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3R Standards Resurfacing, Restoration, & Rehabilitation. Ch. 7. Objectives. Know what “3R” stands for Know basics of 3R standards for freeways Know basics of 3R standards for non-freeways. -Freeway 3R projects (Ch 7). -Non-Freeway 3R projects (download from lectures). Resurfacing.
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3R StandardsResurfacing, Restoration, & Rehabilitation Ch. 7
Objectives • Know what “3R” stands for • Know basics of 3R standards for freeways • Know basics of 3R standards for non-freeways
-Freeway 3R projects (Ch 7) -Non-Freeway 3R projects (download from lectures)
Resurfacing Placement of an additional pavement layer over existing traveled way to provide strength or improve serviceability
Restoration & Rehabilitation Work required to return traveled way to a suitable condition for resurfacing while improving highway safety
Standards same as HDM Ch. 2 for freeways except: Standards of the Day (Table 7-1, pg 7-11) -widths of lanes, shoulders, median -grades -radii -SSD -Max. Super -Median width
Pavt Condition & Treatment • Identify types of deterioration • Perform a pavement evaluation • Decide the appropriate corrective action
Freeway 3R • Single course overlay (40 mm) • T&L & single course overlay >40mm • Multiple overlays • No extensive replacement of exist. Pavt. • No new additional travel lanes
Soils Evaluate when widening pavement
Utilities Relocate or remove from clear zone
Lighting Rehab, upgrade or remove non-functional lighting Locate standards outside of clear zone or deflection distance of barrier, or provide breakaway type
Future MPT Review potential improvements that could be made to improve future maintenance or construction on the freeway (check w/ maintenance)
Traffic Data • Mainlaine (AADT, DDHV, % HV) • Ramps (DDHV) • Crossroads (DHV) • Calc LOS for mainline, ramps, and intersections • Design year (ETC+10) • Accident analysis (most recent 3 years)
Non-Conforming Features • LOS • Clear Zone • Intersection Turning Radii • Super Routs and Roffs • Min. Length of vertical curves • Lane drops • Broken back curves • Compound curve ratios • Accel/Decel lane lengths & types • HOV & Transit Accommodations • Weaving Lengths • Design storm for drainage facilities • TCD
Medians • Check clear zone • Emergency crossovers (1:10 or flatter and culverts >300 mm w/ safety grates)
Curbs • Usually remove • If not removed document as a nonconforming feature (historical parkway, drainage, erosion control, structural integrity of bridge) • Consider traversable versus non-mountable or mountable curb
Clear zone • Provide minimum of 9m • Remove FO • Identify hazards (cliffs, bodies of water, etc)
Guide railing • Consider elimination by regrading • Bring up to current standards • Add new to meet current warrants • Remove trees and FO from deflection area
TCD • Update to current MUTCD
Drainage-Roadside Surface Drainage System • Site Inspection • Recalculate flow rate/capacities if not functioning adequately • Roff should not cover more than shoulder and ½ of travel lane to prevent hydroplaning
Drainage- Cross Drainage Structures • Site Inspection • Evaluate inadequate structures • Consider replacement of structures that are approaching their anticipated design life
Drainage- Hazardous Features • Remove • Modify • Shield
3R: Non-Freeways(http://www.ci.walnut-creek.ca.us/historygifs.html
3 MAJOR STEPS • Assess current conditions • Accident Data • Site Inspections • Design and Traffic Characteristics • Determine project scope • Incorporate minor improvements if cost effective • Document design process • Existing Conditions • Design Criteria (3R) • Design Exceptions • Recommended Design
3R Standards • Design Speed • Pavt./Shoulder Widths -Retain existing except some min’s are listed or if causing safety/operational problems • Pavt/Shoulder Cross Sections • Pavt (1.5-3% accept) • Shoulder (2-8% accept) • Rollover < 8% • Travel lane widths should be constant (vary shoulder widths if necessary)
3R Standards • Horizontal Curvature & Superelevation -Compare safe operating speed (MUTCD Fig 231-1) to design speed. Depending on difference follow 3R book to determine what to do. -Superelevation transition: Use roff only as minimum. 50-70% on tangent; 30-50% on curve 5. Vertical Curvature/SSD -Don’t consider sag curves unless problem -Crest curves: consider reconstruction if accident problem or all 3 below criteria are met: i) Crest curve hides a major hazard ii) AADT>1500 iii) Safe speed > 20mph below design speed
3R Standards 6. Horizontal Clearance to FO -If no accident, choose minimum of what can be reasonably achieved -Evaluate guiderail for replacement 7. Grades -Retain existing unless operational or safety need 8. Bridges -Evaluate for rehab or replacement -Evaluate width using GDPB