Analysis

Career opportunity  You are a proud junior member of “Bridging the gap” an up and coming engineering firm.  You have just been ask to analyze a structure that was considered, in its time, the Eighth Wonder of the World; the Victoria Bridge.  What made this bridge so special and receive such high praise?  As the original bridge, designed in 1859 no longer exists, let’s look at pictures from the 1860 edition of Civil Engineer and Architect’s Journal.

The Original 1859 Victoria Bridge – During Construction What information does this picture tell you about the bridge? What materials do you think were used?

The Original 1859 Victoria Bridge – The Entrance What information does this picture tell you about the bridge?

The Original 1859 Victoria Bridge – The Roof What information does this picture tell you about the bridge? What is the purpose of the machine seen on the roof?

General Facts on the construction and design of the Victoria Bridge

General Facts on the 1859 Victoria Bridge  Superstructure:  The Victoria Bridge was a Tubular Bridge.  The iron tube, built in sections, was feet in length  The Piers:  Stone piers supported the weight of the bridge  The first stone was laid on July 20 th 1854

 In order to support the full weight of the superstructure (9044 tons), the bridge rested on 24 piers and 2 abutments. General Facts on the 1859 Victoria Bridge

 The Victoria Bridge only had one set of tracks.  The Tube itself had no windows.  Although it did have an opening at its top. Light at the end of the tunnel General Facts on the 1859 Victoria Bridge

 Although the bridge was a rectangular box, it did also have a roof (shown by the slanting sides).  The machine on the roof was actually used to paint the bridge. General Facts on the 1859 Victoria Bridge

Puzzling Riddles

Riddle 1 – The Design  Why was the Tubular Bridge design selected?  The Trestle Bridge and the Suspension Bridge designs were far more popular at the time.

Riddle 2- the Piers  How did they manage to build stone piers in the middle of the St-Lawrence River?  Why is the shape of the piers so peculiar?

Riddle 3 – the Superstructure  What is the purpose of having an opening in the top of the tube and then cover it by a roof?

Riddle 1: Why was the Tubular Bridge design selected? Analysis of the Design

What is a tubular bridge?  Tubular bridge designs were used in the 1800’s.  The train travels through the iron tube.

What were the other design options?  The Wooden Trestle bridge and the Suspension Bridge were also popular designs in the 1800’s.  Based on your knowledge of bridges and the following facts, why was the tubular bridge selected over these more common designs?

Suspension bridge summary  Modern Suspension bridges can span up to 2 km  Suspension bridges are known to undergo torsion in high winds or if there is constant vibrations. What makes this particular bridge an unsuitable design for the Victoria Bridge?

Wooden Trestle Bridge summary  Due to the abundance of lumber found in the region, this type would have been inexpensive to build  Wood requires constant maintenance. On average, an untreated trestle bridge lasts 15 years. What makes this particular bridge an unsuitable design for the Victoria Bridge?

Riddle 2: How were the piers built? Why did they have such a peculiar shape? Analysis of the Piers

Facts about the piers  Definition of pier:  Upright support for a bridge  Building Material: Blue Limestone  Thickness of the 2 center piers: 24 feet  Thickness of side piers :16 feet  The original piers only underwent minor adjustments to support the much larger and heavier bridge we see today.

How to build a pier in the middle of the St-Lawrence River?  Floating coffer dams were brought in for the construction of five of the piers.  Brought by steam tug boats, these dams were sunk into the St-Lawrence by opening a valve letting in water.  These dams were reusable by pumping out the water.

Shape of the piers  Why were the piers build with this particular shape in mind?

A second function  The Piers of the Victoria Bridge also served as ice breakers.  The ice would climb the angle and then break under its own weight.

Riddle 3: What is the purpose of the ceiling's opening and the roof? Analysis of the Superstructure

According to you, what is the purpose of the opening and the roof?

Factors that could be considered to solve this riddle.  Type of engine used in the 1800’s  Weather and climatic conditions

The Steam Engine  Trains in the 1800’s used the steam engine, which worked on the combustion of wood to produce steam. Water Vapor

Scientific Side note  Combustion:  Is a form of oxidation which release a large amount of energy.  Three factors are needed to ensure combustion  Fuel: substance that releases energy by reacting with an oxidizing agent  Oxidizing agent: causes the fuel to react  Ignition temperature: minimum temperature required.

 After having considered the type of engine used and the climate of the Montreal region, what is the purpose of the opening and the roof in the tubular bridge?

The 8 th Wonder of the World  Due in part to the engineering methods used, the longest Tubular Bridge in the World (in 1859) was dubbed the 8 th wonder of the World.

Ending with an anecdote

On a visit to Canada, an English shareholder in the Grand Trunk Railway insisted on inspecting the Victoria bridge by foot. He was accompanied by valets, secretaries, relatives and elegant ladies.

Although, orders had been given suspending train activity during the visit in the tunnel, a freight train carrying pigs entered the tube. On hot summer days, this tube could reach temperatures of 125 Fahrenheit (52 Celsius), even with the opening in its ceiling.

The shareholder and his accompaniment managed to get out of the trains way. However, when the train slowed down to climb an incline, many of the woman fainted and some of the men were overcome with nausea at the scent. They were eventually saved by bridge workers.