Steel Frame Bridge For Sale/steel Portable Bridge For Sale

Zinc-rich primer coatings work to prevent corrosion in steel bridges through a combination of mechanisms that provide both physical and electrochemical protection:

1. **Cathodic Protection**
Zinc-rich primers contain a high concentration of zinc particles (typically 60-90%), which act as sacrificial anodes. Zinc is more electrochemically active than iron, so it corrodes preferentially when exposed to moisture and air. This sacrificial corrosion of zinc forms a protective layer of zinc oxide, which prevents the underlying steel from corroding.

2. **Barrier Protection**
The epoxy resin in zinc-rich primers forms a tight, impermeable barrier over the steel surface. This barrier physically blocks water, oxygen, and other corrosive elements from reaching the steel, significantly reducing the risk of rust and corrosion.

3. **Passivation of Steel Surface**
The zinc oxide layer formed during the corrosion of zinc can create a passive film on the steel surface. This film further inhibits the progress of rust formation by reducing the rate of iron dissolution.

4. **Reduced Oxygen Availability**
The combination of the tightly bonded epoxy layer and the zinc oxide formation limits the availability of oxygen at the metal surface. Since oxygen is a key component in the corrosion process, reducing its availability helps to slow down or prevent rusting.

5. **Chemical Protection**
The epoxy resin component in zinc-rich primers provides additional chemical resistance, protecting the steel from reactions with other corrosive chemicals.

Conclusion
Zinc-rich primer coatings protect steel bridges from corrosion through a dual mechanism of cathodic protection and barrier protection. The high zinc content ensures that the coating acts as a sacrificial anode, while the epoxy resin creates a durable barrier against environmental factors. This combination extends the lifespan of steel structures, reduces maintenance needs, and enhances overall durability.

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