1
00:00:00,730 --> 00:00:03,147
(soft music)

2
00:00:07,560 --> 00:00:10,410
- [Narrator] In the construction
of composite steel bridges,

3
00:00:10,410 --> 00:00:11,880
shear studs are used

4
00:00:11,880 --> 00:00:15,600
to connect the concrete bridge
deck to the steel girders.

5
00:00:15,600 --> 00:00:18,480
A large number of these
shear studs are needed

6
00:00:18,480 --> 00:00:21,840
to meet AASHTO strength
and fatigue requirements.

7
00:00:21,840 --> 00:00:24,810
Researchers at the Center
for Transportation Research

8
00:00:24,810 --> 00:00:27,360
at the University of Texas at Austin

9
00:00:27,360 --> 00:00:30,870
have explored the use of
larger diameter shear studs,

10
00:00:30,870 --> 00:00:33,540
which can speed up the
construction process

11
00:00:33,540 --> 00:00:35,940
and improve worker safety.

12
00:00:35,940 --> 00:00:39,660
- This project is really
looking at the feasibility

13
00:00:39,660 --> 00:00:43,860
of using larger diameter shear studs.

14
00:00:43,860 --> 00:00:47,310
And with that, a lot of things happen.

15
00:00:47,310 --> 00:00:50,160
When you can use the larger
diameter shear studs,

16
00:00:50,160 --> 00:00:51,660
there's less shear studs,

17
00:00:51,660 --> 00:00:53,970
so it improves worker safety.

18
00:00:53,970 --> 00:00:57,510
It can expedite the girder
fabrication process.

19
00:00:57,510 --> 00:00:59,160
And then it also,

20
00:00:59,160 --> 00:01:00,840
it facilitates the use

21
00:01:00,840 --> 00:01:04,320
of our partial-depth precast deck panels,

22
00:01:04,320 --> 00:01:05,850
which we call PCPs.

23
00:01:05,850 --> 00:01:08,610
The use of PCPs for deck construction

24
00:01:08,610 --> 00:01:10,860
act as the formwork for the bridge deck.

25
00:01:10,860 --> 00:01:12,240
They speed up construction

26
00:01:12,240 --> 00:01:15,390
and they serve as a safe working platform

27
00:01:15,390 --> 00:01:16,560
for the workers.

28
00:01:16,560 --> 00:01:20,400
- We had quite an extensive
laboratory program.

29
00:01:20,400 --> 00:01:23,520
It was a long project, nearly four years,

30
00:01:23,520 --> 00:01:25,800
and a lot of work in the laboratory.

31
00:01:25,800 --> 00:01:27,180
Much of that was learning

32
00:01:27,180 --> 00:01:30,270
how to weld these larger
diameter shear studs.

33
00:01:30,270 --> 00:01:32,910
They have to be welded to
the top of a steel girder

34
00:01:32,910 --> 00:01:35,100
in the construction process.

35
00:01:35,100 --> 00:01:37,200
And there we had a lot
of help from industry.

36
00:01:37,200 --> 00:01:39,090
So we had a very collaborative project

37
00:01:39,090 --> 00:01:41,130
working closely together,

38
00:01:41,130 --> 00:01:42,390
you know, our research team working

39
00:01:42,390 --> 00:01:45,150
with TxDOT engineers and with industry.

40
00:01:45,150 --> 00:01:46,710
Our work was done at,

41
00:01:46,710 --> 00:01:48,780
it's the University of Texas Ferguson

42
00:01:48,780 --> 00:01:51,240
Structural Engineering Laboratory,

43
00:01:51,240 --> 00:01:54,900
which is at the University of
Texas Pickle Research Campus

44
00:01:54,900 --> 00:01:56,310
in northwest Austin,

45
00:01:56,310 --> 00:01:59,010
where we're testing bridge components

46
00:01:59,010 --> 00:02:01,380
generally to failure

47
00:02:01,380 --> 00:02:02,970
either under fatigue loading

48
00:02:02,970 --> 00:02:05,940
or ultimate strength type loading.

49
00:02:05,940 --> 00:02:09,990
- [Jamie] Push-out tests on
studs at Ferguson Laboratory

50
00:02:09,990 --> 00:02:11,730
were conducted to evaluate

51
00:02:11,730 --> 00:02:13,500
the static and fatigue performance

52
00:02:13,500 --> 00:02:16,470
of the 1 1/8th-inch diameter studs.

53
00:02:16,470 --> 00:02:18,480
The results of those static push-out tests

54
00:02:18,480 --> 00:02:20,220
showed excellent performance.

55
00:02:20,220 --> 00:02:25,080
- We also constructed two
bridge girders in the laboratory

56
00:02:25,080 --> 00:02:26,340
that were quite large.

57
00:02:26,340 --> 00:02:28,740
Each one was a hundred foot long.

58
00:02:28,740 --> 00:02:31,650
Where we could essentially
do a proof of concept

59
00:02:31,650 --> 00:02:34,410
to show that these larger
diameter shear studs

60
00:02:34,410 --> 00:02:38,160
will in fact work successfully
in an actual bridge girder.

61
00:02:38,160 --> 00:02:41,997
- So this project is
definitely ready to implement.

62
00:02:41,997 --> 00:02:45,840
The project included
design recommendations.

63
00:02:45,840 --> 00:02:48,600
Therefore, future steel
bridges can be designed

64
00:02:48,600 --> 00:02:51,180
with larger diameter shear studs.

65
00:02:51,180 --> 00:02:54,870
This research will serve a
national purpose as well,

66
00:02:54,870 --> 00:02:58,050
because what bridge engineers
used to design bridges

67
00:02:58,050 --> 00:03:00,660
was missing ways to design

68
00:03:00,660 --> 00:03:02,460
these larger diameter shear studs.

69
00:03:02,460 --> 00:03:05,190
And so this project will fill a hole

70
00:03:05,190 --> 00:03:08,190
that bridge engineers can
use all over the U.S.,

71
00:03:08,190 --> 00:03:09,780
not just Texas.

72
00:03:09,780 --> 00:03:11,040
- [Narrator] For more information

73
00:03:11,040 --> 00:03:14,070
and to find the publications
for this project,

74
00:03:14,070 --> 00:03:16,680
please visit the TxDOT Research Library

75
00:03:16,680 --> 00:03:18,453
at the link shown below.