The allowable procedures for the repair of metalized and galvanized surfaces are described in C&MS Item 711.02, which refers the reader to ASTM-A-780. The use of a galvanizing spray with zinc dust is not allowed. These unacceptable products go by the name of Spray Galv or Cold Galv. The main problem with these products is that they don’t provide the galvanic protection that is required. Most of them are made out of tin and lead in place of zinc. When zinc and carbon steel are in contact, the zinc sacrifices itself to protect the steel. Conversely, when tin or lead are in contact with the steel, the steel sacrifices itself for the tin and lead.
It is important that the gap set between the armor plates of the joint be consistent along the entire length of the joint. The gap determined for the joint must be adjusted for temperature. The joint manufacturer will supply a table to help calculate this adjustment. This is especially true for more complex joints.
The characteristics of the structure (e.g., skew, crown, super elevation, sidewalk, etc.) can lead to a complicated installation of the joints. The Contractor should not weld anything to the joint or the reinforcing steel.
Joints, like strip seal, compression, and modular, which incorporate a rubber seal into their design, need to have the seals installed per the manufacturer’s written instructions. They should utilize tools that will not cut or puncture the seals. It is not acceptable to elongate or stretch the seal in order to make it narrow enough to fit in the joint gap.
For Integral and Semi-Integral Abutment Expansion Joint Seals, the Contractor must install a 3-foot wide neoprene sheet for waterproofing the backside of the joint between the integral backwall and the bridge seat at locations shown in the plans. The neoprene sheeting is secured to the concrete with 1-1/4 inch by No. 10 gauge (length × shank diameter) galvanized button head spikes through a 1-inch outside diameter, No. 10 gauge galvanized washer. Maximum fastener spacing is 9 inches. Use of other similar galvanized devices, which will not damage the neoprene or the concrete, will be subject to the approval of the Engineer. The neoprene sheeting shall be 3/32-inch thick general purpose, heavy-duty neoprene sheet with nylon fabric reinforcement.
In addition to the protection required in the specification, the Contractor must ensure that the sawcut is not exposed to traffic prior to receiving the sealer without protecting the sawcut. If the sawcuts are not protected, rocks or other hard debris can get lodged in the top of the sawcut, and when driven over the rock, will spall the edges of the sawcut.
Note: If the beam seats are low and elastomeric bearings are utilized, it is not acceptable to use steel shims under the bearing to make up the elevation difference. Elastomeric bearing pads are to set directly on the concrete surface. If the beams seats are sealed with an epoxy or non-epoxy sealer prior to setting the bearings, do not apply sealer to the concrete surfaces under the proposed bearing locations. If these locations are sealed, the Contractor must remove the sealer to the satisfaction of the Engineer before setting the bearings. Contact the Office of Structural Engineering for guidance. Many of the bearings have beveled load plates. This is done to account for the grade in the structure. Make sure the beveled bearings are oriented correctly. Sometimes it is difficult to tell simply by looking at the bearing, as the difference may only be a 1/4 inch. If the short side of the bearing is not already marked by the fabricator, measure the bearing and mark it in the field.
The Contractor must position rockers, elastomeric bearings, and rollers so that, when the completed bridge is at 60 °F (16 °C), the rockers and elastomeric bearings are vertical and the rollers are centered on the base. If the steel is erected at an ambient temperature higher than 80 °F or lower than 40 ºF and the bearing shear deflection exceeds 1/6 of the bearing height at 60 ºF ± 10 ºF, the Contractor must raise the beams or girders to allow the elastomeric bearings to return to their undeformed shape at 60 ºF ± 10 ºF.
Where the load plate of an elastomeric bearing is to be connected to the structure by welding, the Contractor must control the welding so that the plate temperature at the elastomer bonded surface does not exceed 300 °F as determined by use of pyrometric sticks or other temperature monitoring devices.
When galvanized bearings are welded to the embedded load plates on prestressed beams, the weld area must be repaired according to C&MS Item 516.03.
1. Expansion and Contraction Joints.
b. Shop drawings per C&MS 501.04.
c. Test Reports per 501.06.
2. Joint Sealer.
a. Area to be sealed clean and dry.
b. Document depth of poured joints.
c. Note types of bond breakers and bonding agents used.
d. Sealers applied per manufacturer’s directions.
e. Measure and pay in appropriate unit.
3. Bearing devices.
a. Shop drawings per C&MS 501.04.
b. Test Reports per 501.06.
c. Sliding plates lubricated with flake graphite.
d. Lead sheets and bearing pads set to line and level.
e. Rockers and rollers set vertical at 60 °F (16 °C) or adjusted for temperature.
f. Anchor bolts placed to proper depth and alignment and set in mortar.
g. Record quantity(s) and pay in appropriate unit(s) per C&MS 516.09.