davis.draft.bill

(dr req 90-240 - draft 1) 10/19/89

Introduced by Representative Davis of Cavendish Referred to Committee on Date:_______
Subject: Highways; wooden bridges; restoration
Statement of purpose: This bill proposes to provide standards for the restoration and preservation of covered wooden bridges.

It is hereby enacted by the General Assembly of the State of Vermont: Sec. 19 V:S.A. chapter 9, subchapter 9 is added to read:

§ 1002. APPLICABILITY OF STANDARDS
The standards set forth in this subchapter shall apply to all:

1. covered wooden bridges which are the property of the state;
2. covered wooden bridges which are the property of a town but which are being restored, or restored and reconstructed, by the state: and
3. covered wooden bridges which are the property of a town, but which are being restored, or restored and reconstructed, by means of state bridges aid funds.

§ 1003. STANDARDS FOR RESTORATION AND PRESERVATION

1. The standards shall apply to the superstructures of covered bridges only. Covered-bridge abutment and piers shall be rehabilitated in a sensitive manner Care shall be taken to preserve as much of the historic fabric of these structures as is reasonably practicable, in place, and to the extent feasible, functioning as originally intended. The original appearance of covered-bridge abutments and piers shall not be compromised, unless, for imperative structural or financial reasons, it becomes absolutely necessary to alter this appearance.
2. Maximum retention of the historic fabric of the trusses and upper and lower lateral bracing systems of a covered wooden bridge shall be one of the cardinal aims of any covered-bridge restoration project. That is to say all restoration schemes shall be such as to maintain in place, and functioning as originally intended, as many individual timbers bolts, and trunnels, found within the trusses and upper and lower lateral bracing systems of a covered bridge, as is prudent and feasible.
3. If feasible and prudent deteriorated individual truss or upper or lower lateral bracing system timbers shall be braced, spliced or doubled up, rather than being replaced by others of new manufacture. Specific details of the splices to be affected, or of the new braces to be set in place or of how a timber is to be doubled up rather than being replaced, shall be based upon examples known to be of the hand of the builder of the span being restored, or that failing, upon techniques which were in common use at the time the bridge was initially erected..
4. Individual truss or upper or lower lateral bracing system timbers too deteriorated any longer to serve, or other truss or upper or lower lateral bracing system components similarly deteriorated shall be replaced in kind as necessary. Great care shall be taken to match up the new materials used in the replication of deteriorated covered-bridge components with the ones initially employed, both as to type and as to quality: Should certain original materials no longer be obtainable in the necessary quantities or required grades, or at reasonable prices, then other closely similar materials may be substituted for the original ones.
5. Great care in the selection of materials used for the replication of badly deteriorated covered bridge components shall be employed, and any newly-manufactured covered bridge parts shall be such as to perfectly mimic the ones they replace, in form, in proportion, in texture of surfaces to the extent that this is practicable, and finally, in a high level of craftsmanship. Joints which were framed to extremely close tolerances in the original components shall be framed to extremely close tolerances in the new ones and shall be essentially indistinguishable from the deteriorated original it replaces.
6. If as a result of rigorous structural analysis the load-bearing capacity of the-trusses of a covered bridge should be determined to be insufficient for the traffic the span must handle, even if the trusses in question were to be put into a perfectly restored condition, then the trusses may be upgraded to achieve the necessary load-bearing capacity. Any such upgrades shall precisely meet the following requirements:
   1. the upgrading shall be achieved by means of devices and techniques known to the builders of the span being restored and upgraded, or that failing, by means of devices and techniques which were in common use at the time the span was initially erected;
   2. the upgrading shall result in essentially no greater loss of historic fabric than would simple restoration of the trusses and upper and lower lateral bracing systems of the span;
   3. the upgrading shall be of a reversible nature; it shall be Possible to remove whatever has been added in order to achieve a higher load-bearing capacity, without significantly effecting the trusses and upper and lower lateral bracing systems of the span in question;
   4. the use of laminated timber arches as a means to increase the load-bearing capacity of historic covered wooden brides is specifically authorized. Any such arches shall be built up in the traditional manner without recourse to glue or to adhesives; and
   5. nothing in the language, of subdivision (f)(1) of this section shall be construed so as to preclude the use, during restoration and upgrading, of any .particular kind of tool, powered or otherwise, or of any particular method of temporary shoring, ancient or modern.
7. Care shall be taken, when elaborating plans for the restoration or reconstruction of a covered wooden bridge, to assure, as an integral part of any such plans, easy access to those areas of the trusses, abutments. and piers, where dirt and debris normally collect in large quantities,.in order that these areas may be readily and periodically cleaned out.
8. The roof of a covered bridge, including the immediate support system for the roof, shall be repaired or replaced in kind, as necessary, and as appropriate.
9. The sideboarding or endboarding, or both, of a covered wooden bridge shall be repaired or replaced in kind, as necessary, and as appropriate. Care shall be taken to match both the high quality and the specific kinds of materials initially employed whenever feasible. Sideboards or endboards or both, shall be carefully seasoned before installation.
10. The floor and floor joists of a covered wooden bridge may be repaired or replaced in kind as necessary, or, if the trusses of the span will support it, the floor and floor joists of a covered wooden bridge may be upgraded to a higher load bearing capacity. The floors shall be made up of wooden Planks laid down on their flat side and staggered-end splices shall be employed throughout. The floor joists shall be of solid timbers.

§ 1004. CONSULTATION WITH THE DIVISION FOR HISTORIC PRESERVATION
       The Division for Historic Preservation shall be apprized of any plans to restore a covered wooden bridge from the inception of any plans. As plans for the restoration of a particular covered bridge are being elaborated by the Agency of Transportation, the Division for Historic Preservation shall be kept fully informed on a regular basis as to whatever progress is being made. Failure .to consult with the Division for Historic Preservation regarding a covered-bridge restoration project as prescribed, shall automatically place the project on hold until such time as the mandated consultations have taken place. The secretary of the Agency of Transportation shall be responsible for overseeing compliance with this section.

1. For bypassed or abandoned spans:
   1. that the structure in its current condition constitutes a clear and present danger to the lives of individuals who use the structure or to the property of those who live downstream from it; and
   2. that repair or shoring up of the structure is not financially or structurally feasible.
2. For spans on highways which are, or would be in current use were the bridge not closed:
   1. that the structure, even in a restored and strengthened condition, would not prove adequate for the kind and volume of traffic which must pass over it;
   2. that the structure cannot be bypassed by another bridge located at an upstream or a downstream site: and
   3. that the structure cannot be dismantled and stored for future use,` or dismantled and reassembled immediately at another site, or moved without disassembly to another site.

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