The advantage of cable-stayed bridges lies in the fact that it can be built with any number of towers but for suspension bridges it is normally limited to two towers.

With span length less than 1,000m, suspension bridges require more cables than cable-stayed bridges. Moreover, cable-stayed bridges possess higher stiffness and display smaller deflections when compared with suspension bridges. Generally speaking, the construction time is longer for suspension bridges.

This question is taken from book named – A Self Learning Manual – Mastering Different Fields of Civil Engineering Works (VC-Q-A-Method) by Vincent T. H. CHU.

The functions of sleepers 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 longitudinal and lateral track movement.

(iii) It also helps to enhance correct line and level of the rails.

This question is taken from book named – A Self Learning Manual – Mastering Different Fields of Civil Engineering Works (VC-Q-A-Method) by Vincent T. H. CHU.

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.

This question is taken from book named – A Self Learning Manual – Mastering Different Fields of Civil Engineering Works (VC-Q-A-Method) by Vincent T. H. CHU.

In some cases, it may be due to the accumulation of dust and dirt. However, 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

This question is taken from book named – A Self Learning Manual – Mastering Different Fields of Civil Engineering Works (VC-Q-A-Method) by Vincent T. H. CHU.

For a bridge abutment to be supported on raking piles with different orientations, the movement between the ground and the pile group is difficult to predict. For instance, if some of the raking piles of the bridge abutment are extended beneath an embankment, then the settlement of embankment behind the abutment may cause the raking piles to experience severe bending moment and damage the piles as recommended by Dr. Edmund C Hambly (1979).

This question is taken from book named – A Self Learning Manual – Mastering Different Fields of Civil Engineering Works (VC-Q-A-Method) by Vincent T. H. CHU.