Examples of HDG

Applications

62

Power distribution

63

Hot dip Galvanized electricity

transmission towers

64

Hot dip galvanized electricity

transmission poles

Power distribution

65

Hot Dip Galvanized anchor bolts

66

Power distribution Sub-station (using hot dip galvanized steel for

every component)

67

Power distribution

Small fixtures (brackets, clips, straps)

68

Power distribution Transformers

69

Power distribution facilities

HGD cable

protection shield

70

Closer view

71

Electricity generation and distribution is a

critical part of a nations

infrastructure.

Reliable corrosion protection is vital.

This is why the power sector chooses

galvanizing.

Telecommunication infrastructure HDG towers

72

73

Transportation Road & highway infrastructure

HDG safety barriers HDG lighting poles

74

Transportation Road & highway infrastructure

HDG traffic signal support structure

HDG signage support structure

75

Transportation Road and highway water drainage using HDG steel gratings

Transportation Road and highway water drainage using galvanized culverts (drainage tunnels)

76

77

78

Transportation HDG road bridges

79

Built in 1986 No corrosion after 25 years

80

Transportation

HDG pedestrian bridges

Steel structurals are HDG +

paint top-coated for appearance

Pedestrian bridge

81

82

Transportation HDG barriers to prevent rock-falls or landslip

83

HDG security fencing

Fencing and railings

84

HDG safety railings

Fencing and railings

HDG railings on concrete

stairs

Fencing and railings

85

HDG enclosures

86

Fencing and railings

Building construction

HDG for steel scaffolding is now required by law in some countries (eg. Japan & Singapore)

87

88

Building construction (industrial) HDG steel framing

89

Building construction HDG internal framework

90

Building construction

HDG cable trays

Building construction

HDG walkways

91

92

Building construction (residential)

HDG balcony structures

93

Corrosion of painted stairs

Building construction

94

Building construction

HDG stairs

95

Building construction

HDG access and emergency scape ladders

96

Building Construction HDG water storage tanks

97

Marine environments

Painted

HDG

98

Marine environments Comparative performance of conventional

Paint vs HDG

99

Marine environments Marine facilities (eg, ports) use HDG extensively

100

Marine environments

HDG

Marine environments

101

Example showing industrial construction close to seawater. (Formosa Plastics Mai Liao plant, Taiwan)

Marine environments Example showing industrial construction close to seawater. (Formosa Plastics Mai Liao plant, Taiwan)

102

300,000 tonnes HDG steel used in construction

HDG for architectural &

artistic applications

103

Indoors use of HDG in

a modern residence

104

Architectural applications

Modern roofing designs using

HDG steel + paint top-coat

Architectural applications

105

HDG steel artistic structure in building lobby

106

Public park walkway (1 kilometre length) showing use of HDG steel for artistic purpose

107

Elevated “forest” walkway combines functionality with

appearance. All the steel structure

is HDG

Architectural design

108

Protecting steel reinforcement

(rebar) in concrete structures

109

Because fresh concrete is alkaline (high pH) it reacts with the rebar surface to form a a corrosion resistant “passivation” surface layer

110

Rebar surface Passivation layer

Concrete

Over time, O2, H2 O, CO2 can slowly migrate into the concrete via porosity. In marine environments,

salt (chloride) can also penetrate the concrete

111

O2 H2O CO2 Cl-

112

CO2 migrating into concrete reduces its alkaline content. The is termed concrete “carbonation”

As the alkalinity reduces, the rebar surface loses its protective surface passivation layer The rebar is then vulnerable to corrosion as moisture and oxygen penetrate into the concrete

Effect of CO2 entering into concrete

Since the volume of rust is greater than the volume of corroded steel, tensile stresses are generated in the concrete, causing

the concrete to crack 113

Effect of steel reinforcement corrosion

Concrete spalling

114

Effect of steel reinforcement corrosion

Cracks eventually reach the concrete surface. As corrosion spreads

pieces of concrete may break away (“spalling”)

Example of indoors repair being undertaken on a concrete roof exhibiting extensive rebar corrosion. The building is located in Bangkok

115

Example of rebar corrosion on an office building

116

Example of rebar corrosion

on a car parking structure

117

118

At sufficient chloride levels in the concrete, the natural alkalinity of concrete is not able to form the protective passivation layer on the rebar surface The rebar is then at high risk of corrosion if moisture and oxygen penetrate into the concrete, and chloride accelerates the corrosion

Effect of salt (chloride) permeation into concrete

Examples of rebar corrosion in the severe marine environment

119

Examples of rebar corrosion in the severe marine environment

120

Examples of rebar corrosion in the severe marine environment

121

Hot-dip galvanized steel reinforcement

in concrete

“Protecting your investment”

122

Galvanized steel reinforcement products

Straight bars

Welded mesh

Stirrups and ties

123

Cages

Technical benefits of galvanized rebar compared to un-coated rebar

Complete resistance to the effects of carbonation in concrete

A significantly increased resistance to the

effects of chloride-induced corrosion.

An increase in service life of the concrete of at least 4-5 times

Cost savings due to reduced concrete cover over rebar without reducing concrete durability

124

Typical applications for hot dip galvanized rebar

125

Structures located in marine environments (submerged tunnels, sea-walls, wharves, jetties, pontoons) Buildings with areas that are frequently wet due to water remaining for long periods of time (bathroom floors, some parts of balconies and concrete roofs) High visibility prestigious structures where even rust staining will be a problem

Underground tunnel or foundation structures in water permeable soils where there is also an elevated presence of chlorides/sulphate salts (eg, in reclaimed land areas)

126

The following slides show some examples of the

use of HDG rebar

127

Galv Rebar Case Study: Sydney Opera House

128

Galv Rebar Case Study: Sydney Opera House

Galv steel reinforcement used in the pre- cast concrete roof sections and the concrete sea-wall

129

Galv Rebar Case Study: Sydney Opera House

• 200t HDG rebar used.

• HDG cost was only 4% of contract price for the concrete walls

130

Galvanized Rebar Case Study: Intercontinental Hotel, Sydney, Australia

131

Deep Tunnel Sewerage System Project Location: Singapore Project: 2 x 5 km long steel reinforced concrete tunnels positioned on the sea-floor for transporting and discharging treated sewerage (from Changi water treatment plant) Singapore government required 100 years service life

Galv Rebar Case Study

Completed concrete pipes ready for laying on sea-floor. 10,000 tonnes galvanized steel reinforcement used

132

Galv Rebar Case Study: DTSS (Singapore)

Galvanized reinforcement cages

133

Galv Rebar Case Study: DTSS (Singapore)

134

HDG coatings are damage resistant. No special precautions are required during transportation, site storage or usual handling conditions

FBE coatings are more susceptible to damage due to their softer nature (eg, abrasion damage during on-site rebar placement)

Technical comparison of Hot Dip Galvanized (HDG) rebar vs

Fusion Bonded Epoxy (FBE) coated rebar

For more information on Hot Dip Galvanizing please visit the

websites www.galvanizingasia.com www.gaa.com.au www.galvanizeit.org

135

136

Thank you