Bridges & Structures

Technical Advisory

Bridge Temporary Works

October 29, 1993

Technical Advisory 5140.24

PURPOSE

To provide State highway and transportation agencies with guide standards and design specifications, a construction handbook and a certification program to assist owner agency and industry performance in achieving the safe construction of bridge temporary works. These documents may by used in conjunction with Section 3, Temporary Works, of Division II of the latest edition of the AASHTO Standard Specifications for Highway Bridges.

BACKGROUND

1. The falsework collapse of the Maryland Route 198 bridge over the Baltimore/Washington Parkway on Auqust 31, 1989, prompted the Congress to direct the Secretary of the U.S. Department of Transportation to develop specifications and guidelines for use in constructing bridge temporary works. Heretofore, there were national standard code or specification available on bridge temporary works. The only available national standard which addressed this type of construction (ANSI A10.9-1983) was applicable primarily for building construction.
2. The development of these documents for bridge temporary works began with a synthesis of information to pull together, in one document, all of the existing standards, practices, procedures and any other literature available on the subject in the United States and foreign countries. This November 1991 synthesis report has been distributed to all FHWA regional and division offices and to the State highway agencies (SHA's). Copies of this report (Synthesis of Shoring, Formwork and Scaffolding for Highway Bridge Structures, Publication No. FHWA-RD-91-062) are available from the Federal Highway Administration, Research and Development Publications and Report Center, Turner Fairbank Highway Research Center, 6300 Georgetown Pike, McLean, Virginia 22101.
3. Subsequent priorities were to develop the following documents which are the subject of this Technical Advisory:
   1. Guide Standard Specification for Bridge Temporary Works - A guide standard specification that establishes contractual requirements at the bid preparation stage that will apply to all bridge construction projects.
   2. Guide Design Specification for Bridge Temporary Works - A guide design specification that will enable users to update their existing standard specifications for bridge temporary works.
   3. Construction Handbook for Bridge Temporary Works - A handbook for use by field Engineers who are in charge of bridge construction projects.
   4. Certification Program for Bridge Temporary Works - A program developed by the industry as a certification program for manufactured proprietary falsework systems supplied to bridge construction projects.

DISCUSSION

1. General. Past practice, and at times current practice, has been to give the design and construction of temporary falsework structures significantly less emphasis in comparison to the more refined and detailed design used for the permanent structure. Despite the temporary nature of these structures, the safety of project personnel and the general public during the period when temporary works are used requires diligence equal to that exercised in designing and constructing the permanent structure. Assignment of responsibility for design and construction details of temporary falsework structures is given to contractors, subcontractors and suppliers. Without clear and comprehensive standards, the assumption of this responsibility and the quality of owner agency oversight is often inconsistent. The documents covered by this Technical Advisory are offered to owner agencies as guidelines and assistance to help improve not only the design of temporary works structures but also to improve the administration and contractual aspects of the construction project. The States are encouraged to review these advisory documents and, as appropriate, incorporate the items in their standard specifications, project special provisions or standard practices.
2. Function.
   1. The four documents transmitted by this Technical Advisory are intended to be used as integrated, co-supportive guidelines and instruction. This is reflected in numerous cross-references to each other in the text of the documents. Because of the guideline nature of the guide specifications cited in items (1) and (2) of paragraph 2.c, of this advisory, it is the obligation of the owner agencies to place the requirements of the contractor and the owner, and the execution of the contract responsibilities into binding contract language in their standard specifications and/or the project special provisions. It is not intended that those documents be merely referenced as part of the contract provisions.
   2. The handbook is intended for instructional and informational assistance in the implementation of the standard specifications and/or project special provisions during the construction of project temporary works. The, handbook is, in general, for the use of field personnel in performing field inspection functions, but it is not intended as a basis for specification material itself.
   3. The proposed certification program is an attempt to provide the owner and contractor project personnel with the necessary means of easily and positively identifying manufactured equipment furnished to the project with that shown on the approved shop drawings. As with this or any other certification program, it will still take the cooperation and diligence of all parties involved to see that it functions as intended.

DISTRIBUTION

Copies are being provide to the regional offices with the division offices being provided sufficient copies for their use and distribution to the SHA's.

Thomas 0. Willett, Director
Office of Engineering