Little Belt Suspension Bridge – Durable Long Life ... - Icsboc.com
Little Belt Suspension Bridge – Durable Long Life ... - Icsboc.com
Little Belt Suspension Bridge – Durable Long Life ... - Icsboc.com
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<strong>Little</strong> <strong>Belt</strong> <strong>Suspension</strong> <strong>Bridge</strong><br />
<strong>Durable</strong> <strong>Long</strong> <strong>Life</strong> Roadway Surfacing<br />
Vibeke Wegan, The Danish Road Directorate<br />
Matthew L. Bloomstine, Cowi A/S
Presentation<br />
• The <strong>Little</strong> <strong>Belt</strong> <strong>Suspension</strong> <strong>Bridge</strong><br />
• Original Surfacing<br />
• Replacement Project<br />
•Conclusion
<strong>Little</strong> <strong>Belt</strong> <strong>Suspension</strong> <strong>Bridge</strong><br />
Facts:<br />
Opened in 1970<br />
ADT = 50,000 vehicles<br />
Main span: 600 m<br />
Two side spans: 240 m<br />
Steel deck: 1080 m<br />
Total length: 1,700 m
Steel box girder<br />
Total width: 33,3 m<br />
Each direction : 3 lanes of trafic (3.5 m wide)<br />
1 emergency lane (2 m wide)<br />
Total surfacing: 29,000 m 2
Original surfacing<br />
Metallic cleanness Sa 3<br />
8/12 mm chippings<br />
30 mm mastic asphalt<br />
20 mm mastic asphalt<br />
4 mm waterproofing mastix<br />
Adhesive primer, 300 g/m 2
Development of surfacing<br />
Performance tests<br />
• Fatigue, 0 and -20ºC<br />
Load: 5 <strong>–</strong> 45 kN<br />
Frequency: 3 Hz<br />
• Rutting, 30 and 50ºC<br />
• Sliding, 60ºC<br />
0 and -20ºC
Maintenance<br />
Annual inspections since early 80’ies <br />
Before 95: crack sealing<br />
After 95: open cracks, stone tearing and tracking:
☺<br />
Main repair strategies<br />
1. Replacement of the entire<br />
surfacing including waterproofing<br />
2. Replacement of the wearing<br />
course and a total replacement of<br />
the surfacing 15 years later
Alternative wearing course<br />
New SMA material:<br />
• Surface with low air void and high binder content<br />
• Highly polymer modified binder and special<br />
limestone filler with high stabilizing effect<br />
Advantages:<br />
• Keener <strong>com</strong>petition at tender<br />
• Fast application - less traffic disruption<br />
• Cheaper at procurement<br />
• Greater evenness - improved driving <strong>com</strong>fort
Project tender<br />
Removal of existing wearing course<br />
Local repair of waterproofing and mastic<br />
asphalt bearing course<br />
Application of new SMA wearing course<br />
Establishment of elastic joints at the<br />
expansion joints<br />
Road markings on wearing course
Replacement<br />
1. Milling off original wearing course + app. 5 mm<br />
bearing course<br />
2. New wearing course of 35 mm Stone Mastic<br />
Asphalt
1995, North side <strong>–</strong> Test trial<br />
Working days: 15<br />
Area: 2,700 m²<br />
Bearing course: 35 m² ~ 1.3 %<br />
Waterproofing: 10 m² ~ 0.4 %<br />
Damaged<br />
waterproofing layer
1999, North side<br />
Working days: 33<br />
Area: 6,000 m²<br />
Bearing course: 90 m² ~ 1.5 %<br />
Waterproofing: 55 m² ~ 0.9 %<br />
Markingofdamageto<br />
bearing course
2000, South side<br />
Working days: 65<br />
Area: 10,000 m²<br />
Bearing course: 284 m² ~ 2.8 %<br />
Waterproofing: 133 m² ~ 1.3 %<br />
Repair of damaged<br />
bearing course
Replacement - summary<br />
Replacements/repairs<br />
South side, 2000<br />
North side, 1999<br />
North side, 1995<br />
Total in m 2<br />
Total in % of the <strong>Bridge</strong><br />
Wearing course<br />
10,000 m 2<br />
6,000 m 2<br />
2,700 m 2<br />
18,700 m 2<br />
64 %<br />
Bearing course<br />
284 m 2<br />
90 m 2<br />
35 m 2<br />
409 m 2<br />
1.4 %<br />
Mastix<br />
133 m 2<br />
55 m 2<br />
10 m 2<br />
198 m 2<br />
0.7 %
Replacement - execution<br />
64 % wearing course replaced<br />
36 % original surfacing<br />
Avarage daily progress: 180 <strong>–</strong> 185 m²
Economy<br />
Replacements<br />
Side span, 1995<br />
North side, 1999<br />
South side, 2000<br />
Total<br />
replacement<br />
2,700 m 2<br />
6,000 m 2<br />
10,000 m 2<br />
Total<br />
expenses<br />
DKK/ m 2<br />
282<br />
306<br />
322<br />
Average price adjusted to December 2003: 48 Euro/m 2
☺ ☺<br />
☺ ☺<br />
☺<br />
☺<br />
☺ ☺<br />
☺ ☺<br />
Extraordinarily long lifetime<br />
• Optimization of each layer and the entire surfacing<br />
• A stiff bridge deck structure, which minimizes<br />
stress in the surfacing<br />
• A system with a separate wearing course allowing<br />
relatively simple life prolonging repair<br />
• Quality workmanship during the original works<br />
• Regular maintenance from an early stage<br />
• Design provides a good water runoff
Conclusion<br />
• 45 years lifetime<br />
• 64 % of the bridge area repaired after<br />
25 years<br />
• Avarage daily progress: 180 <strong>–</strong> 185 m²<br />
• Avarage price: 48 Euro/m² ex. traffic
Other Steel <strong>Bridge</strong> Decks in DK<br />
Farø <strong>Bridge</strong> (1985)<br />
Great <strong>Belt</strong> East <strong>Bridge</strong> (1998)<br />
<strong>–</strong> primer<br />
<strong>–</strong> 4 mm Waterproofing Mastix<br />
<strong>–</strong> 25 mm Mastic Asphalt<br />
<strong>–</strong> 30 mm Mastic Asphalt<br />
<strong>–</strong> Chippings
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