Consider a balanced doubly-reinforced concrete section. If the material and other sectional properties remain unchanged, for which of the following cases will the section becomes under-reinforced?

An inverted T-shaped concrete beam (B1) in the figure, with centroidal axis X – X, is subjected to an effective prestressing force of 1000 kN acting at the bottom kern point of the beam cross-section. Also, consider an identical concrete beam (B2) with the same grade of concrete but without any prestressing force.

The additional cracking moment (in kN.m) that can be carried by beam B1 in comparison to beam B2 is ________ (rounded off to the nearest integer).

The initial cost of an equipment is Rs. 1,00,000. Its salvage value at the end of accounting life of 5 years is Rs. 10,000. The difference in depreciation (in Rs.) computed using ‘double-declining balance method’ and ‘straight line method’ of depreciation in Year-2 is ___________ (in positive integer).

A slab panel with an effective depth of 250 mm is reinforced with 0.2% main reinforcement using 8 mm diameter steel bars. The uniform center-to-center spacing (in mm) at which the 8 mm diameter bars are placed in the slab panel is __________ (rounded off to the nearest integer).