Evaluating Bridges With Unknown Foundations for Susceptibility to Scour: North Carolina Applies Risk-Based Guidelines to Over 3,750 Bridges
Scour occurs when flowing water removes erodible material such as sand and rock. For bridges over water, scour affects the stability of pier and abutment foundations and contributes to...
National Usage of Geosynthetic-Reinforced Soil to Support Bridges
The Geosynthetic-Reinforced Soil Integrated Bridge System (GRS IBS) was developed by the Federal Highway Administration (FHWA) almost 20 years ago to help meet the demand for the next...
Geosynthetic Materials Help Build Optimized Infrastructure
In recent years, the world has begun to realize the negative impacts that limited infrastructure can have on economic growth and the well-being of humankind. Our infrastructure challenges...
Pervious Concrete
Pervious concrete consists of a hydraulic cementitious binding system combined with an open-graded aggregate to produce a rigid pavement with typically 15% to 25% interconnected void space....
Achieving Success and Avoiding Failures with Permeable Pavements
This chapter provides experienced-based recommendations on how to achieve success with permeable pavements. This information is based on an informational survey completed by designers,...
Maintenance
While site selection and proper construction are the most critical factors in establishing that permeable pavements function as designed, all must be inspected and maintained to maximize...
Scope
This standard guideline covers planning, design, pipe materials, and construction of microtunneling. The term microtunneling is defined as a trenchless construction method for installing...
Initial Criteria
Microtunneling is appropriate for a wide range of conditions. Careful evaluation of certain parameters will determine the applicability and constructability of a potential microtunneling...
Cost Considerations
Cost is an important consideration when comparing microtunneling with other construction methods. Direct costs should not be the only consideration. Microtunneling has other benefits that...
Detailed Site Investigations
This section addresses site investigation issues that are important for detailed design and construction of microtunneling projects. These site investigations include the following: Geotechnical...
Microtunneling Operation
The shaft should provide safe working conditions and fully support the ground. Jacking and receiving shaft support system and sizes are typically determined by the contractor. See Chapter...
Machine Performance
Annular Thickness, Annulus, and Annular Space; Overcut; Slurry or Auger System; Cutter Wheel Design and Select; Slurry Separation Plant; Buried Objects and Obstruction; Steering....
Submittals
The contractor should submit the items listed in the specifications for review and acceptance by the engineer. The submittals are generally divided into preconstruction and postconstruction...
Shafts/Temporary Structures
Shafts should be of a size to accommodate the equipment and pipe selected and to allow for safe working practices. If the shaft must accommodate the permanent works, it is the contractor's...
Construction Support Services
A preconstruction survey of existing structures within the anticipated construction zone of influence should be conducted before any construction begins. A plan for structures that need...
Regulations
The contractor should meet federal, state, and local regulations. The contractor is responsible for jobsite safety....
Instrumentation and Monitoring
A detailed plan for monitoring possible ground surface movements caused by the microtunneling operations should be prepared. The plan is typically prepared by the engineer in consultation...
Restoration and Cleanup
The contractor should be responsible for site restoration and keeping the construction site clean, neat, and orderly at all times....
Measurement and Payment
The owner shall establish a bid schedule to obtain pricing for all work associated with the microtunneling installation. This bid schedule provides the bidders the opportunity to establish...
Filling The Bay: Deepening the Oakland Inner and Outer Harbors
The project to deepen the Oakland Inner and Outer Harbors from elevation -42 to -50 ft was federally authorized in 1999 to accommodate the next generation of post-Panamax container ships....
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