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Early-age performance of lag screw shear connections for glulam-lightweight concrete composite beams

Jiang, Yuchen LU ; Hong, Wan; Hu, Xiamin; Crocetti, Roberto LU ; Wang, Lei and Sun, Weimin (2017) In Construction and Building Materials 151. p.36-42
Abstract

Mechanical behavior of the shear connections has a significant influence on both the load-carrying capacity and the bending stiffness of timber-concrete composite (TCC) beams. All the studies reported so far have concentrated on the performance of TCC connections in mature concrete. The performance of shear connections for TCC beams at early concrete ages, however, has not been investigated yet. This information is essential to evaluate the structural behavior of TCC floors or bridges during construction. In this paper, a total of 18 push-out tests with concrete ages ranging from 12 h to 28 days are performed, to investigate the early-age performance of lag screw shear connections in the lightweight concrete. Development of concrete... (More)

Mechanical behavior of the shear connections has a significant influence on both the load-carrying capacity and the bending stiffness of timber-concrete composite (TCC) beams. All the studies reported so far have concentrated on the performance of TCC connections in mature concrete. The performance of shear connections for TCC beams at early concrete ages, however, has not been investigated yet. This information is essential to evaluate the structural behavior of TCC floors or bridges during construction. In this paper, a total of 18 push-out tests with concrete ages ranging from 12 h to 28 days are performed, to investigate the early-age performance of lag screw shear connections in the lightweight concrete. Development of concrete strength with time is also analyzed. At the concrete ages shorter than 7 days, both the stiffness and strength of the screw connectors increase evidently with time, which follows the same growth trend with the concrete strength. After a 7-day cure, screw shear connections reach almost 100% of both the 28-day serviceability slip modulus and shear strength. Material properties of the glulam and the screw fastener are decisive in the shear performance of connections when the concrete hardens to some degree. Based on the experimental results, the accuracy of the design methods proposed in Eurocode 5 is evaluated. In addition, by non-linear regression of the experiment data, expressions to predict the development of load-carrying capacity and serviceability slip modulus for screw shear connections before 28 days are established.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Early-age performance, Lag screw shear connections, Lightweight concrete, Load-carrying capacity, Slip modulus, Timber–concrete composite
in
Construction and Building Materials
volume
151
pages
7 pages
publisher
Elsevier
external identifiers
  • scopus:85020888710
  • wos:000408183700005
ISSN
0950-0618
DOI
10.1016/j.conbuildmat.2017.06.063
language
English
LU publication?
yes
id
46a4286b-fd1a-4c29-87c1-8aea2c7795ea
date added to LUP
2017-07-04 07:37:14
date last changed
2018-01-07 12:10:28
@article{46a4286b-fd1a-4c29-87c1-8aea2c7795ea,
  abstract     = {<p>Mechanical behavior of the shear connections has a significant influence on both the load-carrying capacity and the bending stiffness of timber-concrete composite (TCC) beams. All the studies reported so far have concentrated on the performance of TCC connections in mature concrete. The performance of shear connections for TCC beams at early concrete ages, however, has not been investigated yet. This information is essential to evaluate the structural behavior of TCC floors or bridges during construction. In this paper, a total of 18 push-out tests with concrete ages ranging from 12 h to 28 days are performed, to investigate the early-age performance of lag screw shear connections in the lightweight concrete. Development of concrete strength with time is also analyzed. At the concrete ages shorter than 7 days, both the stiffness and strength of the screw connectors increase evidently with time, which follows the same growth trend with the concrete strength. After a 7-day cure, screw shear connections reach almost 100% of both the 28-day serviceability slip modulus and shear strength. Material properties of the glulam and the screw fastener are decisive in the shear performance of connections when the concrete hardens to some degree. Based on the experimental results, the accuracy of the design methods proposed in Eurocode 5 is evaluated. In addition, by non-linear regression of the experiment data, expressions to predict the development of load-carrying capacity and serviceability slip modulus for screw shear connections before 28 days are established.</p>},
  author       = {Jiang, Yuchen and Hong, Wan and Hu, Xiamin and Crocetti, Roberto and Wang, Lei and Sun, Weimin},
  issn         = {0950-0618},
  keyword      = {Early-age performance,Lag screw shear connections,Lightweight concrete,Load-carrying capacity,Slip modulus,Timber–concrete composite},
  language     = {eng},
  month        = {10},
  pages        = {36--42},
  publisher    = {Elsevier},
  series       = {Construction and Building Materials},
  title        = {Early-age performance of lag screw shear connections for glulam-lightweight concrete composite beams},
  url          = {http://dx.doi.org/10.1016/j.conbuildmat.2017.06.063},
  volume       = {151},
  year         = {2017},
}