Bridge Engineering MCQ with answer and solution

Concept

Minimum vehicle spacing in 70-R loading

Formula

NONE

Step-by-step solution

1. IRC Class 70R loading represents heavy tracked or wheeled vehicles used for bridge design. 2. To avoid excessive simultaneous live loading on bridge spans, minimum clearance distance rules are specified between vehicles. 3. Standard IRC guidelines mandate a minimum nose-to-tail spacing of 30 m between successive 70R vehicles. Answer: A

Explanation

IRC 70-R loading specifies heavy vehicle live loads used for designing highway bridge structures. To prevent multiple heavy vehicles from simultaneously concentration-loading a single bridge span, IRC rules mandate a minimum gap of 30 meters between consecutive vehicles. Thus, 30 m is the required spacing.

Why the other options are wrong

B) 40 m exceeds the minimum required vehicle spacing of 30 m specified for Class 70R loading. C) 60 m is significantly greater than the 30 m minimum spacing required by IRC standards. D) 70 m is incorrect and exceeds the IRC spacing requirement.

Shortcut

Class 70-R vehicle loading requires a minimum vehicle spacing of 30 m.

Common mistake

Confusing the minimum spacing between vehicles for IRC 70R loading (30 m) with larger vehicle lengths or clearances.