The Bridge Street bridge – (PIP #72)

By Louise Peloquin

Bridges, all kinds of bridges, must be built, used, fixed.

L’Etoile – October 30, 1924

HEAVY TRAFFIC ON BRIDGE STREET BRIDGE

     We can perceive the volume of traffic on the Bridge Street bridge knowing that last Sunday, between 8 AM and 8 PM, a total of 10,368 private automobiles crossed it. On Friday, 6,100 automobiles crossed and on Saturday, 6,900. 

     More cars than heavy trucks use the bridge: Friday 1,123; Saturday 1,176 and only 120 on Sunday.

     Harvard University Professor George R. Swain requested this interesting information. The city of Lowell engaged him to inspect the bridge in order to submit recommendations to either renovate it or to build a new one. First and foremost, the professor asked for a calculation of traffic on the bridge. Therefore, engineer Kearney dispatched members of his department there on Friday, Saturday and Sunday.

     Friday they found that, every hour between 8 AM and 12 PM, 47 trucks crossed heading north and 50 south. Every hour between 12 and 6 PM, 51 trucks headed north and 60 south. Every hour between 6 and 8 PM, 8 trucks crossed towards the north and 22 towards the south.

     The number of private automobiles crossing the bridge was also tallied on Friday – 512 hourly during the 12 hours of observation. An average of 12 tramways crossed the bridge that day.

     Saturday, the average number of automobiles was higher. Sunday fewer trucks but more automobiles crossed.

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L’Etoile November 24, 1924

The 1921 Contract Would Have Been an “Expensive Error”

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Professor George F. Swain of Harvard University recommends immediately replacing the paving under the railway track.

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     Professor George Swain of Harvard University submitted an important report on the condition of the Bridge Street bridge. He asks for the immediate replacement of the wooden bridge under the tramway railway tracks and the replacement of all paving next year.

     The professor believes that the present bridge is sufficiently sturdy and wide to meet city needs for many years to come. There is no immediate threat for the framework to collapse and, at the moment, it would be wiser to maintain the bridge and place the sum for building a new one on necessary repairs.

     In addition, he asks to immediately paint the present bridge, indicating that, according to the 1921 contract, the steel framework had not been painted. He also calls this last contract “an expensive error” for the city insofar as the City Council had awarded the contract for repairs notwithstanding protests from the city engineer and the consultant engineer. 

     According to the professor, the main argument against building a new bridge, is the fact that the present one can adequately meet city traffic demands for some time. Professor Swain estimates that a new concrete bridge would cost approximately $600,000 while a new steel bridge would cost more than $400,000. Replacing the cement paving would cost between $20,000 and $25,000 and replacing it with wood blocks or creosote planks would be cost $40,000. (1)

     “The cement paving on which the automobiles pass does not seem to have caused any problem up to now. Perhaps it will last all winter but this pavement should also be replaced quickly.”

     The professor continues his report by speaking of the weight of cement paving stones. He indicates that a sliding rail should replace the present tramway T-track and that temporary wooden paving blocks should immediately be built under the tracks.

     Many pages of this report deal with traffic issues. Professor Swain concludes that the bridge is not taxed to its capacity and can easily withstand Central Street and Merrimack Street traffic.

     “The bridges are often constructed too wide for traffic only” he says. “A wide bridge is beautiful and appears spacious but it is often a waste of money. In a park or on a boulevard, a bridge can be justifiable for its aesthetic considerations but, in a city, one must think about traffic above all. Furthermore, a wide bridge tends to allow for abuse – overtaking others and speeding.”

     After discussing bridge repairs, Professor Swain speaks about the practicality of constructing a new bridge. He says it would be necessary to examine all of the parameters involved in such a project.

     The professor provides the cost details and indicates that building a larger bridge made of concrete, including its impact on the mills, would fetch $591,000. A new steel bridge would be $421,000.

     The professor’s report concludes with six pages on the need to replace the paving with cement or wood blocks and replace the T-tracks with sliding rails.

     “If I believed that Lowell’s Central Bridge was dangerous for present-day traffic, I would undoubtedly advise immediate reconstruction. However, this is not my opinion. It seems more important and more prudent to keep the present bridge and to save the sum of money necessary for a new bridge. In a few years, the interest would cover the paving expenses until future traffic demands require a wider bridge.” (2) 

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1. Creosote is an active ingredient applied to protect wood used outside – railroad ties and utility poles for example – against termites, fungi, and other pests. It has been classified as a carcinogen and is no longer utilized.
2. Translations by Louise Peloquin.