w88 casino repair of damaged bridge columns using fiber reinforced polymer (FRP) materials
- PI: M. Saiid Saiidi, w88 casino, Reno
- Research assistant: Ashkan Vosooghi, w88 casino, Reno
- Sponsor: California Department of Transportation
- w88 casino monitor: Saad El-Azazy
- w88 casino dates: July - September 2009
w88 casino summary
Past effort in the seismic design of concrete bridges has been on detailing of bridges to prevent collapse. During earthquakes, reinforced concrete bridge w88 casino are designed to undergo cracking, spalling, and yielding of steel and provide significant rotational capacity at plastic hinges so that the integrity of the overall structure is maintained.
With proper design and construction, this objective can be met. However, the serviceability of the w88 casino after the earthquake is in question.
The level of damage to different w88 casino of a bridge varies depending on the intensity of the ground shaking, type of earthquake, and the force/deformation demand on individual members.
Based on the inspection of the damaged columns, engineers have to determine whether the bridge is sufficiently safe to be kept open to traffic. They should also recommend w88 casino methods for the columns.
Any delay in opening of the bridge to traffic can have severe consequences on the passage of w88 casino vehicles, detour lengths, and traffic congestion in the area. Rapid and effective repair methods are needed to enable quick opening of the bridge to minimize impact on the community.
This project subjected three one-third scale single columns to Sylmar earthquake with gradually increasing PGA using one of the shake tables at the University of Nevada, Reno and the mass-rig setup. After each test, the column was repaired rapidly, using CFRP wrapping, and retested to evaluate the w88 casino repair performance.
New design high shear w88 casino
In this test, the two ends w88 casino column are fixed to apply a double-curvature deformation inducing a high shear demand. The main objective w88 casino test is to achieve the highest repairable damage with no bar rupture (DS-5). At this level w88 casino damage, many spirals and longitudinal bars are visible, some w88 casino longitudinal bars are beginning to buckle, and the edge of concrete core is damaged. No bars are ruptured.
The w88 casino underwent approximately 6.4% drift during the shake table test.
The entire w88 casino process consisted of the following steps:
- Straightening the w88 casino
- w88 casino chipping (In this step, only the loose w88 casino was removed)
- Pressurized epoxy injection w88 casino cracks
- Fast set w88 casino pouring/patching
- w88 casino
- Curing
Old design high shear w88 casino
In this study, the column is substandard. It has lap splice at the base and deficient lateral reinforcement. The two ends w88 casino column are fixed to apply a double-curvature deformation inducing a high shear demand. The failure mode w88 casino column is shear. The main objective w88 casino test is to achieve the highest repairable damage with no shear failure.
After the first test, major shear cracks appeared at the w88 casino base.
The entire w88 casino process consisted of the following steps:
- Pressurized epoxy injection w88 casino cracks
- w88 casino
- Curing
Old design low shear w88 casino
In this study, the column is substandard. It has lap splice at the base and deficient lateral reinforcement. The column is cantilever with low shear. The failure mode w88 casino column is degradation w88 casino lap-splice bond.
After the first test, major ring cracks merged to shear cracks appeared at the column base at the end w88 casino lap splice. At the compression side w88 casino column base, extensive spalling was observed.
The entire w88 casino process consisted of the following steps:
- Remove the loose concrete and w88 casino the spalled area using a fast set / non shrink mortar
- Pressurized epoxy injection w88 casino cracks
- w88 casino
- Curing