what is the different betweem expansion and construction joints

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what is the different betweem expansion and construction joints..

Answer / amirthalingam from ariyalur

Expansion ( Isolation) Joints:
Joint provided to take care of weathering effect & uneven
settlement in the building. Both vertical movement &
Horizontal movementIt Helps to minimize the cracks in the
building.

Construction joints:
Construction joints provided at the end of day in
a concreting where the concreting is not able to complete
in the same day. The joint provided normally 1/3rd from the
completed side span of the building (Beams, Slabs). Columns
does not require construction joints. Construction joints
is the joint between two successive placement of concrete.

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what is the different betweem expansion and construction joints..

Answer / harshal.s.khode

Construction joints . Construction joints are provided to
separate the areas of concrete placed at different times,
and may be
either longitudinal or transverse, as required .
(1) The spacing of longitudinal construction joints will
depend largely on the paving equipment . With most present-
day equipment, paving lanes 24 feet or more in width are
possible and may be used . Determination of the width of
paving lane to be used, that is, whether a 24-foot-wide
road or street should be paved in a single lane or in
two 12-foot-wide lanes, is left to the judgment of the
designer .
(2) When a longitudinal construction joint is used at the
center of two-lane pavements, a keyed joint with tie bars
similar to those required for longitudinal contraction
joints, or threaded split 5/8-inch tie bolt, should be
used . When a longitudinal construction joint is used at
the center of pavements having four or more paving
lanes, a doweled joint should be used .
(3) Transverse construction joints should be installed at
the end of each day's paving operation, and at other points
within a paving lane where the placing of concrete is
discontinued a sufficient length of time for the concrete
to start to set . All transverse construction joints in
nonreinforced rigid pavements should be of the doweled type,
and should be located in place of other regularly spaced
transverse joints . When paving is resumed, the regular
transverse joint construction should be used, beginning
with the first regularly Scheduled transverse joint . When
a transverse construction joint is required within a slab
in a reinforced rigid pavement, the reinforcing
steel should be carried through the joint and tie bars
added .
Expansion joints . Expansion joints are provided for the
relief of forces resulting from thermal expansion of the
pavement, and to permit unrestrained differential
horizontal movement of adjoining pavements and/or
structures . There are two types of expansion joints,
doweled and thickened-edge, both of which should be
provided with a nonextruding type filler metal . Usually a
preformed filler 3/4-inch thick will be adequate . The
expansion joint should be so designed as to provide a
complete and uniform separation between the rigid
pavements or between the rigid pavement and the structure
concerned .
1) Doweled expansion joints should be used for all
transverseexpansion joints within rigid pavements except at
the intersections of rigid pavements with structures or
with other rigid pavements . The designer is cautioned that
expansion joints within rigid pavements are difficult to
construct and maintain, and often contribute to pavement
failures . For these reasons, their use should be kept to
the absolute minimum necessary to prevent excessive
stresses or distortion in the pavement . Internal expansion
joints should be omitted in all rigid pavements 8 inches or
more in thickness, and also in pavements less than 8 inches
thick when the concrete is placed during warm weather .