Thesis - Open Access
Master of Science (MS)
Department / School
Civil and Environmental Engineering
bridge, glulam, timber
The most common type of bridges on South Dakota (SD) local roads are prestressed precast double-tee bridges. Currently, there is only one double-tee girder manufacturer in South Dakota (SD). In an attempt to provide more bridge type selection options for local governments, a study was performed at South Dakota State University to investigate the feasibility and performance of new types of single-span bridges suitable for local loads with low traffic. In one part of the study, Mingo (2016) developed a fully precast bridge incorporating full-depth deck-panels and prestressed inverted bulb-tee girders. The study presented in this thesis was performed to investigate the feasibility and performance of glulam timber bridges as additional design alternatives for SD local roads. There are two types of glulam timber bridges: (1) transverse glulam deck on glulam girders and (2) longitudinal glulam deck. The performance of each type was experimentally investigated through full-scale testing. The full-scale glulam girder bridge test model was 50-ft long and 9.25-ft wide. The full-scale glulam slab bridge was 16.5-ft long and 8-ft wide. Both bridges were first tested under the AASHTO Fatigue II limit state loading followed by strength testing. Both bridge types showed minimal damage during the fatigue testing. The only damage of the girder bridge was cracking of male-to-female deck-to-deck connections, which can be eliminated using flat-end panels. Ultimate testing of the two bridge systems confirmed that the AASHTO method of the design for timber bridges is adequate. Girders of glulam girder bridges should be designed as fully non-composite members. Furthermore, design and construction guidelines for both types of bridges were proposed. A cost analysis showed that the superstructure cost of glulam timber bridges and glulam slab bridges can be 70% and 50% respectively of that for double-tee bridges. Based on the construction, testing, and cost analysis, it can be concluded that both types of glulam timber bridges are viable alternatives to the double-tee girder bridges.
Library of Congress Subject Headings
Wooden bridges -- South Dakota -- Testing.
Wooden bridges -- South Dakota -- Evaluation.
Wooden bridges -- South Dakota -- Design and construction.
Includes bibliographical references (pages 141-142)
Number of Pages
South Dakota State University
Carnahan, Zachary Charles, "Glulam Timber Bridges for Local Roads" (2017). Electronic Theses and Dissertations. 1173.