Estimating and Contracting Rock Slope Scaling Adjacent to Highways (2020) / Chapter Skim
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Pages 26-34
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26 Geotechnical specialists from six state transportation departments were interviewed following completion of the broad state-of-the-practice survey. The states were generally selected based on • Unique practice or perspective on scaling practice; • Regular involvement with rock slope scaling projects along highway corridors; • Depth of experience with generating cost estimates, plan sets, and construction specifications for a variety of rock slope scaling projects; • Depth of experience with developing methods to determine job completion and defining successful performance of a scaled rock slope; and • Ongoing efforts to maintain records of past scaling projects and to track project performance over time.
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Case Examples 27 extensive training includes multiple forms to assist scalers in evaluating slope characteristics, site safety, and anchoring conditions, among other items. Slope assessment forms are reviewed by Caltrans's geotechnical personnel before scaling activities begin.
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28 Estimating and Contracting Rock Slope Scaling Adjacent to Highways The remaining scaling work is subdivided into emergency response (30%) or routine maintenance (15%)
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Case Examples 29 the feature being protected is of high value or particularly sensitive, the contractor must submit the proposed design for CDOT review and concurrence. This submittal review takes place after contract award.
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30 Estimating and Contracting Rock Slope Scaling Adjacent to Highways Scaled Slope Performance and Lessons Learned ITD District 6 has learned that executing and maintaining an annual scaling program provides a number of benefits. These benefits include being able to address slopes that may have experienced an uptick of rockfall activity in the late winter or early spring months that can then be scaled that same year.
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Case Examples 31 which impacts how often scalers have to rope up. Production rates and scaled volumes on slopes with significant differential erosion features are more difficult to estimate, but are less common in New Hampshire.
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32 Estimating and Contracting Rock Slope Scaling Adjacent to Highways by routinely tracking rock slopes, NHDOT will have the ability to more accurately incorporate rockfall risks into project selection tools. Earlier incorporation of scaling into project design will make it easier for the department to identify the most cost-effective method for rockfall risk reduction.
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Case Examples 33 ODOT conducts lidar scans of the project area before and after scaling work is conducted to improve their estimates for future projects. Recently, ODOT has acquired UAV technology that has subsequently been used to perform initial inspections following a rockfall event.
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34 Estimating and Contracting Rock Slope Scaling Adjacent to Highways The department has special provisions in the bid package for scaling, specifying minimum experience requirements in terms of years of experience. A prequalified scaler list is also under development by the department, but is not yet readily available to prime contractors.
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