Evaluating and Predicting the Effects of Vibration from Construction and Use of Transportation Structures on Buried Archaeological Deposits.

  Problem

When determining the potential effect a project may have on an archaeological site, indirect effects as well as direct impacts must be considered. Encapsulating a site under fill material or capping it with concrete can provide some direct surface protection but there are many variables that may indirectly affect archaeological deposits from construction and use of the finished transportation structure.

In evaluating effects, construction methods and equipment are key components. Excavators, cranes, graders, etc., can weigh 80-100 metric tons. Effects from vibration, compaction or destabilization of subsurface soils from excavation are possible. Vibrations from pile driving construction shoring or bridge footings can exceed forces created by earthquakes, which may cause liquefaction. Liquefaction occurs because of changes in pore pressure and reduced effective stress between solid particles generated by the presence of liquid. It is often caused by severe shaking, and can cause sediments to mix; much like a liquid. There may also be long term effects from vibration and compaction caused by use of the transportation facility over time.

An alternative method to mitigate adverse effects from transportation projects, other than archaeological data recovery, which can be costly, is the controlled burial of significant sites under highway fill or encapsulation under asphalt or cement. Some literature exists on vibration impacts to the built environment; however, not regarding the archaeological record in a transportation context. Little to no research exists as to how to effectively evaluate vibration impacts, long term effects of vibration and compaction on archaeological sites nor the effectiveness of site burial as a mitigation measure. This project will gather base data for predictive modeling, synthesize this data with existing data and evaluate its applicability to archaeological issues, develop a framework for predictive modeling in evaluating adverse and cumulative impacts from transportation projects and assist in decisions as to appropriate mitigation measures.
Objectives

1. To determine the levels, depth, distance and effects of vibration from the construction and use of transportation structures in differing subsurface environments.
• What degree of compaction and mixing results from vibration levels over the short and long term in various types of sediments from construction and facility use.
2. What research literature is currently available concerning the surface and subsurface effect of vibration during construction and use of transportation facilities; can this be applied to archaeological issues?
• Vibration data is recorded on test pile(s) for analysis prior to driving piles during bridge construction. Geologic cores are taken early in the project design phase to determine engineering design requirements. What form does this data take? Can this data, from previous construction projects, be used to interpolate vibration levels and possible damage to buried deposits in projects with similar subsurface stratigraphy? This knowledge would allow for more accurate assessment of effects on archaeological resources and the built environment at no extra cost for the agency.
• A body of data exists on the effects on surface and subsurface waves from earthquakes. Data also exists on vibration effects from trains on soil and nearby structures. Do engineering studies, modeling, experimental data already exist on effects of vibration on different types of subsurface deposits that can be applied to similar archaeological subsurface sediments.?

3. What effects does vibration have on archaeological materials? What are the thresholds for these effects? (i.e. does vibration and the resulting compaction only effect the individual artifacts or is vibration significant enough to also destroy stratigraphic relationships? What are the vibration thresholds for these effects in the short and long term?)
Results

The results of this study will supply transportation agencies with the necessary information to evaluate:
-The effectiveness of controlled archaeological burial under or near transportation structures with varying subsurface stratigraphy (stewardship).
-Develop predictive models for vibration impacts on cultural resources from construction and use of transportation structures in the short and long term (stewardship).
-To justify the extent of data recovery and costs to regulatory agencies.
-To develop specifications for design and construction techniques and/or site burial requirements. 
- This type of information will improve accuracy of evaluation effects, identify issues early in the process which can effect project timelines and ultimately cost, improve decision making (i.e. time, cost: streamlining).

Key Words
Archaeology, Historic Preservation, Cultural Resources, Historic Properties, Evaluating Effects, Treatment

Related Work
Documents addressing project impacts to cultural resources acknowledge impacts to cultural resources from vibration and subsequent compaction but very seldom attempt to quantify those impacts to archaeological deposits. Vibration monitoring that is conducted, is focused toward the built environment and the public. Although impacts to archaeological resources is acknowledged, there are no specific guidelines setting standards for ground-bourne vibrations and no guidance or specifications exist regarding the archaeological record.

Urgency/Priority

This is ADC50’s third highest research priority.

Cost

Approximately $300,000 (including field tests, evaluation of data by engineers, Principal Investigator, limited clerical assistance, limited travel).

User Community

The community of users for this research includes AASHTO, FHWA, local transportation agencies, State Historic Preservation Officers (SHPOs), the National Conference of State Historic Preservation Officers (NCSHPO), the federal Advisory Council on Historic Preservation, the National Park Service, environmental and engineering consultants.

Implementation

Once disseminated in print and by electronic media, the findings will be implemented by transportation agencies, in consultation with their preservation partners, on a project-by-project basis.

Effectiveness

The research will be effective if it allows transportation projects to move forward more quickly and with less expense while protecting significant archaeological sites from construction and use impacts by assisting in making informed decisions regarding direct and cumulative impacts to buried archaeological deposits left intact adjacent to or encapsulated by transportation facilities or buried as a mitigation measure.


Sponsoring Committee: ADC50, Historic and Archeological Preservation in Transportation
Source Info: Committee member
Date Posted: 08/16/2007
Date Modified: 08/17/2007
Index Terms: Historic preservation, Cultural resources, Historic sites, Vibration, Construction, Archaeological surveying, Archaeology,