389 Pipe guides shall be constructed in the approach trench and may be eithe r timber or steel rail or concrete guides on a cradle. Since the pipe guides will support the pipe as it enters the jacking face, the pipe guides shall be accurately set to line and grade, and excavation for the guides shall be made to grade to avoid occu rrence of settlement. Guides shall be spaced, as required. Reaction of the jack to the pipe shall be transmitted by either a jacking frame or jacking beams constructed of timber or steel. Jacking frames and beams shall be so placed as to exert equal pre ssure on each side of the pipe. For pipes thirty -six (36) inches in diameter or smaller, a steel jacking ring may be used in lieu of the jacking frame. The pressure from the jacking frame or beams may be transmitted to a jacking collar or head on the pip e itself. Jacking collars or heads for concrete pipe shall be constructed to prevent damage to the pipe ends. Jacking collars and jacking frames shall be constructed to allow passage of men and material. Joints of concrete pipe shall be cushioned and pr otected from infiltration of fine materials occurring during the jacking operation by insertion of a plywood or OSB of ½” -¾” thickness cushioning material into each pipe joint. After the pipe is in position, the joints shall be pointed from the inside wit h mortar joint compound. The use of a jacking shield is permitted. To prevent the pipe from "freezing" and becoming incapable of movement, jacking operations should, if possible, be carried out on a 24 -hour basis. Alignment and grade of the pipe guides s hall be checked at least once each shift. To aid in the prevention of "freezing," the pipe shall be lubricated in a manner and with a material meeting the approval of the Engineer. Excavation for the bore shall be to grade at the bottom and approximately one (1) inch greater than the diameter of the pipe at the top and sides. As excavation proceeds, the jacking shall proceed until the effective limit of the jacking is reached, at which time additional blocking shall be added. This process shall be conti nued until there is room for an additional pipe section. For long runs of pipe, the use of intermediate jacking stations will be allowed as approved by the Engineer. Pipe cover shall be a minimum of one diameter or three ( 3) feet from top of pipe to bottom of the subgrade of ballast when jacking under a highway. After the pipe has been jacked into place, the annular area between the pipe wall and the remaining soil sh all be pressure grouted to remove any chance of settling. The backfill shall be tightly compacted around both ends of the culvert to prevent erosion. Any departure from the above specifications necessitated due to site conditions shall be approved in wri ting by the Engineer. Areas resulting from caving or excavation outside the above limits shall be backfilled with grout, or by a method which will fill the voids. Joints shall be completed as specified for the type of pipe being installed .
604.12 Inspec Tion and Acceptance :
In addition to the inspection performed by the Division during the initial installation of pipe culverts, a post installation inspection will be conducted before final acceptance. No sooner than 30 days following installation, the Engineer will visually i nspect all culverts. Pipes larger than forty -two ( 42) inches in diameter will be manually inspected by inspectors on the project for excessive deflection of flexible pipe, excessive cracking in rigid pipe, and joint issues for all pipes. Inspectors will note and document any defects with locations in their daily work reports. Any excessive cracks, differential movement, spalls, exposed reinforcement, delamination, slabbing, dents, buckling, holes, damaged coating, obstructions, improperly engaged joints, improper gasket placement, excessive joint gaps, misaligned joints, excessive deflection, or undue horizontal or vertical misalignment will be cause for repair or replacement at no cost to the 390 Division. Efflorescence and rust stains should be evaluated t o determine if detrimental or just a cosmetic defect.
604.12.1 Rigid Pipe Criteria: Concrete pipe cracks equal to or less than one hundredth
of an inch (0.01) are considered hairline and minor. Cracks greater than one hundredth of an inch (0.01) but less than five hundredths of an inch (0.05), shall be sealed by the method proposed by the manufacturer and approved by the Engineer. Concrete pipe with cracks with width equal to or greater than five hundredths of an inch (0.05) and less than one tenth (0.1) shall be evaluated by the Engineer for repair or replacement. Concrete pipe with cracks one tenth (0.1) inch or greater in width shall be replaced by the Contractor to the satisfaction of the Engineer. Cracking, whether longitudinal or transverse, shall be evaluated as described above. Spalling is defined as a localized pop -out of concrete along the wall of the pipe/culvert, or at the edges of longitudinal or circumferential cracks. If spall/chips are detected, there are 3 classifications:
a.Spalle d areas with no exposed reinforcement, are considered nonstructural and shall be patched with material from approved list and meeting Section 715.4 with R-3 requirements and approved by the Engineer.
b.Spalled area with exposed reinforcement, with a single s pall area less than or equal to 150 square inches, the Contractor shall submit repair plan for remediation to the Engineer.
c.Spalled area with exposed reinforcement with a single spall area greater than 150 square inches, the Contractor shall submit a pipe analysis and remediation plan for repair or replacement. Delamination and Slabbing appears as a separation of the concr ete from the reinforcing steel and can be detected by a hollow sound when tapped with a device such as a hammer. If identified, the Contractor shall submit remediation methods for delamination/slabbing in accordance with recommendations of the pipe manufa cturer, to the Engineer for approval before proceeding. Where delamination/slabbing is of such magnitude that, in the opinion of the Engineer, the integrity or service life of the pipe or culvert is severely compromised, the section(s) of pipe shall be re placed at the Contractor’s expense to the satisfaction of the Engineer. Maximum allowable joint gaps are dependent on each pipe manufacturer’s joint design and equipment. Pipe manufacturers will provide maximum joint gaps based on minimum gasket compress ion required. If any soil infiltration is identified at a pipe joint during inspection, a pipe analysis and a remediation plan for repair or replacement shall be submitted to the Engineer for approval.
604.12.2 Flexible Pipe Criteria: Flexible pipe deflection equal to or less than
5 percent (5%) of the original diameter will not require remediation. Deflections of 5 percent (5%) up to 7.4 percent (7.4%) of the original diameter will be evaluated by the Engineer for repair or replacement; if repaire d the final pipe deflection must be equal to or less than 5 percent (5%) of the original diameter for acceptance. If flexible pipe is deflected 7.5 percent (7.5%) or more than the original diameter, the pipe shall be replaced by the Contractor to the sat isfaction of the Engineer. Flexible pipe with any crack (interior, exterior, or both) shall be replaced to the satisfaction of the Engineer. 391 Pipes showing evidence of crushing at the joints will need a repair plan submitted to the Engineer for appro val. Replacement at no cost to the Division as an option if necessary. I f any soil infiltration is identified at the pipe joint during inspection, a pipe analysis and a remediation plan for repair or replacement shall be submitted to the Engineer for app roval.
604.12.3 Testing of Pipe: A post installation camera/video inspection of pipe culverts and
laser/mandrel deflection inspection of flexible pipe shall be conducted by the Contractor on all pipe culverts that meet the following requirements:
1.Cumul ative total of 200 linear feet or more of pipe culverts on project; and
2.Project located on National Highway Systems ( NHS ) routes The Contractor may visually inspect, in the presence of the Engineer, in lieu of camera/video inspection where pipe culverts size, orientation, and location allow for easy visual examination. When camera/video inspection is required, it shall be conducted by the Contractor in the presence of the Engineer. The Contractor will note and document any defects or flaws with locations in their reports. Equipment used in these inspections must have the following features: Camera/Video inspection equipment shall be:
1.Configured properly in the pipe both vertically and horizontally, and having the ability to pan and tilt to a 90 degree angle with the axis of the pipe and rotate 360 degrees.
2.Low barrel distortion camera capable to measure cracks as small as 0.01”.
3.Color image with a minimum standard resolution of 720x480 pixels.
4.Equipped with sufficient lighting to pro vide a clear image of the full circumference of the pipe.
5.Capable of recording the station, milepost, distance along the invert of the pipe, or other indicators of location superimposed on the video.
6.Capable of moving through the entire length of the pipe.
7.Software capable of generating a report that shows each fault along with its location from the inspection entrance and a still frame image of the fault. Laser deflection measure device on flexible pipe up to forty -eight ( 48) inches in diameter shall be capable of measuring deflection to an accuracy of 0.5% or better with a repeatability of 0.12% or better. Mandrel device must have an odd number of legs (9 minimum) having a length not less than the outside diameter of the mandrel. The mandrel shall b e pulled by hand with no mechanical assistance. The diameter of the mandrel, whether it is fixed or variable size, must be verified with a proving ring or other method as per the manufacturer’s guidelines. The minimum diameter of the installed pipe at a ny point shall not be less than the diameter, as calculated per equation below: Minimum Diameter of Installed Pipe = (Actual Pipe Diameter) x (Deflection Percentage) Where: Actual Pipe Diameter = Inside pipe diameter of pipe being installed prior to installation Deflection Percentage = 0.95 for 5% deflection and 0.925 for 7.5% deflection The Contractor shall provide a digital copy of the camera/video inspection and issue a report in digital format, detailing all issues or deficiencies noted d uring the inspection, including a remediation plan for each deficiency, no later than 7 calendar days after completion of the inspection.
Source: West Virginia Standard Specifications for Road and Bridge Construction, 2023 Edition. Pages 409–411 of 1,006.