Question

1. You are told to design an unreinforced concrete bridge such that the likelihood of the

pillars failing in compression is 1 out of 10,000. You test 100 concrete compression

samples, the same size as your beam, and find that the Weibull modulus is 3.4 and the

characteristic strength is 30.7 MPa.

a) What diameter pillar should you design if each pillar must support 200 metric tons of

load (note 1 metric ton = 1000 kg, 1 kg =9.8 N)?

b) Suggest a good method for strengthening concrete used in pillars.

Answer 1