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Home > Publications > 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 16 Abstracts search results
Document:
SP-339_12
Date:
March 1, 2020
Author(s):
Burkhart Trost, Harald Schuler, and Bozidar Stojadinovic
Publication:
Symposium Papers
Volume:
339
Abstract:
Sliding failure of reinforced concrete shear walls was observed after the Chilean earthquakes in 1985 and 2010, during shaking table tests, and in many quasi-static cyclic shear walls tests. Sliding may occur along cold joints or flexural cracks that remain open due to permanent deformations induced during cyclic loading. If it occurs, sliding can significantly reduce the horizontal force resistance and change the deformation mechanism of reinforced concrete shear walls, and thereby markedly affect the seismic performance of shear wall buildings. This study provides the interaction diagrams intended to help reinforced concrete shear wall designers exclude the sliding failure mode. Regions where sliding, shear, and flexural failure modes are expected are delineated according to the shear wall shear span to length ratio, the axial force, the horizontal and vertical reinforcement ratios, and the concrete strength. These interaction diagrams are derived using a cyclic reinforced concrete wall response model that considers flexure, shear and sliding load-deformation relationships and the interaction between them. The inter-action diagram is used to develop design recommendations on how to avoid the sliding failure of reinforced concrete shear walls under earthquake loading.
DOI:
10.14359/51724703
CI3612Hanskat
December 1, 2014
Hanskat, C.S.
Concrete International
36
Issue:
12
Shotcrete is typically placed in multiple layers. Unfortunately, designers and inspectors often incorrectly confuse the interfaces between those layers with cold joints experienced in cast-in-place concrete construction. The differences between shotcrete and cast-in-place concrete placements are discussed, with strong emphasis on consolidation of both materials. Interlayer bond formation is described, and surface preparation for shotcrete placement is explained.
CI3103Yang
March 1, 2009
Lei Yang and Jonathan J. Shi
31
3
Longtan Dam is a roller-compacted concrete (RCC) dam currently under construction in Guangxi Province, China. Due to its height and large volume, there are a great number of horizontal construction joints, and many of them may become cold joints during construction because weather conditions in the region often disrupt construction. In this study, different methods for treating layer joints in the Longtan RCC project were analyzed. The objective was to identify an efficient, easy-to-use treatment method that can meet the bonding requirements. The findings will help expedite construction and ensure high quality.
SP230-86
October 1, 2005
J.G. Dai, Y. Saito, T. Ueda, and Y. Sato
230
Both short and long-term performances of repaired or strengthenedconcrete structures using external FRP bonding are greatly affected by states ofbonding substrates, which are covercrete and may have experienced various damages.One of them is frost damage in cold regions. This paper intends to investigate how theinitial frost damages in concrete influence the static and fatigue bond performances ofCFRP/concrete interfaces. Concrete specimens were exposed to freeze and thaw cyclesbefore being bonded with CFRP sheets. The initial frost damage of concrete wascontrolled approximately at three different levels in terms of its relative dynamicmodulus of elasticity, which was 100% (non frost damage), 85% and 70%, respectively.Test results showed that failure modes of CFRP/concrete bonded joints with initial frostdamage in concrete were the delamination of covercrete. By contrast the joints withoutinitial frost damage failed in a thin concrete layer as usual. Moreover, CFRP/concretejoints with and without initial frost damage showed different manners in their interfacebonding strength and stiffness. If the initial frost damage existed in concrete substratethe effective bond length of CFRP/concrete joints was increased due to the decrease ofthe bonding stiffness and interfacial fracture energy. Fatigue testing results indicatedthat the linear slopes of S-N curves of CFRP/concrete bonded joints were not influencedby the initial frost damage. The initial frost damage did not shorten the fatigue life ofCFRP/concrete joints if a same relative tensile stress level was kept in the FRP sheets,where the relative tensile stress level was defined as a ratio of the applied tensile forcein FRP sheets for the fatigue tests to the maximum static pullout one achieved in eachtest series.
10.14359/14907
CI2602Yao
February 1, 2004
Sam X. Yao, and Ben C. Gerwick Jr.
26
2
Because concrete placed underwater is inherently susceptible to cement washout, laitance, segregation, cold joints, and water entrapment, it must possess some unique workability characteristics. This article presents factors that must be considered when properly proportioning underwater concrete mixtures.
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