Development of the modified clothoidal (MCL) shape of composite dowels against the background of fatigue and technological issues
et
08 avr. 2024
À propos de cet article
Catégorie d'article: Original Study
Publié en ligne: 08 avr. 2024
Pages: 91 - 110
Reçu: 28 sept. 2023
Accepté: 01 mars 2024
DOI: https://doi.org/10.2478/sgem-2024-0005
Mots clés
© 2024 Wojciech Lorenc et al., published by Sciendo
This work is licensed under the Creative Commons Attribution 4.0 International License.
Figure 1:

Figure 2:
![Results of push-out tests conducted by UBWM [7]: force per dowel versus relative slip for the SA, PZ, and CL shapes (the horizontal axis shows the slip displacement measured in the tests).](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/64737a3e4e662f30ba53f8da/j_sgem-2024-0005_fig_002.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20250911%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20250911T112105Z&X-Amz-Expires=3600&X-Amz-Signature=c32d6637fff5cdf764cf04f8ac98fabf98210ae768e492e2d5e993222d8fd2b1&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Figure 3:
![Cutting technology for production of test specimens for project [7]: a) and b) single cutting line for the PZ and SA shapes and c) two cutting lines for the CL shape.](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/64737a3e4e662f30ba53f8da/j_sgem-2024-0005_fig_003.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20250911%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20250911T112105Z&X-Amz-Expires=3600&X-Amz-Signature=fc4b865962da0450964ebb81c3b1a95eb28429c7cf1a68eaf13313465c8ab921&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Figure 4:
![The idea of the new push-out-test (NPOT) specimen proposed by the author to be used for cyclic tests [7] (2 million cycles).](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/64737a3e4e662f30ba53f8da/j_sgem-2024-0005_fig_004.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20250911%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20250911T112105Z&X-Amz-Expires=3600&X-Amz-Signature=abf521732b4ebf319762376162f51e13a71e12ae953083fd226ea13bc7967b54&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Figure 5:

Figure 6:

Figure 7:

Figure 8:

Figure 9:

Figure 10:
![Documentation of fatigue cracks in the NPOT-PZ2 specimen tested in of the PreCo-Beam project [7]: a–f) view after cutting the concrete part, g) general view of the crack, h) beginning of the crack, and i) end of the crack](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/64737a3e4e662f30ba53f8da/j_sgem-2024-0005_fig_010.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20250911%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20250911T112105Z&X-Amz-Expires=3600&X-Amz-Signature=288bd5e6812c1f2ef6826711394df13aaf2720d0279a732745edc0708ab12709&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Figure 11:
![The original concept of dimensionless resistance of steel dowels regarding local and global effects [5,6] (Fig. 13d in [6]): fatigue coefficients for tension stress for PZ shape (at the left; to be compared with Fig. 20 and [22] for the clothoidal shape) and general prediction for complete stress set (at the right).](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/64737a3e4e662f30ba53f8da/j_sgem-2024-0005_fig_011.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20250911%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20250911T112105Z&X-Amz-Expires=3600&X-Amz-Signature=0bddc21600451d6bc0c4f96af385fa402c8452a97e162b00abc252b564d2364e&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Figure 12:
![Strain gauges on NPOT specimens with CL shapes for purposes of [7].](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/64737a3e4e662f30ba53f8da/j_sgem-2024-0005_fig_012.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20250911%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20250911T112105Z&X-Amz-Expires=3600&X-Amz-Signature=cfda6a09cf719f6eec2bff5fc9a9d5a739e34d4e0b6b2a1657daa79131e4b93a&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Figure 13:

Figure 14:
![Summary of characteristics of the basic shapes highlighting the problems with the idea of a new cutting line and the basis standing behind this idea (original drawing of steel parts of NPOT specimens for discussions with partners of the PreCo-Beam [7] project: only the SA and PZ shapes were used in bridges before construction of the “Wierna Rzeka” Bridge in Poland [62]).](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/64737a3e4e662f30ba53f8da/j_sgem-2024-0005_fig_014.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20250911%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20250911T112105Z&X-Amz-Expires=3600&X-Amz-Signature=2519018aba90f5c8db6871b813af8ad487c6c77d33178ae9d4954b0206b2f28a&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Figure 15:

Figure 16:

Figure 17:

Figure 18:

Figure 19:
![Results of the numerical simulations of the MCL 115/250 shape (the shape after optimization of the ratio according to the procedure presented in Fig. 30 in [57]) by Abaqus software.](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/64737a3e4e662f30ba53f8da/j_sgem-2024-0005_fig_019.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20250911%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20250911T112105Z&X-Amz-Expires=3600&X-Amz-Signature=cbb740a6cda6155e5e6bfdb07ac05246097fa72c135b2dd5751fb8ea9953d392&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Figure 20:
![Dimensionless stress concentration factors (according to [5,6]) for the MCL 115/250 shape and the PZ 300/100 shape.](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/64737a3e4e662f30ba53f8da/j_sgem-2024-0005_fig_020.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20250911%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20250911T112105Z&X-Amz-Expires=3600&X-Amz-Signature=fb37a3dc7979c761156eae0fd0b52b3f7a58c65d83260b534ff146c66e6b6793&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Figure 21:

Figure 22:
![Different shapes and technologies of production of steel dowels with the clothoidal shape: a and b) different shapes of the “nose” of steel dowels by different producers fabricated in Poland out of plates by oxy-cutting, c) small dowels fabricated in Luxembourg by plasma cutting, d) elements of the PE4 bridge design by the author in Poland [12] fabricated in Luxembourg by oxy-cutting and plasma cutting, and e) steel elements of the PE4 bridge at the construction site (a large number of elements were produced with the MCL 115/250 shape).](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/64737a3e4e662f30ba53f8da/j_sgem-2024-0005_fig_022.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20250911%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20250911T112105Z&X-Amz-Expires=3600&X-Amz-Signature=5faee55d52660ada78854b46a680148b0528df3aecb7f47802e4dbff6846e447&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Figure 23:

Figure 24:

Figure 25:
![Implementation of composite dowels in innovative composite bridges in Poland: a) and b) implementation in beams – bridge in Elbląg (presented in [41]) and c) implementation in arches – a new solution as part of a network arch bridge using composite dowels [63].](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/64737a3e4e662f30ba53f8da/j_sgem-2024-0005_fig_025.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20250911%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20250911T112105Z&X-Amz-Expires=3600&X-Amz-Signature=fe8bb87dbfffc438883286a43faee17a47c724d7005192281b66d0c4431e0e56&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Figure 26:
![Nominal geometry of the modified clothoidal shape of a single connector MCL 100/250 according to [16] given as a function of the spacing of connectors ex.](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/64737a3e4e662f30ba53f8da/j_sgem-2024-0005_fig_026.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20250911%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20250911T112105Z&X-Amz-Expires=3600&X-Amz-Signature=5408e66463109006c649d171051af4de44d52f3f812ee3d1569a2d5630c6cd36&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Main stress values (MPa) in the NPOT models estimated using FEA for coarse mesh density – the stress level is given at the minimum (σP = 120 kN) and maximum (σP = 280 kN) load level and their difference (ΔσP = 160 kN)_
CL | 132.0 | 176.0 | 308.0 |
SA | 134.6 | 179.4 | 314.0 |
PZ | 157.6 | 210.2 | 367.8 |