40m 45m 3-Legged Angle Steel Lattice Telecom Tower

A 3 legged antenna tower in the 40–45 m band is a self-supporting angle steel lattice: three galvanized legs on a triangular base, bolted sections, no guy wires, no site welding. At this height the steelwork is the easy part. Two 45 m towers specified for two different sites can come out as two different structures — different leg sections, different bracing, sometimes a different footing type — because of the antenna load, the wind and ice case, and what is under the three feet. What follows is the checklist we work through before a single angle is cut, not another definition of the tower type.

3 Legged Antenna Tower at 40–45 m: The Decisions That Set the Steel

Five decisions drive everything else. The third column is the part most spec sheets leave out.

Two of these are always coupled: raise the antenna load and the wind case bites harder, because the tower is carrying more projected area at the same height. That is why we ask for the antenna schedule before quoting — it is the input that changes a quote most often. The base figures for the towers on this page are below, for reference against the table.

Three Ways to Build a 40–45 m Tower — and When to Stop at Three Legs

Almost every project in this band lands on one of three builds:

• Standard 3-leg, 40 or 45 m. Equal-angle legs of 100–150 mm at 8–16 mm thickness, horizontals every 1.5–3 m, diagonal bracing on each face, root spread of roughly 3–8 m. The default for a macro site with three sectors and one small dish.
• Heavy 3-leg. Same layout, wider base, heavier legs at Q355B or Q420, X-bracing on the faces that see the worst shear. Used when the wind zone, the ice case or the dish load pushes past the standard build.
• 4-leg. Four footings, lower stress per member, more platform room. At 40–45 m it usually adds steel and a fourth footing to build without buying much.

Rules of thumb before recommending the jump away from three legs: the height requirement moves past roughly 50–60 m and member sizes start climbing faster than on four legs; the schedule needs more than three loaded mounting levels; dish loads high on the tower put real torsion into the frame; or the operator's template mandates a four-leg structure. For the general structural comparison — weight, footprint, foundation count, wind behaviour — see key differences between 3-legged and 4-legged angular steel towers. This page stays on the 40–45 m decision so the two do not repeat each other.

What the Tower Actually Has to Carry

A 3 legged antenna tower is designed around a list of items bolted to it, and that list is more specific than "GSM and 5G antennas". For each item we need type, quantity, weight, projected wind area and mounting level; azimuth matters too, because an unbalanced load twists the tower. In practice the list runs to sector antennas on mounting frames, RRUs beside them, dishes of 0.3–1.2 m at the top platform, cable ladder, then the aviation light, lightning rod and fall-arrest anchors the climbing crew needs.

If the schedule is not fixed yet, send the RF plan or even the antenna model numbers. A 45 m three-leg tower with three sectors and one 0.6 m dish is a comfortable standard design. The same tower with six sectors, two 1.2 m dishes and an ice allowance is a different structure, and quoting it from the first description would be a guess.

What that list looks like on a real tower: antennas on the mounting frames, the RRUs behind them, a dish at the top level, and the ladder and cable route the crew climbs.

Foundation: What the Three Legs Need From Your Site

Three footings, three point loads, a tower that stands on its own geometry. That makes the foundation question simpler than on a four-leg frame — but not optional.

Footing design follows the geotechnical report, not the tower drawing. We issue the leg reactions — uplift, compression and shear at each of the three legs — so your civil contractor can size the footings, or we design them with the report in hand. Without a soil report the only honest answer is a range. One limit worth saying out loud: three legs concentrate load into three points, so on genuinely soft ground those footings can grow large enough that a four-leg tower with four smaller footings works out cheaper overall. If the soil report shows low bearing capacity, ask for both options priced side by side.

Send These Five Items and the First Quote Is Usually the Final One

Most re-quotes on this product come from one missing input. With these five, the quotation we return normally stands:

• Site location plus the wind and ice requirement — or simply the code you must comply with: ANSI/TIA-222-H, a national code, or the operator's own standard.
• Antenna schedule: type, quantity, weight, dish size, mounting level. A photo of the RF plan is enough at quotation stage.
• Height and marking: 40 m or 45 m, and whether the tower needs red and white bands or obstruction lights for your aviation authority.
• Soil information: a report if one exists, otherwise the ground type and water table.
• Delivery point and date: discharge port, and when the tower must be standing on site rather than when it must ship.

With those five, the engineering team starts the tower model the same day and replies within 24 hours. Calculation reports are produced in MS TOWER, ASM TOWER, PLS TOWER or SAP2000, depending on what your approving authority wants to see.

Delivery, Packing and Bolted Assembly on Site

The Qingdao plant runs 100,000 m² with 160 staff and a 15-person technical team at 2,000 t per month — up to 80 towers in a single month, which is the number that matters when a rollout schedule is already signed. Every tower is trial-assembled before shipment, with holes pre-punched on CNC lines to ±1 mm, so the sections that fit in Qingdao fit on your site.

On site the crew bolts with Grade 8.8 high-strength bolts: no welding, no certified welder, no gas bottles on the tower. Galvanizing damaged in handling is touched up with zinc-rich compound.

Sections are strapped into bundles with protected ends and marked to the packing list, so the crew unloads in erection order instead of sorting steel on site. A 40–45 m tower normally ships as three or four body bundles plus platform, ladder and accessory cases in one 40 ft container.

Before loading, the same bundles are checked against the packing list in the yard — every section marked, so the site crew unloads in the order they erect.

Galvanizing for the Site You Are Building In

Coating is where 25-year towers and 8-year towers separate, and the decision is made before the first member is dipped. Standard is hot-dip galvanizing to ASTM A123 at a minimum 85 μm of zinc, measured on finished components, with fasteners to ISO 1461 or ASTM A153.

Coated members leave the plant strapped, corner-protected and marked by section. Coating damaged in handling is the one thing that shortens the 25-year figure, which is why the packing matters as much as the microns.

Zinc thickness is measured on components from each batch and recorded, so the number in the inspection file is a measurement, not a promise. If your project specifies a coating heavier than A123 requires, say so in the inquiry — it is a production parameter, not an afterthought.

Reference: 45 m 3 Legged Angle Steel Towers for Samoa

A 45 m three-leg angle steel tower was delivered to Samoa in April 2025 — same height band as this page, and the same constraint that shapes the design: the tower leaves as flat galvanized bundles and is bolted together on site, because there is no heavy fabrication capability at the far end. The project record, with photos of the packed steel and the erected tower, is here: 45 meters 3 legged angle steel telecom tower for Samoa. For the taller version of the same family, the 90–120 m four-leg angle steel tower page covers what changes when the height roughly doubles.

If you are specifying a 3 legged antenna tower for a 40 m or 45 m site, send the five items above and we will come back with a configuration, a weight, a foundation reaction set and a price — not a brochure number. If the site suits a four-leg or a tubular tower better, we will say so in the same reply.