INTRODUCTION:
An expansion joint forms a load-bearing bridging of the joint gap between the abutment and the bridge, or between the single bridge sections. The INTERBUNA expansion joints are designed to provide continuity between two parts of a structure which are in relative movement because of thermal deformation, creep, shrinkage, rotation, vibration or breaking of seism’s. They are capable to support heavy and intensive traffic loads with maximum of comfort and minimum of noise. They permit a good protection of the structure against vibrations, water, salt and foreign bodies. Properly installed INTERBUNA expansion joint gives a good driving comfort with as low noise emission as possible is achieved for the passing traffic.
POSITION OF EXISTING GAP.
It has been conveyed through our Pakistan representative that existing bridge expansion joint was installed on heavy steel angle which is fixed on strong concrete block. The gap between two blocks is properly maintained 50mm. The concrete block is throughout on north and south bond of the bridge. The steel plates which are fixed on block have strengthened the base of expansion joint and it is not advisable to dismantle block and plates. Keeping in view these factors we are recommending as following.
DRAWING
We have mentioned placement , leveling , anchoring and side filling of expansion joint in below drawing.
RESOURCES.
Following equipment and manpower shall be required for the installation of expansion joints.
i. MANPOWER
(1) Supervisor
(2) Engineer
(3) Helpers
(4) Staff
ii. EQUIPMENT
(1) Asphalt Cutter
(2) Blower
(3) Air compressor
(4) Leveling Instrument
(5) Drilling Machine
(6) Steel Brush
PROCESS OF INSTALLATION OF NEW EXPANSION JOINT FOR EXISTING RAVI BRIDGE.
I. STRUCTURE’S LOCATION
Once the New EJN-100 Expansion joint to be install is determined, locate the expansion gap in the concrete deck and mark with chalk the axis of the joint gap, checking its length. Mark on the asphalt the position of the two cuts as to the centre of the centerline of the gap, at the distance marked on the plans.
II. ASPHALT CUT
Cut vertically the bituminous layer following the marked lines using an Asphalt cutter. The objective is to create a recess deep and wide enough to accommodate the EJN-100 expansion joint unit plus its level regulating screed and transition strips.
III. LEVELING OF BED AND HOLES ARRANGEMENT
The steel bed would be leveled properly with the help of leveling Epoxy. The marking of the expansion joint holes would be made properly. Drilling for bolt would be done and quick tightening epoxy would be half filled in the hole and bolts will be fixed in it.
IV. PLACEMENT OF JOINT
After complete leveling Expansion joint would be placed at holes arrangement which is made according to the requirement. After installation of EJN-100 Expansion joint level should be checked and it would be proper zero-zero with asphaltic layer
V. TIGHTENING OF ANCHOR BOLTS
After proper tightening of bolts nut along with washer will be applied on expansion joint and rubber caps would be fixed on it.
VI. OPENING TRAFFIC
With due consultation of engineers and taking complete precautionary measures open traffic.