COMPARISON OF PERCEPTION VERSUS REALITY IN TIMBER BRIDGE PERFORMANCE

Bridge material selection is one of the mast difficult decisions an en gineer has to make. Many factors and individuals are often involved in choosing the proper bridge material for a given site and location. Ph ysical factors such as strength and lifespan of material, and also sit e specific factors like roadway alignment and traffic count, play impo rtant roles in material selection. Often state Department of Transport ation engineers, private consulting engineers, and local highway offic ials all play roles in the material selection process. Each individual may have his/her own perception of bridge materials based upon past e xperience and education, and little is known about how these perceptio ns influence the choice of materials. In this study, perceptions of en gineers and highway officials toward timber as a bridge material in fo ur selected states were compared to the actual performance of timber a s reported in the National Bridge Inventory. Highway officials and eng ineers in Mississippi, Virginia, Washington, and Wisconsin were survey ed by mail and personally interviewed to capture their perceptions tow ard timber as it compared to other major bridge materials (prestressed concrete, steel, and reinforced concrete). This information was compa red with the actual performance data obtained from the National Bridge Inventory. The results indicate that there is a strong correlation be tween highway officials' perceptions toward bridge materials and the r eported performance of these materials.