A Self-Learning Manual - Institution of Engineers Mauritius

A Self-Learning Manual
Mastering Different Fields of Civil Engineering Works (VC-Q&A Method) Vincent T. H. CHU
for the majority of such phenomenon, it is due to fungus or algae growth on
concrete bridges. After rainfall, the bridge surface absorbs water and
retains it for a certain period of time. Hence, this provides a good habitat for
fungus or algae to grow. Moreover, atmospheric pollution and proximity of
plants provide nutrients for their growth. Improvement in drainage details
and application of painting and coating to bridges help to solve this
problem. Reference is made to Sandberg Consulting Engineers Report 18
25. Are there any problems associated with Integral Abutment Bridge?
(BS6)
Integral Abutment Bridges are bridges without expansion joints in bridge
deck. The superstructure is cast integrally with their superstructure. The
flexibility and stiffness of supports are designed to take up thermal and
braking loads.
The design of Integral Abutment Bridges is simple as it may be considered
as a continuous fame with a single horizontal member with two or more
vertical members. The main advantage of this bridge form is jointless
construction which saves the cost of installation and maintenance of
expansion joints and bearings. It also enhances better vehicular riding
quality. Moreover, uplift resistance at end span is increased because the
integral abutment serves as counterweight. As such, a shorter end span
could be achieved without the provision of holding down to expansion joints.
The overall design efficiency is increased too as the longitudinal and
transverse loads on superstructure are distributed over more supports.
However, there are potential problems regarding the settlement and
heaving of backfill in bridge abutment. For instance, “granular flow” occurs
in backfill materials and it is a form of on-going consolidation. Settlement of
backfill continues with daily temperature cycles and it does not stabilize.
Active failure of upper part of backfilling material also occurs with wall
rotations. This leads to backfill densification and can aggravate settlement
behind the abutment.
26. What are the functions of sleepers in railway?
The functions of sleepers [7] in railway works are as follows:
(i) The primary function of a sleeper is to grip the rail to gauge and to
distribute the rail loads to ballast with acceptable induced pressure.
(ii) The side functions of a sleeper include the avoidance of both
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