Painted Steel Truss Pedestrian Bridge / Heavy Duty Steel Structure Bridge

Painted Steel Structure Bridge/heavy Duty Steel Structure Bridge

Hot-dip galvanizing is a process used to coat steel with a protective layer of zinc to prevent corrosion. Here’s a detailed explanation of the process:

1. **Surface Preparation**
Before the steel can be galvanized, it must be thoroughly cleaned to remove any contaminants that could interfere with the bonding of the zinc coating. This typically involves three main steps:
- **Degreasing**: The steel is cleaned to remove oils, greases, and other organic contaminants. This is often done using a caustic solution or a solvent.
- **Pickling**: The steel is immersed in an acid solution (usually hydrochloric or sulfuric acid) to remove rust, mill scale, and other inorganic contaminants.
- **Fluxing**: The steel is then dipped into a flux solution, which helps to remove any remaining oxides and prepares the surface for the galvanizing process.

2. **Galvanizing Process**
- **Dipping**: The cleaned steel is immersed in a bath of molten zinc, which is typically maintained at a temperature of around 840°F (450°C). The zinc reacts with the iron in the steel to form a series of zinc-iron alloy layers, creating a strong metallurgical bond.
- **Reaction**: As the steel is immersed, the zinc reacts with the iron in the steel to form a series of zinc-iron alloy layers. These layers provide excellent corrosion protection and are harder than the base steel.
- **Cooling**: After the steel has been dipped and coated, it is removed from the zinc bath and allowed to cool. The cooling process solidifies the zinc coating, forming a durable and corrosion-resistant surface.

3. **Post-Treatment**
- **Inspection**: The galvanized steel is inspected to ensure that the coating is uniform and free of defects. The thickness of the zinc coating is typically measured to ensure it meets the required specifications.
- **Finishing**: In some cases, additional treatments may be applied to enhance the appearance or performance of the galvanized steel. For example, a passivation layer may be applied to prevent white rust, or a topcoat may be added for additional protection.

Benefits of Hot-Dip Galvanizing
- **Corrosion Protection**: The zinc coating provides a barrier against moisture and corrosive elements, significantly extending the lifespan of the steel.
- **Self-Healing**: If the coating is scratched or damaged, the zinc can continue to protect the underlying steel through galvanic action.
- **Durability**: The zinc-iron alloy layers formed during the galvanizing process are harder than the base steel, providing excellent resistance to mechanical damage.
- **Sustainability**: Both zinc and steel are recyclable, making hot-dip galvanizing an environmentally friendly choice.

Conclusion
Hot-dip galvanizing is a highly effective method for protecting steel from corrosion. By immersing steel in a bath of molten zinc, a durable and corrosion-resistant coating is formed, ensuring the longevity and reliability of steel structures such as bridges, pipelines, and other infrastructure components.

Specifications:

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CB321(100) Truss Press Limited Table
No.	Lnternal Force	Structure Form
		Not Reinforced Model				Reinforced Model
		SS	DS	TS	DDR	SSR	DSR	TSR	DDR
321(100)	Standard Truss Moment(kN.m)	788.2	1576.4	2246.4	3265.4	1687.5	3375	4809.4	6750
321(100)	Standard Truss Shear (kN)	245.2	490.5	698.9	490.5	245.2	490.5	698.9	490.5
321 (100) Table of geometric characteristics of truss bridge(Half bridge)
Type No.	Geometric Characteristics	Structure Form
		Not Reinforced Model				Reinforced Model
		SS	DS	TS	DDR	SSR	DSR	TSR	DDR
321(100)	Section properties(cm3)	3578.5	7157.1	10735.6	14817.9	7699.1	15398.3	23097.4	30641.7
321(100)	Moment of inertia(cm4)	250497.2	500994.4	751491.6	2148588.8	577434.4	1154868.8	1732303.2	4596255.2

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CB200 Truss Press Limited Table
NO.	Internal Force	Structure Form
		Not Reinforced Model				Reinforced Model
		SS	DS	TS	QS	SSR	DSR	TSR	QSR
200	Standard Truss Moment(kN.m)	1034.3	2027.2	2978.8	3930.3	2165.4	4244.2	6236.4	8228.6
200	Standard Truss Shear (kN)	222.1	435.3	639.6	843.9	222.1	435.3	639.6	843.9
201	High Bending Truss Moment(kN.m)	1593.2	3122.8	4585.5	6054.3	3335.8	6538.2	9607.1	12676.1
202	High Bending Truss Shear(kN)	348	696	1044	1392	348	696	1044	1392
203	Shear Force of Super High Shear Truss(kN)	509.8	999.2	1468.2	1937.2	509.8	999.2	1468.2	1937.2

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CB200 Table of Geometric Characteristics of Truss Bridge(Half Bridge)
Structure	Geometric Characteristics
	Geometric Characteristics	Chord Area(cm2)	Section Properties(cm3)	Moment of Inertia(cm4)
ss	SS	25.48	5437	580174
	SSR	50.96	10875	1160348
DS	DS	50.96	10875	1160348
	DSR1	76.44	16312	1740522
	DSR2	101.92	21750	2320696
TS	TS	76.44	16312	1740522
	TSR2	127.4	27185	2900870
	TSR3	152.88	32625	3481044
QS	QS	101.92	21750	2320696
	QSR3	178.36	38059	4061218
	QSR4	203.84	43500	4641392

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Advantage

Possessing the features of simple structure,
convenient transport, speedy erection
easy disassembling,
heavy loading capacity,
great stability and long fatigue life
being capable of an alternative span, loading capacity