Strip Seal Installation Procedure
- The TechStar strip seal joint will arrive either completely assembled or requiring a weld in the field. This is dependent upon the width of the roadway at the expansion joint location or if stage construction is required. If the modular expansion joint requires field splicing of sections to obtain the final overall dimensions, this must be done prior to installing the joint within the blockout. Please request information on the proper welding procedure.
- The strip seal joint should be thoroughly inspected to see if damage occurred during shipment.
- Install the gland (seal) into the joints at this time if possible. Otherwise wait until the joint is in the blockout to install gland, prior to setting the joint width.
- The edge retainer should be inspected for any foreign material such as concrete, mud, and other materials that would inhibit insertion of the neoprene seal. This material should be removed so the void in the retainer is completely void to accept the seal.
- The neoprene seal should be laid out alongside the joint opening and cleaned as well of foreign materials.
- Both the retainer void and seal dart should be adequately coated with a lubricant. TechStar recommends a detergent diluted in water as a good lubricant, however, lubricant adhesives can also be used.
- The seal should be folded along the ‘V’ and forced into the opening.
- The arrow dart of the seal should be aligned with the void opening in the retainer.
- Using a tire iron, the seal can be leveraged into the opening and forced into the void.
- Insert approximately 500 mm on one side and then reverse the procedure to insert the other side.
- Move steadily along the entire joint length trying not to stretch the seal as the installation proceeds across the roadway.
- Upon completion of the seal installation, all excess lubricant should be wiped from the joint area.
- The blockout should be inspected and cleaned of debris. The contractor should have reviewed the TechStar shop drawings.
- The contractor must decide upon the method of forming the expansion joint opening. If wood is selected the joint can be placed into the blockout, leveled to the exact grade of the roadway surface, closed or opened to the proper width and secured to each side of the blockout, either by welding to the existing reinforcing steel or by placing dowels into the blockout and welding the dowels to the back side of the support bar boxes.
- If the contractor wishes to use steel plates as the permanent formwork (skirting—bulkhead plates), the joint should be turned upside down on the bridge deck and a minimum 1/16” (2 mm) plate should be attached (screwed to welded straps welded to the edge beam). The depth of the plate should extend to the bottom of the blockout. The plate should be welded to the inside face of the edge beam. The thicker plate will not bend and the joint can be supported by the plates in the bottom of the blockout.
- Once the joint is placed in the blockout, the joint must be jacked to the correct grade and opened or compressed to the proper joint setting width. The width per cell should be determined by the engineer in charge of the project. TechStar is not responsible for the openings per cell.
- The best procedure for closing the joint is to compress the joint by use small “power pod” hydraulic jacks applied to the back of the boxes (wood shims), the opposite box should be blocked against the concrete blockout face to provide resistance from the entire joint shifting. If both the top and bottom surfaces are compressed evenly the edge beams will not rotate out of position. Commence at one end of the joint and continue evenly across the roadway, box location by box location until the joint is properly positioned to the correct dimension (thermal and permanent movement).
- It is not advisable to weld across the top surface. This can cause a change in the characteristic of the steel beam and leave a stress point at a position where a crack could be induced. Once joint is in the proper location, and is properly set for the temperature, creep and shrinkage, the remainder of the reinforcing steel can be inserted. Remember to consider the “permanent movement” still in the structure
- After all reinforcing steel is in place, the top surface of the joint should be protected. This can be accomplished by placing plywood or plastic across the top. This can also be accomplished with duct tape. In some cases the neoprene seal can be protected by placing sand in the void.
- If the seals have not been installed to this point, the contractor must take extreme care to avoid concrete being placed into the groove where the seal locks into the edge beam. This area must be sealed with tape.
- The concrete (or asphalt) must be poured to the exact level surface of the roadway to assure a smooth transition between the roadway and the joint.
- If the neoprene glands (seals) need to be installed, the center beams of the modular expansion joint can be shifted (jacked) to one side and then the other to permit the installation. This should only be performed once the concrete has firmly set. Installing the neoprene glands prior to closing down the joint greatly eases the gland insertion process.