Quantifying the Environmental Impacts of Standard Bridge Designs

 “A Proposed Methodology for Quantifying the Environmental Impacts of 

Structural Elements of Standard Bridge Designs”

 A thesis prepared and submitted by:

Kevin Lawrence M. Atienza

Carla Maria B. Gonzalez

Jorge Jason K. Joaquino

Mitchel Krisia R. Martinez 

April 2015 

To take into account the environmental sustainability aspect of bridge designs, the study presented a methodology to numerically measure the amount of emission different bridges produce. The researchers gathered a total of eighteen bridge plans of various structural systems such as Reinforced Concrete Deck Girder (RCDG), Pre-stressed Concrete Deck Girder (PCDG), Reinforced Concrete Slab, Steel Girder, and Reinforced Concrete Box Culvert (RCBC). Each plan included a bill of quantities that summarized the type of material and the amount used upon construction. Using LCIA database Ecoinvent v3.1, quantities were translated into corresponding environmental impacts namely Acidification, Eutrophication, Global Warming Potential, Photochemical Oxidant Formation, Stratospheric Ozone Depletion, and Depletion of Abiotic Resources. Numerical results were divided by the total area of the bridge leaving one square meter of bridge area as the functional unit of choice.

To normalize these values, each environmental impact equivalent was divided by the largest value, which was produced by the RCBC bridge design. An Analytical Hierarchy Process (AHP) was conducted to produce the weighting factors of each impact. The normalized values were then multiplied by their corresponding weighting factors and added up to produce an Environmental Impact Score (EIS) that was used to rank and compare the environmental performance of each bridge. In this particular study, the RCDG bridge design generated the lowest score with a value of 0.451, thus indicating that it produced the least amount of impact. On the other hand, the RCBC bridge design produced the largest amount of impact with an EIS of 0.825. Through the proposed methodology of conducting a Life Cycle Impact Assessment (LCIA) and producing an EIS, structural engineers will be able quantify the environmental impacts of different bridge structural systems and in turn apply sustainability in the decision making of future bridge projects.

Special Acknowledgement: 

DPWH Staff and Engineers for sharing bridge data, 

Dr. Mike Promentilla (DLSU ChE Dept) for guidance in the AHP procedure

Model Popsicle-Stick Bridges of the Bridges in Asia



Chaotianmen Bridge (China)

In the recent Civil Engineering Society Bridge Building Contest, students from various civil engineering schools in Metro Manila were challenged to create popsicle stick bridges based on a segment of an actual bridge that can be found in the Asian region. The judging of the bridges took place last March 10, 2012 at the De La Salle University, Manila. It was a marvel to see the creativity of the students. There were model bridges that were really awesome and created meticulously following the photo of the actual bridge. The winner for the best design was the model of the Chaotianmen Bridge (China) submitted by the students from TIP. Marvel at the popsicle stick bridges below.



Asahibashi Bridge (Japan)





Asahibashi Bridge (Japan)



Ayala Bridge (Manila, Phils)

Zhejiang Road Bridge (China)

Merdeka Bridge (Malaysia)

Minamikawa Bridge (Japan)

Wanxian Bridge (China)



Quezon Bridge (Manila, Phils)



Dhamra Bridge (India)

Best Bridge Design

Popsicle-Stick Bridge Testing 2011

At the 7th DLSU Bridge Building Competetion, the bridges were tested using a UTM at De La Salle University-Manila CTM Lab. Two steel bars were placed on the bridge deck. Then a steel frame was placed on top of the steel bars. The load was applied on the steel frame until failure. Date of Testing: March 19, 2011. This competetion was organized by the Civil Engineering Society and was participated by students from PLM, TIP, Mapua, EARIST and DLSU.

Watch the video below. The failure of this bridge was brittle. Kaboom!

Amazing Popsicle-Stick Bridges 2011

Slide Album: Popsicle Stick Bridges

Here is a slide show of the popsicle stick bridges that were submitted to the 7th Bridge Building Competition organized by the Civil Engineering Society at De La Salle University - Manila, Philippines. Thirty-three entries competed for the Strongest Bridge, Stiffness Champion and Best Design (Aesthetics).

Congratulation to the winners:

Strength Category: Winner - Bridge 21 (PLM)

Stiffness Category: Champion - Bridge 21 (PLM)

Stiffness Category: Runner-up - Bridge 22 (PLM)

Aesthetic Design Category: Winner - Bridge 20 (TIP)

7th Bridge Building Contest - Best in Aesthetic Design

The winning bridge from the TIP Team

The 7th Popsicle-Stick Bridge Building Contest organized by the Civil Engineering Society of De La Salle University was held on March 19, 2011. One of the highlights of the contest was the judging of the bridges based on aesthetic design. The criteria includes originality, innovativeness, craftmanship and practicality. The judges were lead by Engr. Mario Lualhati (PICE-LNM President), Dr. Amelia Marquez (PICE-LNM Secretary) and Engr. Mike Baylon (DLSU Alumnus and FEU-East Asia College faculty). Technological Institute of the Philippines (TIP) won the aesthetic design category out of the 33 brige entries. Marvelous!

Popsicle Stick Bridges by DLSU students

Thirteen entries from DLSU competed in the Popsicle Stick Bridge Building Contest hosted by The Civil Engineering Society (CES). Unfortunately, no entry made it in the winning bridges. The DLSU bridges were also good and well-made. Bridge no. 18 actually garnered the largest load of 111 kg with a displacement of about 25.5 mm, but it was too heavy at 1138 g making a score of only 3.82. DLSU ranked 8th in the design category (Bridge No. 23) and ranked 10th in the strength category (Bridge No. 19).

Congratulations to all DLSU participants!

The winning popsicle stick bridges!

In the recent DLSU-CES Popsicle Stick Bridge Building Contest held last Feb. 13, 2010, 31 bridges were tested for the Strength Category. A Universal Testing Machine (UTM) was used to test the bridge. Two 14 mm rebars spaced at a specified distance, were placed on the bridge deck. Then a hollow “cage” was placed on the rebars, on which the load from the UTM was transferred. A displacement transducer was attached to the UTM to measure the bridge displacement (D) in mm. The load P (kg) when the load dial of the UTM stops was noted indicating bridge strength. The Strength Rating is computed as (1000x P)/(D x W), where P in kg, D in mm and W = actual weight of the bridge in kg. The strength rating S is the bridge stiffness (kg/m) per unit weight (kg).

Bridge entry no. 13 from the Technological Institute of the Philippines (TIP) of Manila has the highest score. The bridge has only a weight of about 390.4 g. With P = 43 kg and d = 11.8 mm, its score S = 9.33. Observe the connections at the joints - knowing that failure will occur at the connections, the connections were glued together properly with additional cover.

The 2nd place bridge was from Pamantasan ng Lungsod ng Maynila (PLM) which had a score S=9.15 with P=36 kg, D=8.87 mm and W=443.7 g. The 3rd place goes to another entry from TIP-Manila with S=9.01, P=45kg, D=10.78 and W=463.11 g.

Congratulations to the winners and all participants. You were all winners!

Best Bridge Designs at the 2010 Contest

The De La Salle University Civil Engineering Society (CES) hosted the Popsicle Stick Bridge Building Contest 2010. The bridge entries were judged last Feb. 13, 2010. There were 31 entries from various schools: DLSU, TIP-Manila, PLM, FEATI, DHVTSU, Mapua and FEU-EAC. In the Design Category, the bridges were judged based on the following criteria:

• Creativity and Innovativeness in the design and form: 30%


• Application of bridge design principles: 30%


• Practicality and implementability: 20%


• Neat and well-polished bridge: 20%

There is only one winner in the design category which was the entry from the Technological Institute of the Philippines - Manila. The other entries which ranked 2nd and third came from PLM and TIP-Manila, respectively.

Popsicle Truss Bridge Building Contest 2010

The Civil Engineering Society of De La Salle University-Manila is again inviting civil engineering students from Philippine CE schools to join the Bridge Building Contest. The challenge is to create a popsicle truss bridge which will span a given distance subject to the bridge specifications or limitations in weight, heigth, width and length. The rules can be viewed in the slide show embedded here. There are also tips on how to make your bridge win the strength competition. The deadline and testing of the bridges is on Feb . 13, 2010. You may read related blog posts here such as the testing of the bridges, truss analysis and winning bridges in the last competition. Happy Bridge Building. For more details, join the yahoo group: http://groups.yahoo.com/group/bridgebuilding10.

Bridges are falling down!

Bridge superstructures and substructures have been damaged in recent earthquakes like the 1994 Northridge earthquake and 1995 Hyogeken-Nanbu earthquake in Japan. Bridges are Falling Down ( 5:52 min) is a photo-video presentation that shows the different types of damages in bridges and some retrofitting techniques. This video is part of the "Understanding Earthquakes and Disasters: Photo-Video Presentations for Public Awareness and Education."

CPE Seminar on Computer-Aided Modeling, Design & Analysis of Bridge Structures

Bridges are important structures in infrastructure projects such as highways, elevated expressways, flyovers and water crossings. The effective and efficient design of bridges requires a good understanding of bridge engineering principles and usage of modern computing tools. The objectives of the seminar are (a) To provide an overview of the theoretical and practical background on analysis & design of various types of bridge structures with a special focus on RC bridges, and (b) To introduce the use of up-to-date computing tools for the modeling, analysis, and design of bridge structures.

Dr. Naveed Anwar is the Associate Director of ACECOMS and an Affiliate Faculty of the School of Engineering and Technology of the Asian Institute of Technology, Bangkok, Thailand. Dr. Naveed is the principal author of several engineering software including SDL, GEAR, SYSDesigner. He is also a consultant of CSI, the developer of ETABS, CSI Col, SAFE and SAP2000.

For more info. about the program and fees: Go to the PICE-LNM Website.

Per Tveit's Network Arches

Prof. Emeritus Per Tveit, Dr. Ing. of Agder University, Norway, visited De La Salle University, Manila a few years ago to share his knowledge and expertise about Network Arches. "When I was a student over 50 years ago, I got the idea of the network arch. Optimal network arches are arch bridges where some hangers cross other hangers at least twice. When the arches are less than 18 m apart, the tie should be a concrete slab with partial longitudinal prestress. The arches should be universal columns or American wide flanges. Network arches are best suited for spans between 80 m and 170 m, but will compete well in a wider range of spans. This results in attractive bridges that do not hide the landscape behind them. A network arch bridge is likely to remain the world’s most slender tied arch bridge, " he says. Indeed, Tveit can be considered the "father of network arches." He traveled around the world using his own resources spreading the information about network arches - the basic components, analysis, design and construction. His website has detailed information about network arches.

If you want to know more about Network Arches, contact:

Per Tveit, Dr. Ing. dosent emeritus Agder University N-4876 Grimstad, Norway

E-mail: per.tveit@uia.no

Website: http://pchome.grm.hia.no/~ptveit/

Here is a YouTube video of Mangamahu network arch bridge - the first of its type in New Zealand.

Popsicle Stick Bridges Slideshow

Popsicle Stick Bridge Building Competitions have become a popular activity for students here and abroad. This blogsite had many visitors who "googled" about popsicle stick bridges. Here is a slide show of the popsicle stick bridges that competed in the 5th DLSU Bridge Building Contest.

Two Popsicle Stick Bridges from DLSU

I would like to feature two popsicle stick bridges submitted by my undergraduate students at the 5th DLSU-CES Bridge Building Competition. Bridge No. 09 by Morgan Say and Jet Tugado is a Warren-type truss bridge. It actually ranked no. 4 in both the Strength and Design category. The bridge has the properties, L = 626 mm, W = 1073 g (quite heavy). It's deflection at P = 10 kg was only 3.2 mm but at failure, it posted a very large deflection D = 19.20 mm. Again the arrangement of the diagonal members may have contributed to the large deflection. The diagonal members in this bridge are under compression. If only the weight and the deflection were reduced, it may have joined the top 3. Actually it is ranked no. 1 based on the P/W ratio only.
The second bridge (Bridge 16) by Jefron Gaw, Allan Mariano and Lex Alviar was withdrawn from the competition because its depth D exceeds the limit, making it impossible to test the bridge using two point loads. The bridge has an arch shape. The bridge is quite heavy W=1425 g. It is a well designed bridge and it may have performed well in the competition, if it only passed the specifications. The bridge was actually tested upto failure using the UTM and observe the failure mode - a bending failure at midspan.

I would like to commend the participants for creating the nice popsicle stick bridges. You are all winners!

GRASP Analysis of the Top 3 Popsicle Stick Bridges

In the strength category of the 5th DLSU-CES Bridge Building Competition, the bridges with weight W were subjected to two-point loads using a UTM (Read the blog on bridge testing). The values of P and D at failure were noted to get the Strength rating S=P/(D*W). The bridge with the largest S wins the competition.

The value of S depends on the stiffness (P/D) of the bridge and the weight W. The competition measures how efficient the materials were used to obtain a structure with large ratio of stiffness to weight.

Using the GRASP software, the top 3 winning bridges (B13, B03 and B06) in the strength category were analyzed . Observe the very interesting deflected shapes of the models. The figure also shows the members with axial tensile forces (labeled T). Why did the top bridges perform better than the others? What are the factors that contributed to the large stiffness (P/D) of the bridges? One major factor is the material property of popsicle sticks - the tensile stress capacity is larger than the compressive stress capacity in popsicle sticks. It would be easier to break the popsicle stick due to compression than to tear it due to tension. Hence, if you want to efficiently use the strength of popsicle sticks, design your bridge such that tensile forces not compressive forces are developed in most of the members. In the top 2 bridges - B13 and B03 - relatively large tensile forces were induced in the diagonal members compared to the compressive members.

Another factor is buckling failure in the compression members. If you want to increase the capacity of the members against buckling, then provide braces. The top 2 bridges have horizontal braces at the top and bottom preventing lateral buckling of the members. Bridge B06 which is 3rd in the competition has relatively larger compressive forces in the top chord and diagonal web members. Observe the buckling failure of the top chord. If only horizontal braces were installed at the top, the bridge may have developed a larger capacity and less deflection before failure.

Another factor which increased the stiffness of the bridges, particularly the top 2 bridges is the use of a deep box girder. This results to a relatively light-weight bridge but effective against bending. Sticking together popsicle sticks forming stiff griders like in the bridges shown result to very heavy and not very efficient bridges. They may carry a larger load (P) before failure but the ratio with weight may be smaller because of the large bridge weight.

Modeling your bridges and analyzing them using a software like GRASP before the actual construction will guide you on how to improve the bridge designs. You can redesign the arrangement of the truss members, increase the depth or know the location of braces to prevent buckling failure.

Best Popsicle-Stick Bridge Designs

In the recently concluded 5th DLSU-CES Bridge Building Competition last 7 Feb 2009, the bridges made from popsicle sticks competed for the Best Bridge Design based on the following criteria:

• Creativity and Innovativeness in the design and form: 30%
• Application of bridge design principles: 30%
• Practicality and implementability: 20%
• Neat and well-polished bridge: 20%

Four judges examined and evaluated the bridges. After about an hour of evluation, the scores were tabulated. It was a tight race for the winner. The winning bridge from Don Honorio Ventura College of Arts and Trades (DHVCAT) won by a hairline against the bridge entry from the Technological Institute of the Philippines (TIP), Manila. The 3rd placer is the bridge from the Technological Institute of the Philippines (TIP), Quezon City. Building popsicle-stick bridges using glue takes a lot of planning, patience and ingenuity. Cutting the popsicle sticks to fit the form of the bridge, gluing the sticks and polishing involves a lot of time. In general, the popsicle-stick bridges submitted were impressive. Many of the bridges were unique and may serve as models for future bridges. The students have demonstrated their skills and understanding about bridge construction.

DLSU CES 5th Bridge Building Contest

The 5th DLSU Bridge Building Contest was held on Feb 7, 2009. Seventeen bridges made from popsicle stick bridges were submitted from various engineering schools - Don Honorio Ventura College of Arts and Trades (DHVCAT), Technological Institute of the Philippines (Manila and QC), FEATI University, Far Eastern University (FEU) , Pamantasan ng Lungsod ng Maynila (PLM), University of the East (UE-Manila) and De La Salle University (DLSU-Manila). The bridge must span a distance of 560 mm and must have a width not more than 140 mm, height not more than 200 mm, depth not more than 100 mm, weight not more than 1.50 kg. There were two categories in the competition: Bridge Design and Bridge Strength. In the Bridge Design category, the criteria used were creativity, innovativeness, application of bridge design principles, practicality, implementability and neatness. The winner for this categroy is one of the entries from DHVCAT. In the Bridge Strength category, the bridges were tested using the UTM and the load P and deflection D at failure and the bridge weight W were used to get the Strength Rating (see blog on bridge testing). The winners in this category were 1st: PLM, 2nd: TIP-Manila and 3rd: DLSU-Manila.

View more photos

Photobucket Album

Structural Analysis Tips to Popsicle Stick Bridge Builders (Load Application)

Using a structural analysis software like Graphical Rapid Analysis of Structures Program (GRASP ) developed by the Asian Center for Computations and Software (ACECOMS) can help popsicle stick bridge builders in designing their bridges. The behaviour of bridges depends on how and where the loads will be applied. For example, if two concentrated loads will be applied to test a bridge with a truss design, applying the load as shown in the figure at the bottom or uppr part of the bridge will make a lot of a difference. The GRASP software was used to compare the maximum deflection at the bottom horizontal elements of the two bridges. The structures were analyzed as a "frame" since the joints may be assumed rigid because of the glued connections. The deflection for Bridge 1 where the loads were applied at the bottom is 20% higher than Bridge 2 where the loads are applied at the top. For Bridge 1, the bottom horizontal elements have large bending moments and axial forces and diagonal truss members carry large axial forces - the top horizontal members had minimal stresses. For Bridge 2, on the otherhand, the top horizontal elements may have large bending moments but the axial forces are not so large compared to bridge 1. The bottom horizontal elements now contributed more in resisting the loads by carrying more axial forces as compared to bridge 1. The diagonal truss elements of bridge 2 carry almost the same magnitude of axial forces. So before designing your bridges, know how and where the loads will be applied. It will make a lot of a difference in the bridge performance!

Structural Engineering for Kids 4 - Building Up London Bridge

London Bridge is a nursery rhyme where various concepts in structural engineering may be introduced. Obviously, the concept of structural engineering failures is described in this song - London Bridge is falling down. Structural failure this time is described in relation to different types of construction materials. The behavior and strength of various structural engineering materials and members can be described while playing the song - Build it up with pins and needles…Build it up with wood and clay…Build it up with iron and steel.. Build it up with stone so strong. How the structural members fail depends on the structural properties of the materials – brittle materials like concrete break or crush, ductile materials like iron and steel bend or yield. So London Bridge failed in various ways - Pins and needles bend and break…Wood and clay will wash away…Iron and steel will bend and bow… Stone so strong will last so long. Bridge failures, however, depend on many factors as shown in the video below like the structural design of the piers including the detailing of reinforcement, the bridge deck supports, the soil and foundation...

This nursery ryhme may also be a good opportunity to introduce the concept of strengthening and retrofitting of existing structures. So when London Bridge fell, the ryhme continues - We must build it up again, Up again, Up again. We should not wait for another bridge disaster to occur. We should learn form the previous bridge disasters like those that happened to the Tacoma Narrows Bridge in 1940 or the Hanshin Expressway in 1995. We should act now to strengthen and retrofit existing bridges and structures. The last slide in the video clip shows the bridge pier retrofitted against earthquake effects.

Popsicle Stick Bridge Testing

Popsicle stick bridge building competitions usually choose the winner based on the strength/weight ratio. Usually loads are applied at the mid span of the bridge by placing incremental weights. The load at failure (P) is then determined and divided by the bridge weight (W) to get the bridge performance.

In the DLSU CES Bridge Building Competition, a Universal Testing Machine (UTM) is used to test the strength and displacement of popsicle stick bridges. Since the load will be applied on the bridge deck, an innovative method was devised so that it can be applied to truss bridges. Two 14 mm steel bars spaced at specified distance are placed on the bridge deck. A hollow steel cage is then placed on the two steel bars. The UTM is then applied on the steel cage which then transfers the load to the two steel bars and then to the bridge deck. A displacement transducer is attached to the UTM to measure the displacement (D) in mm. The load is applied and the value of P (kg) is obtained. The value of P can be predefined or when the load dial of the UTM stops which indicates bridge failure. The bridge rating, S = 1000(P/D)/W is then determined. The S rating represents the bridge stiffness (kg/m) per unit weight (kg). For example, the bridge shown in the video below was tested and it’s P = 30 kg, D = 25 mm and W = 1.50 kg. Hence, it’s rating , S = 1000(30/25)/1.50 = 800 (kg/m)/kg. By using the S rating, strength, displacement and weight become parameters in ranking the performance of the popsicle stick bridges.

Video Clip: Popsicle Bridge Testing using a UTM at DLSU CE Lab