CATEGORY 400 STRUCTURES SECTION 478 — JACKING BEAM OPERATIONS
478.01 Description
Jack existing beams for repairs
478.02 Materials
Refer to the Plans and Section 430, Section 436, and 902.11.
478.03 Construction
Refer to the Plans. Use the shielded metal-arc process for all field welding. Adhere to all requirements of the Contract Documents except that for temporary installation, the requirements for radiographic and ultrasonic inspection will be waived if the Engineer’s visual inspection indicates the welds are satisfactory. At the Contractor’s option, submit an alternate jacking beam or method to those specified in the Contract Documents to the Engineer for approval. Alternate jacking beams shall comply with the following restrictions:
a.The alternate jacking beam material must be in new condition.
b.The section modulus and web area (depth x thickness) shall not be less than the jacking beams shown in the Contract Documents unless otherwise specified.
c.If the connection detail, stiffener plate detail, or jacking method is changed; submit detailed calculations to the Office of Structures for approval. These calculations shall be stamped by a professional engineer registered in the State of Maryland. Set jacking beams level unless otherwise specified in the Contract Documents. The existing anchor bolts may be cut above the nut to achieve a level beam. In no instances, will it be permitted to chip away the concrete end diaphragms to achieve a level jacking beam. Thoroughly clean areas under the proposed jacks to provide a flat, clean jacking surface. When jacking surfaces are not level or have slightly deteriorated concrete areas, use nonshrink grout to repair them to a flat level surface. The minimum thickness of the grout shall be as recommended by the manufacturer. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS If the Engineer determines that any jacking surface contains highly deteriorated concrete, delay all work at that location and initiate provisions for cast in place concrete repairs to restore the surface to full capacity for the jacking operations per Section 423. Utilize the correct scheme and jack capacity corresponding to the particular bearing being repaired as shown in the Contract Documents. Repair any damage resulting from misuse of the jacking schemes to any portion of the existing bridge that is to remain in place to the complete satisfaction of the Engineer, at no additional cost to the Administration. Do not remove any steel that has been welded to the existing bridge; it shall remain in place. The Contractor may opt to leave the jacking beam in place unless otherwise specified. The Engineer will determine if any additional bearings are to be repaired by use of a jacking operation.
478.03.01 Jacking Requirements and Restrictions. Adhere to the following requirements and
restrictions during the jacking sequences to provide for a safe repair of deteriorated bearing pedestals, pier caps, and bearing assemblies. The Engineer or his representative shall be present during all jacking operations to check all pertinent dimensions and to ensure conformance with all pertinent Contract requirements before the commencement of the actual jacking. Jacks with a higher capacity than those listed in the Contract Documents may be allowed, but the Contractor shall monitor the jack load to ensure the safety of the bridge. The jack system shall be equipped with a direct reading gauge to directly read the jack force in pounds or kips. However, a gauge accompanied by a chart with which the dial reading can be converted into pounds may be used if approved by the Engineer. An existing bearing may not be raised more than 1/8 in. higher than its as built elevation unless otherwise specified. Do not exceed the maximum jacking forces shown in the Contract Documents. If any repairs were made to the concrete bearing pedestals, do not lower the beams in place until the new concrete achieves 3500 psi minimum compressive strength. The jack hydraulics shall not be used to support the load except during the actual jacking operation. However, a jack with a locking nut may be used if approved by the Office of Structures. Brace as necessary to maintain structural stability and prevent lateral movement until completion of the jacking operation. If any of the above requirements or restrictions cannot be met, the Engineer will notify the Office of Structures.
478.04 Measurement and Payment
for the complete Jacking Beam Operation work required. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS The payment for Jacking Beam Operations will be full compensation for fabricated structural steel; installation, removal, storage, and reinstallation of existing steel end diaphragms or cross frames where required; bolts; paint; welding; jacking bearing plates; hydraulic jacks; any temporary timber blocking; scaffolding; providing non-shrink grout leveling pads if necessary; painting the steel; and for all material, labor, equipment, tools, and incidentals necessary to complete the work.
478.04.01 Jacking Beam Operation will not be measured but the cost will be incidental to other
pertinent items specified unless a Jacking Beam Operations item appears in the Contract Documents. Refer to Section 423 and Section 432 for payment of repaired areas.
478.04.02 Jacking Beam Operations will be measured and paid for at the Contract unit price per
each location jacked. A jacking location is defined as a beam support at which the beam is to be lifted by one or two jacks by the amount specified on the Plans. One payment shall be made for the jacking procedure at any given location to complete the work required. Subsequent jacking procedures required to repair work from Contractor error will not be paid.
478.04.03 Jacking Beam Operation will not be measured but will be paid for at the Contract lump
sum price. The payment will be for full compensation including all jacks, jacking beams, required 479 — PRESSURE INJECTED EPOXY CRACK REPAIR used during the operation. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS CATEGORY 400 STRUCTURES SECTION 479 — PRESSURE INJECTED EPOXY CRACK REPAIR
479.01 Description
Inject epoxy in cracks with a maximum width of 1/4 in.
479.02 Materials
The epoxy resin shall conform to 921.04, C 881, Type I. Submit the grade for approval after the Contractor’s analysis of the areas to be injected. The system shall be moisture insensitive and shall not be used when the ambient or concrete temperature is 50 F or below, nor temperatures lower than recommended by the manufacturer. The expiration date of acceptance of this material shall be one year after the date of manufacture. Any unauthorized tampering or breaking of the seals on the containers between the time of sampling and delivery to the job site will be cause for rejection of the material.
479.03 Construction
The locations for the pressure injection of cracks will be delineated by the Engineer. Ensure that the epoxy manufacturer’s technical representative will be present for the initial day of the epoxy injection process and submit details of the proposed method of repairs and the injection procedure for approval. Inject the epoxy with a positive displacement pump system having a suitable mixing chamber where the epoxy components are accurately metered and thoroughly mixed immediately prior to injection. A clear, legible, and accurate pressure gauge shall be located in the supply line adjacent to the mixing chamber. The equipment shall also be capable of providing a continuous and uninterrupted pressure head to continually force the injection of epoxy into the cracks. Epoxy flow shall be capable of being fully controlled by the operator controls at the mixing chamber. Ensure that all working personnel are familiar with the equipment, materials, and procedures to be
Source: Maryland Standard Specifications for Construction and Materials, 2025 Edition. Pages 600–602 of 1,113.