| 1.0 GENERAL |
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| 1.1 |
Scope |
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These
specifications are for a fully engineered clear span bridge of Fiber
Reinforced Polymer (FRP) composite construction and shall be regarded as
minimum standards for design and construction as manufactured by E.T.
Techtonics, Inc., P.O Box 40060, Philadelphia, PA 19106, phone 215-592-7620
or approved equal. |
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| 1.2 |
Qualified
Suppliers |
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The
bridge manufacturer shall have been in the business of design and fabrication
of bridges for a minimum of five years and provide a list of five successful
bridge projects, of similar construction, each of which has been in service
at least three years. List the location, bridge size, owner and contact
reference for each bridge. |
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| 2.0 GENERAL FEATURES OF DESIGN |
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| 2.1 |
Span |
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Bridge
span will be xxx' xx" (straight line dimension) and shall be measured
from each end of the bridge structure. |
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| 2.2 |
Width |
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Bridge
width shall be xx' xx" and shall be measured from the inside face of
structural elements at deck level. |
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| 2.3 |
Bridge
System Type |
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Bridges
must be designed as a FRP Composite Truss Span or FRP Composite Cable Span |
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| 2.4 |
Member
Components |
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All
members shall be fabricated from pultruded FRP composite profiles and
structural shapes as required. |
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| 2.5 |
Camber |
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Bridges
can be precambered to eliminate initial dead load deflections. Cambers of 1%
of the total span length can be provided on request. |
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| 3.0 ENGINEERING |
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Structural
design of the bridge structure(s) shall be performed by or under the direct
supervision of a Licensed Professional Engineer and done in accordance with
recognized engineering practices and principles. |
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| 3.1 |
Uniform
Live Load |
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Bridges spanning less than 50’-0” will be designed for 85
psf. Bridges spanning greater than 50’-0” will be designed for 60 psf
unless otherwise specified. |
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| 3.2 |
Vehicle
Load (as
required) |
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A
specified vehicle configuration determined by the Operating Agency may be
used for the design vehicle. If an Agency design vehicle is not specified,
the loads conforming to the AASHTO Standard H-Truck is used. The maintenance
vehicle live load shall not be placed in combination with the pedestrian live
load. A vehicle impact allowance is not required |
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| 3.3 |
Wind
Load |
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All bridges shall be designed for a minimum wind load of 25 psf.
The wind is calculated on the entire vertical surface of the bridge as if
fully enclosed. |
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| 3.4 |
Seismic
Load |
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Seismic loads shall be determined according to the criteria
specified in the standard building codes (IBC, ASCE, or UBC) unless
otherwise requested. Response Spectrum Analysis shall be
performed in those designs that require complex seismic investigation. All
necessary response spectra information will be provided by the client for
evaluation. |
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| 3.5 |
Allowable
Stress Design Approach |
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An Allowable Stress Design (ASD) approach is used for the design
of all structural members. Factors of safety used by E.T. Techtonics,
Inc. in the design of FRP bridges are as follows unless otherwise
specified: (Based on the Ultimate Strength of the FRP material)
| Tension |
2.5 |
| Compression |
2.5 |
| Shear |
2.5 |
| Bending |
2.5 |
| End Bearing |
2.5 |
| Connections |
3.0 |
Above information is based on E.T. Techtonics 5 year test
program funded by the National Science Foundation |
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| 3.6 |
Serviceability Criteria |
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Service loads are used for the design of all structural members
when addressing deflection and vibration issues. Criteria
used by E.T. Techtonics, Inc. in the design of FRP bridges are as follows:
Deflection:
Live Load (LL) deflection = L/240
Vertical Frequency (fn):
= 5.0 Hz
The fundamental frequency of the pedestrian bridge (in the
vertical direction) without live load should be greater than 5.0 hertz (Hz)
to avoid any issues with the first and second harmonics.
Horizontal Frequency (fn):
= 3.0 Hz
The fundamental frequency of the pedestrian bridge (in the
horizontal direction) without live load should be greater than 3.0 hertz
(Hz) to avoid any issues due to side to side motion involving the first and
second harmonics. |
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| 3.7 |
Snow
Load |
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Sustained snow load conditions shall be evaluated for time
dependent effects (creep and relaxation) and expected recovery behavior. |
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| 4.0 MATERIALS |
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| 4.1 |
FRP
Composites |
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FRP
bridges shall be fabricated from high-strength E-glass and isophthalic
polyester resin unless otherwise specified.
Weathering and ultraviolet light protection shall be provided by
addition of a veil to the laminate construction.
Minimum material strengths and properties are as follows:
| Tension |
33,000 psi |
| Compression |
33,000 psi |
| Shear |
4,500 psi |
| Bending |
33,000 psi |
| Young’s Modulus |
2,800,000 psi |
The minimum thickness of FRP Composite shapes shall be as
follows unless otherwise specified: Square tube members (closed type
shape) shall be 0.25 in. Wide-flange beams, channel sections, and
angles (open type shapes) shall be a minimum thickness of 0.25
in. Standard plate shall be a minimum thickness of 0.25 in. |
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| 4.2 |
Decking |
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Wood
decking is No. 2 Southern Yellow Pine treated according to the American Wood
Preservers Bureau. The standard 2 in. x 12 in. planks are provided for
pedestrian and bicycle type loading conditions. Standard 3 in. x 12 in.
planks can be provided for equestrian and light vehicle type loading
conditions as required. High strength E-glass/ isophthalic polyester resin
planks or recycled plastic deck planks can also be provided as required. |
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| 4.3 |
Hardware |
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Bolted
connections shall be A307 hot-dipped galvanized steel unless otherwise
specified. Mounting devices shall be galvanized or stainless steel. |
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| 5.0 SUBMITTALS |
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| 5.1 |
Submittal
Drawings |
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Schematic drawings and diagrams shall be submitted to the client
for their review after receipt of order. As required, all
drawings shall be signed and sealed by a licensed Professional Engineer. |
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| 5.2 |
Submittal
Calculations |
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As required, structural calculations shall be submitted to the
client. All calculations will be signed and sealed by a licensed
Professional Engineer. |
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| 6.0 FABRICATION |
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| 6.1 |
Tolerances |
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All
cutting and drilling fabrication to be done by experienced fiberglass workers
using carbide or diamond-tipped tooling to a tolerance of 1/16". No
material deviations beyond industry standards are accepted. All cut edges to
be cleaned and sealed. |
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| 7.0 RAILINGS |
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| 7.1 |
Railings for pedestrian and bicycle use should be a minimum of
42” above the floor deck and equestrian use should be a minimum of 54” above
the floor deck. |
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| 7.2 |
Safety
Rails |
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Continuous horizontal midrails shall be located on the inside of
the trusses. Maximum opening between the midrails shall be available as
required, but should not be greater than 9”. If preferred, vertical
pickets can be provided upon request. |
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| 7.3 |
Toeplates (optional) |
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Park and trail bridge toeplates (if required) are 3” green
channels. |
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| 8.0 FINISHING |
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Bridge
color shall be determined by the client with green, grey, and as standard
options. No painting is required as the color is added during the
manufacturing process. Green is recommended for
park and trail bridge applications. Custom colors can be provided upon
request. |
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| 9.0 DELIVERY and ERECTION |
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Delivery is made by truck to a location nearest the site
accessible by roads. E.T. Techtonics, Inc. will notify the client in
advance of the expected time of arrival at the site.
Bridges are usually shipped to the site in component parts or partially
assembled depending on site requirements. The spans can
then be completely assembled using standard hand tools. Upon request,
bridges can also be shipped totally assembled to the
site. Unloading, splicing (if required) and placement
of the bridge will be the responsibility of the client. |
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| 9.1 |
Erection
Direction |
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For bridges shipped in component parts or partially
assembled, E.T. Techtonics, Inc. shall provide assembly drawings and a
recommended assembly procedure for building the bridge.
Temporary supports or rigging equipment, if needed, is the responsibility of
the client. For bridges shipped assembled, E.T.
Techtonics, Inc. shall advise the client of the actual lifting weights,
attachment points and all necessary information to install the bridge. |
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| 9.2 |
Site Issues and Foundation Design |
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The client shall procure all necessary information about the
site and soil conditions. Soil tests shall be procured by the
client. The engineering design and construction of the bridge abutments,
piers and/or footing shall be by the client. E.T. Techtonics, Inc. will
provide the necessary information pertaining to the bridge support
reactions. The client shall install the anchor bolts in accordance with
E.T. Techtonics, Inc’s anchor bolt spacing dimensions. |
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| 10.0 |
WARRANTY |
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E.T. Techtonics, Inc. shall warrant the structural integrity of
all FRP materials, design and workmanship for 15
years.
This warranty shall not cover defects in the bridge caused by
foundation failures, abuse, misuse, overloading, accident, faulty
construction or alteration, or other cause not the result of defective
materials or workmanship.
This warranty shall be limited to the repair or replacement of
structural defects, and shall not include liability for consequential or
incidental damages. |
