TECHNOLOGICAL INSTITUTE OF THE PHILIPPINES

1338 Arlegui St. Quiapo, Manila

Presented to the Faculty of Civil Engineering

PRESTRESSED CONCRETE DESIGN (CE 513)

“Design of Saint Florida 50 m. Pre-Cast Bridge”

Members:
Arcilla, Francis (Representative)
Chiong, Kenneth
Chiong, Kimberly
Druja, Jeramie
Datumanong, John Lexter A.
Glean Kassandra Xavier
Miguel, Kayla Camille

NOVEMBER 2020
 CHAPTER 1:
PROJECT BACKGROUND

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 Design of Saint Florida Pre-Cast Bridge
Francis Arcilla, Kenneth Chiong, Kimberly Chiong,, John Lexter Datumanong
Kassandra Xavier Glean, Jeramie Druja, Kayla Camille Miguel.
Students, Civil Engineering Department, Technological Institute of the Philippines – Manila

ABSTRACT
The design project "Design of Saint Florida Pre-Cast Bridge" is a 50 meters Bridge combined arch
and prestressed concrete girder bridge crossing the Pasig River between in Quiapo and Padre Burgos
Avenue in Ermita in Manila, Philippines. It connects the districts of Ermita and San Miguel, passing over the
western tip of Isla de Convalecencia.
The bridge, which was constructed in 1950 under the supervision of the engineering firm Pedro Siochi
and Company, replaced the Puente Colgante. Saint Florida Pre-Cast Bridge was designed as a trapezoidal
structural steel bridge and was inspired from the design of Sydney Harbour Bridge.
The design followed the standard codes for National Structural Code of the Philippines (NSCP),
American Concrete Institute (ACI) and American Standards for Testing and Materials (ASTM) and
Association of Structural Engineers of the Philippines Steel Handbook (ASEP). The design of the tower and
building follows the standard codes mentioned above.
This design project used modern civil engineering tools such as Autocad for drafting the
architectural plans, Microsoft Excel for design of finite element. Structural Analysis and Design (STAAD)
software for structural analysis.

PROJECT OBJECTIVES

The objectives of the design are as follows:

To apply knowledge of mathematics, science, and engineering to solve complex engineering

problems and real life situations that the community is facing.

To Identify, formulate, and solve complex engineering problems; solve complex engineering
problems by designing systems, components, or processes to meet specifications within realistic
constraints such as economic, environmental, cultural, social, societal, political, ethical, health and safety,
manufacturability, and sustainability accordance with the standards.

To apply civil engineering standards which involve the principles pre-stressed concrete design.

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 Include multiple constraints such as economic, health and safety, and constructability with the aid
of engineering codes and standards.

To use necessary modern tools in the design process like Microsoft Word, Microsoft Excel, ETABs
Software, Auto-CAD Software and Google Sketch-up Software.

PROJECT SCOPE AND LIMITATIONS

Project Scope

The design project primarily focuses more or less on the civil design aspects and structural
analysis of a 50 meter (m.) bridge that governed by standards and codes specified in the National
Structural Code of the Philippines (NSCP). Main design will be prestressed concrete design.

Project Limitation

The project will cover the design analysis of 50 meters (m). Pre-Cast Bridge. It includes structural
design Computation only focuses on the design of beams only, final design plan and drawings. Above and
under, the designers will use the principles used in Prestressed Concrete Design (PCD) which is the
Ultimate Strength Design (USD), and Working Stress Design (WSD). This project is only limited to the
various problems involving in Prestressed Concrete Design. The sizes and code of standards using PCD.
Other topics and problems which are not part of the said designs are not included in this project.
Mechanical designs and estimates are excluded from the project.

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 CHAPTER 2:
DESIGN INPUTS

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ARCHITECTURAL PLANS
The Architectural Plans consist of the perspective, location plan, site development plan, vicinity
map, elevations and floor plan. The 50 meters (m.) Pre Cast Bridge connects the districts of Ermita and
San Miguel, passing over the western tip of Isla de Convalecencia Manila, Philippines.

Figure 2.1 shows the perspective of the 50 meters Pre Cast Bridge.
Figure 2.2 shows the location map of the site
Figure 2.3 shows the vicinity map
Figure 2.4 shows the transverse section
Figure 2.5 shows the general elevation
Figure 2.6 shows the elevation of the 50 meter Pre Cast Bridge from Point A to B

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 Figure 2.1: Perspective

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 Fig. 2.2: Location Map

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 Fig. 2.3: Vicinity Map

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 Fig. 2.4: Transverse Section

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 Fig. 2.5: General Elevation

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 Figure 2-6.1: Elevation from Point A to B

Figure 2-6.2: Elevation from Point A to B

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 Figure 2-6.3: Elevation from Point A to B

Figure 2-6.4: Elevation from Point A to B

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 CHAPTER 3:
ANALYSIS

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BRIDGE GENERAL DATA:

UNITS DATA:

UNITS DATA:

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TRANVERSE DIRECTION:

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GIRDER DIMENSIONS:

]]

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PRECAST SECTION:

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COMPOSITE SECTION:

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DECK REINFORCEMENT DESIGN:

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GIRDER DIMENSIONS:

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GIRDER CONTROLS:

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ELASTOMERIC BEARING DESIGN:

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CALCULATIONS AND CHECK:

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BEARING:

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 CHAPTER 4:
TRADE OFFS

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INTRODUCTION
This chapter focuses on design constraints and trade-offs. The qualities of all design methods for
Pre-Cast I-Beams are judged by comparing them against each other using different constraints.
Raw Designer Ranking Formula

CHAPTER 4: CONSTRAINTS, STANDARDS AND TRADE OFFS

Design Constraints

A constraint is a condition, agency or force that impedes progress towards an objective or goal. It is the
environment and the limitations of the system which dictates the solutions. Constraints should be identified,
managed, and described in as much detail as possible during the early stages of a project, so that their
potential impact can be managed. These are the design constraints considered in this project:

 Economic Constraint (Cost) - These relate to the project budget and the allocation of resources.
The design technology and selection of construction materials are normally based on this
constraint. The main focus is to economize the construction to present the soundest design with
enough consideration to the budget of the client. The calculation of cost includes material cost,
labor cost and manufacturing cost. The unit of measure to be used will be PhP per linear meter.

 Factor of Safety (Safety) - This constraint refers to the stability of the structure. The design should
be made adequate for all factors affecting the design even despite the accompanying financial or
economic constraints. The design of the structure should still comply with the required standards.
For this constraint, the moment capacity for beam and axial capacity for column and punching
shear for foundation will be considered. The computed factor of safety is unit less.

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  Duration – Duration is one of the factors that should be considered in any construction projects. It
describes the time frame between the start of the project to the completion of it. Time predictability
has been identified as one of the key performance issues to be addressed in providing best value
to construction clients.

 Sustainability - Sustainability analysis has three components: environmental effects, externalities,

and economics and financing. Through our analysis, we are attempting to answer one key
question: What are the sustainability metrics for blends of technologies that are available to meet
different energy needs, given varying resource availabilities and development.

 Environmental - Structural materials consume large amounts of energy during the manufacturing
process. In a world of limited resources, a structure which uses less energy and produces less
carbon footprint in order to be constructed is considered ideal.

SUSTAINABILITY

A sustainable building is a design which focuses on reducing waste and pollution and also increasing the
efficiency of the resources being used like energy, water, and materials while reducing the impacts of the
building towards the environment and human health through design, constructability, operation, and
maintenance.

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DESIGN CODES, STANDARDS AND SPECIFICATIONS
Design codes and standards are the same as the ones used in Chapters 4 and 5.

TRADEOFF FLOWCHART FOR BEAMS

Fig. 4.1 Tradeoff Flowchart for Beams

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CONSTRAINTS: RCD VS PCD
Prestressed Concrete and Reinforced concreted members will be judged using the following
constraints as they are mentioned in the previous paragraphs.
(1) Cost
(2) Safety
(3) Duration
(4) Sustainability
(5) Environmental
Constraints : Prestressed Concrete Design vs Reinforced Concrete Design
ECONOMIC CONSTRAINTS
BEAM
PROPERTIES USD WSD
Concrete: PHP 3,538,875.20 Concrete: PHP 7,964,536.30
Steel: PHP 3,184,040.93 Steel: PHP 4,773,246.62
MATERIAL COST (Php)
Form: PHP 2,617,098.26 Form: PHP 3,156,950.72
Total: PHP 9,340,014.39 Total: PHP 15,894,733.64
Concrete works: PHP 294,464.00 Concrete works: PHP 662,716.00
Steel works: PHP 570,534.03 Steel works: PHP 855,296.68
LABOR COST (Php)
Form works: PHP 963,760.84 Form works: PHP 1,162,564.48
Total: PHP 1,828,758.87 Total: PHP 2,680,577.16
TOTAL COST (Php) PHP 11,168,773.26 TOTAL COST (Php) PHP 18,575,310.80

Table 4.2 - Table of Cost Comparison between USD and WSD

The table shows the total cost between the chosen design methods USD and WSD. For the
material cost in USD it has a value of PHP 9,340,014.39 while in WSD it has a value of PHP
15,894,733.64. For the labor cost in USD it has a value of PHP 1,828,758.87 while in WSD it has a value
of PHP 2,680,577.16. It shows in the total costs that the design in USD is the cheapest.

Factor of Safety Constraints of Prestressed Concrete Design (I-Beams)

Table 4.3 - Table of Safety Comparison between USD and WSD

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The table shows the critical section of Pre-Cast I-Beam (PB-01) and Girders. It also shows the safety factor
between the chosen design methods USD and WSD. By calculating the factor of safety which is the
moment capacity divided by its actual moment. The factor of safety for USD is 1.09 which is bigger than the
factor of safety for WSD which is 1.03.

Duration Constraints of Prestressed Concrete Design

DURATION
USD WSD
Beam prod rate no. of hours no. of men no. of days Beam prod rate no. of hours no. of men no. of days
rebar 96049.5 0.08 7683.96 170 46 rebar 143989.34 0.08 11519.1472 170 68
form 4523 2.8 12664.4 170 75 form 5456 2.8 15276.8 170 90

concreting 856 4.5 3852 110 36 concreting 1926.5 4.5 8669.25 110 79
Column Column

rebar 37321.9 0.08 2985.752 170 18 rebar 80033.8 0.08 6402.704 170 38
form 1649.6 2.8 4618.88 170 28 form 2670.8 2.8 7478.24 170 44
concreting 195.815 4.5 881.1675 110 9 concreting 487.19 4.5 2192.355 110 20
TOTAL 212 days TOTAL 339 days

Table 4.4 - Constructability comparison between USD and WSD

The table shows the total duration for two different design. It significantly indicates that the design
in USD is the shortest in terms of duration compared to WSD.

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 Trade-offs Table of Cost, Safety and Duration

Based on the constraints mentioned above, the various decisions were derived. Using the model
on trade-off strategies in engineering design presented by Otto and Antonsson (1991), the importance of
each criterion (on a scale of 0 to 5, 5 with the highest importance) was assigned and each design
technology’s ability to satisfy the criterion (on a scale from -5 to 5, 5 with the highest) was likewise
tabulated.

ABILITY TO SATISFY CRITERION

CRITERION TRADE-OFF BETWEEN
DESIGN CRITERIA UNIT IMPORTANCE
FACTOR USD WSD
Value Rank Value Rank
COST Php 30 ₱11,168,773.26 5.00 ₱18,575,310.80 3.01
SAFETY % 25 1.09 5.00 1.03 4.74
DURATION Days 20 212 days 5.00 339 days 5
ENVIRONMENTAL kg CO2 15 1.3 5.00 1.38 4.71
SUSTAINABILITY Php 10 7,517,500 5.00 7,517,500 5
OVERALL RANK 500 429.45
*Reference: Otto, K.N. and Antonsson, E.K., (1991). Trade-off strategies in engineering design.

Table 4.5 - Table Raw Designers Ranking for USD vs. WSD

The table shows the trade-off between USD and WSD. We assigned a criterion Importance factor
of 25 for safety, 30 for cost, 20 for duration, 15 for environmental and 10 for sustainability. Using the Raw
Designer’s Ranking, we obtained a ranking of 5 for both cost and duration for USD. The design
methodology for beam shows an overall rank of 5 for USD and a rank of 4 for WSD. Based on the overall
rank we can conclude that the winning or governing design is Ultimate Strength Design.

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 CHAPTER 5:
FINAL DESIGN

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 The design follows the standard as set in the codes such as the National Structural Code of the
Philippines (NSCP), American Concrete Institute, (ACI), and the American Standards for Testing and
Materials (ASTM), the National Building Code of the Philippines and the Association of Structural Engineers
of the Philippines Steel Handbook, Each step in the design process was governed by the above mentioned
codes and is reflected in the design process.
Three constraints were considered in this design project such as economic (cost), factor of safety,
and strength capacity.
The design process started with stage 1 where working stress design and ultimate stress design
trade-off were compared. Only material cost in the economic constraints was considered. Labor cost was
not considered because it has no variance in both concrete design process. After the series of analysis with
respect to the mentioned constraints , the Ultimate Strength Design was chosen to be adopted for
Prestressed Concrete Technology.

Figure 5.1: Final Girder Design Bridge in mm using AutoCAD

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