International Concrete Abstracts Portal

Showing 1-5 of 61 Abstracts search results

Document: 

18-141

Date: 

May 1, 2019

Author(s):

Mariusz Zych and Andrzej Seruga

Publication:

Structural Journal

Volume:

116

Issue:

3

Abstract:

This research paper demonstrates the use of a new crack control model, described in detail in PART I of the series, based on the results of in-place analyses of semi-massive reinforced concrete (RC) tank wall segments. The following results of the measurements are presented: changes in the temperature profile of the segment along its height and the imposed strains and changes in crack widths as a function of time. The calculations take into account the stages of the occurrence of imposed and external loads and the resulting changes in the crack widths. The results obtained are also presented with reference to the currently applicable provisions of the current European standard. In addition, the authors point to those elements of the model from EN 1992-3 that should be analyzed at this stage to make possible amendments to the guidelines of the standard.

DOI:

10.14359/51713318


Document: 

18-140

Date: 

May 1, 2019

Author(s):

Mariusz Zych

Publication:

Structural Journal

Volume:

116

Issue:

3

Abstract:

A new calculation model for crack control in semi-massive reinforced concrete tanks used for liquid storage is proposed. The model includes three basic stages for the development of the crack width. The first stage covers the formation of early-age cracks occurring as a result of imposed loads acting during concrete hardening. The second stage concerns the formation of a stabilized spacing of basic cracks as well as the early period of imposed loads acting on a structure. The third stage involves sufficiently high values of imposed loads or, most frequently, service loads that result in the occurrence of second-order cracks and a simultaneous increase in the width of cracks formed in previous stages. In addition, instead of the degree of restraint, an average degree of relaxation was suggested as the basic parameter determining the crack width and spacing.

DOI:

10.14359/51713317


Document: 

17-311

Date: 

September 1, 2018

Author(s):

Joel E. Parks, Chris P. Pantelides, Luis Ibarra, and David H. Sanders

Publication:

Structural Journal

Volume:

115

Issue:

5

Abstract:

Yielding of anchor bolts is a source of ductility in the seismic response of structures found in industrial facilities including tanks, circular vessels, and nuclear storage containers. Satisfactory seismic performance of anchor bolts with a stretch length has prompted ACI 318-14 to recommend their use with a stretch length of eight bar diameters, based on empirical evidence. In this study, individual ductile anchor bolts with stretch lengths of four, six, and eight bar diameters are tested to examine their performance under cyclic loads under combined tension and shear loads. Two types of steel chairs for connecting the anchor bolts to circular vessels were used: an elastic steel chair designed according to American Petroleum Institute Standards, and a steel chair designed to yield. The experiments show that, under combined cyclic tension and shear loads, anchor bolts with a stretch length of at least four bar diameters create a ductile connection compared to a conventional anchor bolt, while maintaining a similar tension and shear load capacity. At high shear-to-tension load ratios, the maximum tensile displacement capacity is reduced. A yielding steel chair is found to increase the displacement capacity and decrease the stiffness of the connection compared to an elastic chair.

DOI:

10.14359/51702236


Document: 

12-065

Date: 

March 1, 2014

Author(s):

Michael J. Minehane and Brian D. O’Rourke

Publication:

Structural Journal

Volume:

111

Issue:

2

Abstract:

The present study investigated the influence of heated water storage, upward to 95°C (171°F), on precast prestressed concrete circular tanks. Modern design standards for concrete liquid-retaining structures require that thermal effects be considered for the serviceability limit state and the ultimate limit state when deemed significant. Most recognized standards, however, do not provide guidance for the analysis of such effects. Research in this area is also limited and almost exclusively concerned with ambient thermal conditions, with a maximum temperature change of 30°C (54°F) in any instance. A finite element study incorporating thermomechanical coupling investigated the magnitude of stresses associated with thermal storage. A linear eigenvalue analysis examined the ultimate limit state of buckling for restrained tank walls due to the thermally-induced combined axial compression and bending. Consequent design implications were established and recommendations made for accommodating thermal loading.

DOI:

10.14359/51686441


Document: 

107-S34

Date: 

May 1, 2010

Author(s):

Miguel Fernandez Ruiz, Sylvain Plumey, and Aurelio Muttoni

Publication:

Structural Journal

Volume:

107

Issue:

3

Abstract:

This paper investigates the structural behavior of reinforced concrete (RC) arch-shaped members without transverse reinforcement subjected to bending. Such members have typical applications in tunnels, cut-and-cover structures, shells, vaults, ducts, silos, tanks, and off-shore structures. Although such members are mostly subjected to axial forces, bending moments may also develop when the shape of the structure does not perfectly match the ideal funicular shape. In this case, when the intrados reinforcement is in tension, deviation forces developed by the reinforcement increase the splitting stresses originated by bond and can lead to spalling of the reinforcement cover. Such a failure mode is particularly brittle and dangerous, leading to a sudden loss of load-carrying capacity of the structure. In this paper, a series of six tests on 400 mm (15.7 in.) thick arch-shaped beams are presented. They are aimed at investigating spalling failures before and after yielding of the tensile reinforcement. These results, as well as others taken from the literature, were compared to an analytical model accounting for the interaction between bond and deviation forces, showing a good agreement and explaining the various failure modes observed. On that basis, a practical formula for the design of such members is proposed.

DOI:

10.14359/51663700


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