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Load
dispersion profile of block layer in interlocking
concrete block pavement
B.C.
Panda
The
top layer of Concrete Block Pavement (CBP) is discrete
and discontinuous in nature. It is too complex to
incorporate the discontinuities (joints) in the structural
modelling of the block layer. But the design method
can be made simple and similar to flexible pavement
by removing block layer in the analysis and placing
equivalent reduced traffic load intensity spread over
a larger area directly on the base course. Plate load
tests have been carried out to quantify the ability
of block pavers to distribute vertical load. The test
pavements were studied under an applied load of 51
kN. Five shapes and three block thicknesses were used
in the investigation. The horizontal spread and vertical
profile of external load were found out by pressure
cells positioned on top of the base course.
Physical
and mechanical properties of high strength semi-light
weight concrete
Tian Yaogang,
Hu Shugang and Ding Qingjun
The
effect of aggregate composition, the maximum particle
size of lightweight aggregate, mineral admixture and
the volume percentage of sand on high strength semi-lightweight
concrete is investigated. The effects on compressive
strength, splitting tensile strength, modulus of elasticity
and dry apparent specific gravity are reported. Test
results show that aggregate composition affects both
physical and mechanical properties of semi-lightweight
concrete. Reducing the maximum particle size of lightweight
aggregate or introducing mineral admixture can improve
its compressive strength and splitting tensile strength
but these changes have negligible effect on its dry
apparent specific gravity.
Seismic
vulnerability of flat plate column joint
Manohar B.
and A.R. Santha Kumar
A
brittle punching shear failure can arise in flat plate-column
connections during an earthquake because of poor transfer
capacity of shearing forces and unbalanced moments.
To increase the shear capacity of the slab therefore,
various types of shear reinforcement are used around
such connections. This paper presents the response
of slab column connections containing various types
of slab shear reinforcement when subjected to combined
gravity and cyclic lateral loading predicted by a
Finite Element analysis program MASA. First, a calibration
model was developed in MASA to simulate the tested
flat plate-column joint. Then, finite element models
of a flat plate-column joint with various types of
slab shear reinforcement were developed. The presence
of shear reinforcement significantly improves ductility,
energy dissipation and drift capacity of the connection
under the applied lateral cyclic loading. As a result,
slab shear reinforcement, in the form of lacing bars
is proposed in this paper. The simplicity of placement
of this type reinforcement makes it an attractive
alternative to single-leg and stud shear reinforcement.
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