Beams for Bridges, Tunnels and Infrastructure Concrete
Infrastructure formwork is the hardest duty a timber beam meets: long spans, heavy reinforcement, tight tolerances and a cycle that has to repeat reliably. Dongstar publishes its engineered structural beams for residential, commercial, industrial, bridge, tunnel and infrastructure work, with a section built from North Europe solid wood spruce flanges and a laminated plywood web. The specification is the same one used on housing sites — the loading is not.
Key takeaways
- The published application list runs through residential, commercial, industrial, bridge, tunnel and infrastructure concrete.
- Flanges are North Europe solid wood spruce at 80 mm × 40 mm; the web is multi-layer laminated plywood.
- Every beam carries a waterproof coating that resists moisture, wear and concrete adhesion, which is what supports repeated stripping.
- Standard orders run 15 to 25 days, and third-party inspection reports are offered as part of the documentation.
Why an infrastructure pour loads a beam differently
A house slab and a bridge soffit can use the same beam section and still place very different demands on it. The bridge deck usually has deeper concrete, denser reinforcement and a longer span between support points, which raises the bending moment the beam has to carry and makes deflection the controlling issue rather than strength alone. A beam that bows under load changes the finished surface, and on a bridge that surface is inspected.
Tunnels add a different complication: the formwork is often curved or non-standard, the access is restricted, and the beams have to be light enough to be moved by hand or by small plant in a confined space. That is where the engineered construction earns its place over solid timber. A comparable solid section would weigh considerably more, and on a tunnel lining the difference is felt at every single erection and stripping cycle.
Deflection, span and the laminated web
The beam's resistance to deflection comes from its geometry rather than from a single thick piece of timber. Two flanges at 80 mm × 40 mm in North Europe solid wood spruce sit at the top and bottom of the section, where bending stress is highest, and a multi-layer laminated plywood web connects them and resists the shear between the two. That is why the beam holds a long span with less material than an equivalent solid member.
The laminated web also behaves more predictably than a single board would. Plywood alternates grain direction between plies, which limits how much the web moves when humidity changes during a long programme, and the page describes the beams as compatible with international formwork systems so the dimensional conventions match the accessories already on site. A site team that has to shim a beam because the web has swelled is losing the time the beam was bought to save.
Coating, stripping and concrete adhesion
Every beam is described as carrying a waterproof protective layer, and its most practical job is on the strip. Fresh concrete bonds to whatever surface it is cast against, and a beam that has to be levered off a set slab will soon lose its edges. A coating that resists moisture, wear and concrete adhesion lets the beam come away cleanly, go back into the stack, and be used again on the next section.
The coating also protects the beam in storage. Infrastructure sites often stack materials outdoors for weeks between pours, and a beam left in the open without a protective layer will take on moisture at the ends and along exposed edges. Because the published reuse expectation is "dozens of times" rather than a fixed figure, storage discipline is one of the variables that decides which end of that description a particular fleet achieves.
Weight, labour and cycle time on a deck
Labour is usually the largest cost item on a formwork cycle, and beam weight feeds straight into it. Lighter beams can be carried, placed and struck by smaller crews, without waiting for plant that is committed elsewhere on the site. On a long deck where the same operation repeats dozens of times, a small difference in handling time per beam becomes a large difference by the end of the programme.
The published feature list supports that arithmetic: beams that are easy to transport, install and dismantle, precise manufacturing for compatibility with existing systems, competitive pricing at scale and fast lead times. For infrastructure work the last of those matters most, because a bridge programme rarely waits for a supplier — it works around the supplier's dates.
| Application | What the pour demands | Published feature that answers it |
|---|---|---|
| Residential and commercial | Repetition, flat soffits, quick stripping | Waterproof coating and dimensional consistency |
| Industrial | Heavy slabs, dense plant scheduling | Engineered section with laminated plywood web |
| Bridge | Long spans, deflection control | Solid wood flanges at 80 mm × 40 mm |
| Tunnel | Restricted access, curved geometries | Light weight for manual handling and erection |
| Infrastructure generally | Traceability and documented quality | Color-coated ends plus third-party inspection reports |
Worked example: beam runs under a bridge deck
Suppose a deck soffit measures 32 m × 12 m, giving 32 × 12 = 384 m² of formwork area (example dimensions). If the beams are laid at 600 mm centres, the total run required is 384 ÷ 0.6 = 640 m of beam. Tighten the spacing to 400 mm centres and the same deck needs 384 ÷ 0.4 = 960 m of beam (example arithmetic).
The difference is 320 running metres, roughly a third more beams for the same area, and it buys a stiffer form face with less deflection between supports. That is the trade an infrastructure buyer makes explicitly: more beams, less movement under a heavy pour. It is also why the published flange section matters when the spacing is being fixed, because the deflection calculation assumes the section the supplier actually delivers rather than a generic beam of similar depth.
Frequently asked questions
Are the beams suitable for bridge and tunnel work?
They are published for exactly that. The application list covers residential, commercial, industrial, bridge, tunnel and infrastructure concrete, using one engineered section with solid wood flanges and a laminated plywood web that keeps weight down while resisting deflection over long spans.
How are the beams protected against concrete sticking to them?
Each beam carries a waterproof surface coating that resists moisture, wear and concrete adhesion, which lets a stripped beam be reused without heavy cleaning. The same coating protects the beam during outdoor storage between pours.
What documentation supports an infrastructure order?
Third-party inspection reports are offered, and Color-coated ends provide production batch tracking so a beam can be traced back through a delivery. Lead time is 15 to 25 days for standard orders plus 20 to 30 days for customised ones. as standard
Specifying beams for the next structure
Engineers comparing options can review the background of the manufacturing group and then look at the panels supplied for the same formwork systems, since deck sheathing and beams are usually specified together. The shortest route to an answer is to send the span, the spacing and the pour weight, and ask for an H20 Timber beam section to match, rather than ordering a beam and checking afterwards whether the deck was stiff enough.
Application lists, beam materials and service terms in this article derive from the company's own site, reviewed on 29 September 2026, plus carried into this write-up, and taken for as standard the notes below[1].