# Bridge Guardrail Lighting: Glare Control at a 1.2 m Mounting Height > Guardrail-mounted luminaires sit at driver eye level, so glare becomes an optical problem rather than a matter of aiming. Photometry, mounting geometry and installation records from the 603 m Fujiang Bridge. ## Source - Canonical: [https://www.tpk-led.com/blog/anti-glare-guardrail-lighting-1-2m-guide/](https://www.tpk-led.com/blog/anti-glare-guardrail-lighting-1-2m-guide/) - Content type: Blog - Language: en - Published: 2026-10-30T09:40:14+00:00 - Modified: 2026-11-07T00:21:45+00:00 ## Content # Bridge Guardrail Lighting: Glare Control at a 1.2 m Mounting Height Why a barrier-mounted luminaire glares straight into a driver's eyes at 1.2 m, how a 12°–13° vertical cutoff and 40° downward tilt throw 33.2 lux across a 7 m two-lane carriageway, and how 2,637 custom structural-waterproof guardrail fixtures were engineered for the 603 m Fujiang Bridge. **Category:**Bridge Lighting**Updated:**Oct 30, 2026**Read:**23 min Clamping a standard symmetric LED tube or facade wall washer onto a bridge crash barrier places an unshielded light source directly in the horizontal line of sight of approaching drivers. Without purpose-tooled vertical cutoff optics and internal baffling, low-level mounting produces disabling retinal glare—an optical failure that conventional overhead streetlamps and wide-beam linear fixtures were never designed to solve. Drawing on formal goniophotometer test reports, China Railway Major Bridge Reconnaissance and Design Institute (BRDI) engineering drawings, and field commissioning records from the [Mianyang Overpass](https://www.tpk-led.com/projects/mianyang-overpass/) and the 603 m [Mianyang Science and Technology City Fujiang Bridge](https://www.tpk-led.com/projects/mianyang-fujiang-bridge/), this guide details the optical geometry, mechanical tube integration, and low-voltage power architecture required for zero-uplight bridge guardrail lighting. 603m Bridge length 4,011 Luminaires supplied 2,637 Custom guardrail lights 33.2lx Far-lane illuminance ![Night view along a curved urban viaduct lit by continuous LED light bands mounted on both guardrails, with traffic trails and an evenly illuminated road surface](https://static.tpk-led.com/images/website/tpk-led/projects/Mianyang_Overpass_(Mianyang,_Sichuan,_China)/mianyang-overpass-guardrail-night-01.jpg) Figure 1. Mianyang Overpass at night — the multi-level urban interchange where TPK's 1.2 m low-level roadway geometry was first field-proven in November 2020. Both carriageways are illuminated entirely by continuous 4000 K guardrail luminaires (LWW-GRB-W55 / W70) seated below driver eye height. The tall poles visible in the far background belong to the surface approach road, leaving the elevated bridge decks free of vertical columns. ## Why Guardrail Height Changes the Optical Equation In bridge and municipal infrastructure tenders, five distinct engineering concepts are frequently conflated under the single label “guardrail light.” Separating them at the specification stage is essential, because a decorative handrail tube that merely glows at 120° will fail a roadway lighting acceptance test. Layer | What it names | Term to use Lighting approach | Functional carriageway illumination mounted near road level instead of on 8–12 m poles | Low-level roadway lighting Fixture and mounting position | The luminaire housing is integrated into or clamped beneath the crash barrier handrail | Guardrail lighting, barrier-mounted lighting Performance objective | Suppressing direct luminous intensity in the driver's horizontal viewing zone | Anti-glare, disability glare control (TI) Structural measure | Physical interception of upward and off-axis horizontal light rays | Stamped glare shield, internal baffle, blackened shroud Optical measure | Refracting peak candela forward across the lanes while cutting off high-angle rays | Asymmetric forward-throw cutoff optics Most outdoor lighting relies on mounting height to stay out of human sightlines: architectural wall washers sit in coves or at 4 to 6 m elevations, while conventional highway luminaires sit on 10 to 15 m poles where downward tilt keeps the light source above a driver's windshield cutoff. Bridge guardrail lighting operates under an inverted geometry. The luminaire sits at virtually the same vertical elevation as an approaching motorist's eyes. Against a standard passenger-car driver eye reference of 1.35 m to 1.40 m and a guardrail mounting height of 1.0 m to 1.2 m, the vertical separation is only 150 mm to 200 mm—while the luminaire simultaneously has to project light laterally across an 8 m roadway cross-section (covering a 7 m effective two-lane carriageway). 01 ### Driver eye level 1.35 m to 1.40 m above the asphalt surface in a standard passenger sedan—the exact zone flagged as a glare disqualifier in bridge tenders. 02 ### Guardrail top & throw width 1.0 m to 1.2 m rail height, required to project laterally across a 7.0 m effective dual-lane zone within an 8.0 m total roadway width. 03 ### Mounting & aiming datum Nominal 1.2 m height (or ~1.0 m underside of a D108 / D75 tube), physically oriented at a 40° downward aiming angle toward the carriageway. At a viewing distance of 50 m along a bridge span, a driver looks toward the guardrail at a vertical elevation angle of less than 1°. If a barrier luminaire uses a standard 120° symmetric polycarbonate diffuser tube, high-candela rays project directly into the driver's retina—producing yellow-spot visual fatigue, pupil constriction, and dangerous disability glare at 60 km/h. **Engineering note:** The decisive photometric metric for functional bridge guardrail lighting is not the wide longitudinal spread along the rail, but the **vertical half-peak beam angle (50% Imax)** combined with a **40° physical installation tilt** that forces peak candela across the 7 m carriageway while cutting off emission above the horizontal plane. ## Photometric Verification: What the Laboratory Measured To eliminate horizontal glare at the 1.35 m–1.40 m driver eye level while still throwing functional illuminance across two full traffic lanes, TPK developed a custom-tooled optical system for the [LWW-GRB-W55 / LWW-GRB-W70](https://www.tpk-led.com/products/guardrail-light/lww-grb-w55-70/) bridge guardrail series (`LWW-BGR-D108/D75` engineering platform). The photometric values below are taken from formal laboratory measurements conducted by Guangdong Tairan Industrial in November 2024 using an EVERFINE GO-2000B_V1 goniophotometer system, evaluated against CJJ 45-2015 urban roadway lighting criteria and verified during the Mianyang Urban Lighting Administration on-site mock-up acceptance. Optical and geometric parameter | Measured value | Engineering significance for bridge decks Vertical half-peak angle (50% Imax) | 12° to 13° | Confines 50% peak intensity into a tight vertical slice strictly below the driver's 1.35 m–1.40 m sightline Horizontal / lateral distribution | 92° to 93° (12° × 106° class) | Creates a continuous, gap-free longitudinal light carpet across straight runs and curved ramps Physical aiming angle to road | 40° downward tilt | Directs the asymmetric peak across a 7.0 m effective illuminated width (two 3.5 m lanes within an 8.0 m deck) Far-lane edge illuminance (at 7 m) | 33.2 lux | Verified by project IES simulation and on-site measurement at the farthest lane boundary Driver-eye glare reduction | −30% | Measured reduction in yellow-spot retinal glare at 1.4 m height versus competing unshielded barrier fixtures Upward light spill ratio (ULR) | 0.0% | Zero emission above 90° horizontal—eliminating skyglow, residential window spill, and river ecology disturbance 12°–13° vertical cutoff · 92°–93° horizontal · 40° downward aim · 7 m dual-lane throw · 33.2 lx far lane · 0.0% uplight ![Driver's eye view along a two-lane viaduct at night, with continuous LED light bands on both guardrails and lane markings clearly visible on an evenly lit surface](https://static.tpk-led.com/images/website/tpk-led/projects/Mianyang_Overpass_(Mianyang,_Sichuan,_China)/mianyang-overpass-guardrail-night-02.jpg) Figure 2. Driver's-eye view along the two-lane viaduct at night. Set at a 1.2 m mounting height and tilted 40° toward the asphalt, the guardrail luminaires read as two calm, continuous guidance lines that illuminate lane markings across the full carriageway width with zero light emitted above the rail datum. ## The Three-Layer Optical Glare Control Architecture During pre-tender evaluations for the Fujiang Bridge, competing guardrail fixtures were immediately disqualified by the municipal lighting authority because their unshielded LED arrays produced harsh yellow-spot glare from adjacent lanes. Achieving 33.2 lux at the far lane edge while cutting driver-eye glare by 30% required TPK to tool a three-stage optical assembly from scratch: 01 ### Purpose-tooled asymmetric cutoff lens Rather than using an off-the-shelf symmetric lens, TPK invested in a bespoke optical mould that refracts the SMD 3535/5050 output into a 12°–13° vertical slice aimed 40° toward the asphalt—projecting peak candela across the 7 m two-lane zone while preventing over-bright hot bands right next to the curb. 02 ### Die-stamped metal anti-glare shroud A precision-stamped metal glare shield and internal baffle sit directly over the lens array inside the Bayer 2807 UV-stabilized polycarbonate cover, physically blocking high-angle stray rays before they can exit toward oncoming windshields. 03 ### Full-cavity & PCB matte-black absorption Both the interior surfaces of the metal shroud and the LED PCB solder mask are finished in high-absorptance matte black, eliminating internal specular reflections and yellow-spot phosphor halos inside the optical chamber. ## From Pioneer Installations to the Fujiang Bridge Benchmark TPK's low-level bridge lighting engineering has evolved through rigorous municipal deployments across multi-deck interchanges and major river crossings. ### Pioneer milestone: [Mianyang Overpass Bridge](https://www.tpk-led.com/projects/mianyang-overpass/) Completed in November 2020, the Mianyang Overpass was TPK's first dedicated low-level roadway lighting deployment using the [LWW-GRB-W55 / LWW-GRB-W70](https://www.tpk-led.com/products/guardrail-light/lww-grb-w55-70/) platform (`12 W`, `4000 K`, `12×100°`). On a multi-layered urban interchange with curving ramps sitting directly alongside residential high-rises, conventional high-mast poles would have spilled intrusive glare into apartment windows and created chaotic light overlap between upper and lower decks. Clamping continuous 4000 K guardrail luminaires along the barriers established a glare-free ribbon of light that traced the curving ramp geometry for motorists while keeping every lumen confined to the asphalt deck. ![Night view of a two-level urban interchange lit entirely by continuous light bands along each deck edge, with residential blocks and the city beyond](https://static.tpk-led.com/images/website/tpk-led/projects/Mianyang_Overpass_(Mianyang,_Sichuan,_China)/mianyang-overpass-guardrail-night-03.jpg) Figure 3. Multi-tier urban interchange on the Mianyang Overpass. Because every ramp deck is lit by 1.2 m guardrail luminaires with 0.0% upward emission, the high-rise residential towers immediately behind the overpass experience zero vertical light trespass. ![Dusk view along a carriageway showing individual guardrail luminaire bodies fixed along the concrete barrier face at a constant height](https://static.tpk-led.com/images/website/tpk-led/projects/Mianyang_Overpass_(Mianyang,_Sichuan,_China)/mianyang-overpass-guardrail-side-dusk-04.jpg) Figure 4. Dusk view along the Mianyang Overpass barrier face, showing individual LWW-GRB luminaire modules mounted at a constant datum along the parapet wall—blending cleanly into the concrete barrier by day and merging into a continuous optical guidance line at night. ### Pioneer milestone: [Volga River Bridge](https://www.tpk-led.com/projects/volga-river-bridge/) On the Volga River Bridge in Russia, TPK field-validated long-span structural waterproofing, marine-grade anti-corrosion finishes against freezing river humidity, and multi-segment DMX512 synchronization across steel truss spans and concrete piers—establishing the environmental durability baseline later applied to the Fujiang Bridge. ### Master reference: Mianyang Science and Technology City Fujiang Bridge Completed in May 2025 with final government acceptance on 12 November 2025, the [Mianyang Science and Technology City Avenue Fujiang Bridge](https://www.tpk-led.com/projects/mianyang-fujiang-bridge/) is a 603 m six-lane two-way urban arterial featuring China's first 255 m steel-box basket-handle tied-arch span with twin arch ribs inclined inward at 70° (designed under the architectural theme “Fuqin Puyun / Strumming the Zither”). ![Night view from a driver's seat on the Fujiang Bridge with continuous light bands along both guardrails and an evenly lit two-lane carriageway](https://static.tpk-led.com/images/website/tpk-led/projects/Fujiang_Bridge___Architectural_%26_Landscape_Lighting_Project/Fujiang_Bridge___Architectural_%26_Landscape_Lighting_Project_44.jpg) Figure 5. Driver's-seat perspective on the Fujiang Bridge main span. The custom LWW-GRB guardrail luminaires project across the 7 m dual-lane carriageway to deliver 33.2 lux at the far lane edge while the 12°–13° vertical cutoff keeps the emitting aperture comfortable to the eye. Full project record: [Fujiang Bridge case page](https://www.tpk-led.com/projects/mianyang-fujiang-bridge/). ![Daytime site-survey view of the Fujiang Bridge deck before installation, showing the bare concrete barrier, continuous handrail tube and completed arch](https://static.tpk-led.com/images/website/tpk-led/projects/Fujiang_Bridge___Architectural_%26_Landscape_Lighting_Project/fujiang-bridge-before-installation-daytime-60.jpg) Figure 6. Daytime site-survey photograph of the Fujiang Bridge deck prior to luminaire installation, showing the grey steel crash barriers on the main span and the tubular handrails on the approach ramps. Sizing the LWW-GRB housings to tuck inside these exact D108 and D75 rail profiles preserved the bridge's clean daytime silhouette. While the architectural RGBW lighting of the arch ribs, hangers, and piers is examined separately in [Fujiang Bridge Night Lighting, Deconstructed](https://www.tpk-led.com/blog/fujiang-bridge-night-lighting-deconstruction/), the sections below document the specific roadway engineering decisions from the design institute's official plans (`FJDQ-LXD-021` and `FJDQ-LXD-037`) that governed the 2,637 guardrail luminaires. ## The Fujiang Bridge Functional Roadway Engineering: 2,637 Guardrail Luminaires ### Why the Design Institute Rejected Pole Streetlights (6 Engineering Criteria) In Section 3 (`桥上功能照明`, Page 47) of the November 2023 Special Design Report prepared by **China Railway Major Bridge Reconnaissance and Design Institute Group Co., Ltd. (BRDI)**, the institute formally evaluated conventional pole streetlights against low-level guardrail lighting. Although the connecting Science and Technology City Avenue already used ornate 8-arm, 9-luminaires white marble streetlamp poles (`八叉九火汉白玉路灯`), BRDI rejected pole lighting on the bridge deck across six engineering criteria and mandated the LED guardrail lighting scheme: - **Preserving architectural integrity:** A forest of vertical poles (`灯杆林立`) or ornate marble lamps would have clashed visually with the sweeping 255 m parabolic steel arch by day and fragmented the “Rainbow Across the Fujiang” nightscape. - **Superior linear optical guidance (`诱导性好`):** Unlike spaced pole pools that leave uneven light patches when constrained by pier and girder locations, continuous guardrail lighting traces the exact horizontal curves and longitudinal vertical grades of the 603 m deck, giving drivers uninterrupted lane delineation. - **Eliminating residential & river glare (`光污染少`):** Located in an E3 urban lighting zone with strict spill-light limits (`≤15%`), 1.2 m barrier luminaires with `0.0%` uplight prevent glare into riverside high-rises and avoid interfering with navigation or aviation signals. - **Immunity to steel box-girder vibration:** Heavy traffic across the 10,000-tonne steel box girder induces low-frequency structural resonance that rapidly fatigues tall light poles and high-mounted ballast gear; compact, solid-state 24 V DC rail modules eliminate whip vibration. - **Reduced lightning protection requirements (`降低防雷要求`):** Eliminating 10–12 m metallic poles along the highest point of an exposed river crossing significantly reduces lightning-strike attraction and simplifies deck earthing during summer thunderstorm seasons. - **Crane-free deck maintenance (`无需大型机械配合`):** Every guardrail luminaire can be inspected or serviced directly from the walkway or shoulder with basic hand tools—eliminating bucket trucks, hydraulic cranes, and multi-lane traffic closures. ### The As-Built Luminaire & Low-Voltage Power Schedule (`FJDQ-LXD-037`) Developed on an accelerated R&D schedule from October to December 2024 specifically for this bridge (`Project Code XSJH20241011497001`), the 2,637 guardrail luminaires were manufactured in three custom specifications matched to the bridge's two handrail pipe diameters (`D108 mm` and `D75 mm`) and operated alongside the 1,374 architectural RGBW fixtures: ![Mid-span night view from the Fujiang Bridge carriageway, hanger cables converging overhead while both guardrail light runs continue unbroken into the distance](https://static.tpk-led.com/images/website/tpk-led/projects/Fujiang_Bridge___Architectural_%26_Landscape_Lighting_Project/fujiang-bridge-deck-midspan-night-56.jpg) Figure 7. Mid-span carriageway view at night: while the radial hanger cables and 70°-inclined arch ribs run dynamic RGBW scenes overhead, the 4000 K guardrail luminaires along the outer and central barriers maintain a rock-steady, constant-output functional light carpet across the asphalt lanes. Bridge zone & barrier type | Model & delivered quantity | As-built technical specification | Power & operational role (`FJDQ-LXD-037`) Approach & main carriageway straight outer barriers (`D108 mm` tube) | [LWW-GRB-W70-L12-S](https://www.tpk-led.com/products/guardrail-light/lww-grb-w55-70/) (`HL1`), 1,250 units | 1.2 m (`L1200 mm`) · 12 W · 4000 K neutral white · DC 24 V · matched to Ø108 mm steel crash-barrier pipe · 12°–13° vertical cutoff lens + blackened shroud · IP65/IP67 · IK10 | Primary two-lane road illumination (33.2 lx far-lane edge); powered via `350 W` (`AC220V/DC24V`) waterproof PSUs inside parapet junction boxes (1 PSU per 15 units = 180 W, ≤70% load derating) Main span steel crash barriers & vertical/horizontal curve transitions (`D75 mm` tube) | [LWW-GRB-W55-L10-S](https://www.tpk-led.com/products/guardrail-light/lww-grb-w55-70/) (`HL2`), 912 units | 1.0 m (`L1000 × W55 × H24 mm` inner module) · 9 W–12 W · 4000 K · DC 24 V · recessed inside `1,480 mm` long `Ø75 × 1.5 mm` steel sleeve (`990 × 40 mm` slot) on hot-dip galvanized + `RAL 7047` white 40°/45° saddle brackets | Follows longitudinal deck gradients on theupstream, central median, and downstream main-bridge crash barriers; driven by `350 W` waterproof PSUs (1 PSU per 20 units at 9 W = 180 W) Pedestrian & non-motorised inner walkway barriers (`D75 mm` tube) | [LWW-GRB-W55-L6-S](https://www.tpk-led.com/products/guardrail-light/lww-grb-w55-70/) (`HL3`), 475 units | 0.6 m (`L600 mm`) · 4 W · 4000 K neutral white · DC 24 V · matched to Ø75 mm / Ø76 mm walkway handrail post spacing · asymmetric cutoff optic + anti-glare baffle | Glare-free illumination across the “China Red” granite pedestrian footway with zero spill into the river; driven by `100 W` waterproof PSUs (1 PSU per 18 units = 72 W) Pedestrian balustrade fascia & main steel arch ribs / girders | [LWW-PZT-W38A](https://www.tpk-led.com/products/led-wall-washer/lww-pzt-w38a/) (`W38` series), 1,292 units | 36 W RGBW (`15° × 45°`) on arch ribs (`350 W` PSU / 14 units) + 18 W version (`350 W` PSU / 14 units, concealed in stanchion backplates) beneath the `100 × 60 mm` walkway top rail · IP66 | Mounted on zero-penetration welded `L50 × 50 × 5 mm` galvanized angle brackets; grazes the 52 m high inclined arch ribs and washes the outer walkway balustrade Pier bases (Piers 3#–12#) & radial cable hangers | [SP-F310A](https://www.tpk-led.com/products/spot-light/sp-f310a-b/) & high-power floodlights, 82 units | 52 units of 150 W (`25°` asymmetric + anti-glare louvre) on piers + 30 units of 200 W / 300 W (`8°` ultra-narrow RGBW) on hanger anchorages with stainless steel safety lanyards | Synchronized across a 1 km DMX512 / Art-Net backbone via 14 industrial `MR-A28D` 8-port repeater sub-controllers ![Daytime close view of the D108 mm carriageway guardrail pipe with LWW-GRB-W70 luminaires clamped along its shadow line](https://static.tpk-led.com/images/website/tpk-led/projects/Fujiang_Bridge___Architectural_%26_Landscape_Lighting_Project/Fujiang_Bridge___Architectural_%26_Landscape_Lighting_Project_46.jpg) Figure 8. Daytime close-up of the D108 mm carriageway crash-barrier pipe. The LWW-GRB-W70 luminaire tucks flush into the underside shadow line of the top rail at a 40° downward aiming angle, matching the grey steel barrier finish. ![Night view along the Fujiang Bridge pedestrian deck with even illumination from the same guardrail luminaires](https://static.tpk-led.com/images/website/tpk-led/projects/Fujiang_Bridge___Architectural_%26_Landscape_Lighting_Project/Fujiang_Bridge___Architectural_%26_Landscape_Lighting_Project_45.jpg) Figure 9. Night view along the Fujiang Bridge red-granite pedestrian walkway. The 12°–13° vertical cutoff and internal baffle wash the walking surface evenly while preventing any stray light from spilling over the anti-climb balustrade into the Fujiang River. As detailed in the as-built low-voltage distribution diagrams (`FJDQ-LXD-037-1` and `FJDQ-LXD-037-3`, Pages 5, 11, and 14), electrical safety and operational reliability on the bridge deck rely on four engineering rules: - **Complete separation of road safety and landscape control:** All 2,637 guardrail luminaires are powered from the dedicated `XB2` (`100 kVA`) substation across six carriageway crash-barrier circuits (`WL3–WL8` covering upstream, central median, and downstream rails) and two pedestrian rail circuits (`WL9–WL10`), switched by `CJ20-40` contactors and an intelligent street-lighting controller linked directly to the **Mianyang Municipal Street Lighting Remote Control Platform**. Commissioning or reprogramming the 1,374 DMX512/Art-Net arch and pier luminaires (`XB1` / `PJAL1–PJAL2`) can never interrupt roadway illumination. - **Safe 24 V DC operation with mandatory 70% PSU derating:** Every guardrail fixture operates at `24 V DC` with `30 mA` residual-current protection (`DZ47LE-63/4P`) on the AC branch breakers. Remote waterproof `AC 220 V / DC 24 V` power supplies are housed inside parapet junction boxes or vertical stanchion backplates and strictly loaded to `≤70%` of rated capacity (`100 W` PSU driving 18 × `4 W` units; `350 W` PSU driving 20 × `9 W` main-bridge units or 15 × `12 W` approach-bridge units). - **Vibration-proof conduit & anti-theft trunk cabling:** Secondary `DC 24 V` feeds use `RVV-2×4 mm²` cables enclosed in `LV5-24#` flexible metallic conduit (`可挠金属管`) to absorb bridge deck vibration, spliced via waterproof insulation-piercing connectors (`绝缘穿刺线夹`) to `YJLHV-0.6/1KV-4×25+1×16 mm²` aluminum-alloy trunk cables (`铝合金电缆`, specified jointly by the owner and municipal authority to deter copper cable theft). ![Daytime construction view along the footbridge deck with the cable tray dressed along the outer face of the white parapet railing, below the arch rib and stay cables](https://static.tpk-led.com/images/website/tpk-led/projects/Fujiang_Bridge___Architectural_%26_Landscape_Lighting_Project/fujiang-bridge-footbridge-cable-tray-install-01.jpg) Figure 10. Construction view along the walkway parapet showing the VCI-treated `MR 100 × 50 mm` divided aluminum-alloy cable tray (separating high-voltage AC power and low-voltage DMX signal lines) dressed along the structure before cover plates and finished matching coats are applied. ![Close view of a guardrail luminaire clamped under the footway handrail top tube, with the lit fascia of the approach ramp in the distance](https://static.tpk-led.com/images/website/tpk-led/projects/Fujiang_Bridge___Architectural_%26_Landscape_Lighting_Project/fujiang-bridge-footway-barrier-detail-55.jpg) Figure 11. Close-up of the pedestrian balustrade lighting (`FJDQ-LXD-037-9`): the luminaire tucks beneath the top handrail tube to wash the granite footway downward while its `350 W` waterproof `DC 24 V` driver sits concealed inside the vertical stanchion backplate (`立柱背板内`). ## How the Fixtures Were Actually Installed: Structural Waterproofing & Recessed Sleeve Mechanics Two engineering breakthroughs distinguish the Fujiang Bridge guardrail installation from conventional bridge barrier lighting: **potting-free structural waterproofing** and **zero-drilling recessed tube clamping**. As documented in TPK's October 2024 R&D evaluation (`LWW-BGR-D108/D75`), conventional bridge guardrail tubes rely on either full resin potting (`灌胶防水`) or unsealed “water-in, water-out” (`水进水出`) sleeves. Under outdoor UV exposure, freeze-thaw cycling, and exhaust soot, potting resin yellows and delaminates from the LED lens wall, while unsealed tubes trap road dust and condensation inside the optical chamber—rapidly degrading lumen output. While TPK's standard catalogue `LWW-GRB-W55/70` (`120°` beam, potted `IP65 / IK08`) serves general decorative outlining, the Fujiang Bridge custom roadway series eliminated potting compound entirely in favor of a **gasket-sealed structural waterproof cavity (`IP65 / IP67`, `IK10`)** paired with an imported **Bayer 2807 UV-stabilized transparent polycarbonate cover** (`>90%` light transmittance, `<5%` yellowing over 5 years, and `<5%` annual lumen depreciation). ![Cutaway render of the LWW-GRB-W55 luminaire seated against the guardrail tube, showing the extruded body, LED board, lens array and end-cap terminal block](https://static.tpk-led.com/images/website/tpk-led/projects/Fujiang_Bridge___Architectural_%26_Landscape_Lighting_Project/fujiang-bridge-barrier-luminaire-tube-section-48.jpg) Figure 12. Cross-sectional render of the LWW-GRB-W55 seated inside the handrail tube profile. The 6063 aviation-aluminum extrusion (`55 mm` top width tapering to a `37 mm` base, `24 mm` height) houses the blackened PCB, asymmetric cutoff lens array, stamped metal shroud, and Bayer 2807 PC cover inside a compression-gasketed cavity containing zero potting glue. ![Manufacturer installation instructions for the guardrail luminaire showing two steps: screws and clips fitted to the lamp end cap, then pressed into the guardrail tube and locked by rotating the screws](https://static.tpk-led.com/images/website/tpk-led/projects/Fujiang_Bridge___Architectural_%26_Landscape_Lighting_Project/fujiang-bridge-guardrail-luminaire-install-instructions-01.jpg) Figure 13. Factory installation procedure (F-1) for the recessed tube-mounted guardrail luminaire. Step 1: thread the stainless screws and retaining clips onto the luminaire end caps (~5 mm initial engagement) and align the housing flush with the milled guardrail tube slot. Step 2: press the clip heads into the tube interior and rotate the screws to draw the stainless wedge plates tight against the inner tube wall. Following the November 2024 on-site mock-up review by the Mianyang Urban Lighting Administration (`FJDQ-LXD-037`, Item 6 & `附图6：主桥段 9W 护栏灯安装图`), the main-bridge guardrail installation was further refined from a surface-hung mount to a **recessed outer steel sleeve and custom saddle assembly**: - **Precision-milled `Ø75 mm` outer protective sleeve (`FJDQ-LXD-037-6`, Sheet 2):** Each `L1000 × W55 × H24 mm` inner luminaire module (`HL2-LED`) seats inside a `1,480 mm` long, `Ø75 (+1/0) mm × 1.5 mm` wall-thickness steel tube machined with a `990 (+2/0) × 40 (+2/0) mm` emission slot (`41.7 mm` chord opening). - **Pre-indexed `40° / 45°` welded stanchion saddles (`FJDQ-LXD-037-6`, Sheet 3):** The protective tube is carried at each post by full-penetration welded steel saddle brackets (`110 × 100 mm` base plate with `70±2 mm` bolt centres and `4-M8×1.25` tapped threads) whose `Ø80 mm` collars are factory-rotated to lock in the exact `40°–45°` roadway aiming angle with an internal `Ø25 mm` wire pass-through—finished in **hot-dip galvanizing plus `RAL 7047` white electrostatic powder coat (`表面热镀锌+喷白，色号 RAL7047`)** to prevent galvanic corrosion and match the bridge's steel barriers. - **Two-step snap-fit wedge clamping (`Figures 14–15`):** Inside the slotted handrail tubes, the luminaire locks in place via a stainless-steel wedge clamp tightened with a single screwdriver turn—preserving the hot-dip galvanized rail coating without drilling through the outer tube wall and allowing individual modules to be fine-tuned for road gradient or swapped for maintenance in minutes. ![Installer offering an LWW-GRB guardrail luminaire up to the underside of the white handrail tube, cable visible at the end cap](https://static.tpk-led.com/images/website/tpk-led/projects/Fujiang_Bridge___Architectural_%26_Landscape_Lighting_Project/fujiang-bridge-barrier-luminaire-seat-49.jpg) Figure 14. Step 1 on deck: the installer offers the LWW-GRB luminaire up into the milled underside slot of the handrail tube, feeding the 2-core waterproof cable into the concealed rail cavity before engaging the end clips. ![End of a guardrail luminaire fully seated on the handrail tube with the stainless clamp screw and wedge plate still slack, ready to be tightened](https://static.tpk-led.com/images/website/tpk-led/projects/Fujiang_Bridge___Architectural_%26_Landscape_Lighting_Project/fujiang-bridge-barrier-luminaire-clamp-50.jpg) Figure 15. Step 2 on deck: the luminaire sits flush within the tube shadow line with the stainless wedge plate and screw ready to be tightened—locking the fixture at the exact 40° roadway aiming angle without drilling the outer rail. On the concrete arch ribs and piers, where the structural engineer strictly prohibited drilling into primary load-bearing steel or concrete (`FJDQ-LXD-021`, `附图4` & `FJDQ-LXD-037`, `附图7–8`), TPK mounted the 1,292 [LWW-PZT-W38A](https://www.tpk-led.com/products/led-wall-washer/lww-pzt-w38a/) wall washers and 82 [SP-F310A](https://www.tpk-led.com/products/spot-light/sp-f310a-b/) floodlights onto secondary `L50 × 50 × 5 mm` hot-dip galvanized angle-iron frames (`350 × 125 × 12 mm` base plates and `38/23, L=250 mm` Q235B pre-embedded C-channels with 304 stainless `M16` T-bolts, `≥55 μm` zinc + electrostatic topcoat `≥100 μm` matched to the bridge paint), backed by stainless-steel safety lanyards and rubber/stainless vibration-damping washers (`减震垫片`). Similarly, the `L6` (`600 mm`), `L10` (`1,000 mm`), and `L12` (`1,200 mm`) guardrail luminaire lengths were scheduled bay by bay from physical tape-measure surveys of the `D108` and `D75` rail openings across the 603 m span—ensuring every module fits its milled window to within a millimeter. ![Tape measure held vertically across the slot cut in a white tubular handrail on the non-motorised lane, checking the slot height](https://static.tpk-led.com/images/website/tpk-led/projects/Fujiang_Bridge___Architectural_%26_Landscape_Lighting_Project/fujiang-bridge-guardrail-opening-height-58.jpg) Figure 16. Pre-production site survey on the non-motorised walkway rail: verifying the exact chord opening width (`40 mm+` slot across the `Ø75 mm` tube) before freezing the extrusion and saddle tooling. ![Tape measure stretched along the length of the slot in a white tubular handrail, reading past the 1.2 metre mark](https://static.tpk-led.com/images/website/tpk-led/projects/Fujiang_Bridge___Architectural_%26_Landscape_Lighting_Project/fujiang-bridge-guardrail-opening-length-59.jpg) Figure 17. Measuring the longitudinal milled slot length on site. Scheduling custom L6 (0.6 m), L10 (1.0 m), and L12 (1.2 m) variants against bay-by-bay field measurements ensured all 2,637 fixtures seated cleanly between stanchion posts. ## Verification Matrix: Catalogue Standard vs. Fujiang Bridge As-Built Delivery When specifying the [LWW-GRB-W55 / LWW-GRB-W70](https://www.tpk-led.com/products/guardrail-light/lww-grb-w55-70/) family for a new bridge tender, engineers must distinguish between the **standard catalogue configuration** (designed for general 120° decorative delineation) and the **Fujiang Bridge custom roadway configuration** (tooled with the 12°–13° cutoff optic and potting-free structural waterproofing). The matrix below separates verified laboratory and as-built project records from site-specific EN 13201 calculations: Requirement | Source of truth | Fujiang Bridge as-built vs. Catalogue standard | Status Vertical cutoff at 50% Imax | EVERFINE GO-2000B_V1 report (Nov 2024) | 12° to 13° on project units (Catalogue standard ships 120° symmetric) | Verified Horizontal / lateral distribution | Same goniophotometer report | 92° to 93° (12° × 106° asymmetric class) at 40° downward installation tilt | Verified Far-lane illuminance (7 m throw) | Project IES simulation + on-site acceptance | 33.2 lux across two 3.5 m lanes (8 m total deck width) | Verified Upward light spill (ULR) | Goniophotometer, ≥90° upper hemisphere | 0.0% uplight across all three LWW-GRB project variants | Verified Driver-eye glare reduction (at 1.4 m) | Comparative test, shielded vs. unshielded | −30% yellow-spot glare reduction via new lens + blackened shroud & PCB | Verified Waterproofing & lens material | R&D record & construction drawing `FJDQ-LXD-037-6` | Structural gasket seal (no potting glue) + Bayer 2807 UV PC (`<5%` 5-yr yellowing) on project units; catalogue standard is potted | Verified on delivered units Ingress & impact resistance | IEC 60529 / IEC 62262 | Project units: IP65 / IP67 (HL2 drawing) & IK10; Catalogue standard: IP65 / IK08 | Verified on delivered units Low-voltage PSU loading factor | As-built wiring diagram `FJDQ-LXD-037-5` | 24 V DC operation; waterproof AC220V/DC24V PSUs derated to ≤70% capacity | Verified Threshold increment (TI) & Uniformity (Uo, Ul) | EN 13201-2 / CJJ 45-2015 M-class road | Calculated per project road width and spacing using the published D75/D108 IES files | Project-specific (IES available) **How to run your bridge's roadway compliance check:** download the official D75 and D108 `.IES` photometric package (`tpk-lww-grb-w55-w70-photometric-files-d75-d108-zh.zip`) from the product page, import it into DIALux or Relux at your bridge's exact geometry (e.g., 1.2 m mounting height, 40° downward tilt, 7 m carriageway width), and run the CJJ 45-2015 or EN 13201-2 calculation to generate third-party verifiable TI, Uo, and Ul submittals. ## Mechanical and Environmental Requirements As specified in Section 3 (`防震、防腐、防干扰`, Page 42) of the BRDI Special Design Report and TPK's bridge engineering standards, three environmental defenses determine whether a guardrail luminaire survives 50,000 hours on an active river crossing: 01 ### Continuous deck vibration damping Heavy freight across steel box girders creates constant cyclic resonance. Specify dedicated rubber/stainless damping washers (`减震垫片`), IK08–IK10 impact ratings, `LV5` flexible metal conduit, and wedge-clamped terminations. 02 ### Galvanic & river-mist corrosion Cable trays must use VCI anti-corrosion treatment; steel saddles require hot-dip galvanizing (`≥55 μm`) plus marine-grade electrostatic powder coating (`≥100 μm`, e.g., `RAL 7047`) with 304 stainless fasteners to prevent bimetallic corrosion. 03 ### Potting-free structural sealing High-pressure tyre spray and thermal cycling degrade glue-filled tubes. Specify potting-free structural waterproofing (IP65–IP67) with UV-stabilized Bayer 2807 PC covers so condensation and dust never cloud the internal optics. ## Specification Checklist for Bridge Guardrail and Low-Level Roadway Lighting Before issuing tender documents or approving contractor submittals for bridge barrier lighting, confirm the following eight engineering items: - **Cross-sectional geometry verified:** 1.2 m nominal mounting height against a 1.35 m–1.40 m driver eye reference, with the luminaire oriented at a 40° downward aiming angle across the target carriageway width (e.g., 7 m dual-lane throw within an 8 m deck). - **Vertical cutoff & 3-layer glare control specified:** 12° to 13° vertical half-peak angle (`50% Imax`), die-stamped blackened internal shroud, matte-black PCB, and `0.0%` upward light emission—explicitly prohibiting unshielded 120° symmetric tubes on vehicular lanes. - **Assembled-fixture goniophotometer files provided:** Accredited EVERFINE GO-2000B `.IES` / `.LDT` files measured on the complete luminaire assembly (including the PC cover and anti-glare louvre), not bare LED chip data. - **Far-lane illuminance & mock-up confirmed:** Far-lane edge illuminance verified above local roadway codes (33.2 lux achieved on Fujiang Bridge), backed by mandatory on-site trial lighting (`现场试灯打样`) prior to bulk production. - **Potting-free structural waterproofing mandated:** Compression-gasketed 6063 aluminum housing with UV-stabilized Bayer 2807 polycarbonate cover (`>90%` transmittance, `<5%` 5-year yellowing) and IK08/IK10 impact rating—avoiding glue-fill yellowing and water-in/water-out dust traps. - **Exact handrail pipe diameters & bay lengths scheduled:** Custom housing widths (`W55` / `W70`), pre-angled hot-dip galvanized saddle brackets (`RAL` colour-matched), and bay-matched lengths (`L6` 0.6 m, `L10` 1.0 m, `L12` 1.2 m) verified by on-site tape measurement of the `D75` and `D108` rail openings. - **Zero-drilling clamp fixation:** Stainless snap-fit wedge clamps or recessed outer sleeves that preserve the hot-dip galvanized rail coating and allow single-screwdriver angle calibration and maintenance replacement. - **24 V DC isolation & 70% PSU derating:** Functional guardrail circuits kept electrically independent of landscape DMX networks, running at safe 24 V DC from remote waterproof power supplies derated to `≤70%` load inside parapet junction boxes or stanchion cavities. Specification in one sentence Specify a potting-free, structurally waterproof 24 V DC guardrail luminaire with a 12°–13° vertical cutoff and blackened internal shroud mounted at 1.2 m with a 40° downward tilt, verify ≥30 lux far-lane illuminance via assembled-fixture IES files, and custom-match D75/D108 tube diameters and bay lengths so the fixture disappears into the bridge barrier. The official `.IES` photometric package for both `D75` and `D108` guardrail configurations (`tpk-lww-grb-w55-w70-photometric-files-d75-d108-zh.zip`) and the product specification sheet are available on the [Fujiang Bridge case page](https://www.tpk-led.com/projects/mianyang-fujiang-bridge/) and in the [LWW-GRB-W55/70 download section](https://www.tpk-led.com/products/guardrail-light/lww-grb-w55-70/). For earlier multi-deck interchange context, see the [Mianyang Overpass project record](https://www.tpk-led.com/projects/mianyang-overpass/). To request custom handrail saddle tooling, `.IES` DIALux roadway simulations, or a mock-up sample for your bridge tender, contact TPK's bridge engineering team at ES2@topkinglite.com. Bridge LightingGuardrail LightingAnti-GlarePhotometryInstallationStructural WaterproofingIK10 Related Guides [Fujiang Bridge Lighting Deconstructed](https://www.tpk-led.com/blog/fujiang-bridge-night-lighting-deconstruction/)[Bridge Lighting Engineering Guide](https://www.tpk-led.com/blog/led-bridge-lighting-engineering-specifications-ip-ratings-and-system-design/)[Mianyang Overpass Project](https://www.tpk-led.com/projects/mianyang-overpass/)[IP65 vs IP67 vs IP68](https://www.tpk-led.com/blog/ip65-vs-ip67-vs-ip68-which-rating-do-you-actually-need/)[Bridge Lighting Solutions](https://www.tpk-led.com/solutions/bridge-lighting-solutions/) Technical Files IES · LDT · Downloads [Project IES Files (case page)](https://www.tpk-led.com/projects/mianyang-fujiang-bridge/)[LWW-GRB Downloads (product page)](https://www.tpk-led.com/products/guardrail-light/lww-grb-w55-70/) ## Discovery - Site index: [https://www.tpk-led.com/llms.txt](https://www.tpk-led.com/llms.txt) - Section index: [https://www.tpk-led.com/blog/llms.txt](https://www.tpk-led.com/blog/llms.txt)