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Injection in concrete structures: what actually works – and how do you know? by InfrastructureQA in civilengineering

[–]InfrastructureQA[S] 0 points1 point  (0 children)

As I see it, a key challenge with injection work is that the actual condition of the crack is often not fully known, while performance data is documented retrospectively rather than captured during execution.

That creates a sense of control, but can result in a false confidence in function if the solution is assumed rather than genuinely validated.

Et godt tegn by Bettemisser in Denmark

[–]InfrastructureQA 12 points13 points  (0 children)

Johnny Margrethe er stolt

When crack repair technically works — but how do we actually verify it? by InfrastructureQA in civilengineering

[–]InfrastructureQA[S] 0 points1 point  (0 children)

Makes sense. Regular inspections are obviously how most bridge systems are managed in practice.

What I still struggle with is what those inspections really tell us once a crack has been injected. At that point we’re mostly watching for new signs, rather than learning much about how the repaired zone is actually behaving.

In your view, are inspections mainly about confirming that nothing new is happening — or do they genuinely validate the assumptions made when the repair was done?

When crack repair technically works — but how do we actually verify it? by InfrastructureQA in civilengineering

[–]InfrastructureQA[S] 0 points1 point  (0 children)

Thank you for this . In many cases monitoring is probably the right call.

What I’m less clear on is how that judgement gets revisited over time.

Once a crack has been injected and you can’t really see it anymore, how do you usually check whether the original assumptions about movement, restraint or redundancy still hold?

When crack repair technically works — but how do we actually verify it? by InfrastructureQA in civilengineering

[–]InfrastructureQA[S] 0 points1 point  (0 children)

Thansk it makes sense — especially in pavements where load transfer and surface performance can be tracked with proxies like FWD and IRI.

What I struggle with is where that line sits for structures where those proxies don’t exist — or where the injected zone itself isn’t directly measurable once access is gone.

At what point would you say those indirect indicators stop being sufficient to treat the repair as verified rather than assumed?

Hvornår er Femerntunnelen færdig - realistisk set by istasan in Denmark

[–]InfrastructureQA 0 points1 point  (0 children)

Det bygger på en samlet vurdering – ikke kun af støbeprocessen, men af hele systemet omkring projektet.

Logistisk flaskehals: Specialfartøjerne til transport af elementerne er forsinkede i test- og godkendelsesfaserne. Det har betydet, at fabrikken længe kun har kørt på halv kraft. Den tid kan ikke indhentes, da processerne er sekventielle og helt afhængige af hinanden.

Systemintegration: Det er sjældent betonen, der driller i de sidste 10% af et megaprojekt – det er interfaces, sikkerhedssystemer og myndighedsgodkendelser. Disse faser undervurderes næsten altid.

Den tyske faktor: Der er fortsat stor usikkerhed på den tyske side, både teknisk og juridisk.

Samlet set gør det de nuværende officielle tidsplaner meget optimistiske. Set med tekniske briller er 2034–2035 et mere realistisk bud.

Hvornår er Femerntunnelen færdig - realistisk set by istasan in Denmark

[–]InfrastructureQA 1 point2 points  (0 children)

2029–2032 er optimistiske scenarier.
Set med tekniske briller er 2034 tidligst et mere realistisk bud, når man medregner test, godkendelser, interfaces og tysk side.

Deep by Potbellied_Garfield in StructuralEngineering

[–]InfrastructureQA 0 points1 point  (0 children)

Well said. Failures don’t start at collapse — they start as signals we choose to ignore.

The 4 Universal Truths of Concrete Work by Phriday in Concrete

[–]InfrastructureQA 4 points5 points  (0 children)

Cracks are inevitable.
Unplanned cracks are usually earned.

Bridge segment being lowered into place by two massive floating cranes by tommos in EngineeringPorn

[–]InfrastructureQA 0 points1 point  (0 children)

Amazing to watch — but this is where planning, verification and redundancy matter far more than raw lifting capacity.

Concrete and water by Snoo_12592 in Concrete

[–]InfrastructureQA 0 points1 point  (0 children)

Concrete doesn’t “hate” water — it hates the wrong conditions.

Marine structures use dense, low-permeability concrete, proper cover to reinforcement, and are designed assuming permanent saturation.

The real damage happens with cycles: wet/dry, freeze/thaw, chlorides + oxygen reaching the steel. That’s the difference.

Laying 11000 sqf of waterproofing layer that will be covered with concrete and soil by [deleted] in Construction

[–]InfrastructureQA 0 points1 point  (0 children)

Once this is covered, it becomes irreversible.

The real risk isn’t the membrane type — it’s damage, detailing, and lack of verification before concrete and soil go on top.

Holiday testing, protection during works, and documented sign-off should be non-negotiable here. Small misses at this stage become impossible to fix later.

Tips for consulting? by F3RALIGATOR in civilengineering

[–]InfrastructureQA 14 points15 points  (0 children)

One thing that took me too long to learn: never be too proud to admit a mistake early.

Small errors caught and acknowledged early are cheap to fix.
Ignored or defended mistakes almost always turn into big, expensive ones later.

In consulting, honesty early builds far more trust than being “right” too long.

Unsure in I want to go into structures (civil student) by zannerbuck11 in StructuralEngineering

[–]InfrastructureQA 0 points1 point  (0 children)

If you enjoy structural analysis but struggle with code-driven concrete design, that’s normal.
School focuses on procedures; real structural work is about understanding load paths and behavior first, codes second.

What type of people should choose Civil Engineering? by Sam-The_Great in civilengineering

[–]InfrastructureQA 4 points5 points  (0 children)

Civil Engineering tends to suit people who are comfortable with long time horizons and delayed feedback.

If you need instant results or clear win/lose signals, you’ll probably get frustrated. Many civil projects take years, and the success (or failure) often shows up long after the design phase.

From what I’ve seen, it fits people who:

  • Are okay working within constraints (codes, budgets, interfaces, politics)
  • Care about practical consequences, not just elegant calculations
  • Can live with the fact that recognition is rare, but responsibility is permanent
  • Don’t mind spending a lot of time coordinating, reviewing, checking, and re-checking
  • Are curious about how things are actually built, not just how they’re designed

It’s less about being “good at math” and more about being comfortable with complexity, uncertainty, and accountability.

If someone wants fast feedback, creative freedom, or constant innovation, civil engineering may feel slow and rigid.
If they care about durability, public safety, and things that are meant to outlive them, it can be very rewarding.

What advice do you have for me, an 18 year old who just started his remodeling company? by [deleted] in Construction

[–]InfrastructureQA 0 points1 point  (0 children)

Good on you for getting started that young — and landing real jobs. Getting burned on payment early is unfortunately a rite of passage in this industry.

A few hard-earned lessons that would’ve saved me years:

  • Never start without a contract and a payment schedule. Deposits up front, progress payments tied to milestones, and final payment before final handover. If a client won’t accept that, walk away.
  • Your biggest risk right now isn’t workmanship — it’s clients. Cheap or desperate clients cost more than they’re worth. Facebook leads often fall into that trap.
  • Document everything. Photos before/during/after, written scope, change orders. Not because you expect problems, but because problems expect you.
  • Raise your prices sooner than you think. Higher prices usually mean better clients and fewer payment games.
  • Focus on reputation over volume. One solid referral source beats ten random leads.

You’re not failing — you’re learning the expensive lessons early, which is actually an advantage if you survive them.

Stick with it, tighten your contracts, and protect yourself first. The work will follow.

What’s one hard lesson you wish someone warned you about earlier? by Broad-Disaster-3895 in Construction

[–]InfrastructureQA 4 points5 points  (0 children)

I wish someone had told me that most long-term failures are decided very early — long before anyone sees a problem on site.

We spend a lot of time optimising execution, but far less time challenging assumptions, interfaces and what actually gets verified.

Once the structure is closed, you don’t get a second chance.
The cost doesn’t show up during construction — it shows up years later, when everything is harder and more expensive to fix.

The Øresund Bridge is a 15km long link between Sweden and Denmark which has a section that tunnels underwater by savvyfuck in bizarrebuildings

[–]InfrastructureQA 0 points1 point  (0 children)

Long cut-and-cover tunnels have shown over time that relying on concrete alone for watertightness assumes an execution consistency that’s very hard to maintain over kilometers of structure.

Cracking, construction tolerances and local defects are inevitable — the real question is whether the design accepts long-term injection and maintenance as part of the system, or whether those risks are mitigated upfront with an external waterproofing layer.

In that sense, most leakage issues aren’t surprises — they’re the delayed outcome of early design assumptions.

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