Steelflex Strip Seal Expansion Joint Systems are steel retainer rails with mechanically locked elastomeric sealing element cast-in-place into expansion joint.
Answer: Friction occurs inside the support boxes. The support bars are held in place by the springs and bearings inside the support boxes, under pressure, resulting in friction between the support bar and sliding surface. It takes some force to overcome this friction force and open or close the joint.
A D-160 only has one set of springs and bearings inside the support box, so very little friction to overcome. A D-400, for example, has four sets of springs/bearings at each box location, and as a result has much more friction to overcome than the smaller D-160 joint.
Only one tool is needed for joint adjustment, but obviously, if you have more than one tool it could speed up the process. You should place the tool as close to a support box as possible, because this is where the friction is, and the closer to the box you get the more efficient it is. By slowly moving up and down the joint, you adjust the joint width to the desired opening at each box location. For bigger joints, a temperature adjustment device can be very beneficial and worthwhile. For more information, refer to the data sheet/brochure for the adjustment devices sold by D.S. Brown. https://dsbrown.com/wp-content/uploads/2020/12/B_EJS_Modular-Joint-Adjustment-Device_v011.pdf
Learn more about Expansion Joint Systems
Since the early 1960s The D.S. Brown Company has provided expansion joint systems and structural bearing assemblies for bridges around the globe. Bridge expansion joint systems are directly exposed to vehicular wheel loads and, therefore, must resist dynamic forces causing fatigue and wear. In addition, these expansion joint systems must remain watertight to protect the bridge superstructure and substructure from corrosion.
