My school is undergoing some major construction, so I’ve seen lots of dirt get moved around, concrete poured, and steel rise out of the mess. This has inspired me to post about stuff I’ve always wondered.
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[li]The architects and engineers design the building and draw it out on blueprints. How does that information get out to the guys with the hammers and screwdrivers?[/li][li]When a construction employee shows up for work in the morning, how does he/she know what to work on that day?[/li][li]I guess I’m really wondering, how does a school building, skyscraper, freeway interchange, or even a suburban house, emerge from the seeming chaos? With so many different things going on, how do all those people know what to do, how to do it, and where to do it?[/li][/ol]
A key person is the site manager.
The foremen and, of course, the site office have copies of the construction drawings. Occasionally they’re unfolded and consulted, sketches made on the drywall that will later be painted over, etc.
Also remember there are various different trades with specialized tasks; they’re not just interchangeable “construction workers.” The site manager keeps a constantly revised critical path chart telling him when to have the electricians run the conduit that will be within the floor slabs, when to have them back to rough in the wiring runs within the walls, and when they need to make a final visit after the drywallers have finished to install outlets and switches and light fixtures. Each time they show up, they consult the same one-page (fairly simple) plan, which may only show symbols representing outlets and switches scattered around the room (no measurements, even). But that tells them enough to use their own knowledge of the trade to finish that week’s task and make way for the next trade to get going.
A General Contractor team will generally consist of a Project Manager, who is responsible for the budget of the project and is on the hook to the Owner and Architect if the project goes over budget. This person deals with invoices and processes of the various subs. He/she is responsible for the project overall. The Superintendent is next in line and he is the go-to person. In my experience this is the most critical component on the construction side. A good Superintendent has the right mixture of humor and the ability to force the issue with force of personality only. This role is primarily responsible for the schedule and if he is good at his job he will run the project with an iron fist. Under these two roles are various Field Engineers, who are responsible for various trades. One might be the primary on the structural steel, another on MEP, another on the skin of the building, etc.
They have weekly meetings outlining the work scheduled that week, which sub is to be where and how they are going to accomplish this. In addition there are various safety and other construction meetings. Each Sub-contractor has similar project personnel responsible for the same things within their sub trade.
So it isn’t total chaos, if it is scheduled out correctly and you have a good project team on the General Contractors side it is very efficient. If the team is lacking in performance by someone it does impact the schedule in my experience.
I work on the other side of the table–the Architect. But any good Architect will honestly tell you that you can’t build a good building without a good General Contractor. The stereotype is that the Architect and Contractor don’t get along, but in my experience this hasn’t been true. I have worked with some fantastic Contractors, but I have also worked with some poor ones. The good ones invariably had good personnel in the position of Project Manager, Superintendent and Field Engineers.
Adding to what others have said, a Project Manager will utilize what is called a Work Breakdown Structure (WBS). This allows the PM to track and schedule work by task/trade and by critical path (that is, what tasks must be completed before another task can begin). Some work can be performed at the same time, other work requires that another task be completed before it can begin.
Edit: this often results in a milestone chart that can be used to show the progress of a project.
Former contractor.
Through copies of those same “blueprints”. Copies go to the GC shack where the contractor schedules the job and the subs. The subcontractors will also get a copy. Although big construction jobs are complicated on the whole, when you break them down by small jobs they are not that difficult to schedule.
Most workers are employed by subcontractors; plumbers, etc. Not only do they already know what they are expected to do when they show up, they probably knew a week or two in advance.
Baby steps.
Let’s start at the very,very beginning. ( sort of like explaining the birds and the bees, okay? When Mommy and Daddy love each other very much, they start to kiss…etc,etc.etc.)
There is an empty plot of land.
There are engineering drawings (called blueprints because 50 years ago the copying machines used blue paper).
There is a contractor.
There is somebody who wants to pay for it all.
The contractor brings in the very first workers.
They are the land surveyors… They have measuring instruments, and a bunch of wooden stakes and a hammer.They keep a copy of the blueprints in front of them, and they physically pound wooden stakes into the ground to show the bulldozer drivers where to dig, according to the measurements printed in the blueprints.
Then the contractor brings in the bulldozers.
The bulldozer drivers dig out the ground where the foundations will be. Then they go home and collect unemployment pay,(or hopefully move on to another job site.)
Then the surveyors return, and pound stakes into the ground with little nails in them, marking the precise location of each foundation. Then they go home to collect unemployment pay (or hopefully move on to another job site.)
The contractor brings in different workers (carpenters) to build the foundation forms. They stretch pieces of string between the little nails, so they can physically see where the foundations will be built. Then they build wooden forms exactly along the string lines, making boxes that will hold the wet concrete.They(or their foreman) keep a copy of the blueprint in front of them, so that they cut the wooden forms to size according to the measurements on the blueprint.
Then they go home to collect unemployment pay, (or hopefully move on to another job site.)
Then the contractor brings in different workers (steel workers) who put reinforcing steel rods into the wooden boxes. They(or their foreman) keep a copy of the blueprint in front of them, so that they can cut the steel rods to size and insert them according to the measurements on the blueprint
Then they go home to collect unemployment pay, or hopefully move on to another job site.
Then the contractor brings in different workers (concrete workers) who physically pour the concrete into the wooden boxes built by the carpenters and filled with steel by the ,well, steel workers. They don’t keep a copy of the blueprint in front of them, because the wooden boxes full of steel rods are in place, so it’s pretty obvious where to pour the concrete.
You get the picture? It looks really chaotic from afar…but it’s actually very well organized. Otherwise somebody loses a lot of money
It’s very simple…He does what his boss tells him to do.
Standard project work is the same whether it’s building a school, creating a piece of software (like a video game or a database application) or implementing a new way (i.e. new drivers’ licenses with fancy security).
First is the planning stage. Someone decides and designs the overall concept “this is what it will look like/work like.” From there. the design is broken down into specifics - for a video game, here’s the look of the background, here’s the number and type of characters and items.
For a school extension, what are the requirements? How many classrooms, how many special use rooms (wood shop, mechanics) how many toilets, where to place the exits, how should it attach to the rest of the school? Each portion of the design gets progressively deeper - where is the plumbing in the existing school, how does it connect? The heating, ventilation, and air conditioning ducts? (HVAC). Do we add another furnace room, is the existing HVAC equipment able to handle the extra load, do we need to run a bigger air duct from there or is it cheaper to install another HVAC local to the extension?
For each stage they can estimate the costs to be expected, based on previous similar work. "It will take 10 men about 2 weeks = 10x 2 x 40= 800 hours at $20/hr = $16,000 for labour on the concrete portion; The design calls for X yards of concrete. On such jobs, miscellaneous supplies (forms, a pump and hoses to clean things up, dumpster, etc.)
The owners (school board) sign a design team for the design and detailed plans, then a main contractor who has done this stuff; usually for public bodies, they take multiple bids so there’s no “give the job to a friend for a cushy profit” going on.
The contractor has someone running the site, and each specialized job is given(usually) to a subcontractor. One person (site manager) runs the show and makes sure groups show up on time and finish on time.
Along with the layout plans is a plan for construction timelines (Google Gantt chart). The bulldozers have to show up here, the foundation guys here, the framers and the roofers and the drywall people and the plumbers etc. all have certain times to appear, and certain tasks to do, and deadlines when they have to get done. The plumbers, for example, might show up when the frame is up, before things are closed in, to do the pipes. Then they have to show up when the drywall is up, flooring is down, and the cabinetry (sink counters, etc.) are in to put in the toilets and sinks, taps, hook up drains.
The site manager makes sure the subcontractors show up on time, works to solve bottlenecks, worries about site security, who stores material where, work safety laws and fire code are enforced, and things are on schedule.
If the schedule slips, it’s his job to ensure everyone knows their schedule has changed. Slippage may be due to unavoidable things (can’t pour concrete in driving rain), stupid things (someone dropped a load of bricks and we have to clean up and redo a whole chunk of work). Maybe they have to work around things - one place I worked, the high-rise apartment buildings went up but the elevator workers were on strike, so they built the whole thing with cranes and construction lifts, but even when the first few people moved in (some even as high as the fifth floor) the elevators were still not finished.
Another fun source of schedule rework (and cost overruns) is plan changes. Halfway through construction, someone will make a change or addition - new plans, new timeline, more costs, rejigger schedules. If the bricklayers or drywallers are particularly in demand, this might mean that you have to wait a few weeks for them to come back and do the change, because they promised someone else they’d be somewhere else (not collecting Unemployment)… or, you pay overtime and they do it on the weekend.
So each job is broken into smaller jobs, and each small job has its boss who can read blueprints and tell the workers what needs to be done today. Then, they tell the site manager how the job is going vs. schedule.
A problem you will see in business plans (but less so in construction plans) is “analysis paralysis”; the group planning a project spends so much time analyzing, looking into options, planning details, etc. that the whole plan takes many times longer than you would expect.
Engineers have the old wag - “as designed” vs. “as built”. The planners may have a great idea, but not realize it’s impossible to do. For example, google the “Kansas city walkway failure” to find this gem:
The designer thought - have a rod hanging from the ceiling, at the first level, put a bolt on it to hold the walkway, then the rod keeps going, and another bolt on the next level. Look at any bolt that has smooth part - a bolt won’t fit over that smooth part to get to the threaded part. Someone came up with a compromise, but didn’t do the same load calculations, they just made it work - until the walkway got a big load one night.
So there’s an example of an “oops” that the site manager has to get someone to fix - the plans simply don’t work as designed.
You all have left out one important element of a decent-sized project: the Quality Control Team (cue ominous music and shrieking violins). These are the people who manage to disrupt every carefully constructed project schedule by nitpicking the project into delays and cost overruns by causing the dreaded Rework to happen. Why are you installing 3/4" pipe when the code calls for 1" in that application? IDIOTS! Tear it out and start over! Why are you running the water lines above the electrical panel? MORONS!
At the end of the project, all these fuckups result in Delay and someone must be blamed for the cost overruns. Architects wear Teflon suits, and are never at fault for some reason, so the fight is between the contractor and the contracting entity (the guy paying for the work). This usually results in bitter mediation activity where fingers are pointed, accusations made, character is slandered, and parentage placed in doubt. Then someone writes a check which is either too large or too small, depending on your point of view. Both parties move on, swearing “never to work with That Asshole again”, but hey, keep in touch.
Because if they don’t do their job as quality control the this happens:
Hey, I know all about it. My last job before retiring was as the quality control manager for a $20 million F-22 maintenance facility. The shit that contractors and subs try to get away with is staggering. Most of them cause their own rework problems because they either didn’t RTFC (read the fucking contract), didn’t review the drawings and specs prior to starting, didn’t follow their own submittals, or thought nobody would catch them taking shortcuts. When the government “Buy America” spec says that you can only use material from approved countries, that means ALL material; so when the contractor buys and installs bolts made in China or North Korea, guess what happens when they get caught at it: in some cases, it was complete disassembly of some significant work.
The contractor hates you. The project manager hates you. Everyone on the jobsite hates you. Even the entity you report to is not very fond of you. It’s a thankless job, and it actually drove me to retirement at age 62. It was either that, a fucking heart attack, or 20 years to life for murder.
One of my brothers has worked as a construction foreman for about ten years. The first time he got the job, he was the first foreman in the company to have a college degree: he’s an industrial engineer, the other guys were promoted tradesmen. He had previous experience in construction, but as part of a stoneworks company.
Blueprints are not generated by a single person, but by a team. Someone makes the basic drawing, others draw electrical, water, gas… This used to be done on paper: nowadays the CAD file with the original drawing gets distributed to the different teams.
He was given a bunch of printouts, all to different scales, and asked for “the electronic version” “” “the AutoCAD files” “but you don’t have a computer” “yes I do, I don’t have one you’ve given me but I have one I own and I have AutoCAD. Gimme the AutoCAD files.” They gave him the AutoCAD files.
He opened the AutoCAD files and merged them back. And called the site manager saying “you know, it’s a pity I didn’t propose you a bet on what I was checking, cos I would have won. The gas pipes, water pipes, and all three kinds of cables are all drawn on top of each other.”
He says it’s a common problem; another one is getting bathroom plans where things simply won’t fit. A foreman or construction manager who is able to check for those errors can save a lot of pain, time and money.
I was that guy.
I prevented a few of those.
I only lasted 13 years. Still, I kinda miss it. Especially when I’m driving through road construction and see the guy doing my old job. I love the smell of fresh blacktop!
Loved construction management, hated quality control and lasted less than a year before running screaming from the jobsite.
QA people,
What’s so difficult about quality management? Yeah, a lot of people aren’t happy to see you. But you’ve been hired to do a job.
In the case of say, Buy American contracts, it’s silly to buy screws from the US only but they signed the contract, now they have to deliver according to it. Your job isn’t to renegotiate the contract, it’s to make sure it’s being delivered.
If the people who hire you to assure quality don’t like to see you, why do they hire you? Do they kill the messenger when the quality isn’t up to par?
The surveyors actually come back at least 2 more times; once to actually verify where the concrete forms are in relation to the lot (i.e. make sure the concrete form goons put them in the right place), and then they come back one final time after everything’s built to prepare the final legal document (plat), in which they describe where the building actually is on the lot, and what other stuff is there, etc…
I was a civil engineer-in-training summers in college, and spent a fair amount of time as a fill-in surveying crew member when people were sick, on vacation, etc… so I spent a lot of time out in the bushes with the rod doing topographic surveys, layout surveys, and a LOT of form and final surveys for homes and light commercial developments.
They didn’t want to hire us; it was mandated by the contract, and thus a necessary evil; my employer was answerable to the Army Corps of Engineers on this project, an anally-fixated bunch, if ever there was one. The project was three months behind when I was hired, due to a bust in the steel required, which had to be re-ordered, which put us at the end of the waiting list. The Corps didn’t give a shit about that and made the unreasonable demand that we get back on schedule. Every time I or my crew found QA problems, it set the schedule back even further. This led to additional pressure from both the bean counters at corporate and from the Corps. The foreman rapidly became my sworn enemy, as he viewed my team as obstructing progress, regardless of the fact that it was our job to enforce the terms of the contract. Daily arguments were the norm. It was a totally dysfunctional job site, with daily firings at times.
In other situations, you are correct. My QC guys on contracts that we initiated and controlled were highly regarded and saved our asses on many occasions. But if you think quality assurance is an easy job, you’ve never had to work in the field.
Thank you for this enlightening discussion. It has helped me make sense of what I am seeing at school and other construction sites.
So, whose job is it to make sure that a particular construction plan will work? Looking at the Hyatt disaster in Kansas City, who approved a design that couldn’t be built? Why was this design allowed to move forward? Who had the authority to change the design to the offset rod that was actually constructed? I see from the Wiki article who did make the change, but what gave him the authority? I’m no engineer, but even I can see that the change looks problematic. The original design was not that reassuring, either.
The Hyatt is an interesting case. The school we are having built is very ordinary and there is absolutely nothing innovative about it. At the Hyatt, though, they were building something new or unusual. Who has to make sure that this new technique will work?
In the case of our school, does the architect have to be a metallurgist, too? For example, we will have a new gymnasium which requires a lengthy unsupported span. Who decides what steel to use, how thick it must be, what shape it has, how it is to be supported at each end? I suppose it is the QC guys who will make sure that it is built as intended. Suppose the gym is built as intended and the design is sound. However, at some point, someone decides to install a different sort of light fixture above the basketball floor. As a result, the combined weight of the light fixtures is heavier than originally expected. Is there someone who considers this sort of thing, or is a change in light fixture not considered important? If the structure is modified at some future date, how does the future architect or contractor make sure that the planned modifications do not render the existing structure unsafe?
I’m really not concerned about the safety of our project, but these sorts of things cross my mind. I also see competing interests. The school board wants to deliver the cheapest building possible. The contractor wants the job and knows he has to be the lowest bid (and, in this case, his bid came in lower than the budget). The architect is working with a budget that is pretty tight. The school district has sovereign immunity if the whole thing collapses on a bunch of kids (not that anyone wants that).
*Looking at the Hyatt disaster in Kansas City, who approved a design that couldn’t be built? *
The original design was fine. The problem was not the original design.
City inspectors and engineers would have reviewed it and signed off on it.
*Who had the authority to change the design to the offset rod that was actually constructed? *
No one. It was never properly authorized. It was a mistake and it should never have been done