2014 WORKSHOP Field Trip 3

Transcription

1 2014 WORKSHOP Field Trip 3 This trip visits a RoaDrain geosynthetic drainage material demo, GRS-IBS bridge project, and a completed project from Site 1 - Laurel Run Road: Recently completed project that used RoaDrain geosynthetic drainage material. Site 2 - Potter Run Road: An in-progress Geosynthetically Reinforced Soil-Integrated Bridge System (GRS-IBS) project. Site 3 - Sharer Road: A Program project completed in 2011 employing a cooperative effort with multiple entities. We will discuss project details and maintenance. The Ramada 3 2 1

2 Site 1: Laurel Run Road (RoaDrain Demo) Field Trip 3 As part of the Center s Bureau of Forestry (BOF) Demonstration project budget, BOF was interested in utilizing the TENSAR RoaDrain RD-5 roadway drainage system. This product consists of a synthetic sub-surface drainage layer sandwiched in nonwoven geotextile, which TENSAR states, will provide flow rates up to 5X greater than the typical open-graded base layer. Since the product is only 0.5 inches thick, it could greatly reduce the over-excavation depth needed to install a conventional French mattress. This section of Laurel Run Road is plagued with hillside seeps that have historically saturated the road base. Also, shelf rock is evident in the road base, which makes excavation problematic for a conventional French mattress. TENSAR s TX160 Triaxial Geogrid was utilized on top of the RD-5 to provide additional structural support. A new crosspipe was installed above a site to separate the ditch flow from the seep flow drainage. The RD-5 was installed in three steps, as indicated in the design drawing below, to account for the excessive road grade. Each step was sloped from the ditch line side to the out slope side at approximately 5% in an effort to drain the seep flow under the road profile. The lower crosspipe was also replaced as part of normal road maintenance operations. 1 2 Dra Design Drawing 3 This drawing depicts the effort to use the RD-5 to its maximum extent. The steps allow for even distribution of the seep flow away from the road. The four labeled sites correspond to the before and during/after pictures on the following page. Note that all before pictures show road impacted by bank seepage and limited drainage outlets, which combined together, increase flow volumes in the drainage structure. DISCLAIMER: The purpose of this project is to demonstrate a poten al new technology. This project or document is for educa on only and does not cons tute an "endorsement" of TENSAR or RoaDrain by the Center or Program. 4 Site Location: South off of US Route 322 just east of Boalsburg in Rothrock State Forest. A 7% sloped road that faces heavy vehicle traffic because of its direct access from Tussey Mountain to Route 26 at Whipple s Dam. What was done: Installed one new crosspipe and replaced one existing crosspipe. Provided outlet stabilization for the crosspipes. Excavated and constructed three steps that utilized the RD-5 roadway drainage system. TX160 Triaxial Geogrid overlaid on RD-5 to provide additional structural support Reinforced the ditch structure with R-3 riprap to protect the inlet side of the RD-5. All affected areas were seeded and mulched.

3 Site 1: Laurel Run Road (RoaDrain Demo) Field Trip 3 During 1 During Photo: In-progress replacement of existing crosspipe. During 2 During Photo: Installation of RD-5 roadway drainage system and TX160 geotextile. A er 3 After Photo: R-3 riprap lined ditch and bank stabilization through seeding and mulch. A er 4 After Photo: New crosspipe installation with outlet stabilization.

4 Site 1: Laurel Run Road (RoaDrain Demo) Field Trip 3 h p:// content/uploads/2013/08/roaddrain Brochure.pdf

5 Site 2: Potter Run Road (GRS-IBS Bridge) Field Trip 3 This Geosynthetically Reinforced Soil-Integrated Bridge System (GRSIBS) bridge pilot project is part of the Bureau of Forestry s (BOF) ongoing effort to utilize cost-effective methodology for vehicle roadways over waterway crossings. This structure was designed by the BOF s Facility Design and Construction department. The before pictures demonstrate the need to replace a deteriorating bridge structure on the low-volume Potter Run road. A temporary bridge was utilized to enable vehicle traffic access prior to the GRS-IBS bridge installation. Site Location: Located just west of Penn Nursery off of US 322 on Potter Run Road. This site is adjacent to Rothrock State Forest and Bald Eagle State Forest. During During During: The upper photo shows the abutment construction on top of foundation and the lower photo shows the compaction of AASHTO #57 stone.

6 Site 2: Potter Run Road (GRS-IBS Bridge) Field Trip 3 Geosynthetic Reinforced Soil (GRS) Integrated Bridge System (IBS) FHWA GRS-IBS Implementation Guide. GRS-IBS Quick Facts : Bridges constructed with the Geosynthetic Reinforced Soil (GRS) Integrated Bridge System (IBS) cost 25 to 60 percent less than bridges built with traditional methods, depending on the standard of construction and the method of contracting (local forces versus a private contractor). Compared with a DOT standard bridge, a GRS-IBS can potentially save up to 60 percent in cost. GRS IBS uses common, readily available materials and equipment. The use of GRS makes bridge abutments that are easier and faster to build. GRS IBS construction is much faster than traditional construction methods (weeks, not months). GRS IBS eliminates the "bump at the end of the bridge" problem caused by differential settlement between the bridge abutment and the approaching roadway. Construction is simpler with GRS IBS since it has fewer parts, involves basic methods and practice. IBS does not require a deep foundation. GRS IBS is environmentally sensitive and results in minimal environmental impacts. GRS technology is durable if built with quality materials. A GRS bridge performs well in earthquakes if constructed properly with closely spaced reinforcement. GRS IBS can be built in variable weather conditions and can be adapted very easily in the case of unforeseen site conditions. GRS structures are generally more ductile and flexible. Since GRS IBS bridges have fewer parts, they are easier to maintain. Approximately 44 bridges have been built on GRS abutments in the US; 27 of those using GRS IBS FHWA 8/2012 (

7 Site 2: Potter Run Road (GRS-IBS Bridge) Field Trip 3

8 Site 2: Potter Run Road (GRS-IBS Bridge) Field Trip 3

9 Site 3: Sharer Road (Completed in 2011) Field Trip 3 Off-right-of-way flow from a mountain tributary and a new residential development previously drained to the east ditch of Sharer Road at the top of the site. The ditch picked up additional flow from road drainage and was discharged directly to the creek. The stream pipe lacked the capacity to move flood flows through the road, which was washed out on a consistent basis. The installation of a wing plug on the US 322 headwall divides the sources of the run-on flow and notably reduces flow volume handled in the Sharer Road drainage system. Replacement of the stream culvert, installation of overflow pipes and a constructed wetland depression are the primary ESM practices incorporated to reduce the volume of road material and sediment entering Spring Creek during wet weather events. Sta on Map 2 1 Site Location: North off of US Route 322 just east of Boalsburg in Harris Township, PA. Headwaters of Spring Creek, a World-Renowned trout fishery. A moderately sloped road bordered by agricultural lands. 3 4 This station map depicts the work completed in The four labeled sites correspond to the before and after pictures on the following page. Note that all before pictures show road impacted by stream flooding, mountain drainage, and run-on flows from paved roads and developed areas. There were no existing ditch outlets in project area. What was done: Installed a headwall wing/ditch plug at the inlet of the US 322 ditch culvert to reduce run-on flow. Installed ditch protection in eroded ditch section. Diverted ditch flow away from road and stream with a new turn-out that drains to a constructed wetland in the former corn field. Installed four new crosspipes and replaced three existing crosspipes. Constructed a 50 long High Water By-pass. Placed and compacted one lift of 2A base material to gain road elevation. Installed riprap stream bank protection.

10 Site 3: Sharer Road (Completed in 2011) Field Trip After Photo: In-progress installation of high-water bypass After Photo: Relief pipes functioning well during high-water event Stream Crossing Stream Crossing 3 After Photo: Installed turn-out to wetland filter area After Photo: Functioning headwall wing/ditch plug. Reduces flow volume to Sharer Road.