Library builder

While highway bridges are utilitarian structures, they are visible to the public and therefore should be pleasing to the eye. At the outset of design, one should be conscious of the aesthetic qualities of the structure, lest one end the project saying (after Shelley), “Look on my works, ye Mighty, and despair!” Some basic guidelines […]

State departments of transportation, bridge and turnpike authorities, and other agencies often require the services of a consulting engineering firm. This may be because the agency chooses not to maintain an engineering staff of its own, because its workload is greater than its staff can handle, or because expertise in special kinds of bridges is […]

Walter J. Jestings, PE. Formerly, Bridge EngineerParsons Brinckerhoff, Quade & Douglas, Inc.Atlanta, Georgia Mahir Sen, P. E. Professional AssociatePB Americas, Inc. Newark, New Jersey This chapter is directed at practical issues of importance in the design and rehabilita­tion of traditional bridge types for short and medium spans. Subjects addressed include characteristics of various bridge types, […]

It is seldom readily apparent which is the most economical rehabilitation method for a particular pavement. Each rehabilitation strategy has unique initial construction costs, performance expectations, and future maintenance needs. What is most economical for one pavement may not be for another. Local costs may differ from one location to another, and material performance expectations […]

Microsurfacing is the application of a thin cold-applied paving mixture composed of polymer-modified asphalt emulsion, 100 percent crushed aggregate, mineral filler, water, and other additives. A self-propelled continuous loading machine or a truck-mounted machine is used to proportion and mix the materials and apply the mixture to the pave­ment surface. Microsurfacing is used to retard […]

A fog seal is an application of a diluted asphalt emulsion to a weathered asphalt surface. It is used to seal and enrich the surface, seal out moisture, close up hairline cracks, and prevent oxidation and raveling. Fog seals are generally restricted to low-volume, low-speed roadways and parking lots, as they have a tendency to […]

Crack sealing is the placement of a sealant into existing cracks of a pavement. The sealant is made of a mixture of a neat or modified asphalt cement binder, with a number of possible additives such as rubber, polyester or polypropylene fibers, or polymers. Crack sealing can be placed into routed crack reservoirs using backer […]

Preventive maintenance (PM) is a cost-effective strategy of early maintenance done to a pavement as a preemptive measure to preserve the pavement by retarding deterioration. PM is traditionally a low-cost treatment done early in a pavement’s deterioration cycle. By definition, pavement preventive maintenance extends the service life and maintains or improves the functional condition of […]

Asphalt Overlay. Without question the most common method of rehabilitation for flexible pavement is an asphalt overlay. There are many variations of this technique ranging from pavement planing and a thick asphalt overlay to a thin skin patch placed infrequently along a pavement. The existing condition of the asphalt pavement and the results of nondestructive […]

Once a pavement is determined to have unacceptable smoothness or has lost its ability to properly transport goods, it is reasonable to determine the best strategy to return the pavement to its original intended function. Many of the decisions that define the point where corrective action should be taken are management decisions and can be […]