Based on standard test method ASTM C1550 for fibre reinforced concrete (FRC), a modified round panel test method for the material performance of FRC by measuring crack opening width is presented.

In the first four weeks after its opening, two years ago, 15 people were hurt while viewing Doris Salcedo's Shibboleth, a giant crack cut into the floor of the hall.

The sun's magnetic field near Earth has tipped south, opening a crack in Earth's magnetic defenses against the solar wind.