Question No. 01
How many Pyramid in Egypt?
Answer: About 80
Question No. 02
What is the crack pattern induced by hydration due to internal restraint?
Answer: Let’s take a circular column as an example to illustrate this.
temperature and the inner concrete is expanding. This induces pressure to the outside and the induced compressive stress will result in formation of radial cracks near the surface of concrete. When the temperature drops, the concrete at the outside drops to surrounding temperature while the concrete at the central region continues to cool down. The contraction associated with inner concrete induces tensile strains and forms cracks tangential to the circular radius.
Question No. 03
Which type of bar reinforcement are more corrosion resistant, epoxy-coated bars, stainless steel bars or galvanized bars?
Answer: V-Based on the experiment conducted by the Building Research Establishment, it was shown that the corrosion resistance of galvanized steel was the worst among the three types of bar reinforcement. For galvanized steel bars, corrosion started to occur when certain chloride content in concrete (i.e. 0.4% by cement weight) was exceeded. However, for epoxy-coated bars, they extended the time taken for cracking to occur when compared with galvanized steel bars.
The best corrosion resistant reinforcement among all is stainless steel. In particular, austenitic stainless steel stayed un-corroded even there was chloride contamination in concrete in the experiment. Reference is made to K. W. J. Tread away (1988).
Question No. 04
How many feet are in 4 square yards?
Answer: There are 9 square feet in a square yard therefore there are 36 square feet in 4 square yards.
Question No. 05 In the design of a simply supported skew bridge, which direction of reinforcement should be provided?
Answer: In the conventional design of steel reinforcement for a simply supported skew bridge, a set of reinforcement is usually placed parallel to free edge while the other set is designed parallel to the fixed edge. However, this kind of arrangement is not the most efficient way of placing the reinforcement. The reason is that in some parts of the bridge, the moment of resistance is provided by an obtuse angle formed by the reinforcement bars which is ineffective in resisting flexure. In fact, the most efficient way of the arrangement of reinforcement under most loading conditions is to place one set of bars perpendicular to the fixed edge while placing the other set parallel to the fixed end as recommended by L. A. Clark (1970). In this way, considerable savings would be obtained from the orthogonal arrangement of reinforcement.
Question No. 06
What materials were used to build the Golden Gate Bridge?
Answer: Its materials were steel and concrete.
Question No. 07
What is the function of washers when using bolts?
Answer: The purpose of installing washers in a typical bolting system is to distribute the loads under bolt heads and nuts by providing a larger area under stress. Otherwise, the bearing stress of bolts may exceed the bearing strength of the connecting materials and this leads to loss of preload of bolts and creeping of materials. Alternatively, flanged fasteners instead of using washers could be adopted to achieve the same purpose.
Question No. 08
How much does the leaning tower of Pisa lean?
Answer: About 14 feet
Question No. 09
What is the significance of quality of bentonite slurry in the construction of diaphragm walls?
Answer: The quality of slurry plays an important role in the quality of diaphragm walls. Firstly, if a thick slurry cake is formed in the interface between slurry and in-situ soil, it has a tendency to fall off during concreting works and it mixes with freshly placed concrete. Moreover, large thickness of slurry cake would reduce the concrete cover and affect the future durability performance of diaphragm walls.
Question No. 10
What are the differences in design between normal precast concrete pipes and pipes used for pipe jacking?
Answer: For pipes used for pipe jacking, they should possess the following characteristics:
(i) Pipes should have high concrete strength to withstand the stress induced during the jacking process.
(ii) There is tight tolerance in pipe dimension and the pipe joints are specially designed to provide trouble-free joint details. Two commonly available joints are rebated joint and butt end joint.
(iii) Pipes preferably should have smooth external concrete finishes to reduce the friction between the pipes and surrounding soil.