The existing exercise in Bangladesh for erection of girders is putting the girder without delay on the bearing pad and joining the adjacent two spans in deck slab degree by way of adopting expansion joints, because the bridges are presently designed as surely-supported beam bridge. the principle drawback of this form of bridges is that, the seismic resistance is weak, and underneath the outside pressure past the layout range, the bridges are more likely to fall in chance because of failure in girders. also they’ve growth joints for each span, which influences the comfort of riding and the general integrity of the bridge deck is bad [1]. therefore, layout and creation of the bridges were revised to set up continuity between girders of two adjoining spans and rework the bridge as honestly supported non-stop beam bridge [2]. brief bearing (sandbox) approach is proposed on this paper to remedy the machine transformation of continuous beam bridges. layout of the temporary bearing is very simple and can be synthetic at website online. This method has been proved in construction of Arial Kha Bridge and can be carried out for different comparable bridges in Bangladesh.
production of continuous girder bridge is finished with the aid of launching the girders as simply supported span and the girders of adjacent spans are made non-stop through casting the girder cease joint section on pier pinnacle. To cast the end joint at website, the girders of adjacent two spans need to be positioned at their preferred function against the everlasting bearing pad with the help of brief assist. After gaining the target strength at the “cast-in-situ” girder joint Beam Bridge segment, and after final touch of stressing and grouting for bad second tendons, transient bearing is released and the girder is located on the permanent bearing pad [3] . The overall performance of temporary bearings in this method is important. transient bearings have to have enough power, pressure, stability and simplicity of disassembly. when the brief bearing is removed, the beam frame can be uniformly and stably positioned at the constant bearing pad. the use of this technique, construction of the bridge could be very smooth and fast compared to the present practice which has been proved in production of Arial Kha Bridge.
temporary bearing commonly includes two hollow cylindrical frame connected with a base plate at the bottom. design of the bearing is quite simple and it’s far based on trial and mistakes technique. Following criteria are considered at some stage in design of the bearings.
1) Weight of the girder: This weight includes the self-weight of one girder and weight of another girder in an effort to be carried over the girder after setting.
2) No of transient bearings for one girder: range of transient bearing at each Beam Bridge give up beneath the girder is taken considering the overall load on the bearing and potential of each bearing.
three) size of every bearing: length of different elements of transient bearing is decided considering the followings.
4) Cylindrical frame: Diameter of the cylindrical body is chosen thinking about the bottom unfastened area on pier pinnacle against the fixed bearing pad and loose area in the Compressive strength trying out machine with a purpose to be used for testing capability of the bearings. height of the body is chosen thinking about the adjustable height and elevation of the constant bearing pad at special location.
5) Thickness of the metallic plates: Thickness of the steel plates for cylindrical frame and base plate is determined through trial and blunders technique considering the entire design load on a single temporary bearing.
Cylindrical body is attached with the bottom plate by means of non-stop welding at both sides of the cylindrical metal body.
6) For Arial Kha bridge, the transient bearings were designed thinking about the subsequent records:
a) Weight of each girder = two hundred heaps and two brief bearings had been taken at each cease underneath the girder. consequently, total load on every temporary bearing = 2002×2+2002×2 = one hundred heaps thinking about weight of girder launcher device and adding a Beam Bridge few component of safety, overall load on every bearing changed into taken as 120 tons = 1200 kN.
b) Thickness of the steel plate become selected by means of trial technique the use of the compressive strength check for the design load at the bearing. For bottom cylindrical frame, thickness of the metallic plate became selected as 10 mm and for top it turned into taken as five mm. in addition thickness of the bottom plate became taken as 5 mm.
c) The outer diameter of the cylindrical frame changed into taken as 2 hundred mm for the bottom cylinder and for top cylinder, it become taken as 240 mm thinking about the bottom loose area on pier pinnacle against the fixed bearing pad and unfastened area within the compressive power testing device. size of the bottom plate was taken as three hundred × three hundred mm for both top and bottom cylinder.
The specific size of transient bearing used at Arial Kha Bridge is proven in figure 1.
production of continuous girder bridge is finished with the aid of launching the girders as simply supported span and the girders of adjacent spans are made non-stop through casting the girder cease joint section on pier pinnacle. To cast the end joint at website, the girders of adjacent two spans need to be positioned at their preferred function against the everlasting bearing pad with the help of brief assist. After gaining the target strength at the “cast-in-situ” girder joint Beam Bridge segment, and after final touch of stressing and grouting for bad second tendons, transient bearing is released and the girder is located on the permanent bearing pad [3] . The overall performance of temporary bearings in this method is important. transient bearings have to have enough power, pressure, stability and simplicity of disassembly. when the brief bearing is removed, the beam frame can be uniformly and stably positioned at the constant bearing pad. the use of this technique, construction of the bridge could be very smooth and fast compared to the present practice which has been proved in production of Arial Kha Bridge.
temporary bearing commonly includes two hollow cylindrical frame connected with a base plate at the bottom. design of the bearing is quite simple and it’s far based on trial and mistakes technique. Following criteria are considered at some stage in design of the bearings.
1) Weight of the girder: This weight includes the self-weight of one girder and weight of another girder in an effort to be carried over the girder after setting.
2) No of transient bearings for one girder: range of transient bearing at each Beam Bridge give up beneath the girder is taken considering the overall load on the bearing and potential of each bearing.
three) size of every bearing: length of different elements of transient bearing is decided considering the followings.
4) Cylindrical frame: Diameter of the cylindrical body is chosen thinking about the bottom unfastened area on pier pinnacle against the fixed bearing pad and loose area in the Compressive strength trying out machine with a purpose to be used for testing capability of the bearings. height of the body is chosen thinking about the adjustable height and elevation of the constant bearing pad at special location.
5) Thickness of the metallic plates: Thickness of the steel plates for cylindrical frame and base plate is determined through trial and blunders technique considering the entire design load on a single temporary bearing.
Cylindrical body is attached with the bottom plate by means of non-stop welding at both sides of the cylindrical metal body.
6) For Arial Kha bridge, the transient bearings were designed thinking about the subsequent records:
a) Weight of each girder = two hundred heaps and two brief bearings had been taken at each cease underneath the girder. consequently, total load on every temporary bearing = 2002×2+2002×2 = one hundred heaps thinking about weight of girder launcher device and adding a Beam Bridge few component of safety, overall load on every bearing changed into taken as 120 tons = 1200 kN.
b) Thickness of the steel plate become selected by means of trial technique the use of the compressive strength check for the design load at the bearing. For bottom cylindrical frame, thickness of the metallic plate became selected as 10 mm and for top it turned into taken as five mm. in addition thickness of the bottom plate became taken as 5 mm.
c) The outer diameter of the cylindrical frame changed into taken as 2 hundred mm for the bottom cylinder and for top cylinder, it become taken as 240 mm thinking about the bottom loose area on pier pinnacle against the fixed bearing pad and unfastened area within the compressive power testing device. size of the bottom plate was taken as three hundred × three hundred mm for both top and bottom cylinder.
The specific size of transient bearing used at Arial Kha Bridge is proven in figure 1.