Herrera is working with World Concern and students from Seattle University to build pedestrian bridges in remote regions of Tibet’s Qomolangma Nature Preserve.
Herrera evaluated and surveyed sites for various bridge technology applications in Shoda, Gadong, Tsa, and Thongmu, Tingri County and in Gyrong Rong, Gyrong County. Shoda and Gadong have existing cable crossing, where locals use Yak hide ropes with a belt arrangement for crossing the river. Tsa and Thongmu each have temporary wooden bridges that will last a maximum of two more years. These sites are in the Kharta Valley area (southeast corner of Tingri County) and they all need river crossings just above water level. The last site is in Gyirong Rong in the southern part of Gyirong County. There is no existing bridge at this site that would cross over the deep gorge dividing the villages from the township center.
The cost of materials, the lack of adequate technical expertise in the local area and the short but intense summer floods, have made bridge construction a big challenge in the Qomolangma region. Almost all bridges in the area are built without a rigorous design that would include estimating flood levels, and scour depths; nor do they have adequate foundation investigations. This is partially due to lack of budget and partially due to lack of qualified engineers. Villages often build a bridge in autumn only to watch the heavy floods wash it away the following summer. As the farming techniques in the region are advancing, small tractors have become an important part of the regular transportation system. Many of the older bridges are inadequate to carry these loads.
Herrera’s president Carlos Herrera, and vice president Michael Spillane performed the site evaluation and topographic surveys for this project. Mr. Herrera and Mr. Spillane traveled along the Friendship Highway between Lhasa and New Tingri, up the Kharta valley and to Gyirong. Together with the Tibet World Concern office, three bridge sites were selected for final design and the final bridge design packages were submitted to World Concern. Led by Michael Spillane, Herrera engineers completed the bridge designs with assistance of students from Seattle University’s Senior Design Center.
Herrera engineers Mark Ruebel and Kevin Houck, and Seattle University engineering students Herb LeBeau and Elizabeth Schumacher, have been working in Tibet to provide engineering support and technical oversight for the villagers building the bridges. The Shoda bridge is scheduled to be completed by the end of October 2004. Construction of the Gyirong bridge is scheduled to begin in spring 2005.
For additional information please contact Carlos Herrera or Michael Spillane via email or by telephone at (206) 441-9080.
Seattle University’s Department of Civil and Environmental Engineering has several pages with more information about this project:
http://www.seattleu.edu/scieng/engpc/stdntprj/cee041/
http://www.seattleu.edu/scieng/engpc/stdntprj/cee051/
Herrera Environmental Consultants is pleased to welcome Julie Kightlinger, a fisheries scientist, to our Missoula office. Ms. Kightlinger is conducting wetland delineations along 18 miles of roadway scheduled for improvements in the Custer National Forest, and she has worked with private landowners and government agencies to obtain grant funding for a stream restoration project in the Upper Clark Fork River basin involving data collection and analysis, permitting, and construction oversight. She is experienced in surveying stream habitat and hydrology, assessing fish populations and impacts on habitat, and preparing biological assessments of sensitive species for transportation projects.