How many different jobs are creating building a bridge.

Ok. Here is a reasonable list of professionals needed doing a job to create a modern bridge.

Let's start with surveyors theses guys find a place a bridge can be then architects and engineers these firms are needed to draft the prints for the atructure. 

The abutments. These need carpenters and labor's to build the form they need rebar that has to manufactured bent and sheared at a factory.

Then inspectors welders for the cage , crane operators to move the forms . Finally concrete that had to made and trucked to the site. All these guys need insurance training and stay osha compliant.

The structure need support structures tower or cages to support the center of the bridge . Then steel I beam need to placed these have to be rated manufactured shipped and placed by cranes with iron workers and their labors. 

Form carpenter teams then erectus the bunks and forms so concrete can be poured then more rebar these have to placed within specifications a chair is used to space the layers and then more rebar tied to specifications. 

All these guys need tools that wear out.

Finally finish concrete floor teams 100 of yards of concrete poured over the structure another team places blankets of wet burlap and tarps to keep the crate wet and warm so as not to dry to fast.

Pavers come in and place the tar over the structure and electricians set up lighting side walk finishers and rails are erected. 

Possible up to 100 men and women can work on just the project equally their are 100 jobs in manufacturing creating the material and dozens of drivers moving the matwtial.

Finally all these workers need food clothing and shelter and entire industries rely on furnishing them with these commodities banking and payroll personal life health dental 401k and all rally to provide services to workers and their families.

This is how infrastructure projects create wealth in communities. 

Even if these professionals come from other areas . They must stay locally utilizing hotel dining convince store hardware stores grocery and retail laundry services post offices in what ever they find themselves. This is usually handled through company and negotiations of labor contracts.

As per diem per day as work continues to completion

. The material whever purchased can be tagged must be made in USA allowing steel to be purchased in such areas as Pittsburg. 

Steel manufacturing needs oil. The price of steel is directly associated with the cost to produce it and the primary component out side of iron ore is Oil.

Concrete through a manufacturing firm locally

. And delivered timely. The truck has to be inspected registered the driver must liscence to the rating of the truck. This employs training personal. And other unseen jobs . 

Concrete has a shelf life and must be rated for the structure. Making it impossible to import mixed.  

A public bridge has inspectors from the state level who over see everything is being done correctly and entire different department of the state level inspectors are osha and their task is it being done safely and to compliance of regulations.

All these personal have biological needs and entertainment wants and entire communities prosper as infrastructure projects continue.

The personal move onto the next project. 

And the community has a permanent visual structure that will be within the community for 50 to 100 year rating. As road work improves auto expenses diminish less breakage of wheel tire axe components less break downs and more efficient commute times.

Piledrivers.

The Congressional Budget Office estimates the tax cut for the wealthy given by Traitor Trump would cost 1.9 trillion in debt over 10 years.

I believe off setting this by 7 percent corporate rate increase can push the economy into a robust engine again with the American Jobs in infrastructure act. 

America can recover from the covid 19 world economic collapse.

with federal infrastructure monies making their way to the states   u raise a very good point about how this will help the economy   in addition to repairing or building needed infrastructure going forward 

completely unnecessary tax cut                 mostly benefitting the wealthy

   Obvious you put some effort into those first two posts nature1970 and they make a lot of sense!