Bridge Report Summary

7/26/2019 Bridge Report Summary

1/13

i

CVEN 754

Advanced structural Design Studio

A report on

DESIGN OF A PRESTRESSED CONCRETE BRIDGE

by

Alla, Jaya Ram Reddy, (UIN: 224002461)

Spring 2015


2/13

CVEN754BridgeProject

pg. ii

Table of Contents

Author: ....................................................................................................................... i

Table of Contents: ..................................................................................................... ii

1 Scope of the Project .............................................................................................3

2 Construction Methods & Drawings .....................................................................4

3 Typical Design Notes ..........................................................................................9

4 Summary of the Bill of Quantity for 5 design options ......................................10

5 Summary of the Cost estimation for 5 design options ...................................... 11

6 Reply to the Peer Review of the design.. ..........................................................12


3/13


pg. 3

1.

Scope of the Project

This Project is about the design and construction of 900 ft span bridge. The design of the new

river bridges items must be consistent with the requirements of TXDoT. The scope of this Contract is

to design and prepare 5 separate Bridge Plans, special provisions, quantity estimates, and compare the

merits of all the designs.

In response to your current need regarding the design of a 900ft bridge, the following five

designs have been prepared. In detail, we are gonna discuss about the summary of design by Er. Jaya

Ram Reddy Alla. The design has external post tensioning and the construction mthod assumed is big

lift.

SNo. EngineerSpan

ConfigurationGirder

Construction

MethodRemarks

1JAYA RAM REDDY

ALLA

140-190-240-

190-140TX 84 Big Lift

External Post

Tensioning

2KAITHA SHIVA

PRASAD

140-190-240-

190-140TX 70 Haunched

3SANTIAGO SERRANO

APONTE

140-190-240-

190-140TX 84 Shored

4AKESH VARMA

KOTHAPALLI

100-100-150-

200-150-100-

100

TX 70 ShoredWidened

Web

5NIKITHA REDDY

PONAKA

100-100-150-

200-150-100-

100

TX 70Big Lift

Unshored

Internal Post

Tensioning


4/13


pg. 4

2.

Construction Methods and Design Drawings

Engineer Name : JAYA RAM REDDY, ALLA

Construction Method : Big Lift (External Post Tension)

Span Configuration : 140-190-240-190-140

Construction Equipment : Crawler cranes (at Casting yard, site), trailor, pre-stressing

jacks

Construction Method:

Using formwork, the substructure (Pier and Pier cap) are constructed.

For transportation purpose, smaller spans are cast at yard and are transported to site and post

tensioned. (190 ft will be 70+120 and 240 will be 70+100+70).

Pre Tension:o For transportation purposes, pretension is designed for the dead load of the individual

segments.

o On the casting bed, before concreting the tendons are tensioned.

o These individual segments are transported to site on a trailor.

Post Tension:

o At site, individual segments are spliced together and post tensioning is done.

o The post tensioning is designed for the dead load of the girder, slab and weathering

course and railings.

o Once the post tensioning is done, the crawler cranes lift the 190 span in tandem and

place the girder on the pier caps.

o Likewise 240 span and the other 190 span is also erected.

o The deck slab is poured on the girders using sacrificial shutter/ formwork.

Local Post Tension:

o Once the deck is poured, the system acts as a continuous span. So before the railing and

weathering loads, local post tension using dywidag bars will be done over the pier,

nullifying the negative moments over the continuous support.


5/13


pg. 5

o

Simply Supported (only Pretensioning) Harped Solution


6/13


pg. 6

Longitudinal Section of Simply Supported (only Pretensioning) Harped Solution


7/13


pg. 7

Simply Supported Cross Sectional and Longitudinal Section (Pre-Tension + Post-Ten


8/13


pg. 8

Longitudinal Section for 620ft Span


9/13


pg. 9

3.

Typical Design Notes:

Eccentricities are not subjected to change without the notice and approval of the Engineer in

Charge.

Post-tension and pre-tension are to be done under the supervision of a trained Site Engineer. Rebar required for helical reinforcement in the pier has to be done according to the diameter and

spacing provisions provided in the drawings.

Any changes in the drawings are to be taken to the notice of Engineer and should proceed only if

they are approved.

The segments are subjected to lift only after the approval from the client. Equipment is to be

checked thoroughly before lifting.

Diameter of the tendons strands and rebar are not subjected to change without the approval of

Engineer in Charge.

Stirrups for the pier caps are to be bent as per the provisions mentioned in the design drawings.

Splicing and anchoring is to be done under the supervision of site engineer.


10/13


pg. 10

4.

Summary of the Bill of Quantity for 5 design options:

COMPARISION OF QUANTIY FOR 5 DIFFERENT BRIDGE DESIGN P

S.No Engineer Jaya Ram Reddy, A Shiva, K Akesh Varma,K San

1 Span Configuration 140-190-240-190-140 140-190-240-190-140

100-100-150-200-150-100-100

140190

2 Girder TX-84 TX-70 TX-70 TX

3Construction

Method

Big Lift(External Post

Tension)

Haunchedshored

Construction

Shored

Construction Co

4 Concrete Quantity 76043 Cu.Ft 72530 Cu.Ft 72422 Cu.Ft 8

5 Pre-Tension strands 92000 Ft 166089 Ft 136800 Ft

6Post TensionStrands

318200 Ft 355680 Ft 328320 Ft

Legend:

Least Quantity

Highest Quantity


11/13


pg. 11

5.

Summary of the Cost Estimation for 5 design options :

MATERIALS AND EQUIPMENT COST

ENGINEER Concrete Pre-Tension strands Post Tension Strands Crane Sho

Jaya Ram Reddy, A $350,644.92 $202,400.00 $700,040.00

$189,000.00

Shiva, K $334,442.56 $365,396.28 $782,496.00 $189,000.00

Akesh Varma,K $333,944.28 $300,960.00 $722,304.00

$189,000.00

Santiago, S $381,714.51 $222,024.00 $990,399.83

$189,000.00

Nikitha,P $333,944.28 $300,960.00 $722,304.00 $189,000.00

Notes:

Crane

price

is

based

on

$10,500

weekly

(40

Hours)

ShoreSystempriceisbasedon$1.2perSQFTperday(AccordingtoDoka)

DESIGN RANKING BASED ON

PRICE

RANKING ENGINEER

1

Jaya Ram Reddy, A

2 Nikitha,P

3 Shiva, K

4 Akesh Varma,K

5 Santiago, S


12/13


pg. 12

6. Reply to the Peer Review of the design:

Designer: Er. Jaya Ram Reddy Alla

Peer Reviewer: Er. Kelly Ha

The reply to the questions posed by the peer reviewer are addressed herewith.

Design Option 1-A:

1. Does the harping actually balance the end-moments?

a. I have tried to balance the maximum of the end moments. Care was taken that the

maximum possible tendons have been harped (Extra tendons couln't fit because of

the web thickness)

Design Option 1-B:

1.

If you want to use Post tensioning, need to use a modified Tx-84 in order for the ducts to

properly fit in the web. This is going to make your girder heavier and slighly change

sectional properties.

a. I have used 19 no' of 0.5" conduits which has a dia of 3.5" which gives me an clear

of 2.25" on either side in a web. So, I dont have to use a modified section.

2. 0.6" dia strands called out, used wrong area calculation in tendon force.

a. Noted (a typo), the tendon force calculated is correct, I had used 0.5" dia strands.

3. Note sure where ept1 came from?

a. Back calculation was done. The Ept1 required for 3 ducts was calculated and found.

4.

Why does f1e1=f2e2 ?a. Ofcourse, to balance the end moments, 1st post tension was balanced with pre

tension.

5. Was the sheer check and ultimate check conducted?

a. Noted, these checks were calculated and included in the design. Deflection was also

included.

Design of Pier Cap:

1. Have #6, #7 called out for the design.

a. No., only # 7 bars are to be used, please refer drawing. On pg 3.3.

2.

Did the moment for bent caps design come from the seismic forces or localized soft soil.

a. The moment has come from localized soft soil.

3. Need to add harsoil soil design & soft soil?

a. The critical moment was from localized soil, hence the cap was designed for

localized soft soil condition.


13/13


pg. 13

Design of Pier:

1. Need to add hard soil design.

a. The over turning moments were calculated in pg: 4.6, please refer.

2. Longitudinal Rft is large and may pose problems

a.

#14 no' bars were used, no where we need to bend these bars so less problem whileconstruction.

3. Transverse Rft is large and may pose problems

a. #4, #5 no' bars were used as shear reinforcement. There wont be any problem in

bending the bars.

Design of Continuous span:

1. Maybe want to think about splitting up tendons so that can be partially unstressed when

replacing the deck.Maybe want to think about splitting up tendons so that can be partially

unstressed when replacing the deck.a. For the reason, an extra conduit duct (no tendons) for future purpose can be

provided, just incase of maintenaince.

2. Add stress checks at mid span of end spans

a. The stress checks for 190' and 240' spans at Mid span were already included, please

refer Pg: 27.

3. For live load checks, not sure if moments were found correctly.

a. Moment distribution method was adopted to find the live load moments. The lane

load and truck loads were included in the moment calculation. (Refer Pg: 25)

4. Cross section ends, need to show anchors will fit; will be especially large with using 37

strands.a. "VSL" specifies that for strands of 55 needs 6.3" from center for anchorage, for the

240' span, I have provided 6" for 37 strands, which should be enough.

Bridge Report Summary

Documents

Transcript of Bridge Report Summary