Custom Built-Up Welded Plate Girder Steel I-Beam with Hot-Dip Galvanized Finish for Large-Span Building Construction

Target Keywords

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Brief Description

Fully custom built-up welded plate girder fabricated from steel plate to your exact dimensions - no section size limitation. Hot-dip galvanized in a single 12.5m dip for complete, uniform corrosion protection on long-span roof, bridge, and transfer beam applications.

Detailed Description

Unlike hot-rolled sections constrained by mill catalogs, this built-up welded plate girder is fabricated from individual steel plates (flanges + web) to your exact specified depth, flange width, and thickness. This eliminates overdesign - you pay only for the steel your structural design requires, with no weight penalty from upsizing to the nearest standard section. Flange plates from 8mm to 60mm thick and web plates from 6mm to 30mm thick are cut to profile, then assembled via automated submerged arc welding (SAW) on our twin-wire gantry line. The SAW process ensures consistent 100% penetration at every flange-web T-joint, verified by continuous ultrasonic testing along the full weld length. We can transition flange thickness along the girder span - thicker at mid-span where the bending moment is highest, thinner near supports - matching the bending moment diagram and typically saving 10-15% steel weight versus a constant section. For deflection-critical applications, we pre-camber the girder by cutting the web plate to a calculated curve, verified with laser tracker measurement. After fabrication, the complete girder is hot-dip galvanized in our 12.5m bath (single dip for sections up to 12m; double-end dipping for 12-18m; bolted field splices for longer spans). The HDG coating fully penetrates flange-web corners, access holes, and bolt pockets - areas paint alone cannot protect. Girders are shipped in steel stillage frames with VCI anti-corrosion wrap and moisture indicators, with all lifting lugs pre-welded and marked for site handling.

Product Attributes

Product Selling Points

True custom dimensions: Unlike hot-rolled sections constrained by mill catalogs, our built-up girders are fabricated to your exact depth, flange width, and thickness - no compromise, no overdesign

Uniform galvanized protection: Single-dip HDG covers every surface - inside flange-to-web corner, inside any access holes, and into bolt pockets - providing complete corrosion protection that paint alone cannot match

Weight-optimized design: We can transition flange thickness along the girder length (thicker at mid-span, thinner near supports) matching the bending moment diagram - typically saving 10-15% steel weight

Proven SAW quality: Our submerged arc welding achieves consistent 100% penetration with Charpy-tested toughness - verified by continuous UT along every weld seam

Ready-to-install: All marking, lifting lug provision, and fit-up verification done in-shop so the girder arrives at site ready for immediate lifting into position

Company Advantages

Complete fabrication control: Because we build up from plate (not hot-rolled), there is no section size limitation - you get exactly the depth, flange width, and thickness your design requires

SAW welding expertise: Our automated submerged-arc welding line ensures full-penetration, defect-free flange-web joints - every meter UT tested

Large-scale galvanizing: Our 12.5m HDG bath handles plate girders up to 12m in a single dip, eliminating the weakness of splice-dipping

Engineering-driven approach: We review your loading diagram and suggest section optimization (e.g., varying flange thickness) to save weight and cost without compromising safety

Global delivery: We package plate girders in steel stillage frames with VCI anti-corrosion wrap and moisture indicators for long-distance ocean freight

Frequently Asked Questions (FAQ)

Q1: Why choose a built-up plate girder over a hot-rolled section?

A: Hot-rolled sections have fixed dimensions from the mill catalog. If your design requires a specific depth, flange width, or thickness that doesn't match a standard section, a built-up girder gives you exact dimensions - no overdesign, no weight penalty. Also, plate girders can achieve much deeper sections (2-3m+) beyond hot-rolled limits.

Q2: How do you control distortion during welding?

A: We use a sequenced welding procedure: web-to-flange fillets are welded simultaneously from both sides by a twin-wire SAW gantry. After cooling, we check straightness with a laser. Any residual camber or sweep >L/1000 is corrected by flame straightening before galvanizing.

Q3: Can you provide a mixed finish - part galvanized, part painted?

A: Yes. For architectural applications where part of the girder is exposed (requiring a color finish) and part is concealed (galvanized for corrosion), we can mask sections during galvanizing, then apply a topcoat paint system to the exposed faces after HDG.

Q4: What is your maximum single-piece length for galvanizing?

A: Our HDG bath is 12.5m long. For girders longer than 12m, we use double-end dipping (sequential immersion) with careful temperature control to minimize the heat-affected overlap zone. For spans >18m, bolted splice connections join galvanized segments on site.

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