The world's first bridges were created by nature—as simple as a log fallen across a stream. The first bridges made by humans were most likely spans of wooden logs, planks and stones. But the failure of most early bridges to support heavy loads or withstand strong currents encouraged the development of better crossings. For centuries, humankind has searched for improved bridges: the ancient Romans built arch bridges and aqueducts using stone and cement; the Chinese constructed imaginative wood and stone structures during the Sui Dynasty; and rope bridges, a simple type of suspension bridge, were used by the Incas. During the 18th century, a number of innovations in the design of timber bridges were developed by Hans Ulrich, Johannes Grubenmann and others. With the Industrial Revolution of the 19th century, truss systems of wrought iron were developed for larger crossings, and, with the advent of steel and reinforced concrete, innovative pioneers like John A. Roebling, Gustav Lindenthal and Othmar Ammann could design even larger bridges.

Today, bridge designs vary depending on the function of the bridge and the nature of the terrain. Currently, there are six main types of bridges: steel girder, segmental concrete, arch, suspension, cable-stayed and truss. However, because the structural design of bridges is rapidly evolving, engineers must adapt the latest state-of-the-art technology in order to provide clients throughout the world with the most appropriate and cost-effective solutions. Moreover, because each structure is unique, engineers must also address a number of concerns when designing a bridge, including aesthetics, the environment and client needs.

Bridges have long been an important element of the Berger Group's practice. Our structural engineers provide a comprehensive range of services for the planning and design of new bridges, as well as the rehabilitation, demolition and replacement of older structures. In 2007, the Berger Group ranked first among international design firms in bridges. With a distinguished record of award-winning designs and widely recognized for their innovative contributions to the practice, the Group's projects have ranged from imaginative pedestrian bridges to large, state-of-the-art structures.

In this issue of BergerWorld, we proudly present a number of our most exciting and diverse structural engineering accomplishments.