A001.pdf

aaron.sanford Typewritten Text

E-40

CO FLAP 1099(1)

LAKE PUEBLO ROAD & TRAIL IMPROVEMENTS

AMENDMENT A001, 9/14/15

(a) Design.

Design structural members in accordance with recognized engineering practices and principles as follows:

(1) Structural Steel. AASHTO Guide Specification for Design of Pedestrian Bridges, 2nd edition, 2009, and the AASHTO LFRD Bridge Design Specifications, 7th Edition.

(2) Welded Tubular Connections. American National Standards Institute / American Welding Society (ANSI/AWS) and the American Institute of Steel Construction (AISC).

Check all welded tubular connections when within applicable limits, for the limiting failure modes outlined in the ANSI/AWS D1.1 Structural Welding Code and/or in accordance with the "Design Guide for Hollow Structural Section Connections" as published by the American Institute of Steel Construction (AISC).

(3) Synthetic Wood Deck. ASTM WK39017 New Specification for Plastic Composite Decking Boards and Guardrail Systems, Including Guards and Handrails ASTM D5456-99a Specification for Evaluation of Structural Composite Lumber Products. ASTM D7032 – 14 Standard Specification for Establishing Performance Ratings for Wood-Plastic Composite Deck Boards and Guardrail Systems (Guards or Handrails). ASTM D7301-04 Standard Guide for evaluating Mechanical and Physical Properties of Wood-Plastic Composite Products. Synthetic wood decking shall be molded in one piece per specified size. All materials will have UV additives to prevent deterioration of the plastic lumber from exposure to UV light. Decking shall be made of slip resistant material. Color shall be wood color, dark browns.

(4) Top Chord Stability. Structural Stability Research Council (SSRC), formerly Column Research Council. Consider the top chord as a column with elastic lateral supports at the panel points. The critical buckling force of the column, so determined, must exceed the maximum force from dead load and live load (uniform or vehicular) in any panel of the top chord by not less than 50 percent for parallel chord truss bridges or 100 percent for bowstring bridges. Follow the design approach to prevent top chord buckling outlined by E.C. Holt's research work in conjunction with the Column Research Council on the stability of the top chord of a half-through truss.

Design each pedestrian bridge for the following loads and loading conditions:

(a) Dead load (DL): Include the actual weight of all materials and the weight of the timber decking and any utilities under no flow conditions.

(b) Vehicular Load (LL). Design the bridge(s) for a H10 5 Design Vehicle. Distribute the wheel loads on synthetic wood decking in accordance with Section 3.2 of the LRFD Guide Specifications for the Design of Pedestrian Bridges.

(c) Pedestrian Load (PL). Design the main supporting members, including girders, trusses and secondary members including bridge decks and supporting floor systems, secondary stringers, floor beams and their connections to main supporting members, for a pedestrian live load of 90 pounds per square foot of bridge walkway area. Apply the pedestrian live

Untitled

CENTRAL FEDERAL LANDS HIGHWAY DIVISION

12300 WEST DAKOTA AVENUE, SUITE 360

LAKEWOOD, COLORADO 80228

ATTENTION: Joe Wilson 1:

Remove Page E-40 and replace with attached Page E-40 dated September 14, 2015.

NOTE: When printing revised sheets, turn on 'Document and Markups' in the Print Properties menu to illustrate changes on hard copy print.

*FAILURE TO ACKNOWLEDGE THIS AMENDMENT IN ITEM 19 OF THE SF 1442 BY THE DESIGNATED DATE AND HOUR SPECIFIED IN THE SOLICITATION MAY RESULT IN REJECTION OF YOUR BID (REFER TO SF-1442, PAGE A-2, OF THE SOLICITATION)