1107PRE-STRESSED CONCRETE BRIDGE BEAMS

1107.01GENERAL REQUIREMENTS—

beams.

• Items such as chairs, hold downs, tie rod tubes, inserts, and steel bearing plates incorporated into the beams. List inserts and steel bearing plates by source, type, and supplier.

• Incidental items such as plain neoprene bearings, tie rods, and anchor bolts.

• Subassemblies.

• Strand patterns.

• Type of strand.

• De-bonding.

• Deviation from tolerances as specified in Section 1107.03(e).

• Anticipated camber based on the contract drawings.

• Vertical Adjustment Device Assemblies, as shown on the Standard Drawings. Include design related calculations with submission.

If draped strands are used, show the following additional information:

• Hold up and hold down forces.

• Other required data.

1.a Deviations from the Contract Drawings. The total force and the center of gravity of the strands may be adjusted to fit the strand type selected. Forming aid strands tensioned to 3,000 lbs. may be added, as indicated on the shop drawings . If fabricating beams with different strand patterns on the same set-up, full-length de-bonding may be allowed. Alternate strand patterns and the provision of additional strands in the beam for convenience may be used. Submit bridge shop drawings as specified in Section 105.02(d) for review and acceptance showing the alternate pattern and stress computation documenting the change.

1.b De-bonding of Strands. Compute stresses in the beam end zones at each stress change location. Submit computations documenting these stresses. Stress calculations in the beam end zones for I-beams using de-bonding are not required. Reduce tensile stresses due to initial pre-stress force in the end sections of box beams to a maximum of ci'f3 by selective strand de-bonding. If this cannot be accomplished, provide additional reinforcement bars to carry the full tensile force of the tensile stress block. NOTE: f'ci = Cylinder strength of concrete (pounds per square inch) at initial pre-stress. For box beam end block crack control, do not de- bond more than 25% of the total number of strands for the end 36 inches and 50% of the total number of strands for the end 6 inches.

If de-bonding of I-beams is not specified, the fabricator may de-bond up to 50% of the total number of strands for the end 6 inches. Do not de-bond more than 50% of the strands in any one row. If de-bonding results in an odd number of strands in a row, the number of de-bonded strands may be rounded up to the next higher number. Strand de-bonding must maintain a symmetric pattern about the vertical centerline of the beam. De-bonding the exterior strands of any row in the bottom flange is not allowed. Show de-bonding on the shop drawings. De-bonding in the web region of the beam is prohibited.

fabricated separately, such as steel bearings, moment connections, and post -tensioning operations. Shop drawings are not required for such items as closed cell neoprene sponge, waterproofing, and laminated metal shim neoprene bearing pads.

placing concrete. After the concrete hardens, the tendons are released, and the concrete is stressed by bonding.

are free to move in sheaths, and anchoring them at each end of the member, introducing the required force.

defective. Members which do not meet all specification requirements but may be suitable for use may be submitted to the Department for evaluation and final disposition in a ccordance with Section 106.07(c). Replace rejected members.

1107.02MATERIAL—Conforming to the following requirements:

in the structure for each contract.

• Plain bars. ASTM A615; Grade 40 or 60

• Threaded bars. ASTM A615; Grade 40 or 60

• Threaded bars. ASTM A663; Grade 45, 50, 55, or 60

• Threaded bars. ASTM A675; Grade 45, 50, 55, or 60

Grade 50 or 50W. Certify as specified in Section 106.03(b)3.

another acceptable material. The use of cardboard void forms is prohibited. Construct box beam void forms to be watertight and resistant to breakage and deformation during concrete placement. Waterproof the outside of forms if not constructed of approved preformed cellular polystyrene or an acceptable hot-melt wax coated, polymer coated, or asphalt-penetrated material. Test load or subject box beam void forms to a successful member installation, as directed, before acceptance. Certify as specified in Section 106.03(b)3.

to the Inspector. Attach identification tags to each shipment. At the fabrication plant, a representative of the Department will select samples to be submitted to the LTS. Do not use strand larger than 0.60-inch diameter. Certify as specified in Section 106.03(b)3.

• 5 feet of wire requiring heading.

• Enough wire, not requiring heading, to simulate 5-foot parallel-lay cable.

• 5 feet of strand between fittings.

• 5 feet of bar between threads, one sample per heat, and not less than one sample per 100 bars.

• Two anchorage assemblies of each size and type; each assembly complete with distribution plates.

3.a Pre-stressing Wire, Low-Relaxation. ASTM A881

3.b 7-Wire, Uncoated, Low-Relaxation Strand. AASHTO M 203 (ASTM A416), Grade 270. Unless otherwise indicated, use strand conforming to the following requirements:

Nominal Diameter of Strand, (in.) Minimum Breaking Strength of Strand, (lbf) Minimum Load at 1% Extension, (lbf) Minimum Elongation at Breaking Strength, (%) 0.500 41,300 37,170 3.5 0.520 45,000 40,500 3.5 0.600 58,600 52,740 3.5

3.c High Tensile Strength Alloy Bars. Manufacture and process from steel conforming to ASTM A322, A29, and A722. Stress-relieve by heat treatment and cold-stretch (proof stretch) to the minimum yield strength specified below. Required physical properties after cold-stretching:

• Guaranteed minimum ultimate tensile strength, as certified by the manufacturer—150,000 pounds per square inch.

• Minimum yield strength, measured by the 0.7% extension under load method and 0.2% in the offset method—85% and 80% of ultimate for Type I and Type II bars, respectively.

• Minimum modulus of elasticity—29,700,000 pounds per square inch

• Minimum elongation length in 20 bar diameters after rupture —4% and 7% for Type I and Type II bars, respectively.

• Minimum reduction of area after rupture—20%

• Diameter tolerance—+0.03 inch, -0.01 inch

Calculate physical properties using nominal bar areas.

3.d Special Grade High Tensile Strength Alloy Bars. Required physical properties are identical to those for High Tensile Strength Alloy Bars as specified in Section 1107.02(n)3.c, except a guaranteed minimum ultimate tensile strength of 160,000 pounds per square inch is required. Tag and identify these bars for verification with mill certification.

stencil, or otherwise affix this code to each pad at intervals of not more than 24 inches and in letters and numerals of not less than 1/4-inch height. Additional information such as lot or batch numbers, date, plant and place of manufacture, trademark, or name of manufacturer may also be added. Certify as specified in Section 106.03(b)3.

neoprene and may be composed of laminations. Use material conforming to the following:

• ASTM D1056, Type 2, Class C, Grade 2, including the requirements of suffixes B3 and F1 .

• ASTM D1171, Quality Retention Rating of 100% after 6 weeks exposure.

1107.03BEAM CONSTRUCTION—

or change in the use of accepted beds, anchorage, abutments, and the deflecting facilities for draped strands. Provide adequate lighting for operations not completed in the daylight. Provide a drainage system for the removal of rainfall and curing water. For member storage, stabilize areas and grade to a level surface. Furnish necessary facilities for the inspection of material and workmanship. The necessary facilities for inspection include a plant office, as specified in Section 714.5(a), except a four-drawer fire-resistant (D-label) metal file cabinet will be required in place of a two -drawer fire-resistant (D-label) metal file cabinet. Allow the Representative unrestricted access to work in process and stored materials during plant working hours.

of production facilities, QC, testing, and the fabrication of members and who will ensure beams are fabricated as designed. For plants that offer design service, the Chief Engineer is required to be a Professional Engineer, registered in the State.

For standard members, use fixed and movable steel forms. For nonstandard members and bulkheads that have limited use, forms may be of lumber, plywood, or other material. Maintain accurate form alignment during the casting operation. Check alignment and grade for each setting and for proper strand clearance. Verify the pallet is flat and level in the bearing area. Make joints smooth and tight to prevent leakage of mortar. Plug holes and slots in the forms.

For exposed members, use form ties, chairs, and inserts that are recessed in the concrete by at least 1 inch, or use stainless steel accessories. Do not use continuous soffit forms longer than 120 feet if the forms are rigidly anchored to the bed. If slight differential movements between forms and beds can cause damage to the member, anchor the forms to prevent differential movements, or loosen them so movements can occur without damage to the member or forms. Clean beds and forms after each use. Prevent accumulation of coatings used for bond breakers.

4.a General. Do not begin fabrication before the Chief Structural Materials Engineer's inspection and acceptance of the plant. Plant expansions are subject to the same inspection and acceptance. All beams are to be produced from a single producer and plant location. Provide a permanent building for the Department's acceptance. New plants will be required to produce a sample beam and demonstrate an acceptable level of QC and conformance with specifications and product tolerances before receiving approval to begin production. Currently accepted plants will retain approved status unless the acceptance is rescinded for failure to comply with the plant requirements as specified in Section 1107.03(a), or until ownership changes. Reinstatement will be based on conformance with the plant requirements as specified in Section

Material, equipment, testing procedures, methods of fabrication, handling, storage, and transportation are subject to inspection and acceptance. Plants may be accepted to fabricate one or more of the following beam types:

• Box beams—with straight strands

• I-beams—with straight strands

• PA Bulb-Tee Beams—with straight strands

• Box beams—with straight and draped strands

• I-beams—with straight and draped strands

• PA Bulb-Tee Beams—with straight and draped strands

• Box beams—with straight and de-bonded strands

• I-beams—with straight and de-bonded strands

• PA Bulb-Tee Beams—with straight and de-bonded strands

• Box beams—with pre-post-tensioned tendons

• I-beams—with pre-post-tensioned tendons

• PA Bulb-Tee Beams—with pre-post-tensioned tendons

• Next-Beam

• Nonstandard beam sections

Each beam type will be subject to inspection during manufacturing, storage, and shipment. Register and certify the plant under the Pre-stress Concrete Institute (PCI) plant certification program and submit a valid certificate to the Chief Structural Materials Engineer, at 81 Lab Lane, Harrisburg, PA, 17110. Submit an annual endorsed copy for continued qualification.

4.b Bed Approval. For each casting bed offered for production, submit a complete set of construction drawings and detailed design calculations sealed and signed by a Professional Engineer, registered in the State to the Chief Bridge Engineer for review. Theoretical analysis and applicable design code review must be based on a test load equal to 1.5 times the maximum working load and include the following:

4.b.1 Non-self-Stressing Beds

• Overturning safety factor of abutments for beds having vertical uprights embedded into the foundation.

• Stress analysis of embedded vertical uprights, including buckling and foundation analysis .

• Buckling analysis of bed slab, including the effects of hold down forces for draped strands, if applicable.

• Bulkhead design for transferring the strand forces to the uprights.

• Computed theoretical shortening of the bed under full test load.

• Cumulative deflections of all structural components, including tilting of uprights into the full test load and flexure of the bulkhead beams.

4.b.2 Self-stressing beds

• Anchorage of the bed to the foundation, buckling and overturning safety factors, and theoretical bed shortening under the full test load.

When the above requirements are satisfied, test load each bed for approval under the supervision of the Department. Each bed will be approved for and limited to a maximum allowable bed moment (force and eccentricity) that may be used during production and equal to the maximum bed moment applied during the bed test divided by 1.5.

in accordance with the guidelines listed in Publication 145, including mix design(s) to the Chief Structural Materials Engineer, Bridge Design and Technology Division, Structural Materials Section (SMS), for review and approval. Include with the QC Plan a plant organizational chart indicating a separate chain of command from the QC Manager to the Owner/Plant Manager independent of the Production Manager. Resubmit the QC Plan, mix design, and organizational chart, if required, because of changes in materials, processes, or personnel.

facilities, QC, sampling and testing, and fabrication of the product, and who will ensure items are fabricated as designed and specified. Assign plant QC managers certified in the PCI Quality Control Personnel Certification Program, Level III with overall responsibility for the Quality Control program. These requirements may be waived by the Chief Structural Materials Engineer if alternative experience or certifications or both are submitted and considered to be equivalent.

by the Department. Assign sufficient qualified personnel with pre-stress concrete fabrication experience to be responsible for QC and sampling and testing during the complete fabrication process, storage, and shipment. Technicians responsible for concrete sampling and testing are required to provide written evidence they successfully completed the certification requirements for an ACI Grade I Field Technician or have approval from the Chief Structural Materials Engineer as a technician-in-training. Assign plant QC personnel certified in the PCI Quality Control Personnel Certification Program, Level II during tensioning, de-tensioning, and casting

operations. These requirements may be waived by the Chief Structural Materials Engineer if alternative experience or certifications or both are submitted and considered to be equivalent.

applied force and verified by elongation. Do not have the jacking stress exceed 80% of the specified minimum ultimate tensile strength of the pre-stressing steel (0.80 f's). Measure elongations to an accuracy of 0.0625 inches. Verify at the completion of tensioning that the two control measurements, force and elongation, agree algebraically within 5% of the computed theoretical values. Suspend the tensioning operation if discrepancies are in excess of 5% until the source of error is determined and corrected. If the measurements do not agree within 5%, a load cell may be added at the ‘dead end.’ If force measurements agree within 5% between the gauge at the live end and the load cell, the elongation agreement may be waived.

slippage of grips.

measurements using a secondary measuring system. Acceptable methods of stressing force measurement consist of:

2.a Curves. Elongation, determined from current stress-strain or load-elongation curves furnished by the manufacturer. An average modulus may be used if acceptable, provided the force indicated falls within the specified tolerance limits.

2.b Pressure Gauges. Pressure gauges that measure force by the pressure applied to hydraulic jacks. Furnish digital readouts or dials for these gauges, a minimum of 5 inches in diameter and calibrated with the jacking system.

2.c Dynamometers. Dynamometers connected in tension into the stressing system for the initial force application.

stressing forces. Calibrate hydraulic gauges, dynamometers, load cells, or other devices used to measure the stressing load to an accuracy of reading within 2%. Ensure a qualified testing laboratory calibrates and issues a certified calibration curve with each gauge. Recalibrate at intervals not greater than 1 year and if a gauging system shows indication of erratic results . Gauges for single strand jacks may be calibrated by an acceptable and calibrated load cell. Calibrate gauges for large, multiple strand jacks, acting singly or in parallel, by proving rings or by load cells placed on either side of the movable end carriage. Provide pressure gauges and dynamometers with a full -pressure or load capacity of approximately twice their normal working ranges. Limit the loads to not less than 25% or more than 75% of the total graduated capacity, unless calibration data establish consistent accuracy over a wider range. Each gauge is required to indicate loads directly in pounds or be accompanied by a chart with which the dial reading can be converted into pounds. Direct reading gauges are preferred. Equip tensioning systems employing hydraulic gauges with appropriate by -pass pipes, valves, and fittings so the gauge pointers remain steady until the jacking force is released. Mount gauges near eye level, within 6 feet of the operator, and position so readings can be obtained without parallax.

jacks at the required force. For automatic pressure cutoff valves, use valves capable of adjustment so the jacking force corresponds to the required force. At the beginning of each day’s operation and whenever there is reason to suspect improper results the automatic pressure cutoff valve settings must be verified for accuracy.

the possibility of raveling during concrete vibration. For seven-wire strands, remove and replace strands with more than one broken wire, or with more than the following number of wire breaks in a strand pattern:

• Less than 20 strands, no wire breaks allowed.

• 20 to 39 strands, one wire break allowed.

• 40 to 59 strands, two wire breaks allowed.

• 60 and more strands, three wire breaks allowed.

Failure of wires in parallel-wire, post-tensioned tendons is acceptable, provided the total area of wire failure is not more than 1% of the total area of tendons in any member or no more than one wire fails in any tendon.

6.a General. In systems of pre-tensioning, apply the load in two increments. Apply the initial load to the individual strands to straighten them, to eliminate slack, and to provide a starting or reference point for measuring elongation. Apply the final load for which elongation of tendons is computed and measured. Without verification of strand tension by load cells, the maximum permissible holding time for tensioned strands before starting concrete placement is 72 hours. If it is anticipated the holding time for tensioned strands will exceed 72 hours, place loadce lls during initial tensioning on two separate strands selected by the Representative to verify the strand tension remains within 5% of the theoretical value. Upon limited request, re-pulling of strands may be accepted instead of the use of load cells. Submit requests to the Structural Materials Engineer before tensioning the bed. The Representative will select 20%, or 2 minimum whichever is more, of the beam strands to be re- pulled for tension verification. Tension must remain within 5% of the theoretical value.

6.b Forms, Bond Breakers, Strand Surfaces. Before stringing strands, inspect the bottom of forms for cleanliness and accuracy of alignment. Apply bond breaker coating to the contact surface of forms. Use a form coating that dries to a surface hardness and does not contaminate the strands. Make sure the coating is dry before the strands come in contact with it.

6.c Stringing Strands. Furnish strands in either coils, packs without reels, or on reels. String strands individually or in multiples. Relieve the strand rotation if strands are pulled from coils or packs without reels. Do not reuse strands containing former vise-grip points, unless the points are outside the new strand vise locations. Do not reuse portions of strands that have been in contact with draping mechanisms.

6.d Strand Vises. Use strand vises capable of anchoring stressing loads positively with minimal slippage. Assemble strand chucks with compatible components from the same manufacturer to avoid improper fit and seating on strands. Clean, lubricate, and inspect the vises between each use. Do not use grips that become visibly worn, distorted, or that allow slippage in excess of 1/4-inch. Clean and inspect a full set of strand vises before starting each stressing operation.

6.e Measurement of Forces. For gauge readings, elongation measurements, and calculations for elongation, include appropriate allowances for operational losses in the tensioning system. Losses include strand slippage, movement of anchorages and abutments, elongation of abutment anchorage rods , strand rotation, temperature variation, friction, bed shortening, and other forces and influences acting on the strands. Make calculations for elongation available for inspection. After applying initial tensioning, establish reference points for measuring the elongation due to final tensioning.

6.f Operational Losses.

6.f.1 Friction in Jacking System.

6.f.1.a Single Strand Tensioning. If rams used in jacks for single strand tensioning are small, friction losses in the jacking system may usually be ignored. Verify gauge pressure by measured elongation or load cells.

6.f.1.b Multiple Strand Tensioning. In multiple strand tensioning systems, clean and lubricate the sliding surfaces to minimize friction. Determine and establish a force override (compensatory operational loss correction) for strand patterns if the primary and secondary force measurement sys tems exceed the allowable 5% variation.

6.f.2 Thermal Effect . For anchored abutment (non -self-stressing) beds, make thermal adjustments to compensate for the loss in stress due to the change in temperature if the pre-stressing steel is tensioned at a temperature more than 25F lower than the estimated temperature of the concrete and the pre-stressing steel at the time of initial set of the concrete. Increase the calculated elongation 0.5% for each 5F of temperature variation. Pre-stress strands only if the ambient temperature is above 40F. After the strands are tensioned, maintain the temperature of the air surrounding the strand at 40F or more.

6.g Initial Tensioning. For 0.500 inch and 0.520 inch diameter strand, do not exceed 15% of the specified final tensioning force, or 3,000 pounds, whichever is greater. If 0.600 inch diameter strands are approved for use, do not exceed 4,000 pounds. Measure the initial load within a tolerance of ±100 pounds. Do not use elongation measurement as an initial force measure. In single strand tensioning, the initial and final loads may be applied in immediate succession on each strand. Acceptable methods of applying initial stress are:

6.g.1 Pressure Jacks. Use the same jack for single strand tensioning as for initial tensioning, provided the jack is equipped with a proper gauging system for measuring the initial force.

6.g.2 Fence Stretchers. Apply load using fence stretchers and measure with a dynamometer. Refer to Section 1107.03(c)3 for capacity.

6.g.3 Other Methods. Acceptable methods that provide a definite and uniform load.

6.h Final Tensioning. Use paint or other acceptable method to permanently mark the reference point on strands to be used to check slippage.

6.h.1 Tensioning Straight Strands.

6.h.1.a Single Strand Tensioning. Use jack-mounted pressure gauges for the primary system of force measurement. Check elongation against pressure gauge readings on the first and last strands tensioned and at least 10% of the remaining strands, but on not less than six strands. Check slippage at strand vises. The computed elongation, including operational losses and equivalent elongation for initial tensioning converted into force, is required to be within 5% of the pressure gauge reading. At least every 90 calendar days, or as directed, use load cells as a check of the gauging or tensioning system.

6.h.1.a.1. Form Shortening. For self-stressing beds, if the loss in tension from form shortening is expected to exceed 5%, adjust the strand tension of the previously tensioned strands. Re-tension strands with losses exceeding 5%. Do not exceed a strand stress after seating of 80% of the specified minimum ultimate tensile strength.

6.h.1.b Multiple Strand Tensioning. Use jack-mounted pressure gauges for the primary system of force measurement. For uniform application of load to strand, the face of the anchorage at final load is required to be in a plane parallel to its position under initial load. Verify parallel movement by equal measurements of movement on opposite anchorage sides and check the plumb position of the anchorage before and after final load application. Check slippage at strand vises.

At least every 90 calendar days, or when directed, use load cells as a check of the gauging or tensioning system.

6.h.2 Tensioning Draped Strands. Tension draped, pretensioned strands, initially and finally, by one of the following methods:

• Tensioned in the final design position.

• Tensioned first, and then deflected to the final design position.

Use primary and secondary force measuring systems approved by the Department.

6.h.2.a Tensioning Strand in the Final Design Position.

6.h.2.a.1 Single Strand Tensioning. Stress the strands to their final value in their design position for the full-length of the bed. Pass the strands over saddles, roller fixtures, or pins with a minimum 3/4-inch diameter to minimize friction at deflection points and to prevent strand damage. Design hold-up and hold-down devices with an adequate factor of safety, but not exceeding 75% of the yield strength of the material used. Maintain strand positions within required tolerances under the induced loads. Design hold-down devices that are free to move and are able to bisect the drape angle. If devices are not free to move, use safety procedures to eliminate strand bonding or restrain at hold -up or hold-down. Measure strand force and elongation, as specified in Section 1107.03(c)2. If final tensioning is done by jacking strands from one end of the bed, place two load cells at the dead anchor end of two different strands selected by the Representative. The force indicated by these load cells is required to be not less than 95% of the specified design value. If the computed elongation has not been attained at the jacking end when the load value shown by the pressure gauge or load cells is exceeded by 5%, jack the strand from the other end to the balance of the computed elongation. If achieving the computed elongation results in an overstress in excess of 5%, as shown on the gauge, reduce the number of deflection points and, consequently, the number of members on the bed until the elongation can be attained with not more than 5% overload.

6.h.2.a.2 Multiple Strand Tensioning. For draped strands, control the specified tension in strands without exceeding the force tolerance limits specified in Section 1107.03(c)6.h.2.a.1.

6.h.2.b Tensioning of Strand in Straight Condition and Subsequent Deflection. Arrange beams symmetrically to mid-bed. Position deflection devices in longitudinal and vertical directions to fit the anchor system. Measure the intermediate force value by pressure gauge and elongation as specified in Section 1107.03(c)2. Place two load cells on two separate strands selected by the Representative to verify the design load. At the discretion of the Representative, the application of these load cells may be required only at each third line of beams on the same bed for the same bed layout. Provide for simultaneous lifting or depressing at all bed points to distribute friction and restraint at deflection devices. However, if acceptable, depressing may be done on at least 50% of the deflection points simultaneously and alternately symmetrical to the bed center. Load cell readings are required to be within 3% of each other and each within 5% of the gauge reading.

6.h.3 De-bonded Strand at Ends of Member. De-bond as shown on the shop drawings. Use acceptable sleeves or taping.

6.h.4 Strand Splices. Only one splice per strand is allowed unless force measurement is by load cell. For single strand tensioning, the number of strands that may be spliced in each bed is not restricted. For multiple strand tensioning, either splice all strands and adjust the elongation for average slippage or splice no more than 10% of the strands in which case no slippage allowance is required .

Place strands in the same lay or direction of twist. Cut the ends using shears or abrasive cutting wheels. Do not splice strand within the form where other strands are under applied force.

6.h.5 Strand Position. Position strands as indicated. Use chairs to eliminate sagging of strands in the bottom rows.

6.i De-tensioning.

6.i.1 General. Transfer force to members after the concrete strength, determined by cylinder tests, has reached the specified transfer strength. Transfer force immediately following the curing period while the concrete is still warm and moist. Remove or loosen forms, ties, inserts, hold -downs, or other devices that restrict the member's longitudinal movement along the bed or perform alternate de -tensioning by a method and sequence to minimize longitudinal movement. Keep the pre-stressing forces nearly symmetrical around the member's vertical axis and release the tension using a method to minimize sudden or shock loading. Limit eccentricity around the vertical axis to one strand.

6.i.2 De-tensioning of Draped Strands. De-tension using a procedure provided by the fabricator’s Representative for the type of system used.

6.i.3 Multiple Strand De -tensioning for Straight Strands or Draped Strands. Provide a length of 6 inches or more between bulkheads.

6.i.4 Strand De-tensioning by Cutting. In single strand de-tensioning, release the strands by heat-cutting according to a pattern and cutting chart that is available at each cutting location along the bed. The fabricator’s Engineer will provide a pattern and cutting chart for each plant and bed.

6.i.5. Coating of Strand Ends. As an option to a grouted recess as shown in BC -775M, and if the ends of the beams are to be incorporated into a continuity diaphragm, cut pre-stressing strands off flush with the end of the member, clean the exposed strand and the end of the beam within 1 inch of all exposed strands by wire brushing or abrasive blast cleaning to remove all dirt and residue that is not firmly bonded to the metal or concrete surfaces, and apply zinc-rich paint to the exposed strand conforming to the requirements of ASTM A780 to achieve an average dry film thickness over the cut ends of not less than 3.1 mil.

post-tensioning at the plant unless otherwise designated or specified.

material such as grease, oil, wax, dirt, paint, loose rust, or other similar contaminants that reduce the bond between steel and concrete. Do not use steel showing corrosion, etching, pitting, or scaling of the surfaces. A light coating of surface rust is acceptable if it can be removed completely from the steel by wiping with a cloth. Do not store pre-stressing steel on a surface that contributes to galvanic or battery action. Do not use as a ground for electric welding. Protect from electric welding sparks.

as indicated and within specified tolerances. Secure reinforcing to beds and forms using chairs, blocking, or ties to tendons, so the reinforcing maintains its position during placement and vibration of concrete. Bars may be fabricated into cages by tying and tack welding using low -hydrogen electrodes. Use only qualified tack welders to perform tack welding. Inspect welds for soundness and for freedom from undercutting. Do not weld

immediately adjacent to a cold bend. To provide maximum cover, bend tie wire- ends into the member. Do not support cages on tensioned strands. Place inserts as shown on the shop drawings. Recess scaffolding inserts in the concrete at least 1/2 inch or as indicated. Recessing is not required for structural inserts intended to anchor threaded reinforcing bars for diaphragms or utility supports. Fabricate inserts for utility supports from corrosion resistant material, galvanize, or apply another acceptable equal coating. Install self -drilling inserts only at the fabrication plant, and test for soundness. Use chairs that support and space the strands and mild reinforcing within the tolerances specified in Section 1107.03(e). Use stainless steel or plastic -coated legs for chairs set on the bottom pallet or set against a form side. Concrete block supports may be used on box-beam void form tops. If indicated, place epoxy coated- reinforcement as specified in Section 1002 in the top slab of adjacent box beams.

3.a Embedded Steel Bearing Plates. Set embedded plates level, align parallel to each other, and anchor in the exact location indicated.

3.b Concrete Bearing Areas. Finish concrete bearing areas that receive neoprene bearing pads to true, flat planes to ensure uniform bearing on the entire area. Use smooth and unyielding pallet forms.

and vibration of concrete, maintain form positions within the limits of dimensional tolerances with respect to the horizontal and vertical axis of the member. Do not strap void forms to pre-stressed strands. During vibration of the concrete, restrain the tendency of void forms to float. Check void positions during casting at least every 10 feet. Seal ends and splices by taping or by other acceptable means. Unless required, void forms manufactured to provide very tight seams need not be sealed. Vent and drain rectangular void forms for each spliced sub-unit and for the full void compartment length. Puncture box beam void forms at vent and drainage holes after removing the beam from the casting bed.

5.a Testing. Verify the concrete attains both the required de-tensioning and 28-day minimum strengths shown on the accepted shop drawings. If the test results of the acceptance cylinders fail to meet the required 28-day minimum concrete strength, the disposition of the concrete beams will be resolved as specified in Section 110.11.

5.b Air Content. Provide an air content of 6% ± 1.5% for traditional mixes and 7% ± 2% for self - consolidating (SCC) mixes. The air content requirement may be waived if the mix meets the following additional qualification tests before production:

• Rapid Chloride Permeability, AASHTO T 277: 1500 coulombs at 56-days.

• Freeze Thaw Resistance, ASTM C666, Procedure A or B: Minimum durability factor of 90 at 300 cycles.

5.c Mixture. Provide concrete conforming to Section 704, ACI 211, and meeting the specified compressive strength or other requirements shown on the accepted shop drawings. The use of Aggregate Mineral Filler (AMF) is allowed for beams. Use AMF replacements for fine aggregate as specified in Section 714.7(b)1. Use enough water to obtain workability, but do not exceed a water cement ratio of 0.40. Use a maximum of 850 pounds of cement per cubic yard. Make trial mixtures according to ACI 211. Mold, cure, and test cylinders using the procedures specified for the beam concrete. Unless otherwise approved, produce all beams on a bridge from a single concrete mix design.

Fully automated batch systems utilizing in mixer moisture probes may be utilized, at the Fabricator’s request and approval by the Chief Structural Materials Engineer. Fully automated batch systems must be operated according to Publication 145.

5.c.1 Traditional, Non -Self-Consolidating Mixtures. Select an appropriate slump value that will provide a workable mix for the pre-stressed beams. At no time is the slump upper limit to exceed 8 inches for mixes with high range water-reducing admixtures (superplasticizers). Reject the concrete if the upper limit is exceeded on any slump test. Maintain the cement concrete consistency with 1 1/2 inches on either side of the selected value.

5.c.2 Self-Consolidating Concrete Mixtures (SCC). Perform slump flow testing according to ASTM C1611. Evaluate the Visual Stability Index (VSI) of the mixture when the slump flow is measured during testing. Reject mixtures with a VSI>1. Conduct J -Ring testing according to ASTM C1621 whenever the slump flow test is performed. Establish a slump flow target for production of not less than 20 inches nor more than 30 inches and maintain the slump flow within a range of ± 3 inches of the target. Reject the concrete if the upper specification limit is exceeded. If the slump flow test result is less than the lower production range limit or the difference between the slump flow and J-Ring results is greater than 2.0 inches reject the concrete mixture unless the mixture has been approved for vibration and is subsequently vibrated. Take immediate corrective action whenever the slump flow limits, or action points are exceeded and test succeeding batches until material control has been reestablished. Perform the following additional qualification tests for SCC mixtures before production:

• Column Segregation Test, ASTM C1610: 12% maximum

• Rapid Chloride Permeability, AASHTO T 277: 2000 coulombs at 56-days

• Freeze Thaw Resistance, ASTM C666, Procedure A or B: Minimum durability factor of 80 .

• Strand Bond Qualification, PTM No. 630

5.d Mixing and Placing Conditions. Mix and deliver the concrete as specified in Section 704. Fully automated batch systems utilizing in mixer moisture probes may be utilized, at the Fabricator’s request and approval by the Chief Structural Materials Engineer. Fully automated batch systems must be operated according to Publication 145. Discard concrete that develops initial hardening or has become unsatisfactory for any reason. Do not remix or add water. Do not use materials containing frost, lumps, or crusts of hardened material. Do not place concrete in forms, on casting beds, around reinforcement, on pre-stressing steel, or on other fixtures if the ambient temperature is below 40F or above 100F. Place only concrete having a temperature of 70F ± 20F.

5.d.1 During Cool Weather. If the air temperature is below 50F, but not lower than 40F, heat the mixing water to not less than 50F, or more than 150F. Ensure the aggregate is free of frozen lumps and maintains a temperature not less than 40F, or more than 100F at the time the aggregate is charged into the mixer. Do not use water hotter than 90F until the cement has been mixed with the aggregate.

5.e Placing Concrete. Place concrete without segregation using an acceptable method. Deposit the concrete in its final position in each part of the form. Do not work or flow the concrete along the forms from the point of deposit. Work the concrete under and around the pre-stressing steel and reinforcement. Once concrete placement has begun, continue for all beams on the bed. If the concreting operation is stopped for an extended period of time because of mechanical failure, inclement weather, or other causes, begin curing completed beams. Remove the concrete from unfinished beams. Strands may be reused if not damaged during concrete removal and with approval from the Chief Structural Materials Engineer. Place concrete in lifts as shown on the shop drawings or as otherwise directed. Do not consolidate SSC mixtures without approval and unless the mixture was qualified within 2 inches of the upper production slump flow limit during the trial batching and evaluation phase. For traditional mixtures, consolidate the plastic concrete by internal vibration. Use vibrators with 1 -inch to

1 3/8 inch heads for penetrating the strand pattern. Use vibrators only to consolidate the concrete after it has been properly placed. Operate vibrators vertically, pushing into and pulling out of the concrete slowly. Do not hold the vibrators in one spot long enough to cause segregation. External vibrators may be used to reduce surface blemishes.

5.e.1 Test Cylinders. Mold a minimum of four concrete acceptance cylinders for each beam cast under the supervision of a Department representative. Mold the cylinders according to PTM No. 631 with the concrete being placed into each beam. Handle and cure the cylinders in the same manner as the beam. Remove test cylinders from the bed a minimum of 1 hour before the scheduled time for de- tensioning. Cool cylinders from heat-cured beds for approximately 1/2-hour if bonded capping methods are used according to PTM No. 631. Cure the capped cylinders for 1/2-hour before testing. Test the cylinders according to PTM No. 604 to verify minimum concrete transfer strength and 28 day minimum concrete strength. Test cylinders under the supervision of a Department representative. Match and mark test cylinders with the beams they represent and record test results so the beams can be readily identified. Submit the test results to the Department representative at the plant. If acceptance test cylinders fail to meet the 28 -day minimum strength requirement, evaluation and disposition the beam(s) as specified in Section 110.11.

5.e.2 Finishing. Make concrete surfaces true and even, free from rough, open, or honeycombed areas, depressions, or projections. Do not use brush or bag finishing. Do not paint with grout or neat cement. Do not add water to the concrete to facilitate finishing. After the concrete has been placed as specified in Section 1107.03(d)5.e, use a template to strike-off the top of beams level. Before the concrete has initially set, finish the top surface with a stiff wire bristle broom, flat tine wire broom or template. Run the broom or template from edge to edge of the beam in a transverse direction to produce not less than 4 scores per inch, to achieve a final texture from 1/16 inch to 3/16 inch in depth. Do not penetrate the concrete to depths where the brooming or tining operation pulls coarse aggregate to the surface. Finish the top of the beam with the type of finish shown on the shop drawings.

5.f Repairs and Patching. Do not repair damaged areas unless pre-approved procedures according to Publication 145 are used or otherwise approved by the Chief Structural Materials Engineer. Ensure uniform appearance and color. The Department’s representative will inspect repairs. Maintain a minimum 50F environment until the repaired areas have cured. If at any time during the curing period the curing temperature falls below 50F, the Department’s representative will consider the work deficient and will reject the work. Before patching, clean holes left by tie rods, strand hold-down devices, recessed strand pockets, or other temporary inserts. Use a hammer to pack the holes with stiff dry mortar of the same material used in the concrete. Fill surface blemishes on the outside fascia beam surfaces with mortar as specified in Section 1001.2(d).

5.g Curing Concrete. Cure and protect concrete until pre-stress transfer has been accomplished. Construct and maintain a suitable curing enclosure to retain heat and moisture around the beams. Do not use membrane curing. The full concrete curing cycle consists of the initial curing phase, the intermediate curing phase, and the final curing phase.

5.g.1 Initial Curing Phase. The initial curing phase begins when each beam is completely covered with saturated covering. After each beam has been cast and immediately after the concrete has initially set, cover exposed surfaces using a double thickness of saturated burlap or cotton or jute mats. Place covering carefully to avoid damaging the concrete. During the initial curi ng phase, which extends over a period of not less than 2 hours, or more than the time required to achieve initial set, apply artificial heat, if necessary, to maintain the temperature at approximately 70F within the enclosure.

5.g.2 Intermediate Curing Phase. Cure beams using either steam curing or saturated cover curing. Maintain curing for 12 hours or until at least one hour after the required transfer strength is attained, whichever is greater. An additional hour of curing is not required if the transfer strength is attained after 20 hours.

5.g.2.a Steam Curing. Raise the temperature within the enclosure to between 100F and 160F, at a rate not exceeding 40F per hour. Use steam of 100% relative humidity. Ensure full circulation between the beams and the enclosure. Do not direct steam jets onto forms or beams.

5.g.2.b Saturated Cover Curing. Raise the temperature within the enclosure and the temperature of the covering material to between 120F and 160F, at a rate not exceeding 40F per hour. Keep the covering thoroughly saturated throughout the curing process. Use water with a temperature no more than 10F from the enclosure temperature. Control the temperature of the water to maintain a uniform enclosure temperature at the beam surface. Forms may be removed after 5 hours; provided saturated cover curing is continued on all beam surfaces up to the time of transfer.

5.g.2.c Record of Curing Temperatures. Record curing temperatures for the full curing cycle, up to removal of beams from the bed. Provide one continuous record chart of curing temperatures for every 100 feet of casting bed. Use accurate, automatic recording devices with temperature pickup devices properly placed either within the curing enclosure or embedded in the beam. Locate the temperature pickup devices away from direct contact with steam or water jets. If enclosures are removed to facilitate form removal, place any non-embedded pickup devices on top of a 3/4 -inch board directly on the saturated covering and overlay three additional layers of saturated covering. If embedded probes must be temporarily d isconnected from the beam during this process, reattach immediately. Mark the curing chart to indicate the point at which this change of pickup location is made. Use recording charts covering a minimum of 24 hours and a maximum of 72 hours per one full revolution, or as otherwise allowed. Record beam number, shop drawing number, date, start time and time concrete placement was completed, and time of pre-stress transfer on the chart. Every year, certify the accuracy of the recording device. Display the certificate with the recorder. Place the recorder so the chart may be observed at all times during the curing cycle. After completion of curing, submit the charts to the Representative.

5.g.3 Final Curing Phase. This phase consists of pre-stress transfer and beam storage. Following pre-stress transfer, lower the enclosure temperature to 100F at a rate not exceeding 40F per hour until ambient temperature is reached. Conduct transfer of pre-stress as specified in Section

(d)5.h. Store beams as specified in Section 1107.03(f) for a minimum of 48 hours

5.h Transfer of Pre-stress. Do not transfer pre-stress before the specified concrete strength has been attained. Retain the saturated covering on the top and sides of the beams and continue curing until final pre-stress transfer is complete. Transfer pre-stress as specified in Section 1107.03(c)6.i. Transfer pre-stress not later than 5 days after casting, provided the minimum specified concrete strength at transfer has been reached. If this strength has not been reached, the Representative will declare the concrete, “deficient in strength” and may reject the deficient member.

tolerances (tolerances are not cumulative). The Representative will not accept members that deviate from tolerances unless they are accepted in accordance with Section 106.07(c) .

1.a Pre-stressed Concrete I-Beams/PA Bulb-Tee Beams.

• Depth (flanges, web, and fillets) ±1/4 inch

• Depth (overall) +1/2 inch -1/4 inch

• Width (flanges and fillets) +3/8 inch -1/4 inch

• Width (web) +3/8 inch -1/4 inch

• Length of beam (longitudinal tolerances based on design length, as indicated at centerline) +1/2 inch -1 inch

• Center-to-center of bearings +1/2 inch -1 inch

• Web Perpendicularity Greater of 1/4 inch or 1/8 inch/vertical foot

Measurement: While the beam is on the fabrication bed, verify web perpendicularity at beam ends, midspan, and quarter points using a bubble level.

If the level indicates the web is not truly vertical, verify and record measurements establishing offset from center of top flange to center of bottom flange using a plumb bob, square, or other method acceptable to the Chief Structural Materials Engineer at beam ends, midspan, and quarter points along the length of the beam. • Centerline of bearing to beam end ±3/4 inch

• Exposed beam ends (deviation from square or designated skew): horizontal ±1/4-inch; vertical, 1/8 inch per inch of beam height, but not more than 1/2 inch for beams up to 63 inches in depth and 3/4 inch for beams over 63 inches in depth.

• Threaded inserts (spacing between the center of inserts and from center of inserts to ends of beams) ±1/2 inch

• Concrete bearing area (deviation from plane at bottom of beam) ±1/16 inch

• Dap depths, (deviation from the specified dap depth dimensions) as measured from a straight-edge, parallel to the centerline of the beam. ±1/8 inch

• Out of plane deviation from one beam end relative to the other beam end, measured on the bottom of the beam with a level at a right angle to the beam length.(1) ±1/4 inch

• Stirrup bars (projection above top of beam) ±3/4 inch

• Stirrup bars (longitudinal spacing): -2 inches, +1 inch for 12 inches or greater spacing and 1/2-inch for spacing less than 12 inches

• Horizontal alignment (deviation from a straight line parallel to the beam centerline) (1) ±1/8 inch per 10 feet

• Horizontal misalignment of adjacent form sections 3/16-inch max.

• Location of each strand ±1/4 inch

• Location of each deflected strand at the beam end ±1/2 inch

• Position of post-tensioning duct ±1/4 inch • Longitudinal position of hold-down points for deflected strands ±10 inches

• Longitudinal position of handling devices ±6 inches

• Camber differential between adjacent beams(1): 1/8 inch per 10 feet of span up to a maximum of 1 1/4 inches for beams up to 100 feet in length and 1 1/2 inches for beams over 100 feet in length.

• Camber deviation from plan camber, as measured at release or at beginning of beam storage at the fabricating plant:

Plan camber 1 inch or greater ±50% Plan camber less than 1 inch ±1/2 inch

• Position of positive moment connection reinforcement bars (beams made continuous):

Horizontal position of the bar at end face of beam and end of projection, measured perpendicular to the end face of beam 3/8 inch

Projection from end face of beam 1/2 inch

Note (1). Verify tolerance approximately 2 weeks before shipping.

1.b Pre-stressed Concrete Box Beams.

• Depth (overall) +1/2 inch -1/4 inch

• Width (overall) ±1/4 inch

• Beam length at centerline (longitudinal tolerances based on design length indicated) +1/2 inch -1 inch

• Wall thickness (web) +3/8 inch -1/8 inch

• Depth (top slab) ±1/2 inch spread box; +1/2 inch, -1/8 inch adjacent box

• Depth (bottom slab) +1/2 inch -1/8 inch

• Web Perpendicularity Greater of 1/4 inch or 1/8 inch/vertical foot Measurement: While the beam is on the fabrication bed, verify web perpendicularity at beam ends, midspan, and quarter points using a bubble level.

If the level indicates the web is not truly vertical, verify and record measurements establishing offset from center of top flange to center of bottom flange using a plumb bob, square, or other method acceptable to the Chief Structural Materials Engineer at beam ends, midspan, and quarter points along the length of the beam.

• Horizontal alignment (deviation from a straight line parallel to the beam centerline) (1):

Up to 40-foot lengths 1/4 inch 40-foot to 60-foot lengths 3/8 inch Greater than 60-foot lengths 1/2 inch

• Horizontal misalignment of adjacent form sections 3/16-inch max.

• Camber deviation from plan camber, as measured at release or at beginning of beam storage at the fabrication plant:

Plan camber 1 inch or greater ±50% Plan camber less than 1 inch ±1/2 inch

• Camber differential between adjacent beams(1): 1/4 inch per 10 feet, but not greater than 3/4- inch for beams up to 90 feet in length and 1 1/4 inches for beams over 90 feet up to 160 feet in length.

• Camber differential between minimum and maximum camber in one span(1) 2 inches max.

• Location of each strand ±1/4 inch

• Stirrup bars (projection above top of beam) ±3/4 inch spread box; ±1/4 inch adjacent box

• Stirrup bars (longitudinal spacing): -2 inches, +1 inch for 12 inches or greater spacing and 1/2-inch for spacing less than 12 inches

• Longitudinal position of hold-down points for deflected strands ±10 inches

• Bridge barrier bars (projection above top of beam) +1-inch -0-inch* *-1/2” if shop drawings position bar above minimum shown on contract plans. Additional projection must be noted on accepted shop drawings.

• Longitudinal position of handling devices ±6 inches • Concrete bearing area (variation from plane surface, when tested with a straightedge through middle half of member) ±1/8-inch

• Dap depths, (deviation from the specified dap depth dimensions) as measured from a straightedge, parallel to the centerline of the beam. ±1/8-inch

• Out of plane deviation from one beam end relative to the other beam end, measured on the bottom of the beam with a level at a right angle to the beam length.(1) ±1/4 inch

• Dowel tubes (spacing between the tube centers and from the tube centers to the member ends) ±1/2-inch

• Tie rod tubes (spacing between the tube centers and from the tube centers to the member ends) ±1/2-inch

• Tie rod tubes (spacing from tube centers to the beam bottom) ±3/8-inch

• Threaded inserts (spacing between the center of inserts and from center of inserts to ends of beams) ±1/2-inch

• Square ends (deviation from square) ±1/2-inch

• Skew ends (deviation from designated skew) ±1/2 inch

• Vertical and slanted ends (deviation from plan dimension) ±3/8-inch for beams up to 48 inches in depth and ±5/8-inch for beams over 48 inches in depth.

• Slab void position ±1/2-inch from end of void to center of post- tensioning hole • Position of post-tensioning duct ±1/4 inch

• Position of positive moment connection reinforcement bars (beams made continuous):

Horizontal position of the bar at end face of beam and end of projection, measured perpendicular to the end face of beam 3/8 inch

Projection from end face of beam 1/2 inch

Note (1). Verify tolerance approximately 2 weeks before shipping.

1.c Pre-stressed Concrete Next Beams.

• Depth (stem and fillets) ±1/4 inch

• Thickness (top flange) +1/4 inch -1/8 inch

• Depth (overall) ±1/4 inch

• Width (flanges) ±1/4 inch

• Width (stem) ±1/8 inch

• Length of beam (longitudinal tolerances based on design length, as indicated at centerline) +1/2 inch -1 inch

• Center-to-center of bearings +1/2 inch

• Centerline of bearing to beam end ±3/4 inch

• Stem Perpendicularity 1/8 inch/vertical foot

Measurement: While the beam is on the fabrication bed, verify stem perpendicularity at beam ends using a special constructed jig.

• Distance between stems ±1/4 inch

• Exposed beam ends (deviation from square or designated skew) horizontal ±1/4-inch; vertical, 1/8 inch per foot of beam height, but no more than 1/2 inch

• Deviations of ends (vertical batter) ±3/8 inch

• Threaded inserts (spacing between the center of inserts and from center of inserts to ends of beams) ±1/2 inch

• Concrete bearing area (deviation from plane at bottom of beam) ±1/16 inch

• Blockout/Dap depths, (deviation from the specified dap depth dimensions) as measured from a straight-edge, parallel to the centerline of the beam ±1/8 inch

• Stirrup bars (projection above top of beam) ±3/4 inch • Stirrup bars (longitudinal spacing): -2 inches, +1 inch for 12 inches or greater spacing and 1/2-inch for spacing less than 12 inches

• Horizontal alignment (deviation from a straight line parallel to the beam centerline) (1) ±1/8 inch per 10 feet

• Horizontal misalignment of adjacent form sections 3/16-inch max.

• Location of each strand ±1/4 inch

• Position of post-tensioning duct ±1/4 inch

• Longitudinal position of handling devices ±6 inches

• Camber differential between adjacent beams(1) 1/4 inch per 10 feet of span up to a maximum of 3/4 inch.

• Position of positive moment connection reinforcement bars (beams made continuous):

Horizontal position of the bar at end face of beam and end of projection, measured perpendicular to the end face of beam 3/8 inch

Projection from end face of beam 1/2 inch

Note (1) - Verify tolerance approximately 2 weeks before shipping.

• Length 1/2 inch

• Height and Width -1 inch +1/8 inch

of finished, laminated, closed-cell neoprene sponge pads.

boxes.

stressing is not done in a continuous operation, do not handle members before they are sufficiently stressed to sustain the forces and bending moments due to handling. For handling, lift beams from the locations shown on the shop drawings using accepted devices. If the air temperature is below 40F, do not remove beams from the beds until they are surface-dry. If the air temperature is below 32F, do not place beams outside the beds unless the differential between the beam temperature and the air temperature is less than 50F. Store beams to maintain the same direction of reactions as in the final position in the bridge deck. Support stored beams as shown on the accepted shop drawings. Store the beams in areas that are suitable and accessible for inspection until the 28 -day compressive strength is attained. Maintain beams in horizontal and upright positions at all times. Separate stacked members and support them by battens placed across the full width of each bearing point or as detailed on the accepted shop drawings . Stack members so lifting devices are accessible and undamaged. Do not use the upper members of a stacked tier as storage areas for shorter members or for heavy equipment. Before shipment, provide a rough texture to the entire keyway on adjacent box beams and completely remove oil, grease, dirt, or other material that would prevent bonding by sandblasting or other methods approved by the Chief Structural Materials Engineer. Before shipment, mark each beam with an individual and consecutive identification mark at a permanently exposed beam location. Use the identification mark shown on the accepted shop drawings and erect beams according to the framing plan. Do not ship beams until the Inspector places a stamp of acceptance on each beam.

the minimum 28-day compressive strength shown on the shop drawings, or until 48 hours total storage time has elapsed following pre-stress transfer, whichever is greater. Support the members as shown on the accepted shop drawings using adequate bracing to maintain the vertical position. Ensure supports, bracing, and shipment methods dampen vibrations. Provide adequate padding material between tie chains or cables to prevent concrete chipping. For medium length members, pole-type trailers are satisfactory, with the member serving as the connection between truck and trailer. Trucks with double bolsters are generally satisfactory, provided:

• Fabricator provides stability calculations according to AASHTO LRFD Bridge Design Specifications. Calculations must be prepared and sealed by a Professional Engineer, registered in the State.

Observe hauling restrictions as specified in Section 107.23.