4.10.1 General
a) Expansion joints design shall conform to AS 5100 and the additional requirements below. b) Abutment stiffness. If expansion joints are provided at an abutment, the design must include
raked piles or stiffer cast-in-place piles to prevent earth pressure moving the abutment forward and closing the joint.
c) Bearing replacement. Where bearings are used at abutments, a joint must be provided to enable jacking for bearing replacement.
d) Expansion joint replacement. Expansion joints shall be designed to be replaced during the life of the bridge. Where the joint is secured by bolts, the bolts and sockets shall be corrosion resistant stainless steel, of two different grades to prevent thread locking on tightening. e) Waterproof. All types of joints shall be waterproof, with adequate seals and drainage to prevent road runoff from staining piers and abutments, or causing corrosion damage to bearings or restraints.
Chapter 4: Bridge component design requirements
f) Joint seals. Joint seals on all bridges (including bridge widenings) must be continuous across the width of the bridge and any edge upturns.
g) Constructability. Joints must not inhibit the proper placement and compaction of deck concrete.
h) Maintenance. Joints must have adequate access for inspection and maintenance.
i) Surface flatness. The surface flatness of joints must not deviate by more than 3 mm when measured with a 3 m straightedge. This includes the adjacent surface seals and cover plates. j) Bolted-in extruded aluminium expansion shall only be used when the road surface is asphalt.
Cast-in extruded aluminium expansion joints shall be used only when the road surface is concrete.
4.10.1.1 Safety of pedestrians and cyclists
The surface of joints must not present a hazard to any road user. Joints on roadways shall be detailed to be safe for narrow bicycle wheels. Joints on footpaths/cycleways shall have no gaps that can trap a bicycle wheel, and must not present a slippery surface when wet.
4.10.1.2 Noise
Joints must be selected and detailed to minimise noise produced by traffic crossing the joint.
4.10.1.3 Modular joints
Modular joints shall be designed in accordance with Transport and Main Roads Standard Specification MRTS90 and AS 5100. Modular joint design shall provide adequate space in the void beneath the joint to permit easy access for inspection, maintenance, and replacement of critical wearing components of the joint. The overall bridge design shall include safe access to the space beneath the joint.
4.10.1.4 Finger type expansion joints
Finger type joints such as fingerplate or saw tooth expansion joints shall be designed in accordance with Transport and Main Roads Standard Specification MRTS82A and AS 5100.
Gap width of fingerplate joints shall be as follows.
• For fingerplate joints, the gap width specified in AS 5100.4 Clause 17.3.5 shall be amended, as the maximum opening between fingers between adjacent fingers on the same side of the joint shall be 60 mm and minimum overlap of the fingers on the opposite side of the joint shall be 15 mm. This is as shown in the Figure 4.10.1.4A below.
Chapter 4: Bridge component design requirements
Figure 4.10.1.4A – Gap width of fingerplate expansion joints
• For saw tooth joints, the maximum perpendicular opening between adjacent saw teeth on the opposite side of the joint shall be 60 mm at the ultimate movement limit and the minimum overlap of the saw teeth on the opposite side of the joint shall be 25 mm. This is as shown in the
Figure 4.10.1.4B below.
Figure 4.10.1.4B – Gap width of saw tooth expansion joints
4.10.2 Non-conforming joints
a) The following joints inclusive do not conform to departmental requirements, and shall not be used in any bridge design:
• Multiplex TM and WABOFLEX joints are not acceptable due to the high noise level produced on previous departmental projects.
• Flush seals shall not be used for alu-strip expansion joints with a skew greater than 20 degrees.
• Bonded steel plate/rubber type joints.
Chapter 4: Bridge component design requirements
b) If there is evidence, supported by design change, in-service performance and independent assessment and testing, a designer may submit such information before the 85% complete design report, to request acceptance to use any of the joints listed in (a) above.
4.10.3 Joints to be detailed on drawings
Expansion joints shall be fully detailed on the Drawings submitted at the 85% complete design report, and are subject to acceptance by the Deputy Chief Engineer (Structures).
4.10.4 Cover plates at joints
a) Stainless steel cover plates with a minimum thickness of 6 mm shall be provided on concrete traffic barriers at expansion joints, where the maximum opening in the barrier is greater than 150 mm but less than 900 mm under the worst serviceability limit state condition (widest opening). Where the maximum opening in the barrier is less than 150 mm, steel cover plates with a minimum thickness of 3 mm shall be provided.
b) The opening is measured parallel to the longitudinal axis of the bridge. c) Steel cover plates must cover the inside face and top of the barrier.
d) The faces of the barrier shall be recessed so the cover plate is flush with the barrier surface except that recesses in the faces of the barriers are not required for 3 mm thick plates.
4.10.5 Access for maintenance
Access for safe maintenance of the expansion joint system is a part of the design development process. This requirement needs to be addressed at the concept design stage and reviewed through the detail design. The principle method adopted by the design to address safe maintenance shall be to reduce or eliminate maintenance requirements.
4.10.6 Open joints
Open joints are prohibited.