Bridge Construction - Design Considerations and Materials

Bridges have been constructed since ancient times. Simple bridges constructed from felled trees have been improved upon modern ones constructed by the modern light and strong materials. The latest computer technologies have significantly facilitated bridge design and bridge construction.

History Of Bridges

Bridge study has revealed that people have been carrying out bridge construction since humans first assembled into groups. The initial bridge design was basically felled trees that were utilized for moving over the ditches and rivers, and concrete bridges were rare. With the advance of civilization, techniques were discovered to use rocks, stones, mortar, and other materials for the creation of stronger and extended bridges. Subsequently, as the engineers and physicists advanced in the design, materials, and construction technology, modern materials like steel and aluminum were introduced for bridges.

Bridge Construction During 20th Century

The bridge construction skills progressed rapidly during the 20th century. At the end of the century, new techniques were developed that improved the design, strength, and durability of the bridges. Steel bridges were strongly riveted instead of the previous practice of using bolts. Concrete bridges were being cast at the desired place, instead of being precast. Huge bridge elements made from bars and small sections were used, and not rolled as one part. Before the 1980s, the majority of bridge designs included expansion joints for decks, including expansion and fixed support bearings. This technique was used to permit structural expansion and contraction. However, the expansion joints are likely to be filled with debris, and bearings often weaken over time. Thus, the structure is hardened, and maintenance requirements are increased. The bridge engineers explored methods to reduce this trouble, and finally the expansion joints and bearings were eliminated to develop a joint-less bridge. This type of bridge is constructed on a flexible foundation that may expand or contract with negligible trouble.

Modern Bridge Construction Techniques

New technologies are expected to meet the challenging and varying requirements, and also offer options that will guide to innovative engineering and bridge construction standards. With the beginning of the new century, bridge construction is being revolutionized. Modern construction methods and the latest advanced materials are being evolved. Construction technologies like post tensioning, reinforced ground walls, and soil freezing are being developed. Modern surveying techniques are being used that have facilitated the soil selection, and other design parameters, through the use of optical and infrared technology. Progress in the deck technology is creating lighter and stronger decks. Bearings, joints, and seismic elements have become more effective since advanced testing facilities have been introduced. Consistent, economical, fast, and programmed inspection systems will emerge.

New Bridge Construction Materials

Materials with improved characteristics will be used that will make the bridge construction safe, durable, and reliable. Materials like high-performance concretes, polymer concretes, and plastics will be utilized. As the fiber reinforced composites are becoming more tolerant towards temperature, they will be used extensively for bridge construction. Use of larger steel fibers will be used in the tensioned members. The economics of future bridge construction will implement a simple design, with an increased interface between design, erection, and maintenance. Progressive study in modern superior materials and management techniques will facilitate the construction of durable structures that do not require extensive maintenance.