National Academies Press: OpenBook

Bridge Demolition Practices (2019)

Chapter: Chapter 4 - Construction Contractor Questionnaire

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Page 28
Suggested Citation:"Chapter 4 - Construction Contractor Questionnaire." National Academies of Sciences, Engineering, and Medicine. 2019. Bridge Demolition Practices. Washington, DC: The National Academies Press. doi: 10.17226/25478.
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Page 28
Page 29
Suggested Citation:"Chapter 4 - Construction Contractor Questionnaire." National Academies of Sciences, Engineering, and Medicine. 2019. Bridge Demolition Practices. Washington, DC: The National Academies Press. doi: 10.17226/25478.
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Page 29

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28 A questionnaire was sent to seven contractors to solicit their experiences with state procedures and requirements for demolition activities. The selected contractors included four large bridge contractors and two midsize bridge contractors, as well as a specialty demolition contractor. All of the bridge contractors provide demolition as part of their services. The questionnaire was sent to senior operations or engineering staff, with responses incorporating e-mail exchanges and telephone interviews. See Appendix D. Two of the large contractors as well as the specialty demolition contractor work nationally, one large company and the two smaller companies primarily work in the upper Midwest, and another large company works primarily in the Northeast and mid-Atlantic regions. Their demo- lition experience includes all types and sizes of bridges. Responses Demolition activities are often part of a project for a new structure or structure rehabilitation. Contractors estimated that less than 10% of demolition is performed as a standalone project. The contractors agreed that the contract documents normally address demolition requirements. However, several contractors noted that provisions are often minimal and may mostly address staging or traffic restrictions. Owner standard specifications were noted to be referenced for typical projects, though special provisions are generally provided for larger or specialized demolition projects such as major river crossings, large trusses, or movable bridges. All contractors responded that demolition plans are normally required, and three of the con- tractors stated that they always prepare one, whether or not the owner requires it. Demolition plans vary with the complexity of the bridges, the type of demolition equipment to be used, and whether the structure remains partly open. Some demolition plans are rather generic due to project size or limited hazards, while other demolition plans may be extremely complex with extensive staging and supporting analysis. Demolition submittals are required by the owner and normally consist of drawings and written procedures. Calculations are often not required. The contractors generally agreed that owner requirements for the contents of demolition plans are seldom provided and that no criteria are provided for preparing design calculations, even when required. Contractors commented that demolition submittals are not typically “approved,” though they may be reviewed. The contract drawings and specifications define the demolition scope and requirements and form the basis of the demolition plan. As-built bridge drawings are normally provided, though one contractor commented that they may be unavailable or incomplete for older structures. Bridge condition reports, which aid in establishing the structures’ existing load capacities for demolition equipment, are not provided though they may be available. C H A P T E R 4 Construction Contractor Questionnaire

Construction Contractor Questionnaire 29 Only occasionally, on large or complex projects, does an owner require the contractor to supply the credentials of the demolition superintendent. The contractor’s assessment of the resident engineer’s experience with demolition ranged from “not knowledgeable” to “50-50,” with the consensus being “sometimes.” One contractor commented that consultant residents are often less knowledgeable than state personnel. Contractors did note that larger or more complex demolition projects normally have experienced residents. Predemolition meetings may take place but are largely dictated by the project’s resident engineer. Again, they are more common on larger or more complex projects. Contractors consider that staged demolition sometimes has special requirements, particularly for traffic control and protection of remaining structures. However, they are of the opinion that demolition associated with accelerated bridge construction does not pose any unique challenges. In terms of owner-placed constraints on demolition, several contractors noted prohibitions against use of explosives and environmental requirements. Contractors also noted constraints on equipment type and concrete removal methods for redecking. Summary The comments of the contractors indicate that the owner normally requires some type of demolition plan submittal, often as part of the special provisions. Detailed plan requirements vary and tend to be more extensive for larger or more complex projects. That several contractors prepared demolition plans whether required or not required suggests that requiring a submittal may not constitute significant additional effort on the part of the contractor.

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Bridge Demolition Practices Get This Book
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TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 536: Bridge Demolition Practices documents practices used by bridge owners to manage and administer bridge demolition in construction projects.

Each year hundreds of bridges are rebuilt or are entirely replaced as part of highway construction projects. Bridge reconstruction or replacement work often entails demolition of part or all of the bridge structure.

Unintended events resulting in injury, project delays, and traffic disruptions can occur and have occurred during bridge demolition activities. The intention of this synthesis report is to assist in better understanding how to reduce risk associated with bridge demolition.

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