May 3 2022 Q and A.pdf
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- Solicitation number
- 698AF22B000007
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This document contains questions and answers from a pre-solicitation conference for federal contract number 698AF22B000007 for bridge replacement and road improvement projects in California. The Ponderosa Bridge project involves removing and replacing an existing single lane bridge over the American River and improving 2.4 miles of gravel road. The Mountain Quarry Bridge project replaces the existing aggregate surface to address drainage issues and replaces the bridge railing to improve safety for pedestrians and equestrians. Blasting is permitted for footing excavation using controlled techniques. Historical bridge load ratings are available upon request. Excess material must be removed from the site. The steel erector must follow advanced certification requirements and the girder fabricator must meet intermediate certification standards. Top flange bracing is only required at two locations near the piers.
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Questions and Answers during Advertisement for CA FTBR (1) Ponderosa and Mountain Quarry Bridges
May 3, 2022
Questions Answers 1 Specification sections 204, 205, and 208 reference rock blasting for footings. On drawing sheet RG3178-B under the General Notes, Structure Excavation and Backfill it states Explosive blasting of bedrock is not allowed then directs you to section 208. Section 208 goes on to detail “Clean and grout rock overbreak and fractures resulting from blasting. Can you clarify blasting of bedrock for footings is required and/or is an acceptable construction method for footing preparation and excavation?
Blasting is not required, but production blasting is prohibited to minimize over breaking and fracturing of the rock. If blasting is used to complete the excavation, the contractor is permitted to use a controlled or pre-drilled blasting technique.
2 Under the general notes on Drawing sheet RG3178-B USE OF EXXISTING BRIDGE DURING CONSTRUCTION, it details that historical load ratings of the bridge are available upon request. Could you please provide the historical load ratings?
The as built bridge drawings are attached to provide in the solicitation.
3 Mt. Quarry Sheet B8 notes to waste all existing excess material off-site. Can material be utilized along the roadway or shoulders to reduce the need to truck off-site? Was the unit weight for the material taken from a sample on site?
The excess material for the Mountain Quarry Bridge project must be wasted off site and cannot be utilized along the trail or bridge.
4 The south east approach is detailed to be right against the bedrock knob. No roadway blasting is detailed. Can you clarify if any roadway blasting will be required for the new approach, ditch line, culvert crossing, and riprap installation.
See response to #1 above
5 Section 555. Does the steel erector need to be a CSE Certified Erector (Advanced) or do they only need to follow the steel erection procedures according to AISC’s Quality Certification Program category for CSE Certified Erector (Advanced)?
The steel erector will be category CSE Certified Erector (Advanced).
6 Section 555.07 requires certification in CBR (Major Steel Bridges) in AISC. The current fabrication certificates in AISC are for Bridge Fabricator Simple, Bridge Fabricator Intermediate, and Bridge Fabricator Advanced. Please verify the required certification for the steel girder fabricator.
The “Bridge Fabricator Simple” is for a bridge consisting of unspliced rolled sections only. For our bridge we have a built up spliced plate girder, which falls under the Bridge Fabricator Intermediate (IBR) certification:
Certified Bridge Fabricator - Intermediate (IBR) are typical bridges that do not require extraordinary measures. Typical examples might include: (1) a rolled beam bridge with field or shop splices, either straight or with a radius over 500 ft; (2) a built-up I-shaped plate girder bridge with constant web depth (except for dapped ends), with or without splices, either straight or with a radius over 500 ft; (3) a built-up I-shaped plate girder with variable web depth (e.g., haunched), either straight or with a radius over 1000 ft; (4) a truss with a length of 200 ft or less that is entirely or substantially pre-assembled at the certified
7 Sheet S17 Framing Plan identifies Top Flange Lateral Bracing near Pier 1 and Pier 2, with a note (typ.). Sheet S25 details this bracing plan. It appears this top flange bracing is only at the two locations shown and not connecting every diaphragm.
Please verify.
The top flange lateral bracing is only required at the 2 locations shown on sheet S7 adjacent to pier 1 and pier 2, it is not connecting every diaphragm on the span.
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