure modes and the influence of concrete strength are discussed. Minimum and maximum rates of reinforcement are defined, and detailing recommendations are given.
10.14359/51733010
20-171
March 1, 2021
Wei Cui, Qiu-Wei Tang, and Hui-Fang Song
Materials Journal
118
2
This paper aims to find the effects of viscosity on concrete behavior in pipelines. Concrete was prepared according to ACI 304.2R-96. Experiments were conducted for measuring its workability by means of slump test. Fluidity and rheology measurements of fresh mortar were investigated. The concrete behavior in pipes was directly investigated using computational fluid dynamics (CFD) simulation, which is based on the Eulerian approach and the dense discrete phase model (DDPM). Concrete behavior including flow profiles, aggregate distributions, and migration was analyzed and discussed. It was observed that the flow characteristic varies from shear flow to plug flow with increased viscosity, and the aggregate distribution along the central axis is more homogeneous. Aggregate radial migration is more pronounced with increased shearing time, decreased viscosity, and enlarged size of aggregates. It was also found that concrete between 12 and 22 Pa·s (1.74 × 10–3 and 3.19 × 10–3 psi·s) is more suitable for pumping.
10.14359/51729329
18-424
September 1, 2019
Jacob Frappier, Khaled Mohamed, Ahmed Sabry Farghaly, and Brahim Benmokrane
116
5
The current study investigated the behavior of reinforced concrete deep beams with web openings. Seven deep beams were tested: five had web openings—of which three were reinforced with glass fiber-reinforced polymer (GFRP) bars and two reference specimens were reinforced with steel bars—and two solid deep beams, one with GFRP bars and one with steel bars as reference. The beams were 1200 x 300 mm in cross section and 5000 mm in span. The shear span-depth ratio (a/d) was 1.13. The openings in the beam webs were 304 mm high and 340 mm wide. Different GFRP and steel reinforcement configurations were provided around the web opening. The results were analyzed in terms of cracking pattern, mode of failure, load-deflection behavior, opening effect, and efficiency of the reinforcement configuration. The GFRP- and steel-reinforced solid deep beams exhibited similar resistance, while the GFRP-reinforced deep beams with openings had slightly lower capacity than the steel-reinforced ones. Strut-and-tie models (STMs) available in ACI and CSA design codes and the literature were assessed. The accuracy of each model was confirmed, revealing the applicability of the STMs for complex truss models as in deep beams with web openings.
10.14359/51716774
15-304
January 1, 2017
C. Trautner, T. Hutchinson, M. Copellini, P. Grosser, R. Bachman, and J. Silva
114
The stretch length of an anchor is defined as the length over which plastic deformations are expected to occur during seismic loading. Providing system ductility via the stretch length is an attractive design philosophy, particularly for structural system types where energy dissipation and ductility are not easily integrated elsewhere. This paper presents a basis for stretch length design including data from a large testing program of commonly used anchor materials. More than 90 tension tests of all-thread and headed anchors were conducted to determine strength characteristics, the relationship between anchor deformation capacity and stretch length, and serviceability limit states. Subsequently, simple analytical methods to determine the required stretch length for common connection configurations, including building column baseplate connections and nonbuilding structures, are developed. The paper concludes by providing a rational stretch length design framework as an alternative to the current ACI 318 prescriptive requirement of eight times the anchor diameter.
10.14359/51689152
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