Numerical methods can help build disaster resilience

The finite/discrete-element method (FDEM) involves the automatic computation of interacting bodies and is therefore inherently good at representing masonry and other nonhomogenised structures.

Challenging engineering problems need evolving numerical methods

The application FDEM is already well established for predicting the response of masonry structural systems and overall material behaviour of masonry bridges. More recently, this same technique has also been used to develop a retrofit system concept to improve disaster preparedness. This type of informed strengthening process can help make important structures safer in earthquake zones, and save lives.

Carl Brookes, Advanced Engineering and Geomatics Team Director at Ramboll says: “The use of FDEM has already led to a step change in the simulation capability of masonry bridges and, with verification provided by full-scale tests, has given engineers the confidence to take on challenging strengthening projects rather than more conventional but more costly replacement structures.”

Over 350 bridges have been investigated by Carl’s team ranging from small rural bridges in the UK to massive structures used by Indian Railways, resulting in significant economic and environmental benefits through their continued use.

Although there have been many arch bridge projects, few projects have been undertaken on the simulation of collapse mechanisms and energy absorption of masonry buildings exposed to earthquake loads.

This week, Carl will explain to delegates at the International Association for the Engineering Modelling, Analysis and Simulation Community (NAFEMS) how FDEM can be applied to predict failure of masonry structures.

The image below is a FDEM model of a 1000 foot high brick masonry tower, proposed in the latter part of the nineteenth century but never built. The simulation shows that the foundations would have failed and the tower would have collapsed. By correctly representing the contact interaction between the brick particles, as well as their compressive strength, a realistic simulation of the collapse mechanism was produced. Engineers at the time correctly rejected this proposal and favoured a far lighter and more efficient tower in iron which was eventually erected - by Eiffel.