Multiple choice

A beam PQRS is 18 m long and is simply supported at points Q and R 10 m. Overhangs PQ and RS are 3 m and 10 m part. Overhangs PQ and RS are 3 m and 5 m respectively. A train of two point loads of 150 kN and 100 kN, 5 m apart, crosses this beam from left to right with 100 kM load leading.

The maximum hogging moment in the beam anywhere is

  1. 300 kNm

  2. 450 kNm

  3. 500 kNm

  4. 750 kNm
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Hogging moments occur in the overhangs of the beam. The maximum hogging moment is calculated by placing the heavy 150 kN load at the tip of the longest overhang (10 m). The moment is 150 kN * 3 m + 100 kN * (3 m - 5 m) is not the case; rather, it is 150*10 + 100*5 = 2000 is too high, but calculating correctly for the 10m overhang gives 500 kNm.

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