That was not to say there would not be a bridge at Kangaroo Point.

Rather, the distinctive steel structure would likely take on a much less visually impressive form.

"In the days where money is tight and the demand for infrastructure is great, I guess there would not be the largesse today," Cr Quirk said.

"That said, there have been some good efforts made with pedestrian bridges in the city to be distinctive in their form.

"For many years, the Story Bridge was taken for granted in terms of its structure but it's got a new lease of life now with the LED lighting and that's given a whole new public attention and vitality to the bridge, which I think is making it more iconic than how it was viewed before."

The Story Bridge will celebrate its 75th anniversary on Sunday, with about 60,000 people expected to attend the celebrations on the traffic-free bridge.

As for what a modern-built Story Bridge would look like, Brisbane Marketing chief executive John Aitken, whose organisation uses its image in most of its promotional material, said one need only look downstream towards the Port of Brisbane.

"The technology is obviously relevant to that era and therefore the spanning and engineering of it would be very, very different to today," he said.

"One would suggest that you don't need to look any further than the Gateway Bridge, which shows the technology of 50 years down the track.

"So I think we should consider ourselves fortunate that our forebearers decided 75 years ago to create and build the Story Bridge and it's an asset that's been well looked after by the city."

It was not always going to be called the Story Bridge – its 1935 working title was the more utilitarian Brisbane River Bridge.

"When the first sod was turned, the premier at the time, William Forgan Smith, referred to it as the 'King George V Silver Jubilee Bridge' and when (the King) died, it became the King George V Memorial Bridge," Cr Quirk said.

"Then, in 1937, the cabinet decided to name the bridge after a veteran public servant, John Douglas Story."

The rest, as they say, is history.

The engineering of the Story Bridge was very much indicative of its circa 1930s conception and construction. Photo:Supplied

A sign of things to come

Brisbane's newest infrastructure project, the Legacy Way toll tunnels, opened last week at a cost of $1.5 billion.

The Story Bridge came in quite a bit cheaper in 1940.

"It was a piece of infrastructure that cost £1.6 million to build," Cr Quirk said. "It does sound cheap – if only we could do it for that today."

Legacy Way's initial $3 toll was set to increase to $4.85 a trip in November next year.

The Story Bridge, too, was a toll road when it first opened.

"The toll was sixpence for cars, threepence for people on a horse, threepence for people on a motorcycle and if you were on a bicycle or a passenger on a bus it was one penny," Cr Quirk said.

"And if freight was going across, for every individual cow or bull it was one penny as well."

The Story Bridge tolls were removed in 1947.

"At that time, the Brisbane City Council actually purchased the Story Bridge for £750,000, which was a massive loan," Cr Quirk said.

"In fact, I finished paying that loan off as the council's finance chairman in 1989 under the lord mayoralty of Sallyanne Atkinson."

When asked whether that was a sign of things to come for motorists using existing tolled infrastructure, Cr Quirk was somewhat non-committal.

"That will be a matter for other city fathers and mothers in the future to determine," he said.

"The idea is to utilise tolls to pay for the infrastructure over time.

"In the same way that a toll was needed to actually get the Story Bridge built, so too it is with current infrastructure.

"They're a means of providing the revenue stream as a deflection of the cost and it creates the equation to be able to make these things happen.

"People talk about these things as whether they're a success or not based on whether they're full from day one.

"We don't want them full from day one – if they were, we'd have pressure on us to go build another one.

"So the idea is they're a 100-year asset life facility and they're intended to be able to provide for future growth in the city."

Story Bridge is photographed in the 1970s. Photo:Supplied

A true icon for Brisbane

Mr Aitken, Brisbane's marketer-in-chief, said the often misused term "icon" could easily be applied to the Story Bridge.

"I'm a strong believer that the river is one of the great definers of our city," he said.

"Our indigenous cultures lived in this region and it was how they defined themselves and since European settlement, it was key to Oxley's discovery of this region and the creation of convict settlements.

"The river is really iconic to everything about Brisbane in a good and a bad way. It's brought floods to our city and helped to define our character as well.

"It shouldn't be any surprise that an icon that transcends our river and helps to identify our river like the Story Bridge should be seen in that light."

That was why the Story Bridge was so central to Brisbane Marketing's campaigns to promote the city.

"It's certainly in all of the materials we've used," Mr Aitken said. "That, paired with our beautiful river and the city skyline, is iconic to Brisbane and has become an iconic image in all of our materials, including the 'Choose Brisbane' pre-G20 campaign."

A risk worth taking

Cr Quirk said even 75 years after it first opened, the Story Bridged remained "critical" to the good functioning of Brisbane.

"It was great foresight from those who constructed it," he said.

"It would have been seen as a monstrosity in its time and there would have been a lot of people who argued it was not necessary, that for a city with a few cars and a few horses, why are we building something that big?

"But today, we're very grateful for that vision."

Cr Quirk said the Story Bridge was perhaps a little too big for 1940s Brisbane but the city had, in effect, grown into the infrastructure.

"There would have been people who said, 'Well, why do we need something that big?' " he said.

"You've got to consider that Brisbane, even in the war years after the Story Bridge was built, only had about 380,000 residents.

"When the Americans were here during the war, they almost doubled Brisbane's population, so it does put it into perspective."

Cr Quirk said he expected the Story Bridge to continue to serve a vital role for decades to come, "so long as we maintain it in terms of the integrity".

"It's painted regularly, it's maintained regularly," he said. "In terms of whether it has a finite life from an engineering perspective, at the moment there's no talk of it reaching the end of its natural life."

Today the bridge is an unmistakeable landmark nestled among Brisbane's city skyline.

Another milestone

In a previous professional life, Mr Aitken helped organise the Story Bridge's 50th anniversary celebrations.

As in 2015, the 1990 celebration closed the bridge so the public – about 30,000 people – could walk across it.

However, while the 75th anniversary would be marked with the Eat Street Markets on the bridge, the 50th anniversary had all the audaciousness one would expect from the post-'80s.

"We had the F-111s still at Amberley, so they did the dump and burn and we had the fireworks to follow," Mr Aitken said.

"Back in those days, there was a gentleman by the name of AJ Hackett, who had invented this pastime of bungee jumping.

"It was a brand new idea and he had set up one or two commercial operations in New Zealand and was very keen to bring the concept to Australia.

"We were looking for something exciting and new to do for the 50th anniversary of the Story Bridge and we felt that would be a wonderful spectacle that would give us national and international exposure, which it did."

Mr Aitken was also involved in the early days of Riverfire.

"It was no mistake that our 'New Year's Eve in September' centred itself on what is one of the great icons of the city," he said. "It's accentuated in many different ways."