Home / deck overhang design example
Special Design Example 5/17/2017 20 From earlier in the memo, for a 7 slab with 2 wearing course, EOD thickness and
Bridge deck overhangs must be designed to satisfy three different design cases. In the first design case, the overhang must be designed for horizontal transverse and longitudinal vehicular collision forces.
CONCRETE DECK SLAB DECK SLAB DESIGN LRFD CANTILEVER DESIGN PART 2 DATE: 10Mar2015 SHEET 5 of 13 FILE NO. 10.01-5 CANTILEVER DESIGN The cantilever deck slab shall be designed/detailed with additional 5 bars between the transverse bars in the top layer. This is the minimum requirement of reinforcement with or without additional analysis.
3.2.1 LRFD Deck Design . A standard deck is defined as a deck slab on longitudinal beams with main reinforcement placed perpendicular to traffic. As outlined in Article 9.6.1, the AASHTO LRFD Code permits three methods or procedures for designing bridge decks with primary reinforcement perpendicular to the main bridge beams.
bridges, presenting deck types such as concrete deck slabs, metal grid decks, orthotropic steel decks, wood decks, and several others. The choice of the particular deck type to use can depend on several factors, which may include the specific application,
Steel Bridge, Deck Design, Concrete Deck, Precast Concrete Deck, Wood Deck, Metal Grid Deck, Orthotropic Deck 18. Distribution Statement No restrictions. This document is available to the public through the National Technical Information Service, Springfield, VA 22161. 19. Security Classif. of this report Unclassified 20. Security Classif.
The deck overhang should be designed in accordance to the requirements of the AASHTO-LRFD article A13.4 to provide a flexural resistance M S, acting coincident with the tensile force T. At the inside face of the barrier the deck overhang design forces per foot not including dead loads may be taken as:
LRFD DESIGN EXAMPLE: PRESTRESSED PRECAST CONCRETE BEAM BRIDGE DESIGN Table of Contents Cover Section 1: Project Information 1.01 About this Design Example 2.06 Traditional Deck Design 2.07 Deck Overhang Design 2.08 Creep and Shrinkage Parameters 2.09 Expansion Joint Design 2.10 Composite Neoprene Bearing Pad Design
The example illustrates the design of a typical three-span continuous straight steel I-girder bridge with spans of 140-0 175-0 140-0. Specifically, the example illustrates the design of selected critical sections from an exterior girder at the
LRFD Bridge Deck Design Deck Overhang LRFD Bridge Deck Design Deck Overhang A yield line analysis produces the nominal railing resistance.
Therefore, the deck overhang has to be designed to meet the requirements for Extreme Event II. The AASHTO 2012 requires bridge deck overhangs to be designed for the following cases AASHTO Appendix A13.4 : Design Case 1: The transverse and longitudinal forces specified in AASHTO Appendix A13.2 - Extreme Event Load Combination II limit state.
I'm currently designing a deck overhang with a TL-4 barrier using AASHTO LRFD. For Design Case 1 Extreme Event Limit State , the overhang must be designed for the vehicular collision plus dead load moment acting concurrently with the axial tension from verhicular collision force.
railing system. Using a deck overhang thickness of approximately ¾ to 1 thicker than the deck thickness has proven to be beneficial in past designs. For this example, an overhang thickness of 9 in., including the ½ in. sacrificial layer is assumed in the design. Design Step 4.4 CONCRETE PARAPET A Type-F concrete parapet is assumed.
design example includes detailed design computations for the following bridge features: conc rete deck, steel plate girder, bolted field splice, shear connectors, bearing stiffeners, welded connections, elastomeric bearing, cantilever abutment and
deck overhang will be designed for the dead load and live load that occupy the overhang. For design case 3, application of design vehicular live load shall be in accordance with provision .4 of the LRFD Specifications .
2.08 Deck Overhang Design 2.07 Traditional Deck Design 2.06 Empirical Deck Design 2.05 Prestressed Beam Design - Part II 2.04 Prestressed Beam Design - Part I 2.03 Live Load Analysis LRFD Design Example Table of Contents i. Two simple spans 90'-0" each, 30 degree skew. Minor horizontal curvature Multi-column pier on prestressed concrete piles.
Design Example 6 EXAMPLE 6.1 - DECK DESIGN GENERAL INFORMATION 1. Approximate Elastic Method, or "Equivalent Strip" Method AASHTO 2. Refined Methods AASHTO 3. Empirical Design Method AASHTO 9.7.2 MATERIAL AND SECTION PROPERTIES Structure type Girder spacing, maximum SGdr = 8.00 ft. Number of girders NGdr = 3 ea.
The spacing of the vertical reinforcing steel is checked to ensure adequate capacity is provided.1 Type F Barrier Design Example LRFD BRIDGE DESIGN 13-17 This example illustrates a design check of the vertical reinforcing steel that ties a standard Mn/DOT Type F barrier to a concrete deck.