final report (group 5)

Term Project: CE 5309/4363 Prestressed Concrete

Design of Bridge 205 of I-35W Extension Project and

Design of Post Tensioned Two-Way Slab

Submitted to:Dr. Shih Ho Chao

Department of Civil Engineering

By: Group 5

Anaimallur Mani,Lokesh KumarGurjar, Santosh MahendraKintner, Courtney LynnMukati, Gaurav SinghRampurawala, SameerTuladhar, Shuveksha

Nukala, Vishwas

May 5, 2016

CE 5309 Prestressed Concrete Design Group 5Project Final Report Spring 2016

AbstractThis project provides an opportunity to implement the knowledge gained through the prestressed

concrete design course on a real world situation. The problem statement requires group members

to divide the tasks such as planning project schedule, software analysis and preparation of design

calculations, specifications and report. Also from a technical viewpoint, by designing bridge

girders and parking floor slab with material and geometrical constraints, provides the necessary

experience for the group members in their engineering careers. It provides a more detailed study

of the various provisions in the code and its commentary. Also the recommendations stated by

various authors in field of prestressed concrete design and its practice is another addition from

the project. The invaluable benefits gained through this experience boosts the designing skills

and problem solving abilities of the group and this will surely enhance their knowledge in future

design and construction works.

The term project includes two tasks. The first task is a bridge design with pre-tensioned bridge

girders and the second task involves a building design with post-tensioned two-way slabs. The

design and analysis of the given structure is performed as per the guidelines and requirements

stated in the American Concrete Institute Building Code Requirements for Structural Concrete of

(ACI 318) and American Association of State Highway & Transportation Officials (AASHTO

LRFD Bridge Design Specifications).

1


Table of Contents

Abstract..........................................................................................................................................1

List of Figures................................................................................................................................1

List of Tables..................................................................................................................................1

Part 1: Bridge 205 of I-35W Extension Project Design Using PGSuper..................................1

1. INTRODUCTION....................................................................................................................1

1.1 Project Scope......................................................................................................................1

1.2 Software..............................................................................................................................1

2. PROJECT METHODOLOGY..................................................................................................1

2.1 Study of Plan and General Arrangement............................................................................1

2.2 Design Parameters..............................................................................................................1

2.3 PGSuper Analysis and Design Procedure..........................................................................1

3. ANALYSIS AND RESULTS......................................................................................................1

4. DESIGN SUMMARY...............................................................................................................1

5. SHOP DRAWINGS..................................................................................................................1

6. CONCLUSION........................................................................................................................1

Part 2: Design of Post-Tensioned Two Way Slab for Oak Creek Village Apartments Using

ADAPT-PT.....................................................................................................................................1

1. INTRODUCTION....................................................................................................................1

1.1 Project Scope......................................................................................................................1

1.2 Software..............................................................................................................................1

2. PROJECT METHODOLOGY..................................................................................................1

2.1 Study of Plan......................................................................................................................1

2.2 Design Parameters..............................................................................................................1

2.3 ADAPT-PT Analysis and Design Procedure.....................................................................1

2.4 Calculation of effective prestressing force (fse).....................................................................1

3. ANALYSIS AND RESULTS......................................................................................................1

3.1 Design Moment..................................................................................................................1

2


3.2 Check for stresses:..............................................................................................................1

3.3 Deflection:..........................................................................................................................1

4. DESIGN SUMMARY...............................................................................................................1

4.1 Number of Strands.................................................................................................................1

4.2 Tendon Profile....................................................................................................................1

4.3 Shear Design for punching shear........................................................................................1

4.4 Longitudinal Reinforcement...............................................................................................1

4.5 Materials Summary............................................................................................................1

4.6 Summary Report:...............................................................................................................1

5. SHOP DRAWINGS.............................................................................................................1

6. CONCLUSION........................................................................................................................1

WORK DISTRIBUTION..............................................................................................................1

REFERENCES..............................................................................................................................1

APPENDIX A-1: BRIDGE GIRDER DESIGN REPORT OUTPUT.......................................1

APPENDIX A-2: BRIDGE GIRDER DESIGN MANUAL CALCULATIONS......................1

A. Calculation of Flexural Strength for Span 2- Girder A..........................................................1

B. Live Load Distribution Factor for an Interior Beam (For Span 5 – Girder D)......................1

C. Live Load Distribution Factor for an Interior Beam (For Span 1 – Girder D).....................1

APPENDIX A-3: BRIDGE GIRDER SHOP DRAWINGS.......................................................1

APPENDIX B-1: SLAB DESIGN.................................................................................................1

INPUT DRAWINGS FOR OAKLAND CREEKS.........................................................................1

APPENDIX B-2: SLAB DESIGN SHOP DRAWINGS.............................................................1

3


List of FiguresFigure 1: Overall Plan......................................................................................................................1Figure 2: Cross-Sectional View for Spans 1,3,5,6 and 7.................................................................1

Figure 3: Cross-Sectional View for Span 2.....................................................................................1

Figure 4: Cross-Sectional View for Span 4.....................................................................................1

Figure 5: Cross section and Debonding Pattern for Span 2 Girder A.............................................1

Figure 6: Longitudinal View of Span 1- Girder A..........................................................................1

Figure 7:Moment Results at Midspan‐Exterior Girder (Span 1).....................................................1

Figure 8: Shear Results at Midspan‐Exterior Girder (Span 1)........................................................1

Figure 9: Displacement Results at Midspan‐Exterior Girder (Span 1)............................................1

Figure 10: Plan View.......................................................................................................................1

Figure 11: Elevation View...............................................................................................................1

Figure 12: Adapt Model...................................................................................................................1

Figure 13: Moment Diagram...........................................................................................................1

Figure 14: Stress Diagrams..............................................................................................................1

Figure 15: Deflection.......................................................................................................................1

Figure 16: Tendon Height Diagram.................................................................................................1

List of TablesTable 1: Girder Design Summary (All Spans)................................................................................1

Table 2: Mild Steel Reinforcement Design for Span 1- Girder A...................................................1

Table 3: Distribution Factor for an Interior Beam...........................................................................1

Table 4:Sample Girder Schedule.....................................................................................................1

Table 5: Sample Shear Reinforcement Detail.................................................................................1

Table 6: Camber and Deflections....................................................................................................1

Table 7: Prestress Force and Strand Stresses for Span 1- Girder A................................................1

Table 8:Allowable Stress limits.......................................................................................................1

Table 9: Number of Strands and Tendon Force...............................................................................1

Table 10:Critical Section Stresses...................................................................................................1

Table 11: Punching Shear Reinforcement.......................................................................................1

4


Table 12: Longitudinal Reinforcement............................................................................................1

Part 1: Bridge 205 of I-35W Extension Project

Design Using PG Super

5


1. INTRODUCTION

The main objective of this project 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.

1.1 Project Scope

The project scope is to study general arrangement plan, perform analysis in PGSuper and design

all 7 spans using AASHTO LRFD and TxDOT specifications for presressed concrete bridges.

Finally prepare shop drawings and specifications along with a manual design check.

1.2 Software

The analysis was performed by using PGSuper (Prestressed Girder Superstructure Design and

Analysis), V. 2.9 (AASHTO LRFD 2014) for bridge design. Autodesk AutoCAD 2016 is used to

prepare structural drawings (shop drawings) and specifications

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 ParametersThe 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

6


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 PGSuper 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. A sample of the

output from some of these checks can be found in Appendix A-1.

Strand Stresses [5.9.3]

Stress Check for Service I for Casting Yard Stage (At Release) [5.9.4.1.2]

Stress Check for Service I for Deck and Diaphragm Placement (Bridge Site 1)

Stress Check for Service I for Final without Live Load (Bridge Site 2) [5.9.4.2.1]

Stress Check for Compressive Stresses for Service I for Final with Live Load (Bridge Site 3)

[5.5.3.1]

Stress Check for Tensile Stresses for Service III for Final with Live Load (Bridge Site 3)

[5.9.4.2.2]

Stress Check for Compressive Stresses for Fatigue I for Final with Live Load (Bridge Site 3)

[5.5.3.1]

7


Positive Moment Capacity for Strength I Limit State for Final with Live Load Stage (Bridge

Site 3) [5.7]

Ultimate Shears for Strength I Limit State for Bridge Site Stage 3 [5.8]

Horizontal Interface Shears/Length for Strength I Limit State [5.8.4]

Longitudinal Reinforcement for Shear Check - Strength I [5.8.3.5]

Optional Live Load Deflection Check (LRFD 2.5.2.6.2)

Girder Dimensions Detailing Check [5.14.1.2.2]

Stirrup Detailing Check [5.8.2.5, 5.8.2.7, 5.10.3.1.2]

Camber Check

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 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’. Due to its long span, the stress limits in concrete at initial and

service stage had to be increased beyond the project permissible values, as allowed by Dr. Chao.

The final f’ci and f’c in our design are 9 ksi and 15 ksi, respectively. Eventually 15-Tx70 girders

were required in Span 2 (Figure 3 and 4) to ensure the capacity to demand ratio was equal to or

greater than 1.0 for various stress stages and girder locations listed below.

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).

8


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

9


Figure 5: Cross section and Debonding Pattern for Span 2 Girder A

Figure 6: Longitudinal View of Span 1- Girder A

10


3. ANALYSIS AND RESULTSThe 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)

11


Figure 9: Displacement Results at Midspan‐Exterior Girder (Span 1)

4. DESIGN SUMMARYAll 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 1: Girder Design Summary (All Spans)

Span 1 Span 2 Span 3 Span 4 Span 5 Span 6 Span 7Length of Span 102.5 ft 230.58 ft 111.17 ft 130 ft 98.09 ft 114 ft 114 ftGirder Type TX 54 TX 70 TX 54 TX 70 TX 54 TX 54 TX 54Number of Girders 5 15 5 5 5 5 5Spacing 12 ft 3.52 ft 12 ft 7 ft 12 ft 12 ft 12 ftNumber of Strands 48 70 48 56 48 54 54Dia. of Strands 0.6” 0.7” 0.6” 0.7” 0.6” 0.6” 0.6”Straight Strands 40 70 40 40 40 46 46Harped Strands 8 54 8 8 8 8 8Debonded Strands 0 22 0 12 0 0 0

12


Table 2 shows a sample calculation of Mild Steel Reinforcement for a Span 1 Girder A.

Table 2: Mild Steel Reinforcement Design for 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 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

*reduction of LLDF for moment in longitudinal beam on skewed supports

13


Table 4 show the sample girder schedule for span 1 which is extracted from the PGSuper

software.

Table 4:Sample Girder Schedule

Table 5 shows the sample shear reinforcement detail.

Table 5: Sample Shear Reinforcement Detail

Table 6: Camber and Deflections

14


Table 7: Prestress Force and Strand Stresses for Span 1- Girder A

5. SHOP DRAWINGSCAD drawings of Span 1 Girder A were developed using the design developed in PG Super. A

cross section view, elevation view and shear stirrup details have been included in the shop

drawings. They can be found in Appendix A-3.

6. CONCLUSIONIn summary, we optimized the design of this bridge to use only prestressed concrete girders and

to be the most economical design possible. In doing this, we used 5-Tx54 girders in all spans

15


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.

16


Part 2: Design of Post-Tensioned Two Way Slab for

Oak Creek Village Apartments Using ADAPT-PT

17


1. INTRODUCTION

The main objective of this project is to design the post-tensioned two-way slab for the Oak Creek

Village Apartments by using ADAPT/PT 2015 software. This is a slab of a two story garage

building. We were assigned to carry out the design for the strip with 3 spans and a cantilever to

the left of the span.

1.1 Project Scope

The project scope is to study floor plan, perform analysis and design of the two-way slab using

ADAPT/PT 2015 software and ACI 318-2014 specifications for prestressed concrete building

design to find the number of strands, tendon layout and the amount of post tensioning force

required to balance the service load on the slab.

1.2 Software

The analysis was performed by using ADAPT-PT (AASHTO LRFD 2014) for slab design.

Autodesk AutoCAD 2016 is used to prepare structural drawings (shop drawings) and

specifications

2. PROJECT METHODOLOGY

2.1 Study of Plan

According to the plan there are 3 continuous spans of 29 ft. and a cantilever of 16.96 ft. to the

left of the spans. The width of cantilever span and first two continuous spans are 14 ft. while for

the third span it is 27 ft. For cantilever span and first two continuous spans the slab width of 14

ft. spans on left side of the columns as on the right side there is a ramp, while for the third 27ft.

span the slab spans on both sides of the column with span width of 13 ft. on the right side.

According to the plan the columns supporting the slab have the size of 2ft. X 2ft. and a height of

12 ft.

18


Figure 10: Plan View

Figure 11: Elevation View

2.2 Design ParametersThe design was based on ACI 318-2014 Building Design Manual. As per the project statement,

the design was based on an overall slab thickness of 8-in. For design of slab the concrete strength f’c = 4 ksi, f’ci = 3 ksi, Ec = 3605 ksi. was initially used but it was

changed within the limits later. No drop panels or transverse beams were allowed to use. A 0.5-in. diameter, Grade 270 low-relaxation strands with initial prestress = 0.8 fpu were used. Superimposed dead load = 20 psf (uniform) and live load = 40 psf (uniform) was given. The PT tendons were assumed to end at

an intermediate coupler and there was no effect on the slab beyond the coupler. The stress limits

according to ACI are summarized below in Table 8.

19


Table 8:Allowable Stress limits

Limits Values

Tension stress limits √ f ' cAt Top 6.000

At Bottom 6.000Compression stress limits / f'c At all locations 0.450

Tension stress limits (initial) √ f ' cAt Top 3.000

At Bottom 3.000Compression stress limits (initial) / f'c At all locations 0.600

2.3 ADAPT-PT Analysis and Design Procedure

All 3 continuous spans and cantilever are modeled according to given plans. The 3D view of the

slab modelled in ADAPT-PTRC 2015 is shown in figure below. Multiple iterations are

performed to optimize the design and meet project objectives. In order to design the post tension

slabs we need to input the value of effective prestressing force (fse) after all the losses. For this all

the calculations are shown below.

Figure 12: Adapt Model

20


2.4 Calculation of effective prestressing force (fse)1.Losses due to Shrinkage

ε s (t )= tb+ t

εsu K SH K SS

b= 35 …for moist cured normal weight concrete

t= 21 days (assumed)

Assuming relative humidity(H) of 60%.

ε su=6 x10−4

K SH=1.40−0.01 H=1.40−0.01 x 60=0.8

VS

=3.91∈.

K SS=0.86− (0.86−0.77 )( 4−3 )

(3.91−3 )=0.778>0.6 for shrinkage

Assume long-term losses to take place over 50 years (18250 days):

ε st=18250

18250+35( 6 x10−4 ) (0.8 ) (0.778 )=3.727 x10−4

Eps=28500 ksi

∴∆ f ps=28500∗3.727∗10−4=10.62 ksi

2. Losses due to Creep

C ct (t )= t 0.6

10+t 0.6 C cu K CH KCA KCS

C cu=2.0

KCH=1.27−0.0067 H =1.27−0.0067∗60=0.868

t A=21 days (assumed )

21


KCA=1.25 t A−0.118=1.25∗21−0.118=0.873

KCS=0.87−(0.87−0.77 )

( 4−3 )(3.91−3)=0.779>0.68 for creep

C ct (t )= 182500.6

182500.6+10(2.0 ) (0.868 ) (0.873 ) (0.779 )=1.1487

f ci' =6000 psi

Eci=57000√ f ci' =57000∗√6000

1000=4415 ksi

f ci=216∗1000∗17∗0.294/1680=642.6 psi

ε ci=f ci

Eci= 642.6 x10−3

4415=1.455 x 10−4

C c ( t )=εc (t )ε ci

→ εc ( t )=C c (t )∗εci=1.1487∗1.455 x 10−4=1.672∗10−4

∆ f ps=Eps∗εc (t )=28500∗1.672∗10−4=4.765 ksi

3. Losses due to Relaxation of strands

∆ f pr=f pilog ( t )

K [ f pi

f py−0.55]

K=45 for Low relaxation strands

For low-relaxation strands: f py=0.9 f pu=0.9∗270=243 ksi

f pi=0.8 f pu=0.8∗270=216 ksi

∆ f pr=216∗log (18250 )

45 [ 216243

−0.55]=6.931 ksi

∴ Total losses = 22.316 ksi

∴ f pe=216−22.316=193.68 ksi

22


3. ANALYSIS AND RESULTS

3.1 Design Moment

The moment diagram is shown in Figure 13 which shows positive and negative moments at the

supports and midspan.LOAD COMBINATION: Envelope

Moment DiagramsProject: "Design Of Two-Way Slabs" / Load Case: Envelope

Moment Drawn on Tension Side

Figure 13: Moment Diagram

23


3.2 Check for stresses:

According to ACI 318-2014 the checks for limiting stresses at service are given by ADAPT-PT

are as follows:

-500

-400

-300

-200

-100

0

100

200

300

400

500

L-Cant SPAN 1 SPAN 2 SPAN 3

Stress DiagramsProject: "Design Of Two-Way Slabs" / Load Case: Envelope

Tensile Stress Positive

Str

ess

[psi

]

Allowable Stresses Top Max Top Min

-1000

-800

-600

-400

-200

0

200


Stress DiagramsProject: "Design Of Two-Way Slabs" / Load Case: Envelope

Tensile Stress Positive

Str

ess

[psi

]

Allowable Stresses Bottom Max Bottom Min

Figure 14: Stress Diagrams

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3.3 Deflection:

The figure 15 shows the deflection for all the three spans.

2.0

1.5

1.0

0.5

0

Left Cantilever Span 1 Span 2 Span 3

Deflection DiagramsFile: final safe adapt dgn

Def

lect

ion

[in]

Service Env. Max Total Service Env. Min Total

Figure 15: Deflection

4. DESIGN SUMMARY

4.1 Number of Strands The number of strands as per the design parameters, loading and the strength and geometry of

the slab was calculated by the ADAPT-PT. The number of strands was 17.

Table 9: Number of Strands and Tendon Force

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4.2 Tendon Profile

The tendon profile of one of the strands is as shown in the figure below.

Figure 16: Tendon Height Diagram

4.3 Shear Design for punching shear

The results of shear design carried out by ADAPT-PT are as follows The 2-way shear also

known as punching shear was checked near the edge of the columns. Based on the stresses

shown in Table 10, shear studs rails were not provided.

Table 10:Critical Section Stresses

Label Layer Cond.

Factored shear

Factored moment

Stress due to shear

Stress due to

moment

Total stress

Allowable stress

Stress ratio

k k-ft ksi ksi ksi ksi 1 1 1 -97.63 -163.60 0.09 0.068 0.159 0.244 0.6532 1 1 -92.69 +4.83 0.09 0.002 0.089 0.244 0.3653 1 1 -138.31 +197.59 0.13 0.082 0.212 0.230 0.9204 1 2 -85.47 -209.04 0.12 0.097 0.215 0.268 0.799

Table 11: Punching Shear Reinforcement

Reinforcement option: Shear StudsStud diameter: 0.5Number of rails per side: 2

Col. Dist Dist Dist Dist Dist Dist Dist Dist Dist Dist in in in in in in in in in in1 2 3

26


4 Dist. = Distance measured from the face of supportNote: Columns with --- have not been checked for punching shear.Note: Columns with *** have exceeded the maximum allowable shear stress

4.4 Longitudinal Reinforcement

This provision is in place to control cracking and increase ductility of the structure since

unbounded steel is still elastic at the time concrete crushes. The following longitudinal

reinforcement shown in Table 12 is provided. A visual representation of this reinforcement can

be seen in the shop drawings in the appendix.

Table 12: Longitudinal Reinforcement

Span ID Location From Quantity Size Length Area ft ft in2

CL 1 TOP 0.00 4 6 31.50 1.761 2 TOP 17.85 3 6 22.50 1.322 3 TOP 17.85 3 6 22.50 1.323 4 TOP 17.85 3 6 11.50 1.32

CL 5 TOP 7.48 3 6 18.50 1.321 6 TOP 20.75 3 6 16.50 1.322 7 TOP 20.75 3 6 16.50 1.323 8 TOP 20.75 3 6 8.50 1.32

CL 9 BOT 0.00 6 8 104.00 4.74

4.5 Materials Summary

From this design the following quantities of materials will be needed. 1. Concrete

Total volume of concrete = 1527.03ft3 (56.56 yd3)Area covered = 1832.44 ft2

2. Mild steelTotal weight of rebar = 2392.63 lbsAverage rebar usage = 1.31 psf, 1.57 pcf

3. Prestressing materialTotal weight of tendon = 930.0 lbAverage tendon usage = 0.51 psf, 0.61 pcf

27


4.6 Summary Report:

ADAPT - STRUCTURAL CONCRETE SOFTWARE SYSTEMADAPT-PT Version "2015" Date: "05 - 01 - 2016" Time: "21:36" File: final safe adapt dgn

1 - PROJECT TITLE: "Design Of Two-Way Slabs"1.1 Design Strip: Group-51.2 Load Case: Envelope

2 - MEMBER ELEVATION [ft] 16.96 29.00 29.00 29.00


3 - TOP REBAR3.1 ADAPT selected3.2 ADAPT selected3.3 Num. of layers

1 4#6X31'6" 2 3#6X22'6" 3 3#6X22'6" 4 3#6X11'6"

5 3#6X18'6" 6 3#6X16'6" 7 3#6X16'6" 8 3#6X8'6"

1 1 1 1 1 1 1 1 1 1 1 1

4 - TENDON PROFILE

4.1 Datum Line

4.2 CGS Distance A [in]

4.6 CGS Distance B [in]

4.10 CGS Distance C [in]

4.14 Force/Width [kips/ft]

4.3 Force A [kips]

4.7 Force B [kips]

4.11 Force C [kips]

5.00 5.00 5.00 9.00433.872

3.50 9.00433.872

3.50 3.50 9.00433.872

1.75 1.75 5.00433.872

30.99 30.99 30.99 16.07 .00

5 - BOTTOM REBAR5.1 ADAPT selected5.2 ADAPT selected5.3 Num. of layers

9 6#8X104'0"

1 1 1 1 1 1 1 1 1 1 1 1

6 - REQUIRED & PROVIDED BARS6.1 Top Bars [ in2] required provided

6.2 Bottom Bars

max

max

0.01.63.2

1.22.43.64.8

2.83

0.00

2.83

0.00

2.61

0.00

2.61

4.30

7 - PUNCHING SHEAR OK=Acceptable RE=Reinforce NG=Exceeds code NA=not applicable or not performed

0.00 0.00

0.65- 97.63- 163.60OK

0.37- 92.69 4.83OK

0.92- 138.31197.59OK

0.80- 85.47- 209.04OK

7.1 Stress Ratio Shear Force [kips] Bending Moment [kips*ft]7.2 Status

8 - LEGEND Stressing End Dead End

9 - DESIGN PARAMETERS9.1 Code: American ACI318 (2011)/IBC (2012) f'c = 8000 psi fy = 60 ksi (longitudinal) fy = 60 ksi (shear) fpu = 270 ksi

9.2 Rebar Cover: Top = 1 in Bottom = 1 in Rebar Table:

10 - MATERIAL QUANTITIESCONCRETETotal volume of concrete = 1527.0 ft3

Area covered = 1832.4 ft2

MILD STEELTotal weight of rebar = 2374.8 lbAverage rebar usage = 1.296 lb/ft2, 1.555 lb/ft3

PRESTRESSING STEELTotal weight of tendon = 930.0 lbAverage tendon usage = 0.508 lb/ft2, 0.609 lb/ft3

11 - DESIGNER'S NOTES

28


5. SHOP DRAWINGS

A CAD drawing of tendon profile and longitudinal reinforcement details have been included in

the shop drawings. They can be found in Appendix B-2.

6. CONCLUSIONIn conclusion, the final design of the post tensioning two-way slab was carried out with the help

of ADAPT-PT. The minimum number of strands required to compensate the service loading in

the slab was found to be 17 in the particular strip. The strands were arranged with 4 strands

banded together in the direction of the strip. The strands in the transverse direction was equally

spaced at a distance of 3.2 ft. The limits of the stresses calculated was determined to be within

the permissible limits of 125 ksi to 300 ksi in the post tensioned strands. In this case, shear studs

were not required since the allowable stress is greater than the provided stress and safe in

punching shear.

29


WORK DISTRIBUTION

30

Anaimallur Mani,Lokesh Kumar

Adapt PT ModelPreparation of Slab ReportCalculation of prestress losses for slabOptimising bridge design

Gurjar, Santosh MahendraAdapt PT ModelManual calculation of girder flexural strengthPreparation of Slab ReportOptimising bridge design

Kintner, Courtney LynnGroup CoordinationModelling in PG Super, Optimising bridge designPreparation of Bridge ReportShop drawings

Mukati, Gaurav SinghCalculation of prestress losses for slabOptimising bridge designPreparation of Presentation

Rampurawala, SameerModelling in PG Super, Optimising bridge designCalculation of prestress losses for slabPreparation of Bridge Report

Tuladhar, ShuvekshaGroup CoordinationModelling in PG Super, Optimising bridge designCalculation of Live Load Distribution FactorsPreparation of Bridge and Slab reportShop drawings and Overall Review of Report/Presentation

Nukala, VishwasPreparation of PresentationAdaptPT ModelOptimising bridge design

Group 5 Work Distribution


REFERENCES AASHTO (American Association of State Highway and Transportation Officials). 2014. AASHTO LRFD.

ACI (American Concrete Institute). 2014. Building Code Requirements for Structural Concrete and Commentary. ACI 318-14.

Chao, Shih Ho. CE 5309 Spring 2016 Class Lecture Notes.

Naaman, Anthoine E. 2012. Prestressed Concrete Analysis and Design. Third Edition.

TxDOT (Texas Department of Transportation). 2013. TxDOT Bridge Design Manual.

31


APPENDIX A-1: BRIDGE GIRDER DESIGN REPORT OUTPUT

32


33


34


35


APPENDIX A-2: BRIDGE GIRDER DESIGN MANUAL

CALCULATIONS

A. Calculation of Flexural Strength for Span 2- Girder A

dp = 70‐7.129 + 8 = 70.871 inch

bs = 3.75 ft f’c = 15ksi β1 = 0.65 kc = 0.28

A = 9636 in2 yb = 31.91 inch yt = 38.09 inch I = 628747in4

Sb = 19703 in3 H = 70in A’s = #4-6 = 1.2 in2 As = 0 inch2 fy= 60 ksi d’s = 1.75 inch

Aps = 70 X 0.294 = 20.58 in2

fps = fpu(1‐(kc/dp) fps = 270 ‐ 1.067 C

A’s f'y = 72 kft tf = 3.5 inch bw = 9 inch bf = 36.67 inch

Assuming rectangular section behavior

0.85 X 15 X 3.75 X 12 X 0.65C = 20.58 X (270 ‐ 1.067 C) -72

C = 34.4in > 8 inch

Our assumption is wrong.

Assuming T Section behavior

0.85 X 15 X 9 X 0.65 X C + 0.85 X 15 X (36.67-9) X 3.5 = 20.58 X (270 ‐ 1.067 C) – 72

C = 44 inch

a = 0.65 X 44 = 28.61 inch

fps = 270‐1.067(44) = 223.052 ksi

Mn = 20.58 X 223.052 X (70.871-28.61/2)-72 X (1.75-28.61/2) + 0.85 X 15 X (36.67-9) X 3.5

Mn = 21816.65 kft

Calculating Ф factor:

εt = 0.003 X (70.871-34.4)/34.4 = 0.00318 < 0.005 hence transition section.

Ф = 0.75 + 0.25(0.00318-0.002)/(0.005-0.002) = 0.848

ФMn = 0.848 X 21816.65 = 18500.51 kft

From PGSuper фMn = 20243.38 kft

36


B. Live Load Distribution Factor for an Interior Beam (For Span 5 – Girder

D)Beam type: I girder TX54

Type of cross-section: k

Span Length = 98.09 ft

No. of beams (Nb) = 5

S = 12 ft

Live Load Distribution Factor for moment:

( K g

12.0 Lt s3 )

0.1

=1.09 From AASHTO table 4.6.2.2.1.3

1. One Lane Design Load:

D F∫ ¿=0.06+( S

14 )0.4

( SL )

0.3( Kg

12.0 L ts3)

0.1

¿

¿0.06+( 1214 )

0.4

×( 1298.09 )

0.3

× 1.09

= 0.6057

2. Two Lane Design Load: D F

∫ ¿=0.075+( S9.5 )

0.4

( SL )

0.2( K g

12.0 L ts3)

0.1

¿

¿0.075+( 129.5 )

0.4

×( 1298.09 )

0.2

×1.09

= 0.8612

Reduction of LLDF for moment in longitudinal beam in skewed supports

θ = 24.973o which is less than 30o

So, reduction is not required.

37


C. Live Load Distribution Factor for an Interior Beam (For Span 1 – Girder

D)Beam type: I girder TX54

Type of cross-section: k

Span Length = 102.52 ft

No. of beams (Nb) = 5

S = 12 ft

Live Load Distribution Factor for moment:

( K g

12.0 Lt s3 )

0.1


1. One Lane Design Load:

D F∫ ¿=0.06+( S

14 )0.4

( SL )

0.3( Kg

12.0 L ts3)

0.1

¿

¿0.06+( 1214 )

0.4

×( 12102.52 )

0.3

×1.09

= 0.5985

2. Two Lane Design Load: D F

∫ ¿=0.075+( S9.5 )

0.4

( SL )

0.2( K g

12.0 L ts3)

0.1

¿

¿0.075+( 129.5 )

0.4

×( 12102.52 )

0.2

× 1.09

= 0.8542

Reduction of LLDF for moment in longitudinal beam in skewed supports

θ = 37.164o which is greater than 30o

So, reduction is required.

38


c1=0.25 ( K g

12.0 L t s3 )

0.25

( SL )

0.5

( K g

12.0 Lt s3 )

0.25


c1=0.25 × (1.15 )0.25( 12102.52 )

0.5

=0.0885

1−c1 (tanθ )1.5=1−0.0885∗¿

One Lane Design Load: D F∫ ¿=0.5985× 0.9415=0.5634¿

Two Lane Design Load: D F∫ ¿=0.8542× 0.9415=0.8042 ¿

39


APPENDIX A-3: BRIDGE GIRDER SHOP DRAWINGS

40


APPENDIX B-1: SLAB DESIGN

INPUT DRAWINGS FOR OAKLAND CREEKS

41


APPENDIX B-2: SLAB DESIGN SHOP DRAWINGS

42

final report (group 5)

Documents