BRIDGE OF I-35 DESIGN USING PG SUPER - IAEME · 2018-06-30 · 2.3. PG Super Analysis and Design...
Transcript of BRIDGE OF I-35 DESIGN USING PG SUPER - IAEME · 2018-06-30 · 2.3. PG Super Analysis and Design...
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International Journal of Civil Engineering and Technology (IJCIET) Volume 9, Issue 6, June 2018, pp. 355–362, Article ID: IJCIET_09_06_041
Available online at http://www.iaeme.com/ijciet/issues.asp?JType=IJCIET&VType=9&IType=6
ISSN Print: 0976-6308 and ISSN Online: 0976-6316
© IAEME Publication Scopus Indexed
BRIDGE OF I-35 DESIGN USING PG SUPER
Lokesh Kumar Anaimallur Mani
BIM Co-ordinator/Project Manager, Superior concrete products, Raider Drive,
Euless, Texas – 75062, United States
Arunraj E, Vincent Sam Jebadurai S, Daniel C, Joel Shelton J and Hemalatha G
Department of Civil Engineering,
Karunya Institute of Technology and Sciences, Coimbatore, India
ABSTRACT
The main objective of this study is to design all the simply supported pre-tensioned
prestressed concrete TxDOT I-girders for the seven-span Bridge 205 of I-35W
extension project in the most economical way. The minimum number of strands,
minimum number of girders, or minimum weight, or a combination of these items is to
be found and also to replace the steel plate girders at the second span by prestressed
TxDOT I-girders. The general arrangement plan, perform analysis in PGSuper and
design all 7 spans using AASHTO, LRFD and TxDOT specifications for presressed
concrete bridges are studied. The analysis was performed by using PGSuper
(Prestressed Girder Superstructure Design and Analysis), V. 2.9 (AASHTO LRFD
2014) for bridge design. Industry response to a recent survey1 suggests that
prestressed concrete bridge girders are the predominant element in establishing
overall quality guidelines for the advancement of precast concrete operations.
Keywords: Bridge, Girder Design, PG Super
Cite this Article: Lokesh Kumar Anaimallur Mani, Arunraj E, Vincent Sam Jebadurai
S, Daniel C, Joel Shelton J and Hemalatha G, Bridge of I-35 Design Using PG Super,
International Journal of Civil Engineering and Technology, 9(6), 2018, pp. 355–362.
http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=9&IType=6
1. INTRODUCTION
Industry response to a recent survey1 suggests that prestressed concrete bridge girders are the
predominant element in establishing overall quality guidelines for the advancement of precast
concrete operations. The quality control and specification control imposed by state and federal
departments of transportation establish the performance characteristics of these members and
often set the bounds for production strength. For years this upper bound was assumed to be
6000 psi (41 MPa). In the 1970s and early 1980s, considerable attention was given to the
advancement of cast-in-place, high strength concrete for the columns of multistory buildings.
2 During this time, production concrete strengths of 14,000 psi (97 MPa) were developed and
used. Until recently, there has been little corresponding development of high strength concrete
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for the prestressed concrete industry. Research at Construction Technology Laboratories
(CTL) and Tulane University is examining the performance of decked bulb-tee beams using
10,000 psi (69 MPa) concrete.3 High strength concrete girder research is also being conducted
at the University of Minnesota and the University of Texas. These projects are examining the
strength and mechanical properties of high strength concrete for bridge bulb-tee girders. To
gain an insight into the probable performance of these girders, a historical assessment was
made of prestressed concrete girders and their mix designs. In this study, the optimized design
of this bridge to use only prestressed concrete girders and to be the most economical design
possibilities are studied. In doing this, we used 5-Tx54 girders in all spans except for Spans 2
and 4, which used 15 and 5 Tx70 girders, respectively.
2. PROJECT METHODOLOGY
2.1. Study of Plan and General Arrangement
Bridge 205 is a southbound bridge on North Tarrant Expressway Segment 3A North that is
900.35' long with 7 spans. It is on a horizontal curve with a radius of 5,800' and a vertical
curve with an entrance grade of +3% and an exit grade of – 2.46%. The second span utilizes
steel girders to cross the 230.56' between bents 2 and 3. Every other span on the bridge uses
Tx54 girders. Six of the seven bents are placed at a skew angle. The bridge has SSTR rails on
either side of the deck and an 8 ft CLF-RO fence on either side of spans 2 and 3. The overall
width of the bridge varies in span 1 and span 7 from 52'-8'' to 53'-5''. In spans 2-6, the overall
width of the bridge is a constant 53'-5''.
2.2. Design Parameters
The design was based on TxDOT 2013 Bridge Design manual. As per the project statement,
the design was based on an overall bridge length of 900.35', overall width of bridge of 53'.
and a roadway width of 51'. TxDOT T551 railing was used which has a weight of 382 plf. A
typical composite cast-in-place deck that is 8'' thick was used with a strength of f'c=4 ksi,
Ec=3605 ksi. The various type of TxDOT girder was used for each span as per need for the
most economical design.
The girders were designed with f'c = 8.5 ksi, f'ci= 6 ksi, Ec= 5255 ksi initially but it was
changed as per the requirement. The limitation of the practical length of a precast prestressed
concrete girder is 230'. The location of the piers was not allowed to change so we had to use
the same seven span as in the original design drawings. The width of the bridge was also not
allowed to be changed.
2.3. PG Super Analysis and Design Procedure
The PG Super software has a built in material library and modeling template. All 7 spans are
modeled according to the alignment given in the Bridge 205 plans. The overall plan and a
cross section view of span 1 is shown in figures 1 and 2. An initial trial is performed by
modeling the similar cross-sections and number of girders for all spans as given in input
drawings of Bridge 205. Multiple iterations of specification checks are performed with
numerous checks to optimize the design and meet project objectives. Girder size, number of
strands, amount of mild steel reinforcement and debonding patterns are tried in various
combinations to come up with our final design. The following are the checks PG Super does
when analyzing the bridge. Span 2 proved to be the most difficult span to design due to its
length of 230'. The original plans for Bridge 205 show this span using steel plate girders to
make transportation and construction feasible at site. Initial design started with 6-Tx70 girders
Lokesh Kumar Anaimallur Mani, Arunraj E, Vincent Sam Jebadurai S, Daniel C, Joel
Shelton J and Hemalatha G
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and continued until the maximum number of girders could fit within the width of the bridge
while keeping in mind the minimum spacing requirement of 3.5’.
A similar approach is used to design the remaining spans and designs for every span are
grouped to streamline the designs and achieve feasibility in construction planning. 5-Tx54
girders were safe in every span except for Span 4. For Span 4 the maximum number of girders
for Tx54 with the minimum spacing was unsafe, hence increased the girder size to 8-Tx62.
An optional design with 5-Tx70 was checked for span 4 and was finalized since the material
weight was significantly lower than 8-Tx62 (Figure 5).
Figure 1 Overall Plan
Figure 2 Cross-Sectional View for Spans 1,3,5,6 and 7
Figure 3 Cross-Sectional View for Span 2
Figure 4 Cross-Sectional View for Span 4
Figure 5 Cross section and Debonding Pattern for Span 2 Girder A
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Figure 6 Longitudinal View of Span 1- Girder
3. ANALYSIS AND RESULTS
The analysis was carried out in PG Super Software. Below are graphs depicting the shear and
moment diagrams as well as the displacement diagram for Span 1 Girder A.
Figure 7 Moment Results at Midspan‐Exterior Girder (Span 1)
Figure 8 Shear Results at Midspan‐Exterior Girder (Span 1)
Figure 9 Displacement Results at Midspan‐Exterior Girder (Span 1)
Lokesh Kumar Anaimallur Mani, Arunraj E, Vincent Sam Jebadurai S, Daniel C, Joel
Shelton J and Hemalatha G
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4. DESIGN SUMMARY
All girders used normal weight concrete and 270 ksi low-lax strands. A summary of design
specifications for all 7 spans is shown in Table 1. Table 2 shows a sample calculation of Mild
Steel Reinforcement for a Span 1 Girder A. Table 3 shows a comparison of Live Load
Distribution Factors calculated by PG Super for two sample interior beams with manual
calculations. Table 4 show the sample girder schedule for span 1 which is extracted from the
PG Super software. Sample Shear Reinforcement Detail is shown in table 6 and figure 7
shows the Camber and Deflection for Span 1 Girder A. Table 8 shows the Prestress Force and
Strand Stresses for Span 1- Girder A.
Table 1 Girder Design Summary (All Spans)
Span 1 Span 2 Span 3 Span 4 Span 5
Span 6
Span 7
Length of Span
102.5 ft 230.58 ft 111.17 ft 130 ft 98.09 ft 114 ft 114 ft
Girder Type
TX 54 TX 70 TX 54 TX 70 TX 54 TX 54
TX 54
Number of Girders
5 15 5 5 5 5 5
Spacing 12 ft 3.52 ft 12 ft 7 ft 12 ft 12 ft 12 ft
Number of Strands
48 70 48 56 48 54 54
Dia. of Strands
0.6” 0.7” 0.6” 0.7” 0.6” 0.6” 0.6”
Straight Strands
40 70 40 40 40 46 46
Harped Strands
8 54 8 8 8 8 8
Debonded Strands
0 22 0 12 0 0 0
Table 2 Mild Steel Reinforcement Design for Span 1- Girder A
Row# Measured
From
Distance from
End (ft)
Bar Length
(ft)
Girder Face
Cover (in)
Bar Size
# of Bars
Spacing (in)
1 Full Length Top 1.5 #4 4 10.7
2 Left End 0.125 3 Bottom 3.25 #5 2 26
3 Left End 0.125 3 Bottom 5.25 #5 2 26
4 Right End 0.125 3 Bottom 3.25 #5 2 26
5 Right End 0.125 3 Bottom 5.25 #5 2 26
Table 3 Distribution Factor for an Interior Beam
Distribution Factors Span/Girder Calculated PGSuper
Live Load Distribution Factor for Moment (Strength and Service Limit States)
1D 0.8542
0.8042* 0.845
Live Load Distribution Factor for Moment (Strength and Service Limit States)
5D 0.8612 0.908
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Table 4 Sample Girder Schedule
Span 1 1 1 1 1
Girder A B C D E
Girder Type Tx54 Tx54 Tx54 Tx54 Tx54
Prestressing Strands
NO (Nh+Ns) 48 48 48 48 48
Size 0.600 in
Dia 0.600 in
Dia 0.600 in
Dia 0.600 in
Dia 0.600 in
Dia
Strength Grade 270
Low Relaxation
Grade 270 Low
Relaxation
Grade 270 Low
Relaxation
Grade 270 Low
Relaxation
Grade 270 Low
Relaxation
Eccentricity at CL
18.508 in 18.508 in 18.508 in 18.508 in 18.508 in
Eccentricity at End
12.508 in 12.508 in 12.508 in 12.508 in 12.508 in
Prestressing Strands
Depressed Depressed Depressed Depressed Depressed
No. (# of Harped Strands)
8 8 8 8 8
Yb of Top Most Depressed
Strands at End 44.500 in 44.500 in 44.500 in 44.500 in 44.500 in
Concrete
Release strength fci
6.500 KSI 6.500 KSI 6.500 KSI 6.500 KSI 6.500 KSI
Minimum 28-day
Compressive strength fc
7.300 KSI 7.300 KSI 7.300 KSI 7.300 KSI 7.300 KSI
Table 5 Optimal Design
Span 1 1 1 1 1
Girder A B C D E
Girder Type Tx54 Tx54 Tx54 Tx54 Tx54
Design load compressive stress
(Top CL) 3.483 KSI 3.832 KSI 3.832 KSI 3.833 KSI 3.463 KSI
Design load tensile stress (Bottom CL)
-3.595 KSI
-4.025 KSI
-4.025 KSI
-4.026 KSI
-3.560 KSI
Required minimum ultimate moment
capacity
7551.83 kip-ft
8285.01 kip-ft
8285.01 kip-ft
8285.01 kip-ft
7488.70 kip-ft
Live load distribution factor for moment
0.84503 0.84503 0.84503 0.84503 0.84503
Live load distribution factor for shear
1.19982 1.19982 1.08232 1.19982 1.19982
Design load compressive stress
(Top CL) 3.483 KSI 3.832 KSI 3.832 KSI 3.833 KSI 3.463 KSI
Design load tensile stress (Bottom CL)
-3.595 KSI
-4.025 KSI
-4.025 KSI
-4.026 KSI
-3.560 KSI
Required minimum ultimate moment
capacity
7551.83 kip-ft
8285.01 kip-ft
8285.01 kip-ft
8285.01 kip-ft
7488.70 kip-ft
Live load distribution factor for moment
0.84503 0.84503 0.84503 0.84503 0.84503
Lokesh Kumar Anaimallur Mani, Arunraj E, Vincent Sam Jebadurai S, Daniel C, Joel
Shelton J and Hemalatha G
http://www.iaeme.com/IJCIET/index.asp 361 [email protected]
Table 6 Sample shear reinforcement detail
Zone Zone
Length ft
Bar Size, #
Spacing No of
Vertical Legs
No of Legs extended Into
Deck
Confinement Bar Size
1 3.208 4 3 2 2 None
2 10 4 6 2 2 None
3 10 4 8 2 2 None
4 15 4 12 2 2 None
5 to mid span
4 18 2 2 None
Table 7 Camber and Deflections
Camber and Deflection for Span 1 Girder A
Design Camber 4.004 in 0.334 ft
Deflection (Prestresssing) 4.206 in 0.350 ft
Deflection (Girder) -1.427 in -0.119 ft
Deflection (slab and diaphragms) -1.373 in -0.114 ft
Deflection (Traffic Barrier) -0.097 in -0.008 ft
Deflection (Overlay) 0.000 in 0.000 ft
Deflection (User Defined DC) 0.000 in 0.000 ft
Deflection (User Defined DW) 0.000 in 0.000 ft
Screed Camber, C 1.470 in 0.122 ft
Excess Camber (Based on Design Camber) 2.535 in 0.211 ft
Live Load Deflection (HL93 0 – Per Lane) -1.330 in -0.111 ft
Table 8 Prestress Force and Strand Stresses for Span 1- Girder A
Effective Prestress at Midspan
Loss Stage Permanent Strand
Force (Kip) Effective Loss (KSI) Fpe (KSI)
At Jacking 2109.24 0.000 202.500
Before Prestress Transfer 2109.24 0.000 202.500
After Prestress Transfer 1867.44 23.214 179.286
At Lifting 1867.44 23.214 179.286
At shipping 1687.81 40.460 162.040
After Deck Placement 1508.19 57.706 144.794
After Superimposed Dead Loads
1508.18 57.706 144.794
Final 1508.18 57.706 144.794
Final with Live Load 1508.18 57.706 144.794
5. CONCLUSION
The optimized design of this bridge to use only prestressed concrete girders and to be the
most economical design possibilities are studied. In doing this, we used 5-Tx54 girders in all
spans except for Spans 2 and 4, which used 15 and 5 Tx70 girders, respectively. This design
allowed our bridge to be as lightweight as possible, while remaining safe for traffic.
Bridge of I-35 Design Using PG Super
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