Bridges built in timber are enjoying a significant revival, both for pedestrian and light traffic and increasingly for heavier loadings and longer spans. Timber's high strength-to-weight ratio, combined with the ease and speed of construction inherent in the off-site prefabrication methods used, make a timber bridge a suitable option in many different scenarios. This handbook gives technical guidance on forms, materials, structural design and construction techniques suitable for both small and large timber bridges. Eurocode 5 Part Two (BS EN 1995-2) for the first time provides an international standard for the construction of timber bridges, removing a potential obstacle for engineers where timber construction for bridges has not – in recent centuries at least – been usual. Clearly illustrated throughout, this guide explains how to make use of this oldest construction material in a modern context to create sustainable, aesthetically pleasing, practical and durable bridges. Worldwide examples include Tourand Creek Bridge, Canada; Toijala, Finland; Punt la Resgia, Switzerland; Pont de Crest, France; Almorere Pylon Bridge, the Netherlands.

Timber's strength, light weight, and energy-absorbing properties furnish features desirable for bridge construction. Timber is capable of supporting short-term overloads without adverse effects. Contrary to popular belief, large wood members provide good fire resistance qualities that meet or exceed those of other materials in severe fire exposures. From an economic standpoint, wood is competitive with other materials on a first-cost basis and shows advantages when life cycle costs are compared. Timber bridges can be constructed in virtually any weather conditions, without detriment to the material. Wood is not damaged by continuous freezing and thawing and resists harmful effects of de-icing agents, which cause deterioration in other bridge materials. Timber bridges do not require special equipment for installation and can normally be constructed without highly skilled labor. They also present a natural and aesthetically pleasing appearance, particularly in natural surroundings. The misconception that wood provides a short service life has plagued timber as a construction material. Although wood is susceptible to decay or insect attack under specific conditions, it is inherently a very durable material when protected from moisture. Many covered bridges built during the 19th century have lasted over 100 years because they were protected from direct exposure to the elements. In modem applications, it is seldom practical or economical to cover bridges; however, the use of wood preservatives has extended the life of wood used in exposed bridge applications. Using modem application techniques and preservative chemicals, wood can now be effectively protected from deterioration for periods of 50 years or longer. In addition, wood treated with preservatives requires little maintenance and no painting. Another misconception about wood as a bridge material is that its use is limited to minor structures of no appreciable size. This belief is probably based on the fact that trees for commercial timber are limited in size and are normally harvested before they reach maximum size. Although tree diameter limits the size of sawn lumber, the advent of glued-laminated timber (glulam) some 40 years ago provided designers with several compensating alternatives. Glulam, which is the most widely used modem timber bridge material, is manufactured by bonding sawn lumber laminations together with waterproof structural adhesives. Thus, glulam members are virtually unlimited in depth, width, and length and can be manufactured in a wide range of shapes. Glulam provides higher design strengths than sawn lumber and provides better utilization of the available timber resource by permitting the manufacture of large wood structural elements from smaller lumber sizes. Technological advances in laminating over the past four decades have further increased the suitability and performance of wood for modern highway bridge applications.

These standardized bridge plans are for superstructures consisting of treated timber. Seven superstructure types are included: five longitudinal and two transverse deck systems. Both HS20 and HS25 loadings are included, along with L/360 and L/500 deflection criteria.

Bridges built in timber are enjoying a significant revival, both for pedestrian and light traffic and increasingly for heavier loadings and longer spans. Timber's high strength-to-weight ratio, combined with the ease and speed of construction inherent in the off-site prefabrication methods used, make a timber bridge a suitable option in many different scenarios. This handbook gives technical guidance on forms, materials, structural design and construction techniques suitable for both small and large timber bridges. Eurocode 5 Part Two (BS EN 1995-2) for the first time provides an international standard for the construction of timber bridges, removing a potential obstacle for engineers where timber construction for bridges has not – in recent centuries at least – been usual. Clearly illustrated throughout, this guide explains how to make use of this oldest construction material in a modern context to create sustainable, aesthetically pleasing, practical and durable bridges. Worldwide examples include Tourand Creek Bridge, Canada; Toijala, Finland; Punt la Resgia, Switzerland; Pont de Crest, France; Almorere Pylon Bridge, the Netherlands.

Bridges, the least known and understood of China's many wonders, are one of its most striking and resilient feats of architectural prowess. Chinese Bridges brings together a thorough look at the marvels of Chinese bridge design from one of the world's leading experts on Chinese culture and historical geography, Ronald G. Knapp. While many consider bridges to be merely utilitarian civil engineering, the bridges of China move beyond that stereotype, as many are undeniably dramatic, even majestic and daring. Chinese Bridges illustrates in detail 20 well-preserved ancient bridges along with descriptions and essays on the distinctive architectural elements shared by the various designs. For the first time in an English-language book, Chinese Bridges records scores of newly discovered bridges across China's vast landscape, illustrated with over 400 color photographs, as well as woodblock prints, historic images, paintings and line drawings.

Covered timber bridges are historic structures with unique aesthetic value. To preserve this value and maintain bridges in service, robust evaluation of their performance and safety is necessary. The strength of the timber found in covered bridges can vary considerably, not only because of age and condition, but also because of species and grade. For the practicing engineer or inspector evaluating a covered bridge, design values for existing wood members must be determined with as much accuracy as possible by account-ing for bridge-specific conditions. The current practice is to assign wood values for strength and moduli from existing specifications without specific reference to timber species, condition, or grade, which can result in an inaccurate assess-ment of the structure. This manual provides a walk-through for basic wood identification, inspection, condition assess-ment, field grading, and design value estimation for wood in covered bridges.

As many as 15,000 covered bridges were built in North America over the past 200 years. Fewer than 1,000 remain. In America's Covered Bridges, authors Terry E. Miller and Ronald G. Knapp tell the fascinating story of these bridges, how they were built, the technological breakthroughs required to construct them and above all the dedication and skill of their builders. Each wooden bridge, whether still standing or long gone, has a story to tell about the nature of America at the time--not only about its transportational needs, but the availability of materials and the technological prowess of the people who built it. Illustrated with some 550 historical and contemporary photos, paintings, and technical drawings of nearly 400 different covered bridges, America's Covered Bridges offers five readable chapters on the history, design and fate of America's covered bridges, plus related bridges in Canada. Most of the contemporary photography is by master photographer A. Chester Ong of Hong Kong. 55 photo essays on the most iconic bridges including: Cornish-Windsor Bridge between Vermont and New Hampshire Porter-Parsonsfield Bridge, Maine East Paden and West Paden (Twin Bridges), Pennsylvania Philippi Bridge, West Virginia Hortons Mill Bridge, Alabama Medora Bridge, Indiana Rock Mill Bridge, Ohio Knight's Ferry Bridge, California Perrault Bridge, Quebec, Canada Hartland Bridge, New Brunswick, Canada Over time, wooden bridges eventually gave way to ones made of iron, steel and concrete. An American icon, many covered bridges became obsolete and were replaced—others simply decayed and collapsed. Many more were swept away by natural disasters and fires. America's Covered Bridges is absolutely packed with fascinating stories and information passionately told by two leading experts on this subject. The book will be of tremendous interest to anyone interested in American history, carpentry and technological change.