CENG 231 Winter 2015

Quiz #1

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Due 2/19/15, 8:40am You are working on the type selection report for a bridge that will carry a freeway on-ramp over a creek. Bridge length is 50 feet, simple span. There will be 1 lane of traffic, 5’ and 8’ shoulders, and type 742 barriers. Part I. Draw a typical section for the Reinforced Concrete Box Girder (RC Box) bridge option

given the following information:

• Use Caltrans depth/span recommendations to determine bridge depth.

• Use Caltrans Bridge Memo To Designers 10-20 for overhang width and thickness, and top and bottom slab thickness

• Assume the bridge will have four 12” wide girders, and the exterior girders are vertical (not slanted or rounded).

• Use a 2% constant cross-slope. The drawing should be to scale (may be drawn by hand or with AutoCad). It must include:

� Overall width � Lane and shoulder widths � Barrier types & widths � Girder spacing � Overhang width & thicknesses

� Deck, soffit, & girder thickness � Section depth � Cross-slope � Scale and title of drawing

Example: 152/156 Typical Section

CENG 231 Winter 2015

Quiz #1

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Part II. Answer the following questions about the RC Box bridge (attach calculations): 1. Calculate the following Dead Load Moments and Reactions:

• DC (Components & Attachments):

• DW (Future wearing surface):

2. HL-93 Live Load Moment and Reaction (Use BDA 9-1):

• LL + IM moment and reaction (per lane):

• Number of design lanes:

3. Factored Moment (use AASHTO load combinations):

• Strength I Factored Moment:

• Strength I Factored Reaction:

Part III. Type Selection:

4. Using Caltrans 2014 Comparative Bridge Costs, estimate the high to low cost range the following bridge types:

• Reinforced Concrete (RC) Box:

• Cast-in-Place/Prestressed (CIP/PS) Slab:

• Precast/Prestressed (PC/PS) Slab: 5. List at least 2 factors that would you consider when selecting the bridge type: