1112GLUE LAMINATED HARDWOOD TIMBER MEMBERS

1112.01GENERAL REQUIREMENTS—

laminated timber for structural members.

plant, comprising assemblies of suitably selected and prepared laminations bonded together with adhesives.

They may be comprised of pieces jointed to form any specific lamination length. Laminations formed in combination using narrower pieces are not acceptable for bridge stringers. Laminations bent and glued to curve form are accepted for use.

including exposure to weather, marine use, and where approved preservative pressure treatments are used after gluing. Accepted exterior use adhesives conform to current ANSI/AITC A190.1 requirements.

perform work for the Department by establishing proof of their competency in fabricating members conforming to the current ANSI/AITC A190.1. Certification of the plant/shop will be performed by the LTS, and submission of a valid certificate to the Structural Materials Engineer, at 81 Lab Lane, Harrisburg, PA 17110 , is required by the Department. An annual endorsed copy is required for continued qualification.

Design bridge members in lengths, depths, and widths that can be transported from fabrication source to the project. Provide design computations prepared by a Professional Engineer registered in the State for Department approval. It is the Department's prerogative to accept or reject the changes by the Contractor.

days’ notice of the beginning of work to the Department so that arrangements can be made for inspection. The Department may waive fabrication or treatment shop inspection and make a complete inspection at a later stage of the construction sequence. Provide material certification, in duplicate, ensuring that the components used in fabrication were in conformance with material specifications.

Allow Inspectors unrestricted access to the premises during plant working hours. Necessary facilities for inspection include a Type C field office as specified in Section 609.

does not conform to the requirements of these Specifications. In case of dispute, the Contractor may appeal to the Representative, whose decision will be final.

plant and treatment plant may be rejected later if they do not conform to the specifications.

AITC 200 Inspection Manual or another trade association that certifies glued laminated timber under ANSI/AITC A190.1. Perform all preservative testing according to AWPA Standards.

directed. Ensure that the fabricator presents a copy of the shipping invoice to be stamped for verification of inspection and approval of timber items before shipment to the Department’s shop inspec tor. Forward the stamped copy with the shipment for the project file.

Store fabricated glued laminated materials above ground upon suitable platforms, skids, or other supports. Keep material free from dirt or other foreign materials and properly protected from moisture. Store glued laminated materials to avoid water or high humidity exposure.

1112.02MATERIAL—

Softwood Lumber Standard PS 20-70. Use only Red Maple, Northern Red Oak, or Yellow Poplar.

Grade red maple and northern red oak according to Northeast Lumber Manufacturer’s Association (NELMA) rules. Grade yellow poplar according to Northern Softwood Lumber Bureau (NSLB) rules. Certify as specified in Section 106.03(b)3.

Any deviations from these lumber moisture content conditions must be approved.

have been qualified under appropriate sections of ANSI/AITC A190.1. Acceptable face bonding includes either a 100% resorcinolic adhesive or in formulation with phenolic base adhesives. End-joint connections must be bonded with a similar fully exterior adhesive or a 100% melamine base adhesive.

Cascophen RS-254 (Resorcinol Adhesive) Penacolite G1131 (Resorcinol Adhesive) Cascophen LT-75 (Phenol with Resorcinol Adhesive) Cascophen LT-5210 (Phenol with Resorcinol Adhesive) Penacolite G1260 (Phenol with Resorcinol Adhesive)

Acceptable performance with use of these exterior adhesives is species dependent and is maintained through strict lamination procedures to achieve optimum bond development.

Mark straight or slightly cambered members with identification to denote proper top versus bottom beam orientation.

with identifications. Members intended for axial load application or of symmetric construction suited for either up or down installation need not be labelled. Appropriately stamp members with a quality mark or other documentation indicating conformance with ANSI/AITC A190.1. Certify as specified in Section 106.03(b)3.

members with an AWPA accepted oil base preservative. For creosote or creosote solution treat to a minimum 11.5 pounds per cubic foot assay retention. Other oil base treatments must meet m inimum retentions conforming to AWPA C14. Conduct retention and penetration assay according to AWPA C28. Sample Northern Red Oak and Red Maple for soil contact as required for Southern Pine (refer to AWPA C28, Table 1). Sample Yellow Poplar for soil contact as required for Pacific Coast Douglas-Fir (refer to AWPA C28, Table 1).

1112.03FABRICATION—

requirements put forth in the current ANSI/AITC A190.1 and AITC 119. Treat all structural glued laminated bridge members to minimum retention and penetration requirements.

between 12% and 15%.

lamination fabrication according to the general requirements for a 24F -E4 or 24F-E1 southern pine glued laminated timber (refer to AITC 117, Table 1) with special lumber stiffness and edge knot restrictions as follows:

Outer Tension Zone 10% 2.0-1/6 E-rated Inner Tension Zone 10% 2.0-1/6 E-rated Core 50% No. 2 VSR (NELMA, NSLB) Inner Compression Zone 15% 1.8-1/3 E-rated Inner Compression Zone 10% 2.0-1/3 E-rated

Conduct Northern Red Oak lamination according to the AITC 119 for the fabrication of Combination A glued-laminated timbers. For applications other than girders no special laminating requirements apply other than minimum No. 2 lumber grade. Provide hardwood glued laminated timbers at the treatment facility conforming to these requirements with a minimum 12% and maximum 19% moisture content. Accept only hardwood glued laminated timbers that conform to these requirements. Certify as specified in Section 106.03(b)3.

hardwood glued-laminated members.

and swelling of the wood. For dowels, drifts, pins and rods, match the hole diameter with the connection shank. For lag screws, refer to National Design Specifications (NDS), NDS Section 9 .1.2. For machine bolts, refer to NDS Section 8.1.2 for size.

design drawings before shipping components to the job site.

1112.04TREATMENT—

conforming to AWPA C1.

proof of their competency and efficacy of their treating operation with the LTS.

oak, red maple and yellow poplar glued laminated timber bridge members. Provide initial air pressure between 140 kPa and 20 pounds per square inch and 30 pounds per square inch. Creosote solutions shall be introduced into the chamber and pressurized to 150 pounds per square inch to 200 pounds per square inch. The actual pressure will depend upon hardwood species being treated. Treatment temperature shall be between 190F and 210F. Conti nue treatment pressure and temperature until 12 pounds per cubic foot gauge retention is achieved. Gauge retention is confirmed by assay measurement to ensure a minimum 11.5 pounds per cubic foot creosote retention. Following the pressure cycle, the pressure shall be released in a slow step down manner over a 1 -hour period. An expansion bath during the “slow pressure release” shall be used with an increase in temperature in the treating chamber of 43F following the pr essure release. The creosote solution is removed from the cylinder and a minimum vacuum of 11 pounds per square inch shall be applied for 2 hours. At this time the vacuum is released to atmospheric pressure and, if possible, the surface is steamed for 1 hour. A final minimum vacuum of 11 pounds per square inch is applied to the treated members for 2 hours. This treating cycle will ensure a minimum amount of exudate during the service life of the member. It is the Department's prerogative to accept or reject treated hardwood glued laminated members, after pressure treatment that do not minimize exudate.

or sealer treatment. Do not use treated hardwood glued laminated railings where prolonged exposure to direct human contact is likely without application of a finish sealer. Provide a two-coat sealer application for finish treatment for treated railings where prolonged exposure is likely. Acceptable sealers include latex epoxy, urethane, shellac, or other finishes that are effective coating agents that adhere to treated rails.