The bridge is a four span $(45$ft$-60$ft$-60$ft$-45$ft$)$ steel girder bridge. The initial connection detail was simply supported for dead load and continuous for live load. The initial deck was composite only in the interior spans with shear connectors only in positive moment regions. The new superstructure will be fully composite and continuous and designed according to AASHTOLRFD and match the traffic capacity and geometric layout of the original bridge.

The two exterior spans are $45$ feet long, and the two interior spans are $60$ feet long. As shown in Figure $1-9,$ the width of the roadway is $32$ feet. The bridge also carries two $5\text{'}-1"$ sidewalks. It was built in $1966$ as part of a larger project that created the Durham Bypass, which re$-$routed US Route $4$ around Durham. The consultant working on the bridge was Wright & Pierce of Portsmouth, New Hampshire and the contractor was R$.$ G$.$ Watkins and Son, Inc. of Amesbury, Massachusetts. The original bid for the project was approximately $$110,200($NHDOT $-$ Bureau of Bridge Design$).$

The Bagdad Rd$.$ Bridge is supported by $6$ hot$-$rolled, W$36$x$135$ steel beams with $0\mathrm{.}5"$x$10\mathrm{.}5"$ cover plates and uses the steel channels, C$15$x$33\mathrm{.}9$ for diaphragms. It also features a crown created in a deck of uniform transverse thickness by stepping the stringer bearing$$elevation$.$

$1.$ Load Development

a$.$ Influence line or other analysis technique for determining statically indeterminate load effect b$.$Dead Load Moments and Shears for an interior girder

c$.$ Live Load Distribution Factors for an interior and exterior girder d$.$Live Load Moments and Shears for an interior girder

$1.$ Maximum Negative and Positive Moments

$2.$Girder Section and Material Properties Calculations

$3.$Girder Capacity Check

a$.$ Moment Capacity Prior to Curing

b$.$ Positive Moment Composite Capacity for an interior girder

c$.$ Negative Moment Composite Capacity for an interior girder

i$.$ Assume the deck reinforcement is No$.5$ bars at $6-$inches o$.$c$.$ each way top and bottom. d$.$Determine the number of shear connectors required for full composite action

i$.$ Include shear connector size, diameter and length, and spacing

e$.$ Shear Capacity for Strength I only and for an interior girder only

f$.$ Deflection Check for Strength I only and for an interior girder only

g$.$Fatigue Evaluation $-$ Assume ADTTs$1=1000$ trucks$/$per

$4.$ Load Rating for Strength I only and for an interior girder only