Prestressed Concrete (CE 5309)

Term Project

Group 2

Spring 2016

University of Texas at Arlington

PART 1

PRE-TENSIONED PRESTRESSED BRIDGE DESIGN

IH-35W Bridge 205

Design Information

Overall width of bridge = 53 ft; roadway width = 51 ft

Limit maximum Girder length to 120 ft

TxDOT T551 rail – 382 plf

Typical composite cast-in-place deck with 8” thick and f’c= 4 ksi, Ec = 3605 ksi

Girders with ultra-high concrete strength – f’ci = 20 ksi,

f’c = 30 ksi, Ec = 9872 ksi

PGSuper V 2.9.0.9

TxDOT 2013 Bridge Design Manual

Geometry

8 Number of spans

Exterior spans - 105 ft.

Interior spans - 115.06 ft.

Tx70 girders selected

Most economical

Least weight

Least number of girders

4 girders spaced at 16' on center

Design Parameters

PGSuper Model

Strand Layout, Span 8 Girder A

Section @ Mid-SpanSection @ Left-End Section @ ¼ Span

Shear Layout

Concrete Strength

Deck Properties and Overlay Weight

Design Results of Various Girders

Model Number

Girders

Strand Dia (in)

Weight of

Beam(kip/ft)

Number of strands (Exterior spans)

Number of strands (Interior spans)

Total Number

of Strands

Total weight of

girders (kips)

Total number

of girdersExternal

Girders

Internal

Girders

External

Girders

Internal

Girders

Tx 54 6 0.6 0.88 24 28 30 34 1496 38030.78 48

Tx 54 7 0.6 0.88 24 24 28 30 1572 44369.25 56

Tx 62 5 0.6 0.98 24 28 30 34 1236 35293.72 40

Tx 62 6 0.6 0.98 22 24 26 28 1264 42352.46 48

Tx 62 7 0.6 0.98 22 22 24 26 1376 49411.208 56

Tx 70 4 0.7 1.04 32 40 36 44 1248 29963.65 32

Tx 70 5 0.7 1.04 24 24 24 28 1032 37454.56 40

Tx 70 6 0.7 1.04 22 24 22 24 1120 44945.472 48

Final Design

Tx70, total 32 girders

1248 strands

No de-bonding used

Grade 270, Low-relaxation 0.7" strands

Additional mild steel reinforcement used

TxDot standard details used for shear design

f‘ci = 20 ksi, f‘c = 30 ksi

Distribution of L.L for span 8

• From hand calculation = 1.256

• Difference = 8.7%

Moment Capacity at Mid-spanExterior Girder – End Span

Comparison of Multiple Loads Moments And Moment Capacity

Comparison of Multiple Loads Shear And Shear Capacity

Multiple Loads Displacement

Ahmed, Haroon Rasheed

Girder Design (Tx 40 and 46)

Drawings,

PowerPoint Presentation

Bichewar, Namrata

Girder Design ( Tx 70)

Live Load Moment Distribution Factor

Emami Saleh, Arash (Team Leader)

General Model

Moment Calculations,

PowerPoint Presentation

Okagbare, Oghenekevwe Christabel (Team Leader)

Girder Design ( Tx 28 and Tx 34)

Drawings

Project Report

PowerPoint Presentation

Shaltoof, Mohammad Abed Mohammad

Girder Design( Tx 54 and 62)

Moment Calculations

PowerPoint Presentation

Distribution of Work

PART 2

POST-TENSIONED TWO-WAY SLAB DESIGN

Overall Second Level Plan

Design Parameters

Concrete Properties

Slab Thickness = 8 inches

F’c = 4,000 psi, Ec = 3605 ksi

Prestressed Steel Properties

½” dia. Grade 270 low-relaxation strands

Initial Prestress = 0.8 * fpu

Loading

Superimposed Dead Load = 20 psf

Superimposed Live Load = 40 psf

ACI 318-11 used as design code

Design Consideration

4 – span condition utilizing wall as an exterior support

Equivalent Frame Method

Software Inputs

Software Input

12’ floor to floor heights above & below

24” square columns

Exterior shear walls modeled to same width of design strip

Slab assumed to be fixed-fixed at boundary condition

Average Precompression range 125 psi to 300 psi

Percentage of Dead Load to balance 25% to 200%

Post-Tension Strand Cover: 1.5” top

2.0” bottom

Mild Reinforcement Cover: 1.0” top & bottom

Tributary Area

Tributary Area (Cont…)

Loading on the slab

ADAPT Rendering

Final Design Stresses

Max Tensile Stress = 0 x √(f’ci) < 3 x √(f’ci) OK

Max Compressive Stress = 0.164 x f’ci < 0.6 x f’ci OK

Number of tendons : 24 ( 6 – bands with 4 in each )

Final Design Stresses

Sustained Load Stresses

Total Load Stresses

Stress Diagram

-450

-400

-350

-300

-250

-200

-150

-100

-50

0

50

100

150

200

SPAN 1 SPAN 2 SPAN 3 SPAN 4

Stress DiagramsProject: "Term Project" / Load Case: SERVICE_1_Max_LL

+1.00 SW +0.30 LL_Max +1.00 SDL +0.30 XL +1.00 PT +0.00 HYP +0.00 LATTensile Stress Positive

Str

ess

[psi

]

Allowable Stresses Top

Tendon Profile

FINAL DESIGN: 15 – ½”, Grade 270 Low-Relaxation strands

Mild Steel Profile

Tendon layout24 strands – 4/band

Shear stud layout

Distribution of Work

Al Mutar, Sudad Saeed

• Model,

• Hand Calculations

• Project Report

• Presentation

Kadam, Kshitij Chandrakant

• Model

• Hand Calculations

• Project Report

• Presentation

Mazumder, Md Shahadat Hossain –

• Building Model and Bridge General Model

• Shop Drawings

• Project Report

• Presentation